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Journal of Archaeological Science 35 (2008) 3057–3071

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Journal of Archaeological Science

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The devolution of mudbrick: ethnoarchaeology of abandonedearthen dwellings in the Bolivian Andes

Melissa Goodman-Elgar*

Department of Anthropology, Washington State University, College Hall, Pullman, WA 99164-4910, USA

a r t i c l e i n f o

Article history:Received 4 February 2008Received in revised form 9 May 2008Accepted 12 May 2008

Keywords:Mudbrick (adobe)EthnoarchaeologySite formationGeoarchaeologyMicromorphologyAndes

* Tel.: þ1 509 335 4807; fax: þ1 509 335 3999.E-mail address: mage@wsu.edu

0305-4403/$ – see front matter � 2008 Elsevier Ltd.doi:10.1016/j.jas.2008.05.015

a b s t r a c t

This ethno-geoarchaeological study considers the formation of archaeological deposits through a studyof abandoned contemporary mudbrick structures on the Taraco Peninsula, Bolivia. The study site wasa domestic compound with rooms for different functions that had been abandoned for over 50 years.Structures were in variable states of decay in terms of roof cover, walling integrity and abandonment fills.Geoarchaeological samples were collected from intact and weathered adobes, earthen hearths, mudplaster, and flooring. Adobes and mud plaster were locally derived from topsoil containing archaeologicalsediments with added gravel and plant temper. This study found a relatively light anthropogenicsignature for decayed earthen houses.Rising damp exfoliated mud plaster despite un-mortared cobble wall foundations. Organic matter fromroof fall attracted thriving soil faunal populations, which furthered site destruction through bioturbation,particularly packed earth floors. Sediments derived from weathered mudbrick retained little evidence ofprior use as construction materials unless exposed to heat. Sediments exposed to high-temperaturesproduced the most distinctive rubified features but were structurally compromised. Isolated thermalfeatures from decomposed adobe would not be distinguishable from other hearth types. Adobes exposedto low or moderate heat had few distinctive features in thin section. Intact adobes and floors that werenot exposed to heat have fewer pores than natural sediments and distinctive grass inclusions. Theseadobes disarticulated into loose sediments when exposed to weathering. Adobe fall outside the crum-bling structures blended into topsoil.This study sheds light on functional attributes of pre-Columbian construction practices. Thick, fine-textured sterile flooring is commonly encountered in the study region. This would control bioturbationfrom roof fall in a previous occupation enabling reconstruction in abandoned dwellings. In contrast to thecontemporary dwelling, prehistoric mortared cobble foundations would resist rising damp. Cobbleswithout mortar may relate more to design and construction than durability. These contrasts betweencontemporary and prehistory construction practices reflect differences in the design, construction costsand functional use-life of adobe structures.

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1. Introduction

Mudbrick is a common prehistoric building material and widelydistributed in arid and semi-arid lands where other constructionmaterials are scarce. Earthen buildings are vulnerable to de-struction by weathering, especially by wind and water erosion. Thereconstruction and interpretation of decayed mudbrick structuresgenerally relies on models of construction methods encountered inwell-preserved archaeological settings (e.g. Near Eastern tells),‘‘building with earth’’ manuals (e.g. McHenry, 1984; Middleton,1953), conservation studies (e.g. Brown and Clifton, 1978; Brownet al., 1979; Clifton and Davis, 1978) and from observations of

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contemporary structures. This study assessed abandoned contem-porary mudbrick dwellings in order to define pathways of struc-tural decay and to seek stable signatures of earthen constructionmaterials in Andean prehistory.

Mudbricks have a long history in South America including use inmassive monuments such as the Huacas del Sol y de la Luna on thePeruvian coast. The hyperarid west coast promotes outstandingpreservation permitting studies of individual bricks (e.g. Cavallaroand Shimada, 1988) but has produced few geoarchaeologicalstudies. In the semi-arid Lake Titicaca Basin, earthen buildings aresubjected to harsher annual cycles of weathering by rain, frost andbiotic agents. Intact mudbrick is rarely encountered above groundbut may be recovered in buried or tell-like contexts (e.g. Bermann,1994; Hastorf, 1999). Architectural reconstruction is limited by thefrequent absence of intact adobes.

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Little systematic research has been directed towards the pro-cesses and speed with which adobes decay in the Andes. De-terioration of adobe buildings in the Atacama Desert, Chile wasassociated with rainfall erosion, rising damp and wood rot (Schifferet al., 1987). Rainfall erosion removed surface material and washproduces sedimentary structures. Rising damp exfoliates wall baseswhile wood rot causes roof collapse. Other postulated processes ofadobe structural disintegration included plant growth, aeolianaction, catastrophic processes and scavenging.

In West Africa, McIntosh (1974, 1977) found that earthenstructures follow predictable patterns of decay including slow ex-terior wall wash, rainsplash derived wall undercutting, salt exfoli-ation, slow interior accumulation from use, and rapid wall collapseafter roof fall which preserves wall stumps. In arid settings, Butzer(1982: pp. 87–97) characterizes secondary mudbrick tell sedimentsas organic refuse (e.g. hearths, tells), wall collapse, water-lain de-posits, soil formation processes, and aeolian sediment as well ascharacteristics of activity areas (e.g. floors, roads and unroofedspaces). Rosen (1986: p. 12) adds alluvial deposits from tell washand illustrates typical unequal modification of tell slopes. She alsoemphasizes the destructive action of water on mudbrick (humidity,rainfall and rising groundwater), bioturbation (root, burrowingfauna and birds) and aeolian action (Rosen, 1986, pp. 10–11).

This study aimed to define the primary processes and tempo ofadobe decay on the Taraco Peninsula, Bolivia under high elevation,semi-arid conditions (Fig. 1). An abandoned contemporary do-mestic compound was studied to assess structural features andsediment products from decayed buildings. Central aims were toascertain if ‘‘adobe melt’’, a category commonly assigned toarchaeological deposits, produces a sedimentological signature,and to seek stable signatures of use areas.

Fig. 1. The Taraco Peninsula, L

The Taraco Peninsula has a long history of settled occupation.The Chiripa culture emerged during the Formative by 1500 B.C. andlasted until it was subsumed into the Tiwanaku state (Tiwanaku I,250 B.C.–A.D. 300; Whitehead, 1999; Bandy, 2001). Populationgrew throughout the Formative from scattered villages into nu-cleated towns with associated religious sites, including the ChiripaMontıculo described below (Hastorf, 1999, 2003; Bandy, 2004). Thisethnoarchaeological study was conducted in tandem with the TAP’sexcavation of the adjacent archaeological site of Kala Uyuni (Fig. 1).A freshwater spring appears to have attracted both ancient andcontemporary settlement of the site.

