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High-resolution pollen records from Lake Baikal revealed considerable regional differences in the vegetation development and pronounced climate variability during the last glacial-interglacial transition and Holocene. Correlation between cores was successfully based on a chronology constructed from AMS 14 C dating of pollen concentrates. Comparison to other radiocarbon-dated pollen sequences from the Baikal region suggests that the chronology presented is very reliable and thus correlation to other dated events can easily be performed. Pollen indices, which reflect relative changes in major vegetation types and limitations of growing conditions by moisture availability and temperature, demonstrate near-synchronous vegetation changes, which suggest synchronous large-scale climate variation across the Baikal region. Due to the low level or even absence of human impact in the Lake Baikal region, the pollen data illustrate that in the continental interior of NE Eurasia Holocene climate variability was very pronounced. After initial warming and a strong increase in relative moisture (ca. 15-14.6 cal ka BP) the Bölling / Alleröd like event was punctuated by three cool and dry events. These events at approx. 14.2 ka BP, 13.8 ka BP and 13.2 cal ka BP can be compared to coolings as recorded in GISP 2 oxygen isotope records from Greenland ice cores. An expansion of Betula sect.Nane/Fruticosae, Artemisia and Chenopodiaceae marks the Younger Dryas-like cooling event (ca. 12.5-12 cal ka BP). High temperatures and favourable moisture conditions during the first part ofHolocene favoured the optimum development of dark-coniferous taiga between 10-8 cal ka BP in the south and 9.0-7.5 cal ka in the northeast. A fir and spruce decline in the southern mountains (ca. 8-7 cal ka BP) can be related to the 8.2 cal ka BP cooling event. The pronounced mid-Holocene cooling event and a transition towards dry conditions (ca. 7.0-5.5 cal ka BP) preceded the nearly synchronous regional expansion of pine taiga.Maximum distribution of Scots pine forests marks the Holocene thermal optimum (ca. 6.5 -5.7 cal ka BP), which was followed by two subsequent cooling events (ca. 5.5-

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ABSTRACT. This work focuses on the preparation and dating of sporomorph (pollen and spores) concentrates of high purity. Three sediment cores recovered from Lake Baikal within the EU-Project CONTINENT were subjected to palynological analyses and accelerator mass spectrometry (AMS) radiocarbon dating. Laboratory processing of concentrates was aimed at the removal of non-sporomorph organic matter by means of chemical treatment, micro-sieving, and heavy liquid separation. The obtained concentrates were checked under the microscope and sample purity was estimated on the basis of particle counts. The results of AMS 14 C dating show differences in the sedimentation rate among 3 sites of Lake Baikal. METHODSLake Baikal is situated in southeast Siberia in the eastern part of the Russian Federation near the Mongolian border. It is the largest (20% of the total volume of surface freshwater), deepest (>1600 m), and probably oldest (about 25 million yr) lake on Earth.Radiocarbon dating of Lake Baikal sediments is a difficult challenge, as previous studies have proved (Coleman 1996). The main problem is the scarcity of material suitable for dating because the sediments are very poor in organic matter and carbonates. Our work focused on the preparation and dating of high-purity sporomorph concentrates.Three sediment cores recovered from Lake Baikal were subjected to palynological analyses and AMS 14 C dating. The cores come from 3 different locations: Posolskoe Bank, Vydrino Shoulder, and Continent Ridge (see Figure 1). The cores subjected to dating were collected with the use of a Kasten corer, which gives the best assurance of complete recovery of the sediment.The preliminary knowledge about sporomorph concentrations and sporomorph assemblages in Holocene and Late Glacial core sections, necessary for selecting appropriate subsampling levels, was gained during palynological analyses of these cores. Sample sizes ranged between 20 and 160 cm 3 (see Table 1), depending on available material, pollen concentrations, and a rough calculation of pollen mass and carbon content using data available from previous studies (Erdtman 1969;Brown et al. 1989). The volume of samples taken for preparation was adjusted to obtain a minimum carbon content of about 2-4 mg per sample. Extraction of SporomorphsLaboratory processing of pollen and spore concentrates was aimed at achieving a high purity of the samples. The removal of inorganic and non-sporomorph organic matter was carried out using chemical treatment, micro-sieving, and heavy liquid separation.

