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Palaeogeography, Palaeoclimatology, Palaeoecology 356–357 (2012) 1–15

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Palaeogeography, Palaeoclimatology, Palaeoecology

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Quaternary fluvial systems of tropics: Major issues and status of research

Rajiv Sinha a,⁎, Edgardo M. Latrubesse b, Gerald C. Nanson c

a Engineering Geosciences Group, Department of Civil Engineering, Indian Institute of Technology Kanpur 208016, Indiab Department of Geography and the Environment, The University of Texas at Austin, 1 University Station A3100-GRG334, Austin, TX 78712, USAc School of Earth and Environmental Sciences University of Wollongong NSW, 2522, Australia

⁎ Corresponding author.E-mail address: [email protected] (R. Sinha

0031-0182/$ – see front matter © 2012 Elsevier B.V. Allhttp://dx.doi.org/10.1016/j.palaeo.2012.07.024

a b s t r a c t
a r t i c l e i n f o
Article history:Received 16 May 2012Received in revised form 23 July 2012Accepted 25 July 2012Available online 2 August 2012

Keywords:Tropical riversFluvial archivesQuaternary paleoenvironemntsAlluvial stratigraphy

Fluvial systems in tropical regions are not only the lifeline formodern civilizations there but also form an importantcontinental archive for reconstructing Quaternary palaeoclimates and palaeoenvironments. Tropical rivers drainthrough a variety of geological and geomorphological settings across the world and have been studied for their hy-drology, sediment transport characteristics, faciesmodels, stratigraphic development and flood hazards. This paperpresents an overview of the research on tropical rivers globally and identifiesmajor gaps and unanswered researchquestions. As a part of the IGCP 582 on Tropical Rivers, the participants of this project are continuing to tacklemanyof these issues. The collection of papers in this special issue is an outcome of this activity and presents new data onprocesses and alluvial stratigraphy of the tropical rivers from China, India, South America and northern Australia.

© 2012 Elsevier B.V. All rights reserved.

1. Introduction

Tropical rivers form an important component of the continentaldrainage systems and several of them have been classified as largeriver systems in the world (Potter, 1978; Hovius, 1998; Latrubesse etal, 2005; Gupta, 2007) (Fig. 1). Several tropical rivers have sustainedhuman civilizations for more than 5000 years and have provided fertilefloodplains for agriculture. The ancient river valley civilizations in theIndus, Nile and Ganga are good examples where water managementstrategies were quite advanced and so were the flood protection mea-sures. Tropical regions have turned into a population hotspot in thelast few centuries and there are serious threats to freshwater securityand biodiversity owing to overexploitation of water resources. Tropicalrivers are the major dispersal agents of water, sediment and nutrientsfrom the continents to the ocean but our knowledge on interactions ofriver morphology, hydrology and ecology and their implications forriver management, and ecosystem services remains fragmentary.Apart from the anthropogenic impacts, the effects of ensuing climatechange on the hydrology of these rivers are largely uncertain and thepredictive models are primitive.

The International Geosciences Programme (IGCP) of the UNESCOand the International Union of Geological Sciences (IUGS) have beensupporting a project titled ‘Tropical Rivers: Hydro-Physical Processes,Impacts, Hazards and Management’ (IGCP 582) since 2009. The overallscope of this project is to provide an integrated assessment of long-termdirect impacts of climate variability and human-induced changes intropical rivers. It also focuses on developing strategies for management

).

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of tropical rivers basins by identification, quantification andmodeling ofkey hydro-geomorphologic indicators during the past and presenttimes.We consider that the study of tropical systems can provide signif-icant insights in the understanding of facies models, the reconstructionof paleoclimatic, paleogeographic and paleohydrolgoical conditionsduring the Quaternary.

Tropical regions, roughly bounded by the Tropics of Cancer (23°27′N) and Capricorn (23°27′S), are characterized by averagemonthly tem-peratures of >18 °C in all months of the year (Mc Gregor and Nieuwolt,1998). Tropical regions host some of the largest rivers in the world fedby the monsoons and the rainfall within the Intertropical ConvergeZone (ITCZ). However, the tropics are extremely diverse and also harborsome of the hottest and driest regions where rivers are ephemeral.Wettropical or tropical rainforest climate (Köppen Af) typically has rainfall inexcess of 1800mma−1 with all months greater than 60 mm (i.e. no dryseason). These regions are characterized by average temperatures of~28 °C with a low daily range of 2 °C to 5 °C and a lesser annualrange. Tropical monsoon climate (Köppen Am) is similar to the abovebut there is a dry season when rainfall is b60 mm but more than(100−[total annual precipitation {mm}/25]) (McKnight and Hess,2000). Tropical wet-dry or savanna climatic regimes (Köppen Aw) arecharacterized by very pronounced rhythmic seasonal moisture patternsand occur in areas peripheral to tropical rainforest environments. Theyhave a monsoon-driven wet season and a pronounced dry seasonwhere monthly rainfall is less than 60 mm and also less than (100−[total annual precipitation {mm}/25]) (McKnight and Hess, 2000). Insome cases, there is a dry season with no rains at all.

Tropical regions are characterized by the convergence of airflows intothe equatorial trough known as the Intertropical Convergence Zone(ITCZ). A distinctive feature of the tropics is the reversal of the wind

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Fig. 1. Large rivers in tropical regions; these rivers drain a diverse geological and climatic regimes.

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direction and changes in temperature and humidity on the oppositesides of the ITCZ (Balek, 1983). The annual migration of the ITCZ fromnorth to south significantly affects the tropical wet climates (McGregor and Nieuwolt, 1998) and its associated vegetation distribution.The rainforest generally develops best where the ITCZ movement is theminimum but the altitude also influences its distribution. The areasbelow ~1000 m are the most favorable for rainforests above which thehighland vegetation is represented by shorter trees and fewer species.

Nine of the ten largest rivers of theworld in terms ofwater discharge,classified as “megarivers”, are located in the tropical region or are relatedto the tropical climatic circulation (Latrubesse, 2008). They include theAmazon, Congo, Orinoco, Yangtze, Madeira, Negro, Brahmaputra, Japuraand Parana. The distribution of large rivers in the tropics is also far fromuniform. Of the 34 large tropical rivers of the world, 24 are in SouthAmerica and 18 are related to the Amazon basin and the Amazon forest(Latrubesse et al, 2005; Latrubesse, 2012).

Several tropical rivers of the world with depocenters in foreland,foreland-platforms and intracratonic tectonic settings have formedmajor areas of Quaternary sedimentation such as megafans viz. the Kosiand the Gandak megafans in India, the Pilcomayo and Bermejo Grandefans in South America. Megafans and other avulsive systems sustaininglarge seasonal wetlands are also recorded in the Pantanal de MattoGrosso, one of the biggest tropical continental wetlands in the worldand a strategic place for wild life conservation (Assine, 2005), and inintracratonic basins such as the Bananal basin in Central Brazil (Valenteand Latrubesse, 2011). They also occur in the Murray–Darling basinwhere they have provided an extensive record of fan stratigraphy andmajor Quaternary climate change (Page and Nanson, 1996; Page et al.,1996).

The interior and tectonically stable basins of Australia also havebeen acting as a major fluvial and lacustrine archive of the Quaternarycontinental history, and have provided some of the most spectacularexamples of fluvial–aeolian–lacustrine interactions in the world.

This special issue highlights the present status of the knowledge ontropical rivers with focus on India, South America, Australia and someareas of China, and raises somemajor research questions, which remainunanswered till date. This introductory paper presents a brief account ofthe available data on the tropical rivers as sediment dispersal systemsand archives of Late Quaternary climate change. The final section ofthis paper introduces the contributions in this special issue.

2. Role of tropical river systems in global erosion rates

Fluvial erosion in tropical river systems is extreme and several tropi-cal river basins draining orogenic belts have some of the highest erosion

rates in the world. Basins draining high relief, active orogenic belts havevery high sediment production. For example, the rivers draining the oro-genic belts of southern Asia and high elevation islands in the East Indiescontribute more than 70% of the sediment load entering the oceans(Milliman and Meade, 1983). The relatively small drainage basins ofthe East Indies (Sumatra, Java, Borneo, Celebes and Timor) representonly ~2% of the land area of Earth but discharge about 4200 milliontonnes of sediments annually due to their high topographic relief, somerelatively young erodible rocks, earthquakes and tropical wet climates(Milliman et al., 1999). This is equivalent to 20–25% of the global sedi-ment transfer to the oceans.

The Himalayan Rivers also transport a large quantity of sediments.Large river basins such as the Brahmaputra and the Ganges are thelargest sediment producing basins in theworld and transport 792milliontonnes (Islam et al., 1999) and 729 million tonnes (Abbas andSubramanian, 1984) of sediments annually, a reflection of the continueduplift of the Himalaya, steep slopes in the hinterland, mass-wastingprocesses and the monsoonal climate. The Brahmaputra ranksfirst among the largest rivers in the world in terms of sediment yield(852 t/km2/year and seventh in terms of mean annual discharge of21,200 m3/s; Latrubesse, 2008). The Brahmaputra has received consider-able attention due to its large sediment flux (Coleman, 1969; Bristow,1987; Curray, 1994; Goodbred and Kuehl, 2000a,b; Singh, 2006; Singhet al., 2006) and highly dynamic hydrologic regime (Goswami, 1985;Sarma and Phukan, 2004, 2006; Kotoky et al., 2005; Sarma, 2005; Lahiriand Sinha, 2012). Singh et al. (2008) highlighted amajor contrast in con-temporary sediment flux and catchment erosion rates between the Kosiand the Gandak rivers draining the eastern Gangetic plains based on Srand Nd isotopes of river sediments; the computed sediment flux anderosion rates for the Gandak (450–510 mt/yr and 6 mm/yr respectively)is significantly higher than that of the Kosi (60–130 mt/yr and 1 mm/yrrespectively). The estimates of sediment yield provide an indirect indica-tion of tectonic activity in the catchment but such spatial variability insediment flux and erosion rates, even within high-relief areas, highlightsthe importance of climatic and topographic variables on sediment trans-port. Although there have been some studies to provide very preciseestimates of uplift in the Himalayan catchments (Wesnousky et al.,1999; Lavé and Avouac, 2000) which have in turn been related togeomorphic diversity across the Ganga plains (Sinha et al., 2005c), thedata are too scarce at this stage to develop any quantitative relationshipbetween the uplift rate and sediment supply (Tandon and Sinha, 2007).

Sediment production is also very high in the Andes of South America.The Magdalena River draining the Colombian Andes (drainage area257,000 km2) contributes 144 to 220 million tons of suspendedsediment to the Caribbean Sea (Milliman and Meade, 1983; Restrepo

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and Kjerfve, 2000; Restrepo et al, 2006, 2009). The Madeira River con-tributes around 50% of the total suspended load transported by theAmazon River (estimated values range between 248 and 600 milliontons/year) (Martinelli et al., 1993; Meade, 1994; Filizola, 1999).Latrubesse et al. (2005) demonstrated that the relationship betweensediment load and drainage area for orogenic continental rivers ofSouth America and Asia, and Insular Asian rivers (Java, Borneo, Celebesand NewGuinea) are quite similar when comparing themountain catch-ments, suggesting comparable sediment yields in spite of tectonic diver-sity, once again highlighting the importance of topographic and climaticvariables. Themain difference between insular southeasternAsia systemsandHimalayan/Andes tributaries is that the former are short, steep gradi-ent rivers draining directly to the ocean, while the latter are part of largerfluvial networks, such as those of the Amazon, Parana, OrinocoMagdale-na, Ganges and Brahmaputra basins; significant amount of sedimentsare stored within the continents before the rivers meet the Ocean(Latrubesse et al., 2005).

Further, a number of tributaries from lowland or cratonic/platformareas have much lower sediment discharges for the amount of waterdischarged. Rivers draining platforms or cratonic areas in savanna andwet tropical climates are characterized by low sediment yield(Latrubesse et al, 2005; Latrubesse, 2012). Major rainforest fluvial sys-tems such as the Congo, Negro, Tapajos and Xingu transport smallamounts of suspended sediment in spite of their large drainage areasand enormous water discharges. For example, with a drainage area of659,000 km2 and a mean annual discharge of 29,000 m3/s, the Negrocarries just 8 million tonnes of suspended load annually of which alarge part could be organic matter (Filizola, 1999).

In large basins, a part of the sediment load is stored in alluvial plainsand the rest is transported to the ocean. Furthermore, many of the largerivers have formed large deltas at their mouths, whichmark the penul-timate storage of sediments before final discharge into the deep sea.Very little data is available on the partitioning of sediments betweenthe alluvial plains and the deltas but the first order estimates of theGanga-Brahmaputra system have shown that about 30% of the annualdischarge is accommodated within the floodplains and delta plains,~40% of the sediment load stays in the sub-aqueous delta, and theremaining 30% is transported to the deep-sea Bengal fan (Goodbredand Kuehl, 1999). These findings are important as they support earliersuggestions that the clastic sediment flux into the oceans from riversmay be overestimated because the most downstream gauges are up-stream of deltas, and therefore, do not account for the accommodationof a large volume of sediments in delta plains (Milliman and Syvitski,1992).