Early Taraco prehistoric architecture is best represented by theChiripa Montıculo site (Fig. 1), a mudbrick tell of superimposedhouse foundations with associated living floors and intact adobesthat has design features suggesting religious use (Chavez, 1988;Hastorf, 1999). In a preliminary micromorphological study, Mon-tıculo adobe was found to have a fine texture, dense structure andplant pseudomorphs (Goodman (Elgar), 1999). The compositionand microstructure of this mudbrick are similar to Near Easternmudbrick (Matthews et al., 1996), making studies of Near Easternsites appropriate models for interpretation of this site (e.g. Rosen,1986). However, subsequent excavations over the last decade by theTaraco Archaeological Project (TAP) revealed depositional settingsquite unlike Chiripa. Excavations have recovered shallow singleoccupations, structures with cobble foundations but no intactwalling, and deeply stratified deposits with unclear architecturalplans (e.g. Bandy and Hastorf, 2007; Hastorf, 1999, 2003). Severalstratified sites are characterized by thick imported fine-texturedfloors, interspersed with unconsolidated organic- and artifact-richfills. These sequences occur both where stone foundations arerecovered, such as Kala Uyuni (Bandy and Hastorf, 2007) and

ake Titicaca Basin, Bolivia.

Fig. 2. Copralabra Pata in 2003 (1 m scale).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–3071 3059

where no foundations were detected, such as Santiago (Hastorf,1999).

Architectural floor plans from the site are derived by mappingcobble foundations and floor deposits in order to define enclosedareas and assign interior/exterior status, which is used for inter-preting botanical, faunal and artifact assemblages. In the absence ofclear architectural plans, site reconstruction relies on hypotheticaldesigns. For instance, the Llusco site is characterized by a largecentral enclosure denoted by a line of stones enclosing a plastered

Fig. 3. Plan of Copralabra Pa

surface under a thin overburden (Paz Sorıa, 1999). Despite goodpreservation of the plastered surface, no walling or intact mud-bricks were found. Nevertheless, a hypothetical structure wasproposed from the floor plan, ‘‘Presuming the presence of an adobesuperstructure, the Llusco structure would have been an impressiveconstruction.almost 150 meters in size’’ (Stanish, 2003: p. 117).This suggestion is difficult to test in the absence of remains of theadobe superstructure or models from which to reconstruct thecollapsed adobe structure from excavated sediments.

2. The physical setting

The Taraco Peninsula, Bolivia extends into Lake Huinaymarca,the southern part of Lake Titicaca (Fig. 1). The Lake Titicaca Basinwas shaped by orogenies and cycles of tectonic uplift, glaciationand fluvial activity to form the modern topography (Lavenu, 1992).Taraco Peninsula surface geology is dominated by the TaracoFormation of Pliocene conglomerates, which form a disconformityover an older Kollu Kollu Formation composed of conglomerates,sandstones and clayey deposits (Argollo et al., 1996). Theseunconsolidated formations appear as well-sorted, graded beds ofsilty clay to cobble texture where exposed in downcut waterwaysand uplands. The clayey deposits include smectites and kaolinite,which vary widely in color and purity. Contemporary sedimenta-tion includes sands of volcanic, Devonian, Carboniferous and

ta domestic compound.

Table 1Composition and manufacture of common earthen construction materials

Construction material Mudbrick Adobe Pise de terre tapialera Mortar, mud plaster barro, yeso Beaten earth piso de tierra

Texture Highly variable, for example:gravel (3–37%), coarse sand(3–37%), fine sand (16–45%),silt 10–49%), clay (1–25%).a

Can be coarse, i.e. 30–35%silt/clay and 65–70% sand/gravelb

Generally finer than adobe, for example:gravel (0–13%), coarse sand (5–21%), finesand (21–50%), clay 10–30%c

In situ earth cleared of large coarseclasts and organics.

Inclusions Gravel, Clay plant temper Gravel Clay, plant temper (may be ground), recipeadditions.d

None

Manufacture Sediment, inclusions mixedmechanically with water tothick slurry.e Put into moldor left in a pit and cut.Air dried.

Mould built, sediment and enoughwater just to bind are addedwithout temper. Dried in situ.

Clay:temper balanced to prevent cracking.Sediment mixed with water to desiredconsistency (i.e. paste, thin slurry).Applied wet.

Water sprinkled on the surface, beatenwith a wet cloth and let dry. Severalcycles produce a hard earthen floor.

a From 55 adobes from historic US Southwest buildings (McHenry, 1984, Table 3.1).b Middleton (1953, p. 27).c From six mud plaster samples from historic US Southwest buildings (McHenry, 1984, Table 3.2).d Boivin (2000), Middleton (1953, p. 64).e Goldberg and Macphail (2006, p. 282).

Table 2Thin section sample summary

Sample # Context Observations

03KUCP1 New house buried adobe Clustered subrounded gravel (ca. 20%) in two partly laminated fabrics, one darker and moreconsolidated than the other.

03KUCP2 New house buried mud plaster Largely consolidated crumbs with areas of disturbance03KUCP3 Old kitchen west wall adobe Very dense silt with well dispersed pea gravel and pebbles03KUCP4 Old kitchen outside adobe slump Spongy with considerable bioturbation03KUCP5 New kitchen fire black west wall adobe Spongy, coarse inclusions, darker groundmass03KUCP6 New kitchen SW hearth adobe Appears as two fabrics; light fabric suggests redox features around larger pores from heat.03KUCP7 New kitchen SE hearth adobe Dark spongy silty loam with a light-colored interior domain, suggesting redox features from heat.03KUCP8 New kitchen NE hearth burnt surface 8 Microstrata with coloration related to combustion and thermal alteration; partly sorted gravel

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Table 3Thin section descriptions

Sample #and fabric

u-Structure b-Fabric c/f Relativedistribution

Gravel % Clayfeatures

Plants Fauna Bioturbation Comments

03KUCP1fabric 1(dark)

Massive with spongydomains; ca. 5% SPV,1% plane, 10% vugh/pore

Weak dotted togranostriated

Enaulic, monic 20 <1 Grano-coats,some in bone

<1% Root, seed;1% charcoal

Mammal (1%); fish(<1%) some burnt;coprolite fragments

Root pipes, someoriented rootfragments; infilledchannels

Laminated fabrics suggestpoor mixing; inheritedmidden in Fabric 1

03KUCP1fabric 2(light)

Spongy; 18% vugh Granostriated,stipple-speckled

Enaulic–chitonic 5 3% Coarse plant tissue;<1% charcoal

Abundant, often parallelplant tissue temper; chambersuggests trapped air; opalsuggests ash.

