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Abstracts / Quaternary International 279-280 (2012) 462–565482
Mountains show values similar to those for coarse fractions, suggestingthat the sources for fine fractions are the same as those for the coarsefractions. On the other hand, ESR signal intensity and CI of quartz in finefractions of river sediments from the Kunlun Mountains show valuesdifferent from those for the coarse fractions, and converged to theaverage values for the fine fractions of river sediments in the basin. Thevalues are also close to those of the mountain loess, which represents theeolian dust emitted from the Tarim Basin.
HAVE SEA LEVEL FLUCTUATIONS INFLUENCED COASTAL BIOLOGICALCOMMUNITIES IN EASTERN SUB TROPICAL AUSTRALIA?
Kathryn H. Taffs. Southern Cross University, AustraliaE-mail address: [email protected]
Eastern Australia has been tectonically stable throughout the lateQuaternary. This provides an ideal situation to examine sea level changeand the related influences on coastal plains. It is well accepted that sealevel was higher during themid Holocene, and fell to its present position inthe late Holocene in this region. However, detailed sea level reconstruc-tions vary with location and sources of evidence used. Evidence from sub-tropical eastern Australia suggests that sea level was 2.2 metres higherthan present 3600 yr BP and greater than 1 metre higher than present3600-1500 yr BP, before dropping to present levels. This study integratedrecords from a number of sites to examine if sea level changes haveinfluenced the biological communities of coastal lakes and estuaries on thecoastal plain in sub tropical eastern Australia. A range of sites wereinvestigated using palaeolimnological techniques including novel uses ofbiological proxies, sediment and isotopic evidence. Multi-proxy resultsindicate that minimal biological fluctuations have been experienced insub-tropical east Australian coastline for the past 5000 years. The proxiesemployed indicated a small range of environmental variability with nomajor change of community composition. Much of the variability experi-enced is related to salinity and implies changes in effective rainfall, inparticular the effects this has on the balance of freshwater input and tidalexchange within estuarine environments. Evidence of anthropogenicimpacts were observed in younger sediments at some sites, causinga change of biological composition not previously experienced during theHolocene. These changes were most probably due to changes of nutrientstatus rather than water depth or salinity. This compilation of datademonstrates that whilst fluctuations of sea level may have been experi-enced in sub-tropical eastern Australian in the past 5000 years, this hascaused minimal biological change.
OXYGEN AND CARBON ISOTOPE ANALYSES IN SHELLS OF THEFRESHWATER GASTROPOD RADIX SP.: A SUITABLE METHOD FORRECONSTRUCTING LAKE HISTORY ON THE TIBETAN PLATEAU
Linda Taft. Freie Universität Berlin, GermanyE-mail address: [email protected]
The Tibetan Plateau is one of the key regions controlling the globalatmospheric circulation systems particularly in respect of monsoondynamics. On the plateau thousands of lakes are scattered, the history ofwhich is controlled by tectonics and variabilities in regional atmosphericconditions. Lake level changes can be evidence of climatic extreme eventsor long-term trends. In order to obtain information about climate char-acteristics during major lake level changes we consider the analysis of d18Oand d13C isotope compositions in shells of the modern freshwatergastropod Radix sp. which is widespread on the Tibetan Plateau. Ourpurpose is to provide a suitable archive for regional lake histories andpalaeoclimatic dynamics. Radix sp. mineralize their shells using hydrogencarbonate from the ambient water. The isotopic patterns of the shellsmirror both the water composition of the habitats and the regionalclimatic conditions. We selected shells from two exorheic freshwaterlakes: 1) Donggi Cona (4090 m a.s.l.) is situated near the north-easternmargin of the Tibetan Plateau, within the modern East Asian summermonsoon trajectory. 2) The eastern basin of Bangong Co (4250 m a.s.l.) issituated on the westernmost Tibetan Plateau. Nowadays Bangong Co isusually beyond monsoonal influence, the climate conditions beingcontrolled by theWesterlies. However, the lake area can be affected during
extreme monsoon events. At both lake shores outcrops exhibit well-preserved fossil shells of Radix sp. which are potentially suitable forstudying regional palaeoclimate conditions and former climatic extremeevents. Prior to the application to fossil shells we have analyzed the d18Oand d13C isotopic compositions of modern shells to determine what kind ofinformation these samples provide about modern atmospheric conditions.The results show that the precipitation patterns can be derived in highresolution.