3. Alluvial stratigraphy and response of tropical rivers to LateQuaternary climate change

The sedimentary record preserved in alluvial valleys and alluvialplains reveals a complex history of the erosional development and dy-namics of river systems and documents the variability of the processesthrough time and space. The rock record of small to medium scale sys-tems in foreland basins frequently shows transitions from meanderingto braided rivers , which is in line with the downstream variations ofchannel pattern in modern rivers as well as with temporal changes inmorphology as a function of variable discharge and sediment load. It isimportant to emphasize that the anabranching systems are also widelydistributed across the world and their rock records have often beenmisrepresented while reconstructing facies models. Many of the tropicalsystems are anabranching and the use of the traditional sedimentary fa-cies to characterize the sedimentary style is not very useful for theserivers.

There have been significant advances in documenting the alluvialstratigraphy of the plains drained by the tropical rivers for understandingthe depositional environments and for paleoclimatic reconstruction.While several studies have utilized exposed sections along riverbanks,

electrical resistivity surveys, ground radar penetration, and drillinghave also been used. The following sections summarize the data avail-able from three major tropical regions namely, the Himalayan forelandin India, South American river basins, and northern Australia.

3.1. Ganga-Brahmaputra system in the Himalayan foreland, India

The Himalaya is the host to several large river systems of the world(Fig. 2) characterized by large catchment size, length, and large volumesof water and sediment discharges (Sinha and Friend, 1994; Hovius,1998; Tandon and Sinha, 2007). This region is characterized by amonsoonal climate, and more than 90% of water and sediments istransported in just four months of the year. Many of these large riverssuch as the Ganga (Length: 2510 km; Catchment area 980, 000 km2),Yamuna (Length 1376 km; catchment area 366, 223 km2), and Brah-maputra (Length 2840 km, catchment area 610,000 km2) drain the In-dian subcontinent and constitute a major (~50%) source of fresh watersupply in India. These rivers have built one of the largest alluvial plainsin theworldfilling the foreland basinwith sediments duringmost of theQuaternary period and, therefore, constitute an important link betweenthe Himalayan Orogen and the Indian Ocean. These plains have also re-ceived a sizable volume of sediments from the rivers such as the Betwa,Chambal, Ken, and Son that are sourced in the central Indian Craton andthis contribution was certainly much greater in the past (Sinha et al.,2009). Further, two major trunk systems, the Ganga and Brahmaputrajoin to form the Ganga-Brahmaputra delta, which is the largest activedelta in theworld. Understanding the landforms of the Ganga and Brah-maputra plains in terms of their origin, development and dynamic im-prints is of critical significance to plan effectively for sustainabledevelopment of the region. An important task is to track changes inthe alluvial landscape on different time scales, for example, decadal,century, millennial and higher order time scales of 104 to 105 yearsfor developing comprehensive future strategies for utilization of the re-sources of the Ganga plains.

The extensive Ganga basin has provided by far the most importantfluvial archive for reconstructing the Late Quaternarymonsoonal fluctu-ations in the Himalayan foreland. Several studies have suggested how-ever that the processes controlling stratigraphic development areextremely variable in space (Tandon et al., 2006; Tandon and Sinha,2007; Gibling et al., 2011). For example, the parts of the Ganga valleyclose to the mountain front, from where major active faults have beenreported, are influenced by both tectonic and climatic factors in strati-graphic development (see Tandon et al., 2006; Singh and Tandon,2007; Suresh et al., 2007). However, as we move away from the frontalregion, tectonic activity is reduced and subsidence rates becomemoder-ate, climate becomes the dominant factor in stratigraphic development(see Gibling et al., 2005; Sinha et al., 2007a, 2009; Roy et al., 2011). Fur-ther away in the delta region, glacioeustasy has exerted a key control onvalley incision and filling.

The stratigraphic information available from the western Gangabasin for a time period of ~100 ka derived from river bank sections(Gibling et al., 2005, 2008; Sinha et al, 2005a,b; Tandon et al., 2006)resistivity surveys (Yadav et al., 2010) and drill cores (Sinha et al.,2007a, 2009; Roy et al., 2011) reveals that the valley-interfluve config-uration in this region has been stable for most of the Late Quaternaryperiod. Stratigraphic records from the Kanpur and Kalpi areas inUttar Pradesh (see Fig. 2 for location) are characterized by discontinu-ities both in valleys fills as well as interfluves (Fig. 3). The oldest valleyfills recorded so far from the western Ganga plains, based on drillcores, correspond to Marine Isotope Stage (MIS) 5 and suggest aggra-dational events with thin floodplain successions and probable discon-tinuities along the interfluve margin (Fig. 3). Modest fluvial activitycharacterized the mid part of MIS 3 between 37–23 ka with periodsof valley aggradation preceded by incision (Sinha et al., 2007b; Royet al., 2011). The period from Late MIS 2 to early MIS 1 (11–16 ka)also record repeated cycles of valley aggradation and the most recent

Fig. 2. Tropical Rivers of the Himalayan foreland basin. The Ganga-Brahmaputra system forms the most important river system in this region. The Ganga basin is also drained byseveral rivers from the south originating in the craton and the basin has been filled with sediments derived from both the sources during most of the Quaternary period.


and rapid aggradation took place in the latest Holocene (b2.5 ka). TheLast Glacial Maximum (LGM) was a time of greatly reduced fluvial ac-tivity, and no channel sediments have yet been identified that corre-spond with this period. The alluvial records match well with proxyprecipitation records (Prell and Kutzbach, 1987; Clemens and Prell,2003), and the main aggradational periods correspond to times of de-clining monsoonal strength (Roy et al., 2011).

Fig. 3. Shallow sub-surface stratigraphy of the Ganga-Yamuna valleys and the interfluve betMawar, and Kalpi) and drill cores (JP, FP, RD, BP, KPY and KP) covering a period of ~100 kcorresponding to MIS3 and Holocene whereas the Yamuna valley records a quick filling eand thin sands representing minor channels and no major sand bodies are recorded in the

In the interfluve sequences from the western Ganga plains, flood-plains were connected or disconnected from the main channels in re-sponse to monsoon precipitation (and discharge) (Gibling et al., 2005)resulting in characteristic sequences. For example, during a decline inmonsoonal precipitation from marine isotopic MIS 3 into the LGM inmarine isotopicMIS 2, the Ganga river became underfit within its valleyresulting in floodplain disconnectivity which was manifested as a

ween Kanpur and Kalpi (see Fig. 2 for location) based on exposed cliff sections (Bithur,a. The Ganga valley fills are characterized by at least two episodes of channel activitypisode in MIS 1. The interfluve sequences are characterised by thick muddy depositstop 30 m (modified after Sinha et al., 2009).

image of Fig.�2

image of Fig.�3


change in facies from floodplain to non-fluvial deposits (aeolian,lacustrine) as recorded at the Bithur section near Kanpur (Fig. 3;Gibling et al., 2005; Sinha et al., 2007a, 2009). Alternatively, the rivercan incise during a period of increasing precipitation due to increasedstream capacity thereby disconnecting from the floodplain. Such inci-sion events relating to increased monsoonal precipitation have beenrecorded at the Kalpi section on the Yamuna River (~30 ka) and at theMawar section on the Sengar River (~9 ka) (Gibling et al., 2005; Sinhaet al., 2005a) (Fig. 3). These sections are bounded by major discontinu-ities manifested as calcrete and paleosol layers (at Kalpi section) or asgully fills (at Sengar section). Stable isotopic work on calcretes fromthe Ganga plains (Sinha et al., 2006; Agrawal et al., 2012) suggested amodest upsection increase in C4 plants during the time period84–18 ka that was interpreted to be due to increased aridity andlower atmospheric CO2. Agrawal et al. (2012) has recorded three pe-riods of monsoonal intensification in the Ganga plains at 100, 40 and25 ka and ~20% decrease in rainfall during LGM. Such monsoon-driven changes in the hydrological regime of the hinterland also gener-ates a signal in terms of shifts in sediment provenance; for example,both 87Sr/86Sr and εNd values for an interfluve core from the WesternGanga plains showed major excursions at 70 ka and 20 ka coincidingwith lower monsoon intensities and maximum glacial cover therebylimiting the sediment supply from the Higher Himalaya (Rahaman etal., 2009).

In contrast to the western Ganga plains, the eastern Ganga plainsin north Bihar are characterized by large fans and interfan areas. Lim-ited stratigraphic data from the Kosi megafan reveals the presence oflarge, multi-storied sand sheets (generally gravel in upper reaches)interbedded with overbank muddy layers below the fans (Singh etal., 1993). The proximal zone is characterized by a gravelly-sandy fa-cies (~60 m thick), which was interpreted as braided river deposits.In the distal parts, sandy and sand–mud mixtures (typically up to10 m thick but locally up to 40 m) are present up to the confluencewith the Ganga that is primarily a “megafan sweep” succession inan east west direction (Singh et al., 1993). Late Quaternary sequencesin Gandak–Kosi interfan area are characterized by near-continuous,thick (30–50 m) overbank muds intercalated with thin sandsrepresenting short-lived channels or crevassing events (Sinha, 1995;Jain and Sinha, 2003; Sinha et al., 2005d). In the top 50 m of the suc-cession, based on groundwater borehole data, several large sand bod-ies (up to 25 m thick and ~10 km long) were revealed and suggestedmajor channel activity in the past. It was interpreted therefore thatthe present-day depositional setting characterizing avulsive channelsand rapid aggradation has dominated this region for tens of thou-sands of years (Sinha et al., 2005d). Chandra (1993) also mappedmuddy sequences alternating with thick medium sand layers in thetop 10–20 m of the Sharda–Gandak interfan area using resistivity sur-veys and interpreted the coarse sand layer as a possible marker of theRapti palaeochannel. Radiocarbon dating suggests a late Holocene age(b2400 years; Sinha et al., 1996) for the upper few meters of sedi-ments of the eastern Ganga plains , which accumulated rapidly(0.7–1.5 mm/year). These rates aremuchhigher than those documentedfor the near-surface parts of the western Ganga plains in Uttar Pradesh,e.g. 0.2 mm/year (Joshi and Bhartiya, 1991) and 0.2–0.05 mm/year(Chandra et al., 2007) both over a period of 104 years. These plains inUttar Pradesh also show mature soils, 3–4 m thick, with well-developed carbonate horizons, estimated to be as old as 13,500 yearsBP (Srivastava et al., 1994) in line with lower sedimentation rates inthis region.

It has been suggested that the contrasting alluvial stratigraphy in thewestern and eastern Ganga plains is driven by modern geomorphicdiversity in this region as a function of precipitation variability, along-strike variability in hinterland tectonics, and sediment flux (Sinha etal., 2005c). Sinha et al. (2005c) have argued that such spatial heteroge-neity has resulted in complex responses of the river systems to externalforcing due to ‘differential sensitivity’ of river systems to monsoonal

fluctuations. Shallow sub-surface records from both eastern and west-ern Ganga plains, based on exposed cliff sections and drill cores, alsosuggest that this variability most likely extended into the Late Quater-nary period (Sinha et al., 2005d; Tandon et al., 2006). For example,the early Holocenemonsoonal rise wasmanifested as the developmentof incised valleys in the western Ganga Plains (Sinha et al., 2007a) butby rapid valley filling and floodplain aggradation in the eastern GangaPlains (Sinha et al., 1996, 2005d).

TheHolocene records from India suggest that the period ofmonsoonintensification is quite variable across the region. While the recordsfrom theHimalayan region, Ganga plains and Thar desert suggest an in-tensification after 8 to 9 ka and perhaps at 6 ka or even later (Phadtare,2000; Thamban et al., 2001; Sharma et al., 2004; Prasad and Enzel,2006; Staubwasser and Weiss, 2006), other stratigraphic records fromthis region viz. pollen records from Tibet (van Campo and Gasse,1993), marine records from southern Oman (Fleitmann et al., 2003)and modeling (Overpeck et al., 1996) suggest that the southwest mon-soon peaked at 10 to 5.5 ka period. The valley fills in theGanga plains donot often record any signature of widespread Late Holocene aggrada-tion (Sinha et al., 2007b; Roy et al., 2011) and this is attributed tointra-valleymigration of the river and incision. Roy et al. (2011) howev-er show that these valleys aggraded very rapidly during the latest Holo-cene generating ~8 to 10 m of channel sands in a period of b2.5 ka.Such rapid aggradation can be attributed to a sharp decrease in trans-port capacity of rivers in response to a decline in monsoon intensitycoupled with increased anthropogenic sediment flux (Sinha andSarkar, 2009). Again, this is in contrast to the response of the rivers inthe eastern Ganga plains in northern Bihar and fluvio-deltaic plains inthe Bengal Basin where extensive and rapid aggradation for most ofthe mid to Late Holocene period has been recorded (Sinha et al., 1996;Sinha and Sarkar, 2009).