03KUCP2fabric 1

Crumb to massive; 5%plane/compoundpacking voids, 8%chamber, 2% vughs& pores

Crystallitic,porostriated tostipple-speckled

Gerfuric 4 <1 Grano-coats,1% nodules

<1% Phytoliths in ash;1-2% charcoal

<1% Fish andmammal bonefragments

Mite dung Fine than associated adobebut coarse for plaster

03KUCP3fabric 1

Spongy to massive;1% chamber, 3% vugh,2% channel

Stipple-speckledto granostriated

Chitonic, single-porphyric

25 <1% Nodules 2% Coarse plant tissue,low birefringence;<1% charcoal

<1 Fish, eggshell,coprolite

03KUCP4fabric 1

Spongy; 15% vughs, 5%channels, 7% chambers

Stipple-speckledto granostriated

Chitonic, single-porphyric

5 <1 Silt sized nodules 5% Coarse tissue;<1% charcoal

<1% Weathered fishbone fragments

Abundant root &faunal channels,organic coats,mite dung

No consolidation typical ofadobe; as topsoil

03KUCP5(adobe)

Massive with spongydomains; 3% chamber,5% vughs/pores; 1% plane

Stipple-speckled Single-porphyric 10 <1 Cracked nodules 5% Coarse organics, lowbirefringence; <1%pseudocarbon; <1%seeds; ca. 3% smallfragments ingroundmass;<1% charcoal

1% Burnt/rubified fishand mammal bonefragments

Boundary defined by crackand oriented grains; <1%weathered ceramic

03KUCP5(mudplaster)

Massive; 2% SPV, 1% plane Stipple-speckledto granostriated

Single-porphyric <1 Nodules 3% Small tissuefragments; <1% charcoal

<1% Fish bone Very similar to adobe butless temper, no gravel

03KUCP6 Massive with spongydomains

Dotted Double porphyric 3 <1% Cracked nodules 5% Coarse tissue withlow birefringence,some rubified; <1%phytoliths; <1%((pseudo)charcoal

<1% Pigmented,cracked, fish bone

Isolated faunalchannels

5% Weathered ceramic

03KUCP7(dark)

Spongy but dense;<1% channel, 10% vugh/pore

Stipple-speckled Single- to double-porphyric

8 <1% Rubified, cracked,low birefringence

<1% Phytoliths, <1%coarse tissue;<1% seed; 1% charcoal

<1% Rubified fish bone& eggshell fragments

Rubified groundmass

03KUCP7(light)

Spongy; 15% vugh/pore Stipple-speckled Single- to double-porphyric

5 <1% Nodules; highbirefringence

<1% Tissue; <1%charcoal

<1% Fish bone Appears to be a largeredox feature

03KUCP8stratum 1

Massive 1% SPV Granostriated Enaulic 1 <1% Dusty clay <1% Tissue, 1%charcoal

1–2% Dung fragments Infilling; sharp boundary

03KUCP8stratum 2

Massive, 2% vertical crack Granostriated Enaulic 1 1% Brown tissue;<1% charcoal

Laminated silts, sharpboundary; hearthdampening?

03KUCP8stratum 3

Spongy; 10% chamber,25% CPV

Granostriated,low birefringence

Gerfuric–chitonic 35 5% Charcoal;<1% phytoliths

Combustion debris;zigzag boundary

03KUCP8stratum 4

Granular; 5% plane10% chamber

Mosaic- toparallel-striated,bright

Single-porphyric 15 <1% Nodules 1–2% Charcoal,<1% isolated phytoliths

Burning surface (highheat); rubified size-sortedpeds; convoluted boundary

03KUCP8stratum 5

Massive 5% chamber,2% channel, 5% vugh/pore

Stipple-speckled Single-porphyricto chitonic

<1% Dustyclay coats

1–2% Tissue Not rubified but somethermal features sediment;sharp boundary with gravel

03KUCP8stratum 6

Granular to crumb;11% vugh/pore; 1% SPV

Stipple- tomosaic-speckled

Enaulic to chitonicto single-porphyric

60 <1% Dung Organic enrichment,partial sorting ofgroundmass

Subhorizontal gravel bandwith bioturbated matrix

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Fig. 4. New house, excavations were conducted in the foreground right where nostanding walls remained (50 cm scale).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–30713062

Cretaceous formation origin (Rodrigo and Wirrmann, 1992). Con-temporary topsoils are primarily silty fine sand similar to loess withinclusions of subrounded clasts from eroded Taraco Formationdeposits.

Despite fluctuations such as El Nin00o Southern Oscillation, re-

gional climate patterns appear to have stabilized by ca. 2000–1500B.P. towards a wetter climate similar to present conditions (Abbottet al., 1997; Binford and Kolata, 1996; Cross et al., 2000; Rowe et al.,2003; Tapia et al., 2003). The modern surface of Lake Titicaca is about

Fig. 5. New house mudbrick: (A) 5� 7 cm thin section showing very coarse texture, two fab(ppl); (D, E) microlaminations; (F) fine-textured dark fabric; (G) coarse-textured light fabri

3810 masl with an annual fluctuation of �3.2 m (Cross et al., 2000).Climate in the Lake Titicaca catchment is modified by evaporationfrom the vast lake system. Temperature averages 8 �C with a warmerwet season from December to March and a colder dry season fromMay to August (Roche et al., 1992). Frost may occur throughout theyear and night frosts are common in the dry season. Despite annualaverage precipitation of ca. 750 mm, the evapotranspirationpotential is generally higher than rainfall and soils regularly dry out(Binford and Kolata, 1996). Thus, weathering conditions for adobehousing include frequent wet–dry and freeze–thaw cycles withsignificant diurnal temperature fluctuations, which have been foundto expedite earthen wall decay (McIntosh, 1974).