STABLE OXYGEN ISOTOPE OF OPAL PHYTOLITHS FROM JAPANESE SASAAND PHYLLOSTACHYS: BASIC INFORMATION TOWARD THE PALEOEN-VIRONMENTAL RECONSTRUCTION
Masashi Takada. Nara Women’s University, JapanE-mail address: [email protected]
Stable oxygen isotope ratio of the deep sea and ice core record has beenoffered paleoenvironmental information (e.g. Shackleton and Opdyke,1973; Dansgaard et al., 1964, 1993; Bond et al., 1992). It has been revealedglacial-interglacial cycles and other global environment changes in theQuaternary period. In the terrestrial area of the mid-latitude the palyno-logical studies of peat and/or lake sediment have been played importantroles for regional and local paleo-botanical and environment reconstruc-tions. Pollen is, however, not well preserved in the aerobic condition,restricting the use of soil and loess deposits for pollen analysis.Phytoliths, also referred to as plant opal or plant silica bodies, are micro-scopic bodies formed from silica that occurs in groundwater as monosilicicacid. The growing plant absorbs silica into its tissues, forming bodiescomposed of opaline silica (SiO2:nH2O) (Piperno and Pearsall, 1993).Phytoliths is much more preserved in the aerobic condition than pollen,there is a possibility that we can find remnants of phytolilths in sequentialpaleosoil or leoss deposits. If we can use phytoliths as the proxy of pastenvironment, it is quite useful because we could directly estimate paleo-environment from regional or local terrestrial deposits. Thereforewe studythe relationship between stable oxygen isotope ratio of phytoliths andenvironmental factors. In this study we present the preliminary resultsabout phytoliths from living leaves of Japanese Sasa and Phyllostachystoward the paleoenvironmental reconstruction. In this study we willdiscuss the relationship between the stable oxygen isotope ratio of phy-toliths and several environmental factors such as temperature, precipita-tion, distance from sea, altitude, etc.
VEGETATION CHANGES THROUGH GLACIA/INTERGLACIAL CYCLES FORTHE LAST 450,000 YEARS IN EASTERN EURASIA, KAMIYOSHI BASIN,WESTERN JAPAN AND LAKE BAIKAL, SOUTHEASTERN SIBERIA
Hikaru Takahara. Kyoto Prefectural University, JapanE-mail address: [email protected]
Comparison with vegetation changes under the maritime and inlandclimate is indispensable for the better understanding of vegetationresponse to global climate changes in east Eurasia. Long cores were takenfrom a paddy field in Kamiyoshi Basin, western Japan (alt. 335 m,35�06.3’N, 135�35.1’E). The chronology of these cores was based on tephralayers (AT: 29 ka , Aso-4: 87 ka, K-Tz: 91 ka, Aso-1: 249 ka, Ng-1:294 ka,Kkt:334 ka, the age of tephra after Nagahashi et al. (2004)) and AMS 14Cdates. These cores provide a continuous vegetation history of the glacial/interglacial circles from theMIS12 toMIS3. A palynological study for MIS6-MIS3 was reported in Hayashi et al. (2009). Basically, in the interglacial,temperate conifers such as Cryptomeria japonica (Japanese cedar), Scia-dopitys verticillata (Umbrella pine) were dominant, whereas in the glacialperiod, conifer forests (Picea, Tsuga, Abies, Larixand Pinus) developed.However, prominent increase of Cyclobalanopsis (evergreen oaks) pollenwas recognized in MIS5.5 and MIS11. Also, the MIS5.5 is characterized byLagerstroemia, which grows in southwestern Islands of Japan at present.For other interglacial periods, in MIS7, Cryptomeria japonicaand Fagusweredominant in forests with small amount of Cyclobalanopsis. For MIS9.3,Fagus was dominant with small amount of Cyclobalanopsis. In MIS11.3,Cyclobalanopsis was main component of the vegetation in MIS11, after thedominance of pinaceous conifers in MIS12. This type of vegetation issimilar to that of the mid-Holocene in the Pacific side of western Japan.