In the Bay of Bengal, based on estimates of sediment volumes in a se-ries of cores, it was suggested that sediment flux during the period11–7 ka was 2.3 times higher compared to the modern values; the pe-riod of high sedimentflux coincideswith the earlyHolocenemonsoonalrise thereby suggesting a tight source-to-sink linkage (Goodbred andKuehl, 2000b; Goodbred, 2003). However, later modeling work byOvereem and Goodbred (2005) showed that such an increase in sedi-ment flux would require the water discharges to go up by 1.5–1.6times which is not commensurate with themodeled increase in precip-itation during Early Holocene based on paleo-monsoon proxies (Prelland Kutzbach, 1987; Clemens and Prell, 2003). Further, the responseof a large river system such as the Ganga to Holocene monsoonal riseis likely to be influenced by the spatial geomorphic diversity, and there-fore, a strong source to sink linkage is debatable (Sinha et al., 2005c).Several records from the Lower Ganga plains and delta plains have doc-umented repeated aggradational phases and enhanced chemicalweathering under warm and humid conditions in response to climaticfluctuations, in addition to the effect of sea level changes (Goodbred,2003; Heroy et al., 2003; Chauhan et al., 2004; Sinha and Sarkar, 2009).

3.2. South American river systems

The South American continent hosts an extensive river network(Fig. 4) where ~66% (∼11,800,000 km2) of the continent is drained byseven major rivers that discharge ~28% of the total global river waterto the oceans. These river systems include the Amazonas, Parana, Orino-co, Tocantins, Sao Francisco and Magdalena. The Andes, the longestmountain belt on Earth, extend like a backbone all along the west sideof the continent and produce an asymmetric divide at continentalscale. While small rivers characterize the Pacific watershed, large riverssuch as the seven listed above drain towards the Atlantic Ocean. Almostthree quarters of the South American continent are spread between thetropics and it hosts not only the largest fluvial basin of the planet, theAmazon, but also several large alluvial plains such as the Llanos ofColombia and Venezuela and the Chaco plain, and large seasonal

Fig. 4. Major Tropical river basins, tropical plains, wetlands and megafans in South America.


wetlands such as the Pantanal of Mato Grosso (Brazil), the Monposinadepression (Colombia), and the Bananal plain (Brazil).

Unfortunately, the Lower and middle Pleistocene fluvial records ofthe tropical regions of South America are still almost unknown exceptfor some information from the subtropical zone in the Parana andUruguay basins. Probably, some records can be attributed to theItuzaingo Formation (Pliocene-Lower Pleistocene?) in the ParanaRiver basin (Iriondo and Kröhling, 2009) but this Pleistocene recordis not well supported by detailed stratigraphic analysis. In the UruguayRiver, fluvial deposits of the Palmar Formation were attributed to theMIS5 and climatic conditions were interpreted as warm and humid(Krohling, 2009). Some data is now available from the large tropical flu-vial system in the Bananal plain in Central Brazil, which constitutes thelargest intracratonic basin of South America (Valente and Latrubesse,2011). The best records of large tropical South American Rivers howevercome from the Late Pleistocene (Last Glacial) and the Holocene periods.

The most complete records of Pleistocene chronology, palaeoecologyand geology come from the period before 24 ka BP, possibly correspond-ing to the Middle Pleniglacial (ca 65–24 ka BP). In the Amazon basin,sedimentation in the fluvial belts occurred during this period in riverswith their headwaters in the Andes (Ucayali, Madre de Dios, Solimões)(Rasanen et al., 1990, 1992; Dumont et al., 1992; van der Hammen et

al., 1992; Rossetti et al., 2005; Rigsby et al, 2009), in the lowlands(Latrubesse and Rancy, 1998, 2000; Latrubesse and Kalicki, 2002), andin rivers draining cratonic areas (Latrubesse and Franzinelli, 1998,2005; Valente and Latrubesse, 2011). Some authors suggest that the allu-vial sedimentation could have been directly associated with glacialadvances and enhanced rainfall in the central and northern Andeswhere the rivers deposited sand and gravel (Dumont et al., 1992; vander Hammen et al., 1992). However, the rivers with headwaters in thelowlands of the southwestern Amazon (Purus and Jurua basins, for ex-ample) and those with headwaters in cratonic areas such as the NegroRiver also carried abundant sediments that were coarser than thepresent-day load (Latrubesse and Franzinelli, 1998, 2005; Latrubesseand Rancy, 1998, 2000; Latrubesse and Kalicki, 2002). In the lowlands,the Amazonian rivers which currently transport ~98% of sediments assuspended load, the occurrence of coarse sand, pebbles and conglomer-ate deposits and Late Pleistocene Lujanian fossil mammals characteristicof more open vegetation than today suggest significant changes in thehydrological regime and sedimentary environment. The MiddlePleniglacial is characterized by abundant precipitation in the Andes anda continuing change towards dry conditions in the lowlands, includingthe cratonic areas (Latrubesse, 2000, 2003). Dune-field chronologies(Carneiro et al., 2002) confirmed the earlier suggestions that the aridity

image of Fig.�4


in the lowlands of Amazonia began during the Middle Pleniglacial orearly stages of the Upper Pleniglacial (Latrubesse, 2000). The MiddlePleniglacial–early Upper Pleniglacial episode of fluvial sedimentation isalsowell recorded in the Upper Parana basin. Coarse sedimentswere de-posited at this time in the Parana basin indicating a more arid periodthan at present (Stevaux, 1994, 2000; Stevaux and dos Santos, 1998).

The aridity in South America reached its maxima during the UpperPleniglacial (MIS 2) when the aeolian sedimentation was still activealong the Venezuelan and Colombian Llanos and over parts of centraland northern Amazonia. At that time, more open vegetation (savannaand seasonal forest) reached its maximum extent in the Amazon; theLlanos had an arid climate, and the aeolian remobilization reached thecore of the Amazon region. The Upper Pleniglacial was also a time of ex-tensive aeolian activity in response to increasing aridity in Central Brazil,Chaco (Latrubesse et al., 2012) and Pampa (Iriondo and Garcia, 1993).During the last glacial, a large sand sea with large dunes was formed inthe Pampean region (Argentina) and loessic sediments were depositedin the Chaco and were spread thoroughly along the Pampean plain.The aeolian activity peaked during the Upper Pleniglacial. At this time,the Upper Parana in Brazil had a smaller discharge than it does today.

The Chaco megafan activity was reduced during the UpperPleniglacial and deflation of the older alluvial belts spread. Dune fieldsformed in the Grande and Parapeti fans, and loessic sediments were de-posited in the Chaco along the Sub-Andean foothills (Iriondo, 1993;Latrubesse et al., 2012). The large basins of Central Brazil, such as theSão Francisco and Tocantins–Araguaia, have also experienced climaticdeterioration since the Middle Pleniglacial (Oliveira et al., 1999;Valente and Latrubesse, 2011).

Wind-circulation models were proposed for the Amazon and theLlanos area for the period close to Late Pleistocene (ca 40–14 ka BP)(Iriondo and Latrubesse, 1994; Latrubesse and Ramonell, 1994; Iriondo,1997; Latrubesse, 2000; Latrubesse et al., 2012). In the middle Amazonregion, second-order changes in regional climate dynamics were suffi-cient to result in a shift to a dry climate phase (Iriondo and Latrubesse,1994). Trade winds were stronger and drier than at present, producingextensive deflation corridors and aeolian sedimentation. Northeasterntrade winds were dominant approximately north of the Equator,removing sand and silt in the Llanos, “Pantanal Setentrional” and inRoraima (Latrubesse and Nelson, 2000; Carneiro et al., 2002). South-eastern trade winds that originated in the anticyclonic circulation ofthe southern hemisphere were dominant in the region south of theEquator reaching as far as the western Chaco along the Sub-Andeanfoot-slopes, forming dunes and loess deposits. The palynological recordin Carajas and Rondonia (van der Hammen and Absy, 1994), thepalaeomammals (Latrubesse and Rancy, 1998; Rossetti et al., 2004)and the palaeohydrologic records of the southwestern Amazon showthat itwas characterized by a dominant seasonal forest-savannamosaic,similar to the current Cerrado biome. during the Upper Pleniglacial,with a dry season that was more pronounced and prolonged than thatof the present. Aridity was also widespread in central and northeastBrazil resulting in the deflation of fluvial deposits and the formation ofsand dunes in the middle São Francisco (Latrubesse, 2003).

Cold air masses of the South Pacific Anticyclonic (SPA) circulationwere dominant in the Argentinean Pampas and part of the EasternChaco during the Middle and Upper Pleniglacial when the climate wasdry and cold (Ramonell and Latrubesse, 1991; Iriondo and Garcia,1993). These air masses penetrated up to the Upper Parana and upperAraguaia basin and thenmoved to the south and southwestern Amazon,resulting in a distinct fall in winter temperatures (Latrubesse andRamonell, 1994). The SPA winds were strengthened by katabaticwinds coming from the ice field of the Patagonian Andes (Iriondo andGarcia, 1993). After 14 ka BP, fluvial sedimentation in this region wasstrongly influenced by the climatic changes associated with the last de-glaciation. The gradual recuperation of the rainforest occurred, and thissedimentation phase probably culminated with the marine transgres-sion of the Middle Holocene.

3.3. Northern Australian river systems

The emphasis here is on three of Australia's northern rivers: theCooper Creek and the Diamantina River, that drain into the Lake Eyrebasin, the world's fourth largest endorheic basin, and the Gilbert Riverthat drains monsoon flows into the Gulf of Carpentaria (Fig. 4). At1.14 M km2, the Lake Eyre basin covers nearly 15% of the Australian con-tinent. The Cooper and Diamantina are the focus of study here becausethey are amongst the most intensively studied tropically fed rivers. Theyrun to Australia's lowest point, Lake Eyre, a salt playa nearly 10,000 km2

in area and some 15 m below sea level. The Gilbert River is anotherwell-studied system but one that adds an important element to under-standing of the tropical rivers in the formof high temperatures and chem-ically reactive sediments that result in rapid induration of alluvium andalteration of channel geometry and planform.

With a mean elevation of just 340 m, Australia is the world's lowestand most stable continent, and it is also the driest inhabited continent,only Antarctica being more so. These factors have had a profound im-pact on the nature of Australia's rivers, particularly the Cooper and theDiamantina, which are highly seasonal (Knighton and Nanson, 1997,2001). Furthermore, these transport almost entirely fine sediment but,rather remarkably, mostly as aggregated mud in the form of bed load(Nanson et al., 1986, 2008). Because the northern extent of the conti-nent is seasonally wet, the headwaters of these rivers flow at leastonce a year, sometimes flooding very extensively over plains manytens of kilometres wide (Knighton and Nanson, 1994). In the australsummer, the Asia-Australian monsoon trough extends south overnorthern Australia, and tropical cyclones and northwest troughs prog-ress into the central and even southern parts of Lake Eyre basin. Thebasin is also supplied with moisture from the southeast trade windsthat cross the Great Dividing Range flanking the east of the continent(Nanson et al., 2008).

Large repositories of Quaternary alluvium have been deposited in se-quences of shallow neotectonic depressions along the Cooper andDiamantina rivers, and they form an extensive system of floodplainsknown collectively as the ‘Channel Country’ (Fig. 5) (Nanson et al.,1986, 2008; Rust and Nanson, 1986). On lower Cooper Creek, the Tirariand Kutjitara Formations in the Tirari Desert reveal widespread fan-delta alluviation in the Late Pliocene and Early Pleistocene towards agreatly expanded eastern shoreline of Lake Eyre, all evidence of muchgreater tropical runoff conditions at that time (Nanson et al., 2008).