3. The ethnoarchaeological study

This study focused on an abandoned domestic compound,Copralabra Pata, composed of rooms arranged on two sides ofa quadralinear patio (Figs. 2 and 3). The current owners lived out-side the community and their nephew, who lives less than 100 mfrom the site, acted as informant. Videotaped interviews in Spanishaddressed local demographics, house construction, use of space,abandonment and decomposition of structures. Standing featureswere planned and excavation concentrated on two rooms identi-fied as kitchens and a structure that had collapsed. Cooking, humanhabitation, animal habitation and storage were spatially differen-tiated on site (Fig. 3).

The compound was constructed primarily of earthen construc-tion materials including adobe, tapialera, mortar, wall plaster andbeaten earth flooring. Typical manufacturing sequences are

rics and mammal bone below large gravel; (B) plant inclusions (ppl); (C) possible dungc.

Fig. 6. New house mud plaster: (A) 5�7 cm thin section the crack pattern is from drying the sample; (B, C) dominant organic-rich silty fabric (ppl, xpl); (D) coarse plant inclusions(ppl); (E) ash ped (ppl); (F, G) ash ped higher magnification, note articulated phytoliths in center of F (ppl, xpl).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–3071 3063

described in Table 1. Additional construction materials includedcobble foundations, eucalyptus beams, tortora reed (Schoenplectustotora) roofing and ichu grass (Stipa ichu) temper. All materials weregathered or prepared locally. In the past, trees other than euca-lyptus would have been available for roofing (Paduano et al., 2003).Copralabra Pata is adjacent to a Formative site and mudbricksproduced for it contain archaeological materials. Siliceous ichugrass from the lakeshore was reportedly used as temper for mud-brick and plaster but not in tapialera walling. Packed earth flooringwas identified by texture in the absence of a clear stratigraphicsignature.

Two construction and occupation phases were reported forCopralabra Pata. In 1918, the ‘‘old house’’ and ‘‘old kitchen’’ wereconstructed and occupied by a family of three until the 1950s whenthey abandoned the site. The compound was reoccupied in 1963 bya family of three who added the ‘‘new house’’ and ‘‘new kitchen’’and resided there until 1973. The site was then used secondarily foranimals and storage. The new kitchen and new house abut a roomcurrently used as a storeroom, which was not investigated. The newhouse was reportedly abandoned after hail damage not long afterconstruction. The north end of the room was said to extend beyondthe current extent of the wall. Several smaller buildings around thepatio were identified as pens for various animals (Fig. 3). The pe-rimeter wall, store rooms and chicken coop were made of tapialeratopped with mudbricks. Apart from small garbage dumps withinroof fall, midden was absent from the site and it was reported thathousehold waste was used as fertilizer off-site.

Surface vegetation and large debris was cleared before sam-pling. The kitchens were excavated following hearth features. In the

new house, two 1�1 m units were excavated to reveal buried wallfoundations. In total, 16 block micromorphology and 19 bulk sam-ples for geoarchaeological, faunal and botanical analyses werecollected. Eight thin sections are considered here including fiveadobes with different degrees of thermal exposure, two mudplaster samples, one burnt floor and a sample of external adobeslump (Tables 2 and 3).

The focus of this study was on thin sections in order to ascertainthe composition of construction materials and to identify stablefeatures associated with the use-life of the structures. Thin sectionswere made by Spectrum Petrographics (Vancouver, WA) and ana-lyzed on a Leica DMPL petrographic microscope following Stoopsand Vepraskas (2003) using a Motic 2000 image capture system.

4. Excavations and geoarchaeological results

4.1. New house

The new house was roofless with much of the wall area missingwhen excavated. The standing walls were approximately 2 m highwhere adjacent the storeroom and tapered down to the groundsurface (Fig. 4). There was little adobe rubble in the house interiorand bricks found in the pigpen, the east perimeter wall and a corralappear to derive from this structure. In 2003, the northernboundary was delimited by post-occupation features and the housefoundations were buried. The house interior contained weedyvegetation, recently burnt garbage and tortora reeds, suggestinga planned re-roofing event that never occurred.

Fig. 7. New kitchen after cleaning. Note the soot pattern, the room was exposed at leftand vulnerable to weathering. Sample KUCP5 was taken below the window top leftand KUCP8 was taken from the bottom right corner before this photograph was taken(20 cm scale).

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The buried north wall was exposed in two 1�1 m units exca-vated to the north of the standing walls. Removal of the topsoilrevealed the exterior edge of a wall running east–west with intactadobes and mud plaster. The internal corner contained adobe wallfall over very fragile laminated deposits suggesting wall wash overa compact beaten earth floor. Potsherds, plastic and metal inclusionswere found in the fill over the floor. Under the compacted floor wasa pebbly sterile soil. No bioturbation was observed in this area andpreservation was good. The exterior of the wall was less well definedand one adobe was out of alignment. Aggregated wall fall wasnot identified and the sediment surrounding the wall was indis-tinguishable from topsoil. This adobe slump accumulated approxi-mately 5 cm above the patio level.

A buried adobe (03KUCP1) had a very coarse texture, includingabundant subrounded gravel, with coarse plant and dung in-clusions (Fig. 5A–C). The brick was poorly homogenized with twodistinct microfabrics that were roughly laminated (Fig. 5F, G). Or-ganic-rich microlaminations further indicate incomplete mixing(Fig. 5D, E).

Buried mud plaster was sampled parallel to the wall surface(03KUCP2, Fig. 6A) and had a considerably finer texture than theadobe but still included pea gravel, plant temper and ash (Fig. 6B–F), and therefore was coarse for interior surfacing. Peds were densebut the plaster was brittle and fractured during drying (Fig. 6A)suggesting poor long-term resilience to weathering.

4.2. New kitchen

The new kitchen walls were largely intact and part of the tortoraand ichu roof was in place. The walls adjacent to the doorway areoffset by approximately 20 cm with several different adobe typessuggesting rebuilding. The southwest exterior corner had a grayadobe foundation that extends beyond the wall perimeter and maybe remains of the old house. The lower portion of the walls wasconstructed of rocky, reddish-brown adobes. The rest of the easternwall is composed of gray mudbrick of a finer texture as was thenortheast wall suggesting a similar origin.

The new kitchen interior is covered in a coarse mud plaster withvisible grass temper, which was also used to form three smallshelves (Fig. 7). The room interior was covered by roof fall andcontemporary burnt garbage, which supported thriving colonies ofinsects including large and small beetles, caterpillars and beetlelarvae. Spiders and crawling insects lived between loose adobes inthe walls. Much of the interior was soot blackened but not burnt.Mud plaster was exfoliating soot-black mud plaster from the baseof the walls revealing light-yellow staining on the lower adobeswith reddish mudbrick.

