Abstracts / Quaternary International 279-280 (2012) 462–565542

Cenozoic. Moreover, the succession of mollusk species indicated short-term environmental changes such as millennia climate variabilityduring Last Glacial Maximum and instable climate fluctuation in glacialand interglacial periods like MIS11 and last glacial periods.

4. The authors prospect mollusk research future and further potentialapplication in loess paleoenvironemntal study.

NEW COUPLED MODEL USED INVERSELY FOR RECONSTRUCTING PASTTERRESTRIAL CARBON STORAGE FROM POLLEN DATA: VALIDATION OFMODEL USING MODERN DATA

Haibin Wu. Institute of Geology and Geophysics, Chinese Acade, ChinaE-mail address: haibin-wu@mail.igcas.ac.cn

The knowledge of potential impacts in climate change on terrestrialvegetation is crucial to understand long-term global carbon cycle devel-opment. Discrepancy in data has long existed between past carbon storagereconstructions since the Last Glacial Maximum by way of pollen, carbonisotopes, and general circulation model (GCM) analysis. This may be due tothe fact that these methods do not synthetically take into account signif-icant differences in climate distribution between modern and pastconditions as well as the effects of atmospheric CO2 concentrations onvegetation. In this study, a newmethod to estimate past biospheric carbonstocks is reported utilizing a new integrated ecosystem model (PCM) builton a physiological process vegetation model (BIOME4) coupled witha process-based biospheric carbon model (DEMETER). The PCM was con-strained to fit pollen data to obtain realistic estimates. It was estimatedthat the probability distribution of climatic parameters, as simulated byBIOME4 in an inverse process, was compatible with pollen data whileDEMETER successfully simulated carbon storage values with correspond-ing outputs of BIOME4. The carbon model was validated with present dayobservations of vegetation biomes and soil carbon, and the inversionscheme was tested against 1491 surface pollen spectra sample sitesprocured in Africa and Eurasia. Results show that this method cansuccessfully simulate biomes and related climates at most selected pollensites providing a coefficient of determination (R) of 0.83 to 0.97 betweenthe observed and reconstructed climates, while also showing a consensuswith an R value of 0.90 to 0.96 between the simulated biome averageterrestrial carbon variables and the available observations. The resultsdemonstrate the reliability and feasibility of the climate reconstructionmethod and its potential efficiency in reconstructing past terrestrialcarbon storage.

CHEMICAL WEATHERING IN A SMALL WATERSHED DRAINING TYPICALSILICATE ROCKS: CONTROLLING FACTORS AND IMPLICATIONS FOR THEGLOBAL CARBON CYCLE STUDY

Weihua Wu. School of Geographic and Oceanographic Sciences, N, ChinaE-mail address: wuwh@nju.edu.cn

We detailedly studied the geochemistry of a small watershed (the XishuiRiver d a tributary of the Yangtze River) draining typical silicate rocks insubtropical zone. The catchment located in the Dabie Proterozoic meta-morphic zone consists of abundant felsic gneisses, leptynites, amphibolitesand small amounts of mafic rocks, granites and marbles. By analyzingmajor ion contents and 87Sr/86Sr ratios of river water and snow water, wecalculated chemical weathering rates, atmospheric CO2 consumption anddiscussed their controlling factors.The results show that anthropogenic activities haveno obvious influence onthe chemical compositions of river water. Atmospheric inputs greatly affectK+ and Cl-, then Ca2+ and SO4

2-. Contributions from silicate weathering toCa2+, Mg2+, Na+ and K+ in river water are 35-63 %, 55-88 %, 61-79 % and 7-78%, respectively. Sr concentrations are 1.30-3.17 mmol/l and 87Sr/86Sr ratiosare 0.708515-0.709305, which inherit the Sr isotopic characteristics ofsource rocks in catchment, indicating that silicateweathering is not entirelyequivalent to low Sr concentrations and high 87Sr/86Sr ratios. While usingthe increase of seawater 87Sr/86Sr ratios to index intensification of thecontinental silicate weathering, differences of background 87Sr/86Sr ratiosof silicate rocksmust be considered. The calculated silicateweathering rates(SWR) are 3.4-12.5 t/km2y and the atmospheric CO2 consumption rates are1.22-4.0�105 mol/km2y. Compared with the other small rivers drainingsilicate rocks in the global, SWR in theXishui catchment is higher than those

rivers draining basalts in high latitude regions and draining granites insimilar latitude, but is far lower than those draining basalts in low latitude/equator. Therefore, temperature and lithology are more important to sili-cate weathering in the global. Those rivers draining mafic rocks in tropiczones may have disproportional contribution to the global carbon cyclewith their drainage areas.