Luminescence dating has yielded a chronostratigraphy from~750 ka to Late Holocene (e.g. Nanson et al., 1988, 2008) and this evi-dence shows that higher tropical precipitation than today suppliedmuch more powerful rivers in the north and eastern Lake Eyre basinduring the Early to Middle Pleistocene. Climate must have fluctuatedgreatly during the Quaternary (Nanson et al., 1992). At times of pro-nounced wetness and increased tropical runoff, the rivers were able tolaterally migrate and rework a vast store of sandy bed load now sealedwithin extensive floodplains capped by 2–6 m of alluvial mud (Nansonet al., 1988, 2008). Bankfull discharges on Cooper Creek in OIS 7‐6 areestimated from palaeochannel channel cross sections and meanderplanform at one location to have been at their maximum about 5 to 7times larger than those of today (Nanson et al., 2008). However, frommarine isotope stage (MIS) 7 or possibly earlier, an overall dryingtrend appears to be superimposed on these intense climatic variations.For example, during MIS 6 and earlier, the entire Cooper Creek flood-plain was reworked at one particular location (Nanson et al., 2008),but in MIS 5 fluvial episodes, only about one third of it was replacedat the same location. Even less has happened since then. During orprobably before MIS 7 to 5, the Cooper Creek incised to a lower lakelevel due to increasing aridity (or a series of lower lake levels), leavingdeposits only along two relatively narrowmeander tracts. A progressiveincrease in aridity during the middle to late Quaternary has beennoted in Australia and is especially recognizable over the past ~350 ka(e.g. Hesse, 1994; Kershaw et al., 2003; Nanson et al., 2008).

Fig. 5. Tropically supplied rivers of the Lake Eyre basin in central Australia and the monsoon-fed Gilbert River basin in northern Australia.


River alluvium is juxtaposed with source-bordering aeolian dunesthat must have been supplied when discharges were much larger andwhen much more sandy alluvium was in transport than is the casealong these mud-load rivers today (Fig. 6). However, it is likely thatthis was a time of strongly seasonal and probably windier climate,such that fluvial sand could be supplied from active rivers but thenblown from seasonally dry river beds to form adjacent dunes. Suchstrongly seasonal conditions prevailed during late MIS 5, 3 and 2,but no such sandy channels occur in the Channel Country today,and neither is source-bordering dunes currently forming (Marouliset al., 2007; Cohen et al., 2010). It is likely that increasing ariditygreatly diminished the major Australian inland rivers between MIS5 and 2.

Only proximal to the Innamincka Dome, where local flow confine-ment and steepening has amplified declining stream powers, has analluvial signature of enhanced flows along Cooper Creek being pre-served after ~35 ka. This location indicates larger discharges duringor near the LGM than today, and again in the early tomiddle Holocene.Computations from palaeochannel dimensions in the InnaminckaDome indicate that bankfull flows on Cooper Creek in the midHolocene could have been a remarkable 8–9 times greater than pres-ent (Nanson et al., 2008). If this is the case, then a lack of reworkingelsewhere on Cooper Creek floodplain at that time suggests flows dur-ing the LGM and mid Holocene were short lived, perhaps characteriz-ing catastrophic events rather than a systematic change to regularly-supplied large discharges.

image of Fig.�5

Fig. 6. A summary transect at Chookoo Dunes location on Cooper Creek (see Nanson et al., 2008) showing the aeolian units and underlying alluvial units divided by luminescenceages into oxygen isotope stages (OIS) (after Maroulis et al., 2007).


Confirmation of greatly enhanced runoff into plunge pools onsmall streams near Darwin in northern Australia at about the timeof the LGM, and again in the early to middle Holocene, has beenobtained by Nott and Price (1994) and Nott et al. (1996). Australiais generally regarded as having been relatively dry during the LGM.Such features, therefore, could indicate relatively short-lived tropicalcyclones or clusters of cyclones in the northern and central Australia,rather than an overall upward shift in the overall flow regime. Thissuggests more erratic climate and flooding conditions during thetemperature maxima and minima of the glacial-cycles compared tothe more sustained periods of systematic perennial or seasonal runoffthat reworked the extensive floodplains of the Lake Eyre basin duringthe intervening periods.

Late Quaternary induration of alluvium in the monsoon tropics ofAustralia has been rapid and greatly influenced contemporary chan-nel morphology of some northern rivers. The Gilbert River flowingto the Gulf of Carpentaria anabranches over one of an extensive sys-tem of coalescing low-gradient and partly indurated fan-deltas onthe western slopes of Cape York (Fig. 5). The upper ~15 m or so ofits alluvium was deposited by much larger flows between MIS 5 andthe Holocene. A tropical climate in a catchment of reactive lithologyhas resulted in enhanced chemical weathering and rapid alluvial lith-ification (Nanson et al., 2005). This has resulted in the formation ofsmall rapids, waterfalls and inset gorges (Fig. 7) — landforms morecharacteristic of bedrock rather than an alluvial system. Lumines-cence ages of the sediments and U/Th ages of pedogenic calcreteand Fe/Mn hydroxide/oxide accumulations show that these indura-tions formed during the Late Quaternary in what must have been aseasonally alternating wet–dry climate; calcrete in the dry andferricrete in the wet. Such induration has restricted channel migra-tion and reduced the capacity of the channel to adjust and accommo-date sudden changes in bed load supply. Periodic avulsions havecaused local stream powers to increase by an order of magnitude, in-ducing knick point erosion, local incision and sudden bursts of addi-tional bed load that have triggered further avulsions (Nanson et al.,2005). The Gilbert River, while less energetic than its Pleistocene an-cestors, remains a periodically powerful avulsive system. This empha-sizes the importance of induration of alluvium for reinforcing thebanks in some tropical rivers, concentrating stream power, generat-ing knick points, reworking sediment and thereby developing andmaintaining an indurated and anabranching river style.

Evidence for episodes characterized by huge river discharges in thetropically fed rivers of what is now the globe's driest continent (exclud-ing Antarctica) begs two important questions: where did all the watercome from and why has this supply varied so dramatically? Nanson etal. (1992, 2008) found that fluvial activity in the Channel Country dur-ing MIS 5 probably peaked not at the beginning but at ~110 ka, and

then again during MIS 3. If maximum precipitation and runoff wereachieved under conditions inmid to late MIS 5 andMIS 3, episodes def-initely cooler than present, then Australia's northern monsoon is un-likely to have been a major source of moisture. Alternatively, someform of western Pacific warm pool, trapped close to eastern Australiaby reduced sea levels and the confinement of both the passage throughTorres Straight north of Cape York, and the Indonesian archipelagomaywell have been sufficient. Such conditions could have created a semi-permanent ‘La Nina’ with trade winds crossing the Coral Sea andQueensland and irrigating the Lake Eyre basin. However, the resolutionof the timing and cause of major changes in precipitation and runoff intropical Australia during the Quaternary will require additional datafrom diverse sources and improved chronological resolution.

3.4. African River systems

This special issue has not covered several regions such as CentralAfrica which host several large tropical rivers and Central America,which host a few small understudied systems. There is considerableamount of data available on the African rivers and this section attemptsto summarize the information available on two important tropical riversof Africa, the Congo and the Zambezi. Their hydrology, geomorphologyand Quaternary history have each been studied to varying extent in thepast six decades. The Congo (earlier called Zaire) is one of the longest riv-ers in the world with a total length of 4374 km. Originating at an eleva-tion of 1400–1500 m in the savanna highlands of Shaba, the catchmentarea of 3,747,320 km2 of the Congo basin is shared between eight coun-tries in Central Africa including Democratic Republic of Congo, Angola,Zambia, Tanzania, Burundi, Central African Republic (CAR), Cameroonand Republic of Congo. It flows to the Atlantic Ocean through very com-plex geological and geomorphological settings includingmanyheadwaterstreams and several lakes. The Congo is particularly well known for thelarge falls along its course between Kinshasha and the sea, and for thefact that it has no delta at its mouth. The source area of the Congo basinhas a seasonal wet and dry regime with an average rainfall of 1200 mmwhile the middle parts of the catchment receive a slightly higher annualrainfall of 1800–2400 mmwith almost no dry season. These two distinctrainfall patterns result into twoflow regimes for the Congo basin— a clearsingle peak hydrograph with a maximum in September–November or inMarch–May for the tributaries in upper reaches and a double peak dis-charge regime in the central Congo basin (Runge, 2007). The estimatesof sediment load carried by the Congo are quite variable and range from47 million tonnes (Meybeck, 1976) to as much as 91.8 million tonnes(Laraque et al., 2001). The Congo River has formed a 400 km long canyon~30 km before it enters the Atlantic Ocean (Buchanan, 1887; Stallibrass,1887). This canyon, down to a water depth of 3000–3200 m, is believedto have formed by sub-aerial fluvial erosion during the LGM (cf. Runge,

image of Fig.�6

Fig. 7. (a) Channel knick point (2.5 m high vertical waterfall face) incised into induratedMIS 5 and 3 alluvium of the Gilbert River in northern Australia (background figure forscale) (b) Carbonate cemented Quaternary alluvium of MIS 3 age forming the presentstream bed and a knick point (3.5 m high undercut waterfall face) providing a markederosion-resistant layer. (c) An oblique aerial view of incised anabranching channels of theGilbert River showing the extensive exhumation of the indurated alluvium forming prom-inent cliffed ‘terraces’. Flow is towards the bottom of the picture. All views are at low flow.


2007) but tectonic origin and submarine sliding are more likely mecha-nisms (Burgoin et al., 1963; Giresse, 1978, 1980; cf. Runge, 2007).

The Congo basin is a good example of a region where rapid geomor-phic changes have been recorded during the Quaternary period asmanifested in frequent occurrence of multi-layered alluvium and fansin river valleys as well as stratified slope deposits that reflect formermodifications of the environment (Runge, 2001; cf. Runge, 2007). Earlywork in the Congo basin in the Malebo-(Stanley) Pool near Kinshasa/Brazzaville documented four stratigraphic levels for the Late Quaternary

(de Ploey et al., 1968). Reconstruction of climatic fluctuations indicatedstrong erosion followed by the abundant accumulation of sand between42 ka and 37 ka. During the period of 40–30 ka, this sand waspodzolized under alternating humid warm to cool climatic conditions.Before the onset of the Holocene, the alluvium was remobilized anddeposition of surface layer in the Congo basin occurred between 16 kaand 11 ka. De Ploey et al. (1968) argued for a temporary, climatecontrolled thinning out of vegetation cover but a predominant tendencyto a renewed propagation of rain forest is noted during 12–3 ka in Cen-tral Africa. Alexandre et al. (1994) differentiated fluvial deposits formedin humid and arid periods in the Shaba Province where alluvial sedi-ments with Holocene ages of 6.8–6.3 ka (van Zinderen Bakker andClark, 1962; De Ploey et al., 1968) are often underlain by a compactgravel layer partially indurated by iron segregations. They are coveredby interbedded sandy and clay deposits with single stone-lines,which were interpreted as residual debris that were exposed and re-deposited under more humid conditions. Van Zinderen Bakker andClark (1962) attributed similar detrital accumulations at the LuembeRiver in northeastern Angola primarily to a period of arid climate.Runge and Tchamié (2000) also described a related phenomenon fromthe Niantin River valley in northern Togo (West Africa) and reconfirmedthe efficacy of erosion and re-deposition during Late Quaternary. Runge(2002) reported undisturbed alluvial sediments, several meters thick,of Early Holocene (~8 ka) age in the Mbari valley in the Central AfricanRepublic; these were interpreted to have been deposited under humidclimatic conditions. In Nigeria, at the northwestern limit of the volcanicJos Plateau, Zeese (1991, 1996) identified two incision events during20–18 ka and around 11 ka and a valley-filling episode during late gla-cial time.

The Zambezi is the largest river in southern Africa with a total drain-age area of 1,331,000 km2 and ranks 6th in the world in terms of itsmean annual discharge of 17,600 m3/s (Cyaza, 1981; RivDIS, GlobalRiver Discharge, 2003). It rises in the Pre-Cambrian rocks of the SouthernEquatorial Divide in northwest Zambia, flows north towards the Congofor about 30 km and then swings to southwest to flow into Angola andfinally turns southeast to the Indian Ocean. Rainfall in the drainagearea of the river is primarily determined by the position of the ITCZ,which is at its southern limit over the Zambezi during the austral sum-mer (Walker, 1990); the mean annual rainfall varies from 1200 mm inthe north to 600 mm in towards the south (Walling, 1996;Wohl, 2007).