A mudbrick sample (03KUCP5) from the west wall below thewindow was processed horizontally through the mudbrick andsurface mud plaster (Fig. 8). The division between mud plaster andmudbrick was subtle in thin section and indicated primarily byplanar voids parallel to the wall surface and oriented grains. Thegroundmass was very similar in mudbrick and plaster suggestingthe same sediment origin with additional coarse mineral and plantinclusions in the adobe (Fig. 8A). The brick surface facing inside theroom should have experienced more heat than the brick interiorbut the sediment was remarkably homogeneous throughout thesample (Fig. 8B, C). This adobe had a dark fabric punctuated byflecks of organic matter (Fig. 8D, E), carbon and ash features(Fig. 8F–I) and low birefringence of organics and clays. Bricks fromthis wall appeared gray in the field and contained weathered ce-ramics (Fig. 8I). Low birefringence of plant inclusions, probablypoorly mixed grass temper, may be from heating (Fig. 8J, K). Therelatively spongy texture, low clay content and coarse inclusionsindicate that adobes of this composition are likely to decomposerapidly once exposed to weathering.

Several hearths lined the corners and walls of the new kitchen.Our informant explained that hearths were generally split for twopots with a central adobe. The built features of hearths were raisedapproximately 35 cm above the floor surface with side areas forhousing guinea pigs. It was explained that hearths were cleanedperiodically and that the hearth position was shifted regularly. TheSW hearth was the best preserved (Fig. 9) and an adobe from thishearth appeared thermally altered and structurally compromisedin thin section (03KUCP6, Fig. 10A). It was characterized by siltyloam fabric with gravel, ceramic, and coarse plant inclusions(Fig. 10A, H). A dark sesquioxide-rich fabric dominates with do-mains of a lighter ashy fabric with thermal features (Fig. 10B–F)suggesting different oxidation conditions in the brick depending onproximity to voids (Fig. 10G). The spongy texture suggests rapiddegeneration from water saturation if exposed to rain.

The SE hearth exhibited moderate- to high-temperature alter-ation of minerals and the groundmass (03KUCP7, Fig. 11A). Visualinspection of the thin section shows dark peds surrounded bya lighter fabric with notable depletion pedofeatures around largervoids. Under the microscope, this pattern appears to reflect theeffects of unevenly distributed temperature exposure with lightercolored ashy sediment along voids and crack planes surroundinga darker groundmass to the ped interiors (Fig. 11B, C). The lighterfabric shows a higher degree of thermal alteration (Fig. 11D, E).

Fig. 8. New kitchen wall mudbrick: (A) 5� 7 cm thin section cut across the mudbrick horizontally to capture the sooty interior surface; (B) fabric, interior edge of brick (ppl); (C)fabric, middle of brick (ppl); (D, E) as B (ppl, xpl); (F) interior surface showing surface soot (ppl); (G) pseudocarbon (ppl); (G) carbon and ash at lower right (ppl); (H) burnt,weathered ceramic (ppl); (J, K) parallel organics suggestive of unmixed temper.

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Thermal features are common such as dull clays with sesquioxidestaining (Fig. 11F) in the dark fabric and rubified clay nodules in thelight fabric (Fig. 11G). Charred coarse organics are suggestive oftemper (Fig. 11H). The sediment contains several ceramic fragmentsand bone, which are also thermally altered. Overall, it appears thatarchaeological sediments were used for this feature with addedcoarse plant temper. Heat compromised the brick integrity, as seenin the spongy texture and larger voids.

The NE hearth was defined by a clearly visible black lens overburnt packed earth flooring, which was reported to have beencleaned of coarse debris. Our informant stated that the thin char-coal layer indicated that hearth had been cleaned. In thin section,

the microstratigraphy shows several different events, variablecomposition and different degrees of heat exposure (Fig. 12A).Coarse organics and dung were found throughout the slide sug-gesting temper. From the top of the slide, stratum 1 was a dense,mixed deposit with charcoal, ash and dung and had a sharp lowerboundary (Fig. 12B, C). Stratum 2 was composed of laminated siltssuggesting a possible surface from cleaning the hearth (Fig. 12B).Ashy stratum 3 is characterized by carbon-rich bands (Fig. 12C, D).An undulating boundary starts stratum 4, which includes coarsecharcoal, plant material, burnt dung and bone. This layer has beendisturbed by bioturbation, as the large chamber in Fig. 12A illus-trates. Stratum 4 grades into ashy stratum 5 (Fig. 12F, G). Although

Fig. 9. New kitchen SW double hearth after cleaning. Note cobble foundation anddiscoloration of wall (20 cm scale).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–30713066

highly fragmented, stratum 6 is characterized by consolidatedrubified peds, presumably disturbed thermal features (Fig. 12H, I).The underlying stratum 7 includes dense, silty peds, coarse organicmatter, pseudocarbon and some thermal features (e.g. small redpeds, ash, carbon flecks; Fig. 12J). Stratum 8 is denoted by a band ofsub-angular gravel oriented sub-horizontally. The underlyingstratum 9 had poorly sorted spongy peds, some thermal features,coarse organic and dung inclusions (Fig. 12K).

Fig. 10. New kitchen SW hearth adobe: (A) 5� 7 cm thin section showing mottled fabrics anxpl); (D, E) ashy light fabric (ppl, xpl); (F) sesquioxide-stained altered clay nodule in dark fafrom large plant inclusions (ppl).

4.3. Old kitchen

The old kitchen was constructed of mudbrick on a single-coursecobble foundation. The roof was missing (Fig. 13). The doorway wasblocked, reportedly from a secondary use as an animal shelter.There was little to suggest the function of the old kitchen prior toexcavation. The original wall surface was missing and the interiorwas partly filled with fallen walling, decaying roofing and refuse.Burrowing insects colonized the organic-rich parts of the fill andspiders and insects lived between the adobe walls. The originalpacked earth floor was identified during cleaning by a texturechange, with patches of in situ hearths, which has been cleaned andlater infilled. Small, non-local clay inclusions found in hearth areaswere reported to be clay figurines used as holiday offerings. A lowcobble wall had been added after the roof fell to separate the oldkitchen from a corral (Fig. 13). The old kitchen walling had slumpedtoward the compound perimeter and sloped away from the moundindicating adobe slump (foreground Fig. 2).