International Continental Scientific Drilling Program (ICDP) drilled a complete succession of the lacustrine sediment sequence deposited during the last ~500,000 years in Lake Van, Eastern Anatolia (Turkey). Based on a detailed seismic site survey, two sites at a water depth of up to 360 m were drilled in summer 2010, and cores were retrieved from sub-lake-floor depths of 140 m (Northern Basin) and 220 m (Ahlat Ridge). To obtain a complete sedimentary section, the two sites were multiple-cored in order to investigate the paleoclimate history of a sensitive semi-arid region between the Black, Caspian, and Mediterranean seas. Further scientific goals of the PALEOVAN project are the reconstruction of earthquake activity, as well as the temporal, spatial, and compositional evolution of volcanism as reflected in the deposition of tephra layers. The sediments host organic matter from different sources and hence composition, which will be unravelled using biomarkers. Pathways for migration of continental and mantle-derived noble gases will be analyzed in pore waters. Preliminary 40Ar/39Ar single crystal dating of tephra layers and pollen analyses suggest that the Ahlat Ridge record encompasses more than half a million years of paleoclimate and volcanic/geodynamic history, providing the longest continental record in the entire Near East to date. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.14.02.2012" target="_blank">10.2204/iodp.sd.14.02.2012</a>

More than 400 samples for paleobotanical and sedimentological investigations were collected from Late Pliocene and earliest Pleistocene beds in the open-cast lignite mine Hambach. They were analysed to obtain information about the paleoecology and paleoclimate of this time interval. The sedimentation type changed from a high-energy meandering fluvial system to floodplain, swamp and oxbow lake sedimentation. The typical Tertiary floral elements decreased with the onset of increasingly cooler climatic conditions and disappeared at the beginning of the Pleistocene to be substituted by a impoverished and coldadapted flora. These combined litho-and biostratigraphic investigations led to an improved and reproducible separation of Late Pliocene from Early Pleistocene deposits.

The forest-steppe ecotone in southern Siberia is highly sensitive to climate change; global warming is expected to push the ecotone northwards, at the same time resulting in degradation of the underlying permafrost. To gain a deeper understanding of long-term forest-steppe carbon dynamics, we use a highly resolved, multiproxy, palaeolimnological approach, based on sediment records from Lake Baikal. We reconstruct proxies that are relevant to understanding carbon dynamics including carbon mass accumulation rates (CMAR; g C m À2 yr À1) and isotope composition of organic matter (d 13 C TOC ). Forest-steppe dynamics were reconstructed using pollen, and diatom records provided measures of primary production from near-and off-shore communities. We used a generalized additive model (GAM) to identify significant change points in temporal series, and by applying generalized linear leastsquares regression modelling to components of the multiproxy data, we address (1) What factors influence carbon dynamics during early Holocene warming and late Holocene cooling? (2) How did carbon dynamics respond to abrupt sub-Milankovitch scale events? and (3) What is the Holocene carbon storage budget for Lake Baikal. CMAR values range between 2.8 and 12.5 g C m À2 yr À1 . Peak burial rates (and greatest variability) occurred during the early Holocene, associated with melting permafrost and retreating glaciers, while lowest burial rates occurred during the neoglacial. Significant shifts in carbon dynamics at 10.3, 4.1 and 2.8 kyr BP provide compelling evidence for the sensitivity of the region to sub-Milankovitch drivers of climate change. We estimate that 1.03 Pg C was buried in Lake Baikal sediments during the Holocene, almost one-quarter of which was buried during the early Holocene alone. Combined, our results highlight the importance of understanding the close linkages between carbon cycling and hydrological processes, not just temperatures, in southern Siberian environments.