The Zambezi River has been divided into three distinct geomorphicunits: (1) headwaters to Victoria Falls, (2) Falls to the edge of theMozambique coastal plains, and (3) the stretch traversing the coastalplains to the Ocean (Wellington, 1955; Moore et al., 2007). It has beensuggested that the modern course of the Zambezi River is quite recent;the upper and middle parts of the river having evolved separately andthen joined together through several stages of river capture and tec-tonic activities (Shaw and Thomas, 1988, 1992; Goudie, 2005) perhapsin Pliocene ormid-Pleistocene (Thomas and Shaw, 1991). Based on sev-eral lines of evidences,Moore and Larkin (2001) suggested that the evo-lutionary sequence of the Zambezi River started in early Cretaceouswhen the upper Zambezi was probably linked to the Limpopo via theShashe River. The middle Zambezi was linked to the Shire system. Theupper Zambezi was captured by the middle Zambezi because ofdownwarping and tectonically triggered headward erosion, possiblyin lower Pleistocene. Following this capture, complex drainage reorga-nization took place in this area. The enhanced downwarping along theGwembe trough caused rejuvenation leading to the development ofthe Victoria Falls and the incisedmiddle Zambezi gorge. Very little strat-igraphic information is available on the Quaternary sediments in theZambezi basin although extensive alluvium and lacustrine depositshave been reported between the Kafue Flats and the Machili Basin(Dixey, 1945; Thomas and Shaw, 1991). These alluvial deposits provideevidence for a former major inland lake, Lake Makgadikagadi, intowhich the Zambezi River was diverted (Thomas and Shaw, 1991). Ithas been suggested that the limit of the older alluvium reflects the

image of Fig.�7


approximate extent of this lake that comprised of two subsidiary basinslinked via a narrow neck along the Boteti River valley (Thomas andShaw, 1991). Timing of the high lake level and thus the diversion ofthe Zambezi River into northern Botswana is not well constrained butis considered to be during mid-Pleistocene (~300 ka or older) basedon Acheulian artifacts from the floor of Lake Makgadikagadi (Barhamand Smart, 1996; McBrearty and Brooks, 2000; McFarlane andSagadika, 2001).

The Zambezi River has had a long history of human occupation butextensivemeasures to control tsetse fly in the basin have helped to pro-tect largewilderness areas. However, the continued exploitation and in-creasing population pressure have resulted in construction of severallarge dams along the Zambezi River that have had adverse ecologicalimpacts. Further interventions planned on this river will require carefulmanagement strategies.

4. In this issue

The present volume is a collection of nine papers on tropical rivers in-cluding the introduction paper, which provides an overview of the re-search on tropical rivers on three continents. This volume includes onepaper on theYellow river in China, three papers on the Himalayan Riversin India, two papers on the rivers draining the SouthAmerican continent,and one paper on themega-lakes fed by the northern and southern riversystems of central Australia. This volume therefore covers a wide geo-graphic region hosting tropical rivers. A brief account of the salient pointsof the different papers of this volume follows next.

Botian and others have discussed the planation surface and incisionof the Yellow river in China. Using magneto-stratigraphic data, theypostulate that the planation surface and the uppermost Yellow Riverterrace formed 3.7 Ma and 1.2 Ma ago respectively. The accelerated up-lift of the Tibetan Plateau in the Late Pliocenemight have contributed tothe dissection of the planation surface and the Yellow River developedits rectangular course around the Ordos Plateau since 3.7 Ma.

Dutta and others have presented new stratigraphic data from the ter-races around the Yamuna Exit in the frontal parts of the northwesternHimalaya with the objective of understanding the coupling of tectonicsand climate in their genesis. The authors have documented five levels ofterraces (T1 to T5), cutting across numerous tectonic planes, depositedby both glacier-fed perennial and piedmont-fed ephemeral streamsduring Late Pleistocene-Holocene. Contrary to the assumed dominanceof tectonic processes in the formation of such terraces, the authors haveargued that climate played an important role in their genesis. Based on asound OSL chronology of these terraces, the authors have documentedfive distinct fluvial aggradation phases separated by incision eventsspanning a time period of ~30 ka. Age data indicate that the abandon-ment of these terraces occurred during major climatic transitions fromarid to humid or vice versa. Two major aggradational phases arerecorded in the Late Pleistocene (>37 to 24 ka and >15 to 11 ka) andthese are similar to the aggradation events recorded in the distal partsof the Ganga plains (Gibling et al., 2005; Tandon et al., 2006; Roy etal., 2011). Out of three minor aggradation phases recorded by the au-thors during mid- to late Holocene (7–4 ka; 3–2 ka; and b2 ka), thelast two in the latestHoloceneperiodmatchwith the rapid valley aggra-dation in the Ganga plains (Roy et al., 2011). The authors note an ab-sence of warping, tilting and dislocation in these terraces whichreflects that they were not affected by hinterland tectonics after theirformation. However, they note the abrupt termination of the lower ter-races (T1 to T3) at themountain front and decrease in valleywidthwithstaircase of terraces which suggests tectonic uplift along the HimalayanFrontal Thrust which could have amplified the incision.

Roy and others have presented their investigation of stratigraphicdata from the Ganga valley fills and the interfluve based on a series ofdrill cores and exposed cliff section covering a time span of ~100 ka asindicated by luminescence dating. Stratigraphic data, based on a seriesof drill cores down to ~25 m, suggest five aggradational periods

separated by incisional episodes in the valley fill, some of which havecorrelative strata along the valley margin. The Ganga valley hadwidespread fluvial activity during MIS 4 and 5 with minor discontinu-ities recorded in the valley fills as well as in valley margin sequences.Several periods of aggradation preceded by incision are recorded inthe valley duringMIS 3 and 2 resulting in composite channel sand com-plexes separated by thin floodplain muds. In several cores, more than10 m of sediments are documented to have accumulated in the last2.5 ka demonstrating very rapid aggradation possibly due to anthropo-genic factors during the latest Holocene period. Therewasmodest accu-mulation of floodplain, lacustrine and aeolian deposits, punctuated bydiscontinuities, through to early MIS 2 after which the interfluve wasapparently not inundated by the Ganga and underwent degradationthrough gully erosion. The authors do not record any fluvial activityduring the LGM period and have suggested that the Ganga River mayhave been underfit during this period, in line with earlier work in theadjoining area (Sinha et al., 2007a). One of the major conclusions ofthis paper is that the periods of valley aggradation correspond totimes of declining monsoonal strength whereas the timing of incisionevents corresponds broadly with periods of monsoonal intensification.

Pal and others have presented a detailed sedimentological and claymineralogical investigation of two cores from the Ganga-Yamuna inter-fluve in theHimalayan foreland tounderstand the coupling of provenanceand climate change over the last 100 ka. A systematic analysis of sedi-mentary facies and clay mineralogy of different grain size fractions havebrought out (a) significant spatial difference in clay mineral assemblage,and (b)marked temporal (depth distribution) changes in claymineralogyin the cores sediments from the northern and southern parts of the inter-fluve.While the spatial difference in claymineralogy has been interpretedas amanifestation of provenance (Himalayan vs. cratonic), the depth dis-tribution is attributed to varying degree of pedogenesis and sedimentsupply over the last 100 ka. Amajor discovery in this paper is the distinc-tion of hydroxyl-interlayered dioctahedral low-charge smectite (LCS) andtrioctahedral high-charge smectite (HCS) in sediment samples and thedifferent pathways of their formation. The LCS has been interpreted as aresult of plagioclaseweathering (Pal andDeshpande, 1987) and represen-tative of a cratonic sources. On the other hand, the HCS is generally de-rived from the Himalayan source formed from the weathering ofbiotites (Srivastava et al., 1994, 1998; Srivastava et al., 2010). The authorsnote that the humid interglacial stages (MIS 5, 3, and 1) are marked bydominance of hydroxyl-interlayered vermiculite (HIV), pseudo-chlorite(PCh), and LCS. In contrast, the semi-arid stages (MIS 4 and 2) show adominance of HCS together with pedogenic carbonate (PC). The authorsmake an important observation that “the preservation of LCS, HIV, kaolinand PCh is a clear indicator of climate shift fromhumid to semi-arid in theGanga plains as their formation does not represent contemporary pedo-genesis in the alkaline chemical environment induced by the semi-aridclimate.” Such interpretations have significant implications in terms ofuse of the clay minerals as proxies for interpreting climate change duringthe Quaternary.

Valente and Latrubesse postulate the first paleoenvironmental andstratigraphic framework for the largest Quaternary intracratonic basinof South America, the Bananal. The Bananal, located in central Braziland spreading over ~106,000 km2, preserves a good record of thepaleohydrological conditions of Central Brazil at the Cerrado–Amazonecotone. Avulsive channels and floodplain sediments of the Araguaia–Mortes fluvial system, filled the basin. TL and OSL chronologies of theAraguaia Formation allowed the authors to postulate that sedimenta-tion started at least in the Middle Pleistocene (MIS 7) but aggradationand avulsion processes were important in the Lower–MiddlePleniglacial between 70.5 ka and 34.0±4.6 ka (MIS 4 and 3) and inthe Upper Pleniglacial between 24.5±3.1 and 17.2±2.3 ka (MIS 2).The Bananal plain is unique because of its particular style of sedimenta-tion and geomorphologic processes that generated a mega-scaleanabranching like complex pattern of paleochannels presently occupiedby underfit streams.


Latrubesse andothers have provided thefirst paleogeographic frame-work for the Bolivian Chaco. The Chaco is a large plain and a major bio-geographic biome of South America where some of the world's largestriver-fans such as the Parapeti and Grande river megafans have devel-oped on the Andes footslope through Bolivia, Argentina and Paraguay.Based on morpho-sedimentary information and OSL dating of fluvialand aeolian sediments, the authors have demonstrated that the Chacomegafans and large piedmont fans reached their maximum develop-ment during the middle Pleniglacial and early Pleniglacial (ca. 60 to28 ka). The main mechanism triggering the megafan development wasan intense monsoon during MIS 3 and the early part of MIS 2 on theEastern flank of the Andes that enhanced rainfall due to orographic ef-fects thereby increasing river discharge and sediment supply. The defla-tion of fluvial beltswas coevalwith fluvial processes and large sand dunefields developed by winds blowing from North to South, the same pat-tern the South American lower level jet follows presently. Maximumaridity was reached during MIS 2 and the late glacial period was aridbut probably less extreme than the LGM. During a good part of the Holo-cene, the climatic conditions were still arid to semiarid but became sim-ilar to the present sub-humid climate since ~1.5 ka.

Cohen and others have used ooptically stimulated and thermo-luminescence ages along with accelerator mass spectrometer 14C agesfrom freshwater molluscs from relict shorelines on a system of lateQuaternary playa-lakes that were filled by tropically-sourced riversdraining southwards in the Lake Eyre basin of Australia. The record ex-tends back to 105 ka, confirming that tropical moisture during MIS 5down flowed with sufficient discharge to fill lakes Mega-Frome andMega-Eyre, and connect them with an overflow channel, to create thelargest system of Quaternary palaeolakes on the Australian continentuntil as recently as 50–47 ka. The palaeohydrological record indicatesa progressive shift to more arid conditions, with marked drying after45 ka. Subsequently, Lake Mega-Frome was filled at least partially bytropically fed rivers at 33–31 ka and at the termination of the LGM tovolumes some 40 times those of today. Further, sequentially decliningfilling episodes (to volumes 25–10 times to those of today) occurredimmediately prior to the Younger Dryas stadial, in the mid Holoceneand as recently as the medieval climatic anomaly (medieval warmperiod). An examination of multiple active moisture sources suggeststhat palaeolake phases were driven independently of insolation and attimes by some combination of enhanced Southern Ocean circulationand strengthened tropical moisture sources.

5. Concluding remarks and future perspectives

Tropical rivers occur in a wide range of tectono-geomorphic andmorpho-climatic settings and as a result there is a great diversity intheir form and processes. Inmost regions, they form themost importantsource of freshwater. Future uncertain availability of freshwater due toclimate change and escalating demands due to population explosionhave brought the freshwater security at the forefront. Further, severalhydropower facilities and innumerous dams are being planned or areunder construction in tropical river basins such as the Mekong, theMadeira, the Xingú and many others in Asia, Africa and Latin America;these interventions pose serious threats to the ecology and biodiversityof these rivers (Xue et al., 2011; Finer and Jenkins, 2012; Latrubesse,2012, among others). The hydro-geomorphological characteristics ofthe tropical rivers can be irreversibly disrupted over decadal scale ifthese interventions are allowed. A sustainable management of theserivers requires that their inherent diversity, complexity and variabilityare properly understood. This means that new data from tropical riversneeds to be generated in their different and diverse regions. Severalissues remain unresolved as far as the current understanding of tropicalrivers is concerned. For example, the interactions of morphology, hy-drology and ecology, which have a pronounced effect on water avail-ability and biodiversity, are largely unknown. The generation of newfacies models and more detailed channel-floodplain classifications for

tropical anabranching systems should form a high priority research.The knowledge of pre-historic sediment budgets of the tropical riversin response to large-scale landuse/landcover changes and their hydro-meteorological feedbacks are crucial for assessing the hydrological im-pacts of climate change on these rivers including their connectivitystructure and sediment dynamics. Reconstructions of river dynamicsand flood records need to be taken up on a priority basis as the analysisof the daily rainfall for the last 5 decades has shown a significant risingtrend in frequency and magnitude of extreme rain events (Goswami etal., 2006). Such ‘modified’ hydrologic regimes are likely to increase thefrequency of extreme events and the variability of sediment dynamicsin tropical river systems.