A mudbrick from the west wall of the old kitchen was madefrom silty loam with >25% coarse inclusions (03KUCP3; Fig. 14A, Fand G). Although coarse, the brick was well consolidated with lowporosity. The silty matrix was punctuated by unusual clay-richdomains (Fig. 14B, C), which suggest intentional inclusions. Planttemper inclusions were of variable diameters, randomly distributedand of low birefringence (Fig. 14D, E).

A 1�0.5 m long trench was cut perpendicular to the wall ex-terior to investigate ‘‘adobe slump’’ from the collapsed upper por-tion of the old kitchen wall. The profile was devoid of adobe

d depletion pedofeatures on voids; (B, C) boundary between dark and light fabrics (ppl,bric (ppl); (G) depletion pedofeature on large void, marked v (ppl); (H) carbon and ash

Fig. 11. New kitchen SE hearth adobe: (A) 5� 7 cm thin section; (B, C) sesquioxide punctuated fabric 1 (ppl, xpl); (D, E) ashy fabric 2 (ppl, xpl); (F) undifferentiated ash (ppl); (G)ashy plant remains (ppl); (H) heat-altered clay, note this was anisotropic on xpl (ppl).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–3071 3067

fragments and the soil was indistinguishable in composition andtexture from topsoil. No microstratigraphy or aggregates suggestiveof mudbrick were identified in thin section (03KUCP4; Fig. 15A).The spongy, aerated structure with connected channels and soilfaunal features (Fig. 15C–E) also suggests topsoil.

5. Discussion

The mudbrick, wall surfacing and flooring at Copralabra Patawere of local origin. Although the groundmass is largely composedof fine sand and silt, larger inclusions are abundant making evenmud plaster remarkably coarsely textured. In thin section, color andtexture differences in mudbrick corresponded to inclusions of ash,charcoal, food refuse and ceramics. As the bricks were reportedlymade adjacent to the compound from archaeological deposits,these variations often reflect heterogeneity inherited from thearchaeological deposits. Substantial gravel, coarse temper and in-complete mixing contributed to poor structural integrity, suggestedby the collapse of new house walling in a storm. Overall, thecomposition of adobes and mud plaster studied suggests expedientmanufacture using coarse local materials for short-term use.

Heat-treated hearth adobes had relatively stable rubified ag-gregates and heat-altered organics (e.g. carbonized temper). Thecoarse poorly mixed composition of new kitchen bricks resulted inlow thermal resistance from differential heat absorption due tocoarse inclusions and large voids. Heat-treated bricks had a brittleconsistency, which provides a rationale for the frequent hearthreconstructions observed in the new kitchen as failing hearthadobes would be dangerous substrates for hot pans. The strongest

stable sediment signature identified was rubified aggregates inhearth structures and associated altered plant temper. However,such features are not particular to adobe and are also found in openair fires (e.g. Mallol et al., 2007). Once these adobes were exposed toweathering and disintegrated, it would be difficult to differentiateburnt adobe from other burning installations. The laminated hearthsequence from the NE hearth in the new kitchen illustrates subtlefeatures as it was cleaned, presumably of ash and charcoal. Rubifiedpeds, and possibly the dense, laminated upper deposits, would bestable as aggregates once the hearth is exposed to more intenseweathering when the roof falls.

A sequence of devolution can be proposed for mudbrick struc-tures at Copralabra Pata. Exposed walls weather slowly to producethin laminated sedimentary structures with an ephemeral presencedue to bioturbation unless buried (e.g. new house foundation). Theinterior is relatively well preserved and fills may build up fromprimary and secondary use. Rising damp leads to salt accumulationand exfoliation of mud plaster and surface adobe from the wallbase, which encourages wall collapse (McIntosh, 1974; Schifferet al., 1987). As roofing decays and falls into structures, both theinterior and the exterior walls become subject to intensified surfaceweathering. At Copralabra Pata, the new kitchen roof had begun tofall after 30 years whereas the old kitchen was roofless after 85years and walls had lost about half their height. Organic matter,including roof fall and refuse, attracts a wide range of insects andspiders, leading to bioturbation that churns fallen debris intoflooring, expanding and aerating it. Plants colonizing the aban-doned structures contribute to bioturbation. Unsurprisingly, in-terior floors are best preserved when organic matter is absent and

Fig. 12. New kitchen NW hearth mudbrick: (A) 5� 7 cm thin section, the numbers at right refer to microstratigraphic layers; (B) boundary of strata 1 and 2 (ppl); (C) ash features instratum 1 (xpl) and Dung in stratum 1 (xpl); (D, E) carbon-rich bands in stratum 3 (ppl, xpl); (F, G) laminations of strata organic-rich stratum 4: ashy stratum 5 and a fragment ofrubified fabric 6; (H, I) rubified ped in stratum 6 (ppl, xpl); (J) thermal features in stratum 7 (ppl); (K) dung in stratum 9 (xpl).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–30713068

they are buried rapidly, as in the new house. As walls weather,upper mudbrick courses become weaker and collapse both insideand outside the structure. The relic walls may provide some pro-tection to interior deposits by limiting faunal access from outsidethe structure when internal organic matter is low. Degradation wasmore intense outside structures where soil fauna and vegetationcontribute to the rapid homogenization of exterior house debrisinto topsoil. This adobe melt thickens the topsoil and raises theground surface but in the absence of artifacts or other stable fea-tures, reveals little about the degraded structure. Stable hearthfeatures were only seen where direct heat is intense enough torubify sediments. The old kitchen indicates that soot and charcoalare rapidly diluted by bioturbation.

This sequence compares well the degradation observed inother studies (e.g. Butzer, 1982; McIntosh, 1974, 1977; Rosen,1986; Schiffer et al., 1987). Given the semi-arid setting hydro-logical processes would be expected to contribute substantially to

site destruction. Destructive hydrological pathways are seen inlaminated wall wash in the new house, degraded walls in the oldkitchen and rising damp in the new kitchen. Moist conditions alsofavor soil fauna and volunteer plants giving bioturbation a prom-inent role in site destruction. The insects found inside thekitchens ranged from 1 to 4 cm long and their substantial bur-rows churned through beaten earth, midden roof debris and finerwall fragments. Exterior wall fall was effectively homogenizedover 85 years by plants and smaller insects.