SEDIMENT GEOCHEMISTRY OF LARGE RIVERS ORIGINATING FROM THETIBETAN PLATEAU: PROVENANCE AND WEATHERING

Weihua Wu. School of Geographic and Oceanographic Sciences, N, ChinaE-mail address: wuwh@nju.edu.cn

We investigated the geochemical characteristics of major, trace and rareearth elements and Sr–Nd isotopes of bed sediments from the headwatersand upper reaches of the six large rivers originating from the TibetanPlateau (the Jinsha River – Yangtze, Lancang River –Mekong, Nujiang River– Salween, Huang He – Yellow, Indus, Yarlung Tsangpo – Brahmaputra).The sediment provenances are complex, and clastic, carbonate, volcanic,metamorphic rocks and granitoids widely distributed in the plateau havecertain effect on these river sediments. Nevertheless, some typicalcontributors to the different catchment sediments can still be identified.Carbonate rocks and Permian Emeishan basalts are predominant in theJinsha River. The Yellow River sediments have similar geochemical char-acteristics with loess in catchments. The Indus River sediments are mainlyfrom potassic volcanic rocks, and the Cenozoic granitoids importantlycontribute to the Yarlung Tsangpo River. Chemical Indices of Alteration(CIA) of the six rivers are from 46.5 to 69.6, indicating relatively weakchemical weathering intensity. Though the Three–River catchments (theJinsha River, Lancang River and Nujiang River) have abundant moreweathered mafic minerals and very large river fall which favor to rapidlyerode, low-intermediate weathering intensities (CIA from 62.2 to 69.6) aremainly attributed to the cold and arid conditions which inhibit chemicalweathering processes. The headwaters of the Indus and Yarlung TsangpoRiver located in the rain shadow area of the northern Himalaya have verylow CIA. Therefore, the climate conditions are the most important factorcontrolled the weathering intensity of these river catchments. The sedi-ments in the headwaters and upper reaches seem to have weak contri-bution to the material in the lower reaches and estuaries, which may beattributed to the sequestration of dams, reservoirs, and lakes and siltationof the abrupt turns in catchments.

GLACIAL STRATIGRAPHY AND PALAEOGEOGRAPHY IN CENTRALPOLAND IN THE LIGHT OF NEW LUMINESCENCE DATING

Wojciech Wysota. Institute of Geography, Nicolaus Copernicus University,PolandE-mail address: wysota@umk.pl

Large continental ice sheets are known to have repeatedly expandedduring Pleistocene glaciations, but their timing and extent remainscontentious both in Eurasia and North America. There is a broad consensusthat after the Eemian interglacial major advances occurred during marineisotope stages 5d, 4 and 2, however the delineation of particular ice limitsand synchronicity of ice advances in different areas is still uncertain.Problems with constraining glacial events of the Scandinavian Ice Sheetduring the Weichselian glaciation are perplexing also in the type area ofthis glaciation in central Poland. Previous investigations in this areaconsidered three ice advances, i.e. the Torun advance in the Early Weich-selian (MIS 5d), the Lwiecie advance in theMiddleWeichselian (MIS 4) andthe Main advance in the Late Weichselian (MIS 2), separated by ice-freeinterstadials. However dating control of the age of these ice advances andretreats is highly uncertain. Weichselian sediments in central Poland weredatedwith the OSLmethod supported by radiocarbon dating. A total of 148OSL samples were dated from 29 sites spread along a N-S transect coveringthe area of the Weichselian glaciation from its maximum extent to thePomeranian ice marginal position. Wherever possible, waterlaid depositsbracketing till units were dated. The OSL ages obtained do not yieldsupport for the ice advance during MIS 5d, neither do they show anyunequivocal evidence of MIS 4 glacial sediments. The OSL results suggestoccurrence of till deposits of the pre-LGM ice advance (c. 30 ka BP) butmore dating control of this suggested ice advance and the delineation of its