Despite the complex tectonic andmorpho-climatic settings, tropicalregions are excellent fluvial archives. This special issue has covered sev-eral important tropical river basins in Asia, Australia and South Americabut we could not include any paper from Africa although we haveattempted a brief summary on the status of research in this region.There are also no papers from the small and understudied CentralAmerican systemswhich badly need new data on Quaternary stratigra-phy and hydrological processes. TheQuaternaryfluvial record of severaltropical river basins in the Indian sub-continent such as the Ganga basinis moderately well known and has provided important insights to re-construct the palaeo-environmental conditions during the last 100 ka.However, more such records are needed from other river basins inthis region particularly from the Godavari and Cauvery basins that areinfluenced by both summer and winter monsoons and have importantimplications for climate models. Records for the Lower Pleistocene arerather scarce from most parts of India due to lack of exposed sectionsand there is an urgent need to penetrate deeper through drill cores.Similar studies are needed for most of other tropical river basins andparticularly on the African river systems from where stratigraphicdata is really scarce despite a long history of research.

The chronological framework of the stratigraphic records also needsto be strengthened and amuch stronger database is needed for develop-ing high-resolution stratigraphy for theHolocene period to help paleocli-matic reconstruction to test climate modeling for future projections. InAustralia, a detailed record has been generated of deposits laid downsince ~750 ka representing the interactions between paleolakes, aeoliansource-bordering dunes and fluvial systems providing useful indicatorsfor paleoenvironmental reconstructions. Also in Australia, the remark-able impact of rapid weathering and induration on the morphology ofsome tropical river systems has been graphically illustrated. In SouthAmerica, knowledge of the fluvial systems is mainly constrained to theLast Glacial and Holocene. Reconstructions of the fluvial environmentsof some of the largest rivers of the world during the Lower and muchof the Upper Pleistocene are still almost unknown.

Acknowledgments

We are grateful to R.J. Wasson andMartin Gibling for reviewing thispaper and for providing valuable suggestions. We thank the editors ofthe Palaeo-3 for accepting this special issue on tropical rivers for publi-cation that has helped to compile the current status of research on thissubject. The support from IGCP 582 is thankfully acknowledged and thishelped to bring the researchers together on a commonplatform.We aregrateful to all the authors who agreed to contribute to this special issueon tropical rivers and have waited patiently for the finalization of thisissue.

References

Abbas, N., Subramanian, V., 1984. Erosion and sediment transport in the Ganges Riverbasin, India. Journal of Hydrology 69, 173–182.

Agrawal, S., Sanyal, P., Sarkar, A., Jaiswal, M.K., Dutta, K., 2012. Variability of Indianmonsoonal rainfall over the past 100 ka and its implication for C3–C4 vegetationalchange. Quaternary Research 77, 159–170.


Alexandre, J., Aloni, K., de Dapper, M., 1994. Géomorphologie et variations climatiquesau Quaternaire en Afrique Centrale. Géo-Eco-Trop 16, 167–205.

Assine, M., 2005. River avulsion on the Taquari megafan, Pantanal wetland, Brazil.Geomorphology 70, 357–371.

Balek, J., 1983. Hydrology and Water Resources in Tropical Regions. Elsevier, Amsterdam.271 pp.

Barham, L., Smart, P.L., 1996. An early date for the Middle Stone Age of Central Zambia.J. Human Evol. 30, 287–290.

Bristow, C.S., 1987. Brahmaputra River: Channel migration and deposition. In: Ethridge,F.G., Flores, R.M., Harvey, M.D. (Eds.), Recent developments in fluvial sedimentology:Society of Economic Paleontologists & Mineralogists: Special Publication, 39,pp. 63–74.

Buchanan, J.Y., 1887. On the land slopes separating continents and ocean basins espe-cially those on the west coast of Africa. Scot Geol Mag 3, 217–238.

Burgoin, V., Reyre, D., Magloire, P., Krichewsky, M., 1963. Les canyons sous-marinsdu Cap Lopez. Cah Ocean 15, 372–387.

Carneiro, F.A., Schwartz, D., Tatumi, H., Rosique, T., 2002. Amazonian paleodunesevidencing a drier climate during late Pleistocene–Holocene. Quaternary Research58 (2), 205–209.

Chandra, S., 1993. Fluvial landforms and sediments in the north central Gangetic Plain,India. PhD (unpublished) thesis, University of Cambridge, Cambridge, UK.

Chandra, S., Rhodes, E., Richards, K.S., 2007. Luminescence dating of late Quaternaryfluvial sediments in the Rapti Basin, north-central Gangetic plains. QuaternaryInternational 159, 47–56.

Chauhan, O.S., Patil, S.K., Suneethi, J., 2004. Fluvial influx and weathering history ofthe Himalayas since Last Glacial Maxima- isotopic, sedimentological and magneticrecords from the Bay of Bengal. Current Science 87, 509–514.

Clemens, S.C., Prell, W.L., 2003. A 350, 000 year summer–monsoon multi-proxy stackfrom the Owen Ridge, Northern Arabian Sea. Marine Geology 201, 35–51.

Cohen, T.J., Nanson, G.C., Larsen, J.R., Jones, B.G., Price, D.M., Coleman, M., Pietsch, T.J.,2010. Late Quaternary aeolian and fluvial interactions on the Cooper Creek Fanand the association between linear and source-bordering dunes, Strzelecki Desert,Australia. Quaternary Science Reviews 29, 455–471.

Coleman, J.M., 1969. Brahmaputra River channel processes and sedimentation. Sedi-mentary Geology 3, 129–239.

Curray, J.R., 1994. Sediment volume and mass beneath the Bay of Bengal. Earth andPlanetary Science Letters 125, 371–383.

Cyaza, E., 1981. Rivers of the World. Cambridge University Press, Cambridge. 248 pp.De Ploey, J., Lepersome, J., Stoops, G., 1968. Sedimentologie et origine des stables de la

serie des sables ocre et de la serie des 'gres polymorphes 9ststeme du Kalahari auCongo. Geol Wetens 61, 1–72.

Dixey, F., 1945. The geomorphology of northern Rhodesia. Proc. Trans. Geol. Soc. S.Africa 47, 9–45.

Dumont, J.F., Garcia, F., Fournier, M., 1992. Registros de cambios climáticos para losdepósitosy morfolog´ýas fluviales en la Amazonia Occidental. In: Ortlieb, L.,Macharé, J. (Eds.), PaleoENSO Records. International Symposium. ExtendedAbstracts. ORSTOM, Lima, pp. 87–92.

Filizola, N.P., 1999. O fluxo de sedimentos em suspensaõ nos rios da bacia AmazoˆnicaBrasileira. ANEEL, Brasilia. 63 pp.

Finer, M., Jenkins, C., 2012. Proliferation of hydroelectric dams in the Andean Amazonand implications for Andes–Amazon connectivity. PLoS One 7 (4), e35126.

Fleitmann, D., Burns, S.J., Mudelsee, M., Neff, U., Kramers, J., Mangini, A., Matter, A., 2003.Holocene forcing of the Indian monsoon recorded in astalagmite from southernOman. Science 300, 1737–1739.

Gibling, M.R., Tandon, S.K., Sinha, R., Jain, M., 2005. Discontinuity bounded alluvial se-quences of the southern Gangetic Plains, India: aggradation and degradation in re-sponse to monsoonal strength. Journal of Sedimentary Research 75, 369–385.

Gibling,M.R., Sinha, R., Roy, N.G., Tandon, S.K., Jain, M., 2008. Quaternaryfluvial and eoliandeposits on the Belan River, India: paleoclimatic setting of Paleolithic to Neolithicarcheological sites over the past 85,000 years. Quaternary Science Reviews 27,392–411.

Gibling, M.R., Fielding, C.R., Sinha, R., 2011. Alluvial valleys and alluvial sequences:towards a geomorphic assessment. SEPM Special Publication 97, 423–447.

Giresse, P., 1978. Le controle climatique de la sedimentation marine et continentale enAfricque Centrale Atlantique a la fin du Quaternaire. Problemes de correlation.Paleogeography, Paleoclimatology, Paleoecology 23, 57–88.

Giresse, P., 1980. Carte sedimentologique du plateau continental du Congo. ORSTOMNot explic, 85, pp. 1–24.

Goodbred Jr., S.L., 2003. Response of the Ganges dispersal system to climate change: asource-to-sink view since the last interstade. Sedimentary Geology 162, 83–104.

Goodbred, S.L., Kuehl, S.A., 1999. Holocene and modern sediment budgets for the GangesBrahmaputra river system: evidence for highstand dispersal to flood-plain, shelf anddeep-sea depocentres. Geology 27 (6), 559–562.

Goodbred Jr., S.L., Kuehl, S.A., 2000a. The significance of large sediment supply, activetectonism, and eustasy on margin sequence development: Late Quaternary stratig-raphy and evolution of the Ganges–Brahmaputra delta. Sedimentary Geology 133,227–248.

Goodbred, S.L., Kuehl, S.A., 2000b. Enormous Ganges-Brahmaputra sediment dischargeduring strengthened early Holocene monsoon. Geology 28 (12), 1083–1086.

Goswami, D.C., 1985. Brahmaputra River, Assam, India: Physiography, BasinDenundation and Channel Aggradation. Water Resources Research 21, 959–978.

Goswami, B.N., Venugopal, V., Sengupta, D., Madhusoodanan, M.S., Xavier, P.K., 2006. In-creasing trend of extreme rain events over India in a warming environment. Science314, 1442–1445.

Goudie, A.S., 2005. The drainage of Africa since the Cretaceous. Geomorphology 67,437–456.

Gupta, A., 2007. Introduction. Tandon, S.K. and Sinha, R., 2007. Geology of large riversystems. In: A. Gupta (Editor), Large rivers: Geomorphology and Management.John Wiley & Sons, Ltd, 1–5.

Heroy, D.C., Kuehl, S.A., Goodbred, S.L., 2003. Mineralogy of the Ganges and Brahmaputrarivers: implications for river switching and Late Quaternary climate change. Sedimen-tary Geology 155, 343–359.

Hesse, P.P., 1994. The record of continental dust from Australia in Tasman Sea sedi-ments. Quaternary Science Reviews 13, 257–272.

Hovius, N., 1998. Controls on sediment supply by larger rivers. In: Shanley, K.W.,McCabe, P.J. (Eds.), Relative Role of Eustasy, Climate, and Tectonism in Conti-nental Rocks: Society for Sedimentary Geology (SEPM) Special Publication, 59,pp. 3–16.

Iriondo, M., 1993. Late Quaternary and geomorphology of the Chaco. Geomorphology7, 289–305.

Iriondo, M., 1997. Models of deposition of loess and loessoids in the upper Quaternaryof South America. Journal of South American Earth Sciences 10 (1), 71–79.

Iriondo, M., Garcia, N., 1993. Climatic variations in the Argentine Plains during the last18,000 Years. Palaeogeography, Palaeoclimatology, Palaeoecology 101 (3–4),209–220.

Iriondo, M., Kröhling, D., 2009. From Buenos Aires to Santa Fe: Darwin´s observationsand modern knowledge. Revista de la Asociación Geológica Argentina 64 (1),109–123.

Iriondo,M., Latrubesse, E., 1994. A probable scenario for a dry climate in Central Amazoniaduring the Late Quaternary. Quaternary International 21, 121–128.

Islam, M.R., Begum, S.F., Yamaguchi, Y., Ogawa, K., 1999. The Ganges and Brahmaputrarivers in Bangladesh: basin denudation and sedimentation. Hydrological Processes13, 2907–2923.

Jain, V., Sinha, R., 2003. River systems in the Gangetic plains and their comparison withthe Siwaliks: A review. Current Science 84, 1025–1033.

Joshi, D.D., Bhartiya, S.P., 1991. Geomorphic history and lithostatigraphy of a part ofeastern Gangetic plain. Uttar Pradesh. Journal of Geological Society of India 37,569–576.

Kershaw, A.P., van der Kaars, S., Moss, P.T., 2003. Late Quaternary Milankovitch—scale cli-mate change and variability and its impact on monsoonal Australia. Marine Geology201, 81–95.

Knighton, A.D., Nanson, G.C., 1994. Flow transmission along an arid-zone anastomosingriver, Cooper Creek, Australia. Hydrological Processes 8, 137–154.

Knighton, A.D., Nanson, G.C., 1997. Distinctiveness, diversity and uniqueness in aridzone rivers. In: Thomas, David (Ed.), Arid zone Geomorphology: Process Formand Change in Dryland. Wiley, Chichester, pp. 185–203.

Knighton, A.D., Nanson, G.C., 2001. An event-based approach to the hydrology of arid-zone rivers in the Channel Country of Australia. Journal of Hydrology 254,102–123.

Kotoky, P., Bezbaruah, D., Baruah, J., Sarma, J.N., 2005. Nature of bank erosion along theBrahmaputra River channel, Assam, India. Current Science 88 (4), 634–640.