6. Conclusions

The Copralabra compound had a relatively short use as a do-mestic compound. The sampled adobes were poorly constructedand reflected the needs of expedience rather than long-term oc-cupation. Differences between the old and the new kitchensdemonstrate the relatively light imprint of locally derived adobe

Fig. 13. Old kitchen after cleaning. The hearth at right was not visible until the roomwas cleaned.

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–3071 3069

constructions once the roof falls. The new kitchen interior wasrelatively protected by partial roof cover, whereas roof fall in the oldkitchen exposed the interior to weathering, washing the walls ofsoot and promoting adobe weathering. Comparison of the newhouse and the old kitchen demonstrate that the organic matterfrom roof fall is a major attractant to soil fauna and promotedbioturbation in floor deposits. In addition to destroying the in-tegrity of the earthen floor, this level of bioturbation will also

Fig. 14. Old kitchen mudbrick: (A) 5� 7 cm thin section showing oriented coarse inclusions(ppl, xpl); (F, G) dominant silty fabric (ppl, xpl).

obscure accumulation from any hiatus of occupation (i.e. aeoliandeposition) through homogenization into adjacent household de-bris layers. The most stable signatures were rubified peds fromhearths. However, once the structurally heat-weakened hearthadobes disaggregate, these rubified features cannot be differenti-ated from other burning installations.

There are both parallel and significant differences in the con-struction materials and techniques observed in Copralabra Pataand those used on prehistoric sites excavated on the Taraco Pen-insula. At Copralabra Pata, secondary cultural deposits arose frombioturbation of organic-rich interior fills which blended roof andwall fall with flooring and occupational debris. These deposits arecomparable to organic-rich, bioturbated material found in theexcavations of Chiripa, Santiago, Kala Uyuni and Sonaji (Bandy andHastorf, 2007; Hastorf, 1999; Hastorf et al., 2005, 2006). However,unlike Copralabra Pata, in the archaeological settings these or-ganic-rich deposits are interspersed with imported, highly pig-mented clay-rich strata, which are culturally sterile. This studyillustrates that these sediments contribute to structural resilience,through protection from rising damp, and resistance to bio-turbation. Prehistoric cobble foundations at Kala Uyuni are alsomortared with fine temperless sediment, which further resistsdamp and discourages soil fauna. Contemporary dwellings arebuilt expediently without the use of imported sediments thatwould improve structural durability, even if those sources areavailable within 0.5 km or less from the site. In contrast, pre-historic Taraco residents were willing to invest additional labor inprocuring imported sediment for structural and, also aesthetic,properties. The durability of these construction techniques

; (B, C) clay-rich ped (ppl, xpl); (D, E) coarse organic inclusions with low birefringence

Fig. 15. Old kitchen exterior ‘‘adobe slump’’: (A) 5� 7 cm thin section with spongy structure (note: top is at left); (B, C) partial sorting of groundmass typical of faunal bioturbation(ppl, xpl); (D, E) excrement pedofeatures of mite droppings and ‘‘bubbly’’ void structure (ppl, xpl).

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–30713070

indicates an interest in structural stability in contrast to the shortlifecycles of contemporary buildings.

Acknowledgements

Many thanks to our informant, to the landowners and to thecommunity of Coa Collu. Kate Moore, Maria Bruno, Bill Whiteheadand Richard Elgar assisted with fieldwork and photography.Funding was provided by the National Science Foundation GrantNo. 023401 under co-PIs Christine Hastorf and Matthew Bandy anda WSU College of Liberal Arts Meyer Completion Grant. Thanks aredue to the organizers of the DIG 2007 conference where an earlierversion of this paper was presented and to a WSU Faculty TravelGrant, which supported my attendance.

References

Abbott, M.B., Binford, M.W., Brenner, M., Kelts, K.R., 1997. A 350014C yr high-resolution record of water-level changes in Lake Titicaca, Bolivia/Peru.Quaternary Res. 47 (2), 169–180.

Argollo, J., Ticcia, L., Kolata, A.L., Rivera, O., 1996. Geology, geomorphology, and soilsof the Tiwanaku and Catari River Basins. In: Kolata, A.L. (Ed.), Tiwanaku and itsHinterland: Archaeology and Paleoecology of an Andean Civilization. Smith-sonian Institution Press, Washington, D.C., pp. 57–88.

Bandy, M.S., 2004. Fissioning, scalar stress, and social evolution in early villagesocieties. Am. Anthropol. 106 (2), 322–333.

Bandy, M.S., 2001. Population and History in the Ancient Titicaca Basin. Ph.D.dissertation. Department of Anthropology, University of California, Berkeley.

Bandy, M.S., Hastorf, C.A. (Eds.), 2007. Kala Uyuni: an Early Political Center in theSouthern Lake Titicaca Basin. Archaeological Research Facility Contribution, No.64 Berkeley, CA.

Bermann, M., 1994. Lukurmata: Household Archaeology in Prehispanic Bolivia.Princeton University Press, Princeton, NJ.

Binford, M.W., Kolata, A.L., 1996. The natural and human setting. In: Kolata, A.L. (Ed.),Tiwanaku and its Hinterland: Archaeology and Paleoecology of an AndeanCivilization. Smithsonian Institution Press, Washington, D.C., pp. 23–56.

Boivin, N.L., 2000. Life rhythms and floor sequences: excavating time in ruralRajasthan and Neolithic Catalhoyuk. World Archaeol. 31 (3), 367–388.

Brown, P.W., Clifton, J.R., 1978. Adobe I: the properties of adobe. Stud. Conserv. 23,139–146.

Brown, P.W., Robbins, C.R., Clifton, J.R., 1979. Adobe II: factors affecting the dura-bility of adobe structures. Stud. Conserv. 24, 23–39.

Butzer, K.W., 1982. Archaeology as Human Ecology. Cambridge University Press,New York.

Cavallaro, R., Shimada, I., 1988. Some thoughts on Sican marked adobes and labororganization. Am. Antiq. 53 (1), 75–101.

Chavez, K.M., 1988. The significance of Chiripa in Titicaca Basin developments.Expedition 30 (3), 17–26.

Clifton, J.R., Davis, F., 1978. Mechanical Properties of Adobe. Center for BuildingTechnology, Institute for Applied Technology. National Bureau of Standards,Washington, D.C.

Cross, S.L., Baker, P.A., Seltzer, G.O., Fritz, S.C., Dunbar, R.B., 2000. A new estimate ofthe Holocene lowstand level of Lake Titicaca, central Andes, and implicationsfor tropical palaeohydrology. The Holocene 10 (1), 21–32.