Abstracts / Quaternary International 279-280 (2012) 462–565 483
Detailed pollen data of MIS12 to MIS1 from Lake Baikal, southeasternSiberia (Shichi et al, 2007, 2009) can be compared with pollen data fromKamiyoshi Basin. In the Lake Baikal region, pinaceous conifer forestsdeveloped in the interglacial, whereas shrub and herb vegetation spread inthe glacial. Biome shift between different interglacial periods indicated inJapan was not recognized in Siberia.
CHANGES IN LATE QUATERNARY LOCAL POLLEN ASSEMBLAGESASSOCIATED WITH FAULTING EVENTS ALONG THE ITOIGAWA-SHIZUOKA TECTONIC LINE ACTIVE FAULT SYSTEM, CENTRAL JAPAN
Hitomi Takemoto. Hiroshima University, JapanE-mail address: [email protected]
We examined the relationship between the late Quaternary pollenassemblage changes and local geomorphic development on the Itoigawa-Shizuoka tectonic line active fault system (ISTL) in central Japan. The ISTL isone of the most active and important fault systems in Japan. There aremany topographic features caused by faulting. Coseismic subsidenceevents and subsequent geomorphic changes had affected local vegeta-tional assemblages. In the region highly affected by the fault activity, thepollen assemblages recorded past fault activity.The topographic features were classified according to the levels of fluvialterrace surfaces. The samples for pollen analysis were collected frompaleoseismological trench walls and the drilling core.We estimated the age of some terraces in the study areas through radio-carbon dating and tephras. The development of the terraces shows thelocal level of erosion in the basin. The results of pollen analysis showedevidence of, for example, the pollens indicating vegetation of wetland alsoincrease in phase during subsidence events.The results showed the correlation between the pollen assemblageschange of herbs, ferns and shrubs and the local topographic and hydrologicchange caused by fault activity.These assemblages presumably correspond to moisture levels in theregion. Hence we presume that the moisture in the local region increasedor decreased. Then, It is concluded that the changes observed on the pollenassemblages reflect the coseismic subsidence of the hanging wall side ofthe fault. Considering that landform changes were caused by faulting, thepollen assemblages were possible to record past fault activity based on thealternations verified.
STRATIGRAPHY OF THE LAKE BIWA SEDIMENT DURING THE PAST 1 MA,CENTRAL JAPAN
Keiji Takemura. Kyoto University, JapanE-mail address: [email protected]
Lake Biwa is the largest and oldest lake in Japan. The drilled core in 1982-1983 (i.e., the 1400 m core) conducted by late Professor Shoji Horie hasrevealed more than 900 m lake and terrestrial sediments overlying thebasement rock (Takemura, 1990). Sedimentary sequences are subdividedinto 5 units, and they are P, Q, R, S, T units in ascending order. Uppermostunit T (250 m thick) is composed of massive and continuous clay beds,which is very useful for chemical, biological andmagnetic analysis. The agedata at first stage obtained from fission-track dating and tephra correlationindicated the discontinuity of the sedimentary sequence in present LakeBiwa. Recently, the doubt on discontinuity of the sequence in present LakeBiwa was completely cleared by the reinvestigation of the fission-trackages and tephra identification of Danhara et al. (2010). Improvements onfission-track timescale have successfully identified the paleomagnetic datafrom middle Matuyama reversed Epoch including the Jaramillo event,determining time coverage of the Lake Biwa sediments as about 1.5 Ma. Ahighly linear sediment accumulation rate curve is thus given to the 900m-deep Lake Biwa sediment. This secures the stable sedimentary environ-ment of the basin, and the significance of Lake Biwa sediment as a goodrecorder for paleoenvironmental changes. Lake Biwa is, therefore, an idealterrestrial site to explore paleoclimate and tectonic history during the past1 Ma of East Asia. Wewill introduce the staratigraphy of new core (6 pistoncores and two drilling cores) (Takemura et al., 2010) obtained in 2007 and2008 from the viewpoint of lithological characteristics and teph-rochronological evidences at different sites.