Krohling, D., 2009. La Formación El Palmar: una unidad fluvial asignable al subestadíocálido EI 5ª (Pleistoceno tardío) de la cuenca del Río Uruguay. Natura Neotropicalis40 (1–2), 61–86.

Lahiri, S.K., Sinha, R., 2012. Tectonic controls on themorpho-dynamics of the BrahmaputraRiver System in Upper Assam valley, India. Geomorphology http://dx.doi.org/10.1016/j.geomorph.2012.04.012.

Laraque, A., Mahe, G., Orange, D., Marieu, B., 2001. Spatio-temporal variations in hydro-logical regimes within Central Africa during the 20th century. Journal of AppliedHydrology 245, 104–117.

Latrubesse, E., 2000. The late Pleistocene in Amazonia: a palaeoclimatic approach. In:Smolka, P., Volkheimer, W. (Eds.), Southern Hemisphere Paleo and Neoclimates.Springer, pp. 209–222.

Latrubesse, E., 2003. The Late Quaternary paleohydrology of large South-American fluvialsystems. In: Gregory, K., Benito, G. (Eds.), Palaeohydrology: Understanding GlobalChange. Wiley, Chichester, pp. 193–212.

Latrubesse, E., 2008. Patterns of anabranching channels: the ultimate end-member ad-justment of mega rivers. Geomorphology 101, 130–145.

Latrubesse, E., 2012. Lakes Paleolakes and Reservoirs in the Amazon basin. In: Bengtsson,R.W., Herschy, R., Fairbridge, R. (Eds.), Encyclopedia of Lakes and Reservoirs. Springer,pp. 13–26 http://dx.doi.org/10.1007/978-1-4020-4410-6.

Latrubesse, E., Franzinelli, E., 1998. Late Quaternary Alluvial Sedimentation in theUpper Rio Negro basin, Amazonia, Brazil: Palaeohydrological Implications. In:Benito, G., Baker, V., Gregory, K.J. (Eds.), Palaeohydrology and EnvironmentalChange. Wiley, Chichester, pp. 259–271.

Latrubesse, E.M., Franzinelli, E., 2005. The late Quaternary evolution of the Negro River,Amazon, Brazil: implications for island and floodplain formation in largeanabranching tropical systems. Geomorphology 70 (3–4), 372–397.

Latrubesse, E., Kalicki, T., 2002. Late Quaternary Paleohydrology of the Purus river Amazon,Brazil. Zeitschrift Fur Geomorphologie 129, 41–59.

Latrubesse, E., Nelson, B., 2000. Evidence for Late Quaternary aeolian activity in theRoraima–Guyana Region. Catena 43, 63–80.

Latrubesse, E., Ramonell, C., 1994. A climatic model for Southwestern Amazonia at lastglacial times. Quaternary International 21, 163–169.

Latrubesse, E., Rancy, A., 1998. The late Quaternary of the Upper Jurua River, South-western Amazonia, Brazil: geology and vertebrate paleontology. Quaternary ofSouth America and Antarctic Peninsula 11, 27–46.

Latrubesse, E., Rancy, A., 2000. Neotectonic influence on tropical rivers of SouthwesternAmazon during the late Quaternary: the Moa and Ipixuna river basins, Brazil.Quaternary International 72, 67–72.

Latrubesse, E.M., Stevaux, J.C., Sinha, R., 2005. Tropical Rivers. Geomorphology 70(3–4), 187–206.

http://dx.doi.org/10.1016/j.geomorph.2012.04.012

http://dx.doi.org/10.1007/978-1-4020-4410-6


Latrubesse, E.M., Stevaux, Jose C., Cremon, Edipo H., May, Jan-Hendrik, Tatumi, SoniaH., Hurtado, Martín A., Bezada, Maximiliano, Argollo, Jaime B., 2012. Late Quaterna-ry megafans, fans and fluvio-aeolian interactions in the Bolivian Chaco, TropicalSouth America. Palaeogeography, Palaeoclimatology, Palaeoecology. http://dx.doi.org/10.1016/j.palaeo.2012.04.003.

Lavé, J., Avouac, J.P., 2000. Active folding of fluvial terraces across the Siwalik Hills,Himalayas of central Nepal. Journal of Geophysical Research 105 (B3), 5735–5770.

Maroulis, J.C., Nanson, G.C., Price, D.M., Pietsch, T., 2007. Aeolian-fluvial interaction andclimate change: source-bordering dune development over the past 100 ka onCooper Creek, central Australia. Quaternary Science Reviews 26 (3–4), 386–404.

Martinelli, L.A., Forsberg, B.R., Victoria, R.L., Devol, A.H., Mortatti, J.R., Ferreira, J., Bonassi, J.,de Oliveira, E., 1993. Suspended Sediment load in theMadeira river. Mitteilungen ausdem Geologisch-Palaeontologischen Institut der Universite Hamburg 74, 41–54.

Mc Gregor, G.R., Nieuwolt, S., 1998. Tropical Climatology. Wiley. (139 pp.).McBrearty, S., Brooks, A.S., 2000. The revolution that wasn't: a new interpretation of

the origin of modern human behavior. Journal of Human Evolution 39, 453–563.McFarlane, M.J., Sagadika, P., 2001. Archaeological evidence for the reassessment of the

ages of the Makgadikgadi. Botswana Notes Rec. 33, 83–90.McKnight, Tom L., Hess, Darrel, 2000. Climate Zones and Types. Physical Geography:

A Landscape Appreciation. Prentice Hall, Upper Saddle River, NJ0-13-020263-0.Meade, R., 1994. Suspended sediments of the modern Amazon and Orinoco rivers.

Quaternary International 21, 29–39.Meybeck, M., 1976. Total mineral dissolved transport by world major rivers. Hydrological

Sciences Bulletin 21, 265–284.Milliman, J.D., Meade, R., 1983. World-wide delivery of river sediments to the oceans.

Journal of Geology 91, 1–22.Milliman, J.D., Syvitski, P.M., 1992. Geomorphic/ tectonic control of sediment discharge

to the ocean: the importance of small mountainous rivers. Journal of Geology 100,525–544.

Milliman, J.D., Farnsworth, K.L., Albertin, Ch., 1999. Flux and fate of fluvial sedimentsleaving large islands in the East Indies. Journal of Sea Research 41, 97–107.

Moore, A., Larkin, P., 2001. Drainage evolution in south-central Africa since the breakup of Gondwana. South African Journal of Geology 104, 47–68.

Moore, A.E., Fenton, P.D. Cotterill, Main, Mike P.L., Williams, Hugh B., 2007. The ZambeziRiver. In: Gupta, A. (Ed.), Large Rivers: Geomorphology and Management. Wileyand Sons, Chicester, Singapore, pp. 293–310.

Nanson, G.C., Rust, B.R., Taylor, G., 1986. Coexistent mud braids and anastomosingchannels in an arid-zone river: Cooper Creek, central Australia. Geology 14,175–178.

Nanson, G.C., Young, R.W., Price, D.M., Rust, B.R., 1988. Stratigraphy, sedimentologyand late-Quaternary chronology of the Channel Country of western Queensland.In: Warner, R.F. (Ed.), Fluvial Geomorphology of Australia. Academic Press, Sydney,pp. 151–175.

Nanson, G.C., Price, D.M., Short, S.A., 1992. Wetting and drying of Australia over thepast 300 ka. Geology 20, 791–794.

Nanson, G.C., Jones, B.G., Price, D.M., 2005. Rivers turned to rock; Late Quaternaryalluvial induration influencing the behaviour and morphology of an anabranchingriver in the Australian monsoon tropics. Geomorphology 70, 398–420.

Nanson, G.C., Price, D.M., Jones, B.G., Maroulis, J.C., Coleman, M., Bowman, H., Cohen,T.J., Pietsch, T.J., Larsen, J.R., 2008. Alluvial evidence for major climate and flow re-gime changes during the middle and late Quaternary in eastern central Australia.Geomorphology 101 (1–2), 109–129.

Nott, J.F., Price, D.M., 1994. Plunge pools and paleoprecipitation. Geology 22,1047–1050.

Nott, J.F., Price, D.M., Bryant, E.A., 1996. A 30,000 year record of extreme floods in trop-ical Australia from relict plunge-pool deposits: implications for future climatechange. Geophysical Research Letters 23 (4), 379–382.

Oliveira, P., de Barreto, A.M.F., Suguio, K., 1999. Late Pleistocene/Holocene climatic andvegetational history of the Brazilian caatinga: the fossil dunes of the middle SãoFrancisco river. Palaeogeography, Palaeoclimatology, Palaeoecology 152 (3–4),319–337.

Overeem, I., Goodbred Jr., S.L., 2005. Numerical modeling of the impact of an en-hanced monsoon on the Ganges-Brahmaputra river system. Abstract Volume,8th International conference on fluvial sedimentology, August 7–12, 2005,Delft, Netherlands.

Overpeck, J., Anderson, D., Trumbore, S., Prell, W., 1996. The southwest Indian mon-soon over the last 18000 years. Climate Dynamics 12, 213–225.

Page, K.J., Nanson, G.C., 1996. Stratigraphic architecture resulting from late Quaternaryevolution of the Riverine Plain, southeastern Australia. Sedimentology 43,927–945.

Page, K.J., Nanson, G.C., Price, D.M., 1996. Chronology of Murrumbidgee Riverpalaeochannels on the Riverine Plain, southeastern Australia. Journal of QuaternaryScience 11, 311–326.

Pal, D.K., Deshpande, S.B., 1987. Characteristics and genesis of minerals in some bench-mark Vertisols of India. Pedologie 37, 259–275.

Phadtare, N.R., 2000. Sharp decrease in summer monsoon strength 4000–3500 cal yrB.P. in the central Higher Himalaya of India based on pollen evidence from alpinepeat. Quaternary Research 53, 122–129.

Potter, P.E., 1978. Petrology and chemistry of modern big river sands. Journal ofGeology 86, 423–449.

Prasad, Sushma, Enzel, Y., 2006. Holocene Paleoclimates of India. Quaternary Research66 (3), 442–453.

Prell, W.L., Kutzbach, J.E., 1987. Monsoon variability over the past 150,000 years.Journal of Geophysical Research 92, 8411–8425.

Rahaman, W., Singh, S.K., Sinha, R., Tandon, S.K., 2009. Climate control on erosion dis-tribution over the Himalaya during the past 100 ka. Geology 37, 559–562.

Ramonell, C., Latrubesse, E., 1991. El loess de la Formación Barranquita: comportamientodel Sistema Eólico Pampeano en la provincia de San Luis, Argentina. Third Meeting,IGCP 281: Quaternary Climates of South America, Spec. Publ., Lima, No. 3, pp. 69–81.

Rasanen, M., Salo, J.S., Jungnert, H., Romero Pitman, L., 1990. Evolution of Western Am-azon lowland relief: impact of Andean Foreland dynamics. Terra Nova 2, 320–332.

Rasanen, M., Neller, R., Salo, J., Jungens, H., 1992. Recent and ancient fluvial depositionsystem in the Amazonian foreland basin Peru. Geological Magazine 129 (3),293–306.

Restrepo, J.D., Kjerfve, B., 2000. Magdalena river: interannual variability (1975–1995)and revised water discharge and sediment load estimates. Journal of Hydrology235, 137–149.

Restrepo, J.D., Zapata, P., Díaz, J.M., Garzón, J., García, C., 2006. Fluvial fluxes into theCaribbean Sea and their impact on coastal ecosystems: the Magdalena River,Colombia. Global and Planetary Change 50, 33–49.

Restrepo, J.D., López, S.A., Restrepo, J.C., 2009. Geomorphic factors controlling sedimentyield in the Andean rivers of Colombia. Latin American Journal of Sedimentologyand Basin Analysis 16, 79–92.

Rigsby, C.A., Hemric, Erin M., Baker, Paul A., 2009. Late Quaternary Paleohydrology ofthe Madre de Dios River, southwestern Amazon Basin, Peru. Geomorphology 113(3–4), 158–172.

RivDIS (Global River Discharge), 2003. Dataset at http://www.eosdid.ornl.gov/daacpages/rivdis.html.

Rossetti, D.F., Toledo, P.M., Moraes-Santos, H.M., Santos Jr., A.E.A., 2004. Reconstructinghabitats in Central Amazonia using megafauna, sedimentology, radiocarbon andisotope analysis. Quaternary Research 61, 289–300.

Rossetti, D.F., Toledo, P.M., Góes, A.M., 2005. New geological framework for WesternAmazonia (Brazil) and implications for biogeography and evolution. QuaternaryResearch 63, 78–89.