Goldberg, P., Macphail, R.I., 2006. Practical and Theoretical Geoarchaeology. Black-well Scientific, Oxford.

Goodman (Elgar), M.A., 1999. Micromorphology of depositional sequences fromMonticulo and Santiago excavations. In: Hastorf, C.A. (Ed.), Early Settlement atChiripa, Bolivia. Archaeological Research Facility Contribution, No 57, Berkeley,CA, pp. 51–60.

Hastorf, C.A. (Ed.), 1999. Early Settlement at Chiripa, Bolivia. ArchaeologicalResearch Facility Contribution, No 57 Berkeley, CA.

Hastorf, C.A., 2003. Community with the ancestors: ceremonies and socialmemory in the Middle Formative at Chiripa, Bolivia. J. Anthropol. Archaeol.22 (4), 305–332.

Hastorf, C.A., Bandy, M.S., Whitehead, W.T., Steadman, L.H., Moore, K., Paz Soria, J.L.,Roddick, A., Bruno, M., Fernandez, M.S., Killackey, K., Logan, A., Ullua Vidaurre,D., Callisaya, L., Capriles Flores, J., Stovel, E., Raath, M., Antonites, X., 2005.Proyecto Arqueologico Taraco: Informe de las Excavaciones de la Temporada del2004 en los Sitios de Kumi Kipa, Sonaji y Chiripa. Report presented to theUnidad Nacional de Arqueologıa de Bolivia.

Hastorf, C.A., Bandy, M.S., Whitehead, W.T., Steadman, L.H., Moore, K. Goodman-Elgar, M.A., Roddick, A., Bruno, M., Fernandez, M.S., Killackey, K., Fontenla, R.,Callisaya, L. Capriles Flores, J., Leighton, M., Machicado, E., Peterson, M., An-thony, N. Jimenez, X., 2006. Proyecto Arqueologico Taraco: Informe de las Ex-cavaciones de la Temporada de 2005 en los Sitios de Sonaji y Kala Uyuni. Reportpresented to the Unidad Nacional de Arqueologıa de Bolivia.

Lavenu, A., 1992. Formation and geological evolution. In: Dejoux, C., Iltis, A. (Eds.),Lake Titicaca: a Synthesis of Limnological Knowledge. Kluwer Academic,Boston, MA, pp. 3–13.

Mallol, C., Marlowe, F.W., Wood, B.M., Porter, C.C., 2007. Earth, wind, and fire:ethnoarchaeological signals of Hadza fires. J. Archaeol. Sci. 34 (12), 2035–2052.

Matthews, W., French, C.A.I., Jones, M.K., Cutler, D.F., Lawrence, T., 1996. Multiplesurfaces: the micromorphology. In: Hodder, I. (Ed.), Catalhoyuk: the Surfaces ofThings. British Institute of Archaeology at Ankara Monograph, No 22. McDonaldInstitute, Cambridge, pp. 301–342.

McHenry, P.G., 1984. Adobe and Rammed Earth Buildings: Design and Construction.Wiley, New York.

McIntosh, R.J., 1974. Archaeology and mud wall decay in a West African village.World Archaeol. 6, 154–171.

McIntosh, R.J., 1977. The excavation of mud structures: an experiment from WestAfrica. World Archaeol. 9 (2), 185–199.

Middleton, G.F., 1953. Build your House of Earth: a Manual of Pise and AdobeConstruction. Angus and Robertson, Sydney.

Paduano, G.M., Bush, M.B., Baker, P.A., Fritz, S.C., Seltzer, G.O., 2003. A vegetationand fire history of Lake Titicaca since the Last Glacial maximum. Palaeogeogr.Palaeoclimatol. Palaeoecol. 194 (1), 259–279.

Paz Sorıa, J.L., 1999. Excavations in the Llusco area. In: Hastorf, C.A. (Ed.), EarlySettlement at Chiripa, Bolivia. Archaeological Research Facility Contribution, No57, pp. 31–36. Berkeley, CA.

M. Goodman-Elgar / Journal of Archaeological Science 35 (2008) 3057–3071 3071

Roche, M.A., Bourges, J.C., Mattos, R., 1992. Climatology and hydrology of the LakeTiticaca basin. In: Dejoux, C., Iltis, A. (Eds.), Lake Titicaca: a Synthesis ofLimnological Knowledge. Kluwer Academic, Boston, MA, pp. 63–83.

Rodrigo, L.A., Wirrmann, D., 1992. General aspects of present day sedimentation. In:Dejoux, C., Iltis, A. (Eds.), Lake Titicaca: a Synthesis of Limnological Knowledge.Kluwer Academic, Boston, MA, pp. 23–28.

Rosen, A.M., 1986. Cities of Clay: the geoarchaeology of Tells. University of ChicagoPress, Chicago, IL.

Rowe, H.D., Guilderson, T.P., Dunbar, R.B., Southon, J.R., Seltzer, G.O., Mucciarone, D.,Baker, P., Fritz, S., 2003. Timing of late Quaternary lake level change: LakeTiticaca, South America. Glob. Planet. Change 38, 273–290.

Schiffer, M.B., Baron, A.M., Cortes, P.P., Sepulveda, J.T., 1987. Deterioration of adobestructures: a case study from San Pedro de Atacama, Northern Chile. In:

Nash, D.T., Petralgia, M.D. (Eds.), Natural Formation Processes and theArchaeological Record. British Archaeological Reports International Series, 352,pp. 10–29. Oxford.

Stanish, C., 2003. Ancient Titicaca: the Evolution of Complex Society in SouthernPeru and Northern Bolivia. University of California Press, Berkeley, CA.

Stoops, G., Vepraskas, M.J., 2003. Guidelines for Analysis and Description of Soil andRegolith Thin Sections. Soil Science Society of America, Madison, WI.

Tapia, P., Fritz, S., Baker, P., Seltzer, G., Dunbar, R.A., 2003. Late Quaternary diatomrecord of tropical climatic history from Lake Titicaca (Peru and Bolivia).Palaeogeogr. Palaeoclimatol. Palaeoecol. 194, 139–164.

Whitehead, W., 1999. Radiocarbon dating. In: Hastorf, C.A. (Ed.), Early Settlement atChiripa, Bolivia. Archaeological Research Facility Contribution, No 57, Berkeley,CA, pp. 17–21.