MODELING THE PAST - A GIS BASED STUDY FOR THE RECONSTRUCTIONOF PAST LAND USE AND HUMAN IMPACT ON THE ENVIRONMENT(NIEDERLAUSITZ, SÜDBRANDENBURG)
Melanie Takla. Brandenburg University of Technology/Research Cent,GermanyE-mail address: [email protected]
Within the opencast mining in Lower Lusatia (Brandenburg, Germany)archaeologists discovered in the “Jänschwalder Heide” the probably largestarchaeologically investigated charcoal production area, at least in Germany.To date more than 400 circular upright kilns are prospected and excavated.The large number of kilns and especially the great part of ground planswithlarge diameters suggest charcoal production for industry presumablylinked with the iron works at Peitz where bog iron ore was smelted since1567. Charcoal burning and related activities certainly had tremendousconsequences for the environment. This study aims to develop a GIS-basedmodel of the anthropogenic induced environmental change. The focus lieson the impact of the charcoal burning and related activities on the envi-ronment in the area of the “Jänschwalder Heide”. The project is performedin close cooperation with archaeologists of the BLDAM. The study site issituated c. 100 km southeast of Berlin in Lower Lusatia, South Brandenburgin the apron of the opencast mine Jänschwalde.The following data and information will be used for modeling using theGeographic Information System ArcGIS (ESRI): Airborne laser scanningdata with an accuracy of 1m, archaeological finds, physio-geographic datalike topography, soils, geology, hydrology, historical maps from 1767 on,forest history and data from absolute age determination. A Digital Eleva-tion Model (DEM) is used for visualization and as a base for past surfacemodeling. The location of archaeological finds, particularly the location ofthe charcoal hearths will be examined with regard to the physio-geographical settings and the land tenure. In addition, historic maps areevaluated in terms of the past road network, and forest-open land ratio.The model will be calibrated and supplemented with data from ongoinggeomorphological and pedological investigations which are carried outconcurrently within the project.
LATE SAALIAN – EEMIAN TRANSITION: A NEW HIGH-RESOLUTIONRECORD OF ENVIRONMENTAL CHANGES FROM THE NORTHEASTERNWHITE SEA REGION, NORTHERN RUSSIA
Ekaterina Taldenkova. Moscow State University, Russian FederationE-mail address: [email protected]
In relation to the overall importance of reconstructing interglacial marineenvironments and water mass evolution in subpolar and polar northernregions we carried out a high-resolution investigation of a 4.5 m thicksequence of Eemian marine beds directly overlying Saalian till in Bychye,the White Sea Region. The obtained sediment samples allow for a new,detailed evaluation of past events on the basis of changes in lithology,microfossils (foraminifers, ostracods, pollen, aquatic palynomorphs) andbenthic foraminiferal isotope data (d 18O, d 13C). The early stage of inun-dation is featured by accumulation of marine clays overlying the till andstands out as a period of harsh, fluvially-affected environmental conditionswith cold turbid waters and heavy seasonal sea-ice cover. Further climateamelioration and increasing influence of open-sea waters correspond toaccumulation of silts and sands of the middle part of the section. These areevidenced by increasing total abundance and diversity of microfossils, highpercentage of foraminifers characteristic of the Arctic shelves with highseasonal productivity (Islandiella spp., Nonion labradoricum), occurrenceof relatively deep-water Arctic species among foraminifers (Melonis bar-leeanus) and ostracods (Krithe glacialis), sharp increase in d18O values,and growing representation of broad-leaved species in pollen spectra. Thefinal regressive stage, which was caused by isostatic crustal rebound,witnessed the accumulation of sands, gradually decreasing taxonomicdiversity and abundance of microfossils, and a growing proportion ofrelatively warm-water and shallow-water species especially amongostracods (Finmarchinella finmarchica, Patagonicythere dubia, Cytherelutea, Hemicytherura clathrata). Climatic conditions characterized as themost humid and warm gradually deteriorate towards the end of therecord. No direct indicators of the penetration of Atlantic waters have beenfound among the composition of microfossils.