Roy, N.G., Sinha, R., Gibling, M.R., 2011. Aggradation, incision and interfluve flooding inthe Ganga Valley over the past 100,000 years: testing the influence of monsoonalprecipitation. Palaeogeography, Palaeoclimatology, Palaeoecology. http://dx.doi.org/10.1016/j.palaeo.2011.08.012.

Runge, J., 2001. Landschaftsgenese und Palaoklima in Zentralafrika. Relief, Boden,Palaoklima 17, 1–294.

Runge, J., 2002. Holocene landscape history and palaeohydrology evidenced by stablecarbon isotope (δ13C) analysis of alluvial sediments in the Mbari valley (5°N/23°E),Central African Republic. Catena 48, 67–87.

Runge, J., 2007. Congo River. In: Gupta, A. (Ed.), Large Rivers: Geomorphology andManagement. Wiley and Sons, Chicester, Singapore, pp. 293–310.

Runge, J., Tchamié, T., 2000. Inselberge, Rumpfflächen und Sedimente kleiner Einzugsgebietein Nord-Togo: Altersstellung und morphodynamische Landschaftsgeschichte.Zentralblatt fur Geologie und Palaontologie, Teil 1 5/6, 497–508.

Rust, B.R., Nanson, G.C., 1986. Contemporary and palaeochannel patterns and the lateQuaternary stratigraphy of Cooper Creek, southwest Queensland, Australia. EarthSurface Processes and Landforms 11, 581–590.

Sarma, J.N., 2005. Fluvial process and morphology of the Brahmaputra River in Assam,India. Geomorphology 70, 226–256.

Sarma, J.N., Phukan, M.K., 2004. Origin and some geomorphological changes of MajuliIsland of the Brahmaputra River in Assam. India, Geomorphology 60, 1–19.

Sarma, J.N., Phukan, M.K., 2006. Bank erosion and bankline migration of the riverBrahmaputra in Assam, India, during the twentieth century. Journal of GeologicalSociety of India 68, 1023–1036.

Sharma, S., Joachimski, M., Sharma, M., Tobschall, H.J., Singh, I.B., Sharma, C.,Chauhan, M.S., Morgenroth, G., 2004. Late glacial and Holocene environmentalchanges in Ganga plain Northern India. Quaternary Science Reviews 23 (1–2),145–159.

Shaw, A., Thomas, D.S.G., 1988. Lake Capirivi: a late Quaternary link between the Zambeziand middle Kalahari drainage. Zeitschrift für Geomorphologie 32, 329–337.

Shaw, A., Thomas, D.S.G., 1992. Geomorphology, sedimentation and tectonics in theKalahari Rift. Israel Journal of Earth Sciences 41, 87–94.

Singh, S.K., 2006. Spatial variability in erosion in the Brahmaputra basin: causes andimpacts. Current Science 90, 1272–1276.

Singh, V., Tandon, S.K., 2007. Evidence and consequences of tilting of two alluvial fansin the Pinjaur dun, Northwestern Himalayan Foothills. Quaternary International159, 21–31.

Singh, H., Parkash, B., Gohain, K., 1993. Facies analysis of the Kosi megafan deposits.Sedimentary Geology 85, 87–113.

Singh, S.K., Kumar, A., Lanord, C.F., 2006. Sr and 87Sr/86Sr in waters and sediments ofthe Brahmaputra river system: silicate weathering, CO2 consumption and Sr flux.Chemical Geology 234, 308–320.

Singh, S.K., Rai, S.K., Krishnaswami, S., 2008. Sr and Nd isotopes in river sediments fromthe Ganga Basin: sediment provenance and spatial variability in physical erosion.Journal of Geophysical Research 113 (F03006), 1–18.

Sinha, R., 1995. Sedimentology of Quaternary alluvial deposits of the Gandak–Kosiinterfan, North Bihar plains. Journal of Geological Society of India 46 (5), 521–532.

Sinha, R., Friend, P.F., 1994. River systems and their sediment influx, Indo-Gangeticplains, Northern Bihar, India. Sedimentology 41, 825–845.

Sinha, R., Sarkar, S., 2009. Climate-induced variability in the Late Pleistocene–Holocenefluvial and fluvio-deltaic successions in the Ganga plains, India. Geomorphology113, 173–188.

Sinha, R., Friend, P.F., Switsur, V.R., 1996. Radiocarbon dating and sedimentation ratesof Holocene alluvial sediments of northern Bihar plains, India. Geological Magazine133 (1), 85–90.

Sinha, R., Jain, V., Prasad, Babu G., Ghosh, S., 2005a. Geomorphic characterization anddiversity of the fluvial systems of the Gangetic plains. Geomorphology 70,207–225.


http://www.eosdid.ornl.gov/daacpages/rivdis.html

http://www.eosdid.ornl.gov/daacpages/rivdis.html



Sinha, R., Gibling, M.R., Tandon, S.K., Jain, V., Dasgupta, A.S., 2005b. Quaternary stratigra-phy and sedimentology of the Kotra section on the Betwa River, Southern Gangeticplains, Uttar Pradesh. Journal of the Geological Society of India 65, 441–450.

Sinha, R., Tandon, S.K., Gibling, M.R., Bhattacharjee, P.S., Dasgupta, A.S., 2005c. LateQuaternary geology and alluvial stratigraphy of the Ganga basin. Himalayan Geology26 (1), 223–240.

Sinha, R., Gibling, M.R., Jain, V., Tandon, S.K., 2005d. Sedimentology and avulsion pat-terns of the anabranching Baghmati river in the Himalayan foreland basin, India.In: Blum, M., Marriott, S. (Eds.), Fluvial Sedimentology: Special publication of theInternational Association of Sedimentologists, 35, pp. 181–196.

Sinha, R., Tandon, S.K., Sanyal, P., Gibling, M.R., Stuben, D., Berner, Zsolt, Ghazanfari, P.,2006. Calcretes from a monsoon-dominated Late Quaternary interfluve in theSouthern Ganga Plains: isotopic data and palaeoenvironmental implications.Palaeogeography, Palaeoclimatology, Palaeoecology 242 (3–4), 214–239.

Sinha, R., Bhattacharjee, P., Sangode, S.J., Gibling, M.R., Tandon, S.K., Jain, M., Godfrey,D., 2007a. Valley and interfluve sediments in the southern Ganga plains, India:exploring facies and magnetic signatures. Sedimentary Geology 201, 386–411.

Sinha, R., Kumar, R., Sinha, S., Tandon, S.K., Gibling, M.R., 2007b. Late Cenozoic fluvialsuccessions in India: an overview and synthesis. Quaternary Science Reviews 26,2801–2822.

Sinha, R., Gibling, M.R., Kettanah, Y., Tandon, S.K., Bhattacharjee, P.S., Dasgupta, A.S.,Ghazanfari, P., 2009. Craton-derived alluvium as a major sediment source in theHimalayan Foreland Basin of India. GSA Bulletin 121 (11/12), 1596–1610.

Srivastava, P., Parkash, B., Sehgal, J.L., Kumar, S., 1994. Role of neotectonics and climatein development of the Holocene geomorphology and soils of the Gangetic Plainsbetween the Ramganga and Rapti rivers. Sedimentary Geology 94, 129–151.

Srivastava, P., Rajak, M.K., Sinha, R., Pal, D.K., Bhattacharyya, T., 2010. A high resolutionmicromorphological record of the Late Quaternary paleosols from Ganga-YamunaInterfluve: stratigraphic and paleoclimatic implications. Quaternary International227, 127–142.

Srivastava, P., Parkash, B., Pal, D.K., 1998. Clayminerals in soils as evidence of Holocene cli-matic change, central Indo-Gangetic Plains, north-central India. Quaternary Research50, 230–239.

Stallibras, E., 1887. Deep sea sounding in connection with sub-marine topography.Journal of the Society of Telegraph Engineers 16, 479–511.

Staubwasser, M., Weiss, H., 2006. Holocene climate and cultural evolution in lateprehistoric–early historic West Asia. Quaternary Research 66, 372–387.

Stevaux, J.C., 1994. The Upper Parana river (Brazil): geomorphology, sedimentologyand paleoclimatology. Quaternary International 21, 143–161.

Stevaux, J.C., 2000. Climatic events during the late Pleistocene and Holocene in theUpper Parana River: correlation with NE Argentina and South-Central Brazil.Quaternary International 72, 73–85.

Stevaux, J.C., dos Santos, M., 1998. Palaeohydrological changes in the Upper Paran´ariver, Brazil, during the late Quaternary: a facies approach. In: Benito, G., Baker, V.,Gregory, K.J. (Eds.), Palaeohydrology and Environmental Change. Wiley, Chichester,pp. 273–285.

Suresh, N., Bagati, T.N., Kumar, R., Thakur, V.C., 2007. Evolution of Quaternary alluvialfans and terraces in the intermontane Pinjaur Dun, Sub-Himalaya, NW India:interaction between tectonics and climate change. Sedimentology 54, 809–833.

Tandon, S.K., Sinha, R., 2007. Geology of large rivers. In: Gupta, A. (Ed.), Large Rivers:Geomorphology and Management. Wiley, Chichester, pp. 7–28.

Tandon, S.K., Gibling, M.R., Sinha, R., Singh, V., Ghazanfari, P., Dasgupta, A., Jain, M., Jain,V., 2006. Alluvial valleys of the Gangetic Plains, India: causes and timing of incision.Incised Valleys in Time and Space: SEPM Special Publication, 85, pp. 15–35.

Thamban,M., Purnachandra Rao, V., Schneider, R.R., Grootes, P.M., 2001. Glacial to Holocenefluctuations in hydrography and productivity along the southwestern continental mar-gin of India. Palaeogeography, Palaeoclimatology, Palaeoecology 165, 113–127.

Thomas, D.S.G., Shaw, T., 1991. The Kalahari Environment. Cambridge University Press,Cambridge.

Valente, C.R., Latrubesse, E.M., 2011. Fluvial archive of peculiar avulsive fluvial patternsin the largest Quaternary intracratonic basin of tropical South America: TheBananal Basin, Central-Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology.http://dx.doi.org/10.1016/j.palaeo.2011.10.002.

Van Campo, E., Gasse, F., 1993. Pollen- and diatom-inferred climatic and hydrologicalchanges in Sumxi Co Basin (Western Tibet) since 13,000 yr B.P. Quaternary Re-search 39, 300–313.

Van der Hammen, T., Absy, M.L., 1994. Amazonia during the last glacial.Palaeogeography, Palaeoclimatology, Palaeoecology 109 (2–4), 247–261.

van der Hammen, T., Duivenvoorden, J.F., Lips, J.M., Espejo, N., Urrego, L., 1992. The lateQuaternary of the middle Caquet´a river area (Colombian Amazonia). Journal ofQuaternary Science 7, 45–55.

van Zinderen Bakker, E.M., Clark, J.D., 1962. Pleistocene climates and cultures in North-Eastern Angola. Nature 196, 639–642.

Walker, N.J., 1990. Zimbabwe at 18,000 B.P. In: Gamble, C., Soffer, O. (Eds.), The worldat 18,000 BP: v.2, Low Latitudes. Unwin Hyman, London, pp. 206–213.

Walling, D.E., 1996. Hydrology and rivers. In: Adams, W.M., Goudie, A.S., Orme, A.R.(Eds.), The Physical Geography of Africa. Oxford University Press, Oxford,pp. 103–121.

Wellington, J., 1955. Southern Africa: a geographical study. Physical Geography, vol. 1.Cambridge University Press, Cambridge.

Wesnousky, S.G., Kumar, S., Mohindra, R., Thakur, V.C., 1999. Uplift and convergencealong the Himalayan Frontal Thrust of India. Tectonics 18 (6), 967–976.

Wohl, E.E., 2007.Hydrology andDischarge. In: Gupta, A. (Ed.), Large Rivers: Geomorphologyand Management. Wiley and Sons, Chicester, Singapore, pp. 31–44.

Xue, Z., Liu, J.P., Qian, G., 2011. Changes in hydrology and sediment delivery of theMekong River in the last 50 years: connection to damming, monsoon, and ENSO.Earth Surface Processes and Landforms 36, 296–308.

Yadav, G.S., Dasgupta, A.S., Sinha, R., Lal, T., Srivastava, K.M., Singh, S.K., 2010. Shallowsub-surface stratigraphy of interfuves inferred from vertical electric soundings inwestern Ganga plains. India, Quaternary International 227, 104–115.

Zeese, R., 1991. Fluviale Geomorphodynamik im Quartär Zentral- und Nordostnigerias.Freiburger Geographische Hefte 33, 199–208.

Zeese, r, 1996. Oberflächenformen und Substrate in Zentral- und Nordostnigeria. EinBeitrag zur Landschaftsgeschichte.Berichte aus der Geowissenschaft, Habil-SchriftUniv. Köln. Shaker Verlag, Aachen, pp. 1–195.


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