Pollen records of the Bykovsky Peninsula

New pollen and radiocarbon data from the Bykovsky Peninsula document the Late Pleistocene and Holocene environmental history of the Laptev Sea coast. More than 60 AMS-14C and conventional 14C dates indicate that the deposits accumulated during the last 60,000 radiocarbon yr BP. High concentration of green alga colonies (Pediustrum and Botryococcus) in the investigated sediment show that sedimentation was mostly in shallow water environments. Scarce grass and sedge communities dominated the vegetation 53-60 kyr BP. Climate was cold and dry. Open Poaceae and Cypcraccae associations with Asteraceae, Ranunculaceae, and Cichoriaceac, dominated in the area about 48-42.5 kyr BP. Steppic communities with Artemisia and shrubby tundra communities with Salix and Betula sect. Nanae were also present. Climate was dry, but relatively warm. Vegetation cover became denser about 42.5-33.5 kyr BP, reflecting more favorable climate conditions. Scarce Poaceae communities with some Caryophyllaceae, Asteraceae, Cichoriaceae, and Selaginella rupestris covered the Bykovsky Peninsula area during the Sartan (Late Weichselian) stage about 26-16 kyr BP. Disturbed, uncovered soils were very common in the area. Climate was extremely cold and dry. Poaceae and Cyperaceae associations with Caryophyllaceae, Asteraceae, Cichoriaceae dominated the vegetation in the late Sartan, ca 16-12.2 kyr BP. Climate was significantly warmer than in the early Sartan time. The lee Complex sedimentation was interrupted about 12 kyr BP; most likely it was connected with the beginning of the Allerod warnring. Shrubby (Betula sect. Nanae, Alnusfnuicosa, Salix, Ericales) tundra was widely distributed on the Bykovsky Peninsula during the early-middle Holacene. Climate was most favorable between 8200 and 4500 yr BP. Vegetation became similar to modern after 4500 yr BP, suggesting a deterioration of climate.

Abundance of plant macrofossils, mollusca and ostracoda in sediments obtained near Tessin, north Germany

A depression filled with Late Glacial and Holocene sediments was excavated during the geological exploration and recovery of a dump area near Tessin close to Rostock, and initiated the studies of the present paper. Pebble analysis of three exposed or respectively drilled till horizons as well as pollenanalytical, carpological and faunistical studies carried out allow the stratigraphical subdivision of the Quaternary sequence of the dump area. The basal till was probably the result of dead ice decay, and was lithostratigraphically assigned to the Pomerian Stage (qw2). The palynological results of boreholes RKS 19/93 and A/92 reveal pre-Allerod and other sediments instead of the expected interweichselian deposits. Based on the palynological and carpological findings, we correlated the beginning of the late glacial development in the locality with the end of the Meiendorf-lnterstadial sensu Menke in Bock et al. (1985, doi:10.3285/eg.35.1.18). The limnic-telmatic sedimentation could be observed pollen floristically probably starting with the Meiendorf-lnterstadial (Hippophae-Betula nana-phase) followed by the Bolling-(Betula nana-B. alba s.l.-Artemisia-Helianthemum-Poaceae-phase) and the Allerad-lnterstadial [Betula alba s.l.-(Pinus)-Cyperaceae-phase] lasting up to the Younger Dryas (Juniperus-Artemisia-Poaceae-phase). Sedimentation closed during the Younger Dryas with the accumulation of fine sands. It was reactivated later during the Holocene due to the anthropogene influence (Older and Younger Subatlantic, dampness of the depression by clearing).

High-resolution multi-proxy record of the last interglacial period from Lake Van, eastern Anatolian high plateau, Turkey

A high-resolution multi-proxy record from Lake Van, eastern Anatolia, derived from a lacustrine sequence cored at the 357 m deep Ahlat Ridge (AR), allows a comprehensive view of paleoclimate and environmental history in the continental Near East during the last interglacial (LI). We combined paleovegetation (pollen), stable oxygen isotope (d18Obulk) and XRF data from the same sedimentary sequence, showing distinct variations during the period from 135 to 110 ka ago leading into and out of full interglacial conditions. The last interglacial plateau, as defined by the presence of thermophilous steppe-forest communities, lasted ca. 13.5 ka, from ~129.1-115.6 ka BP. The detailed palynological sequence at Lake Van documents a vegetation succession with several climatic phases: (I) the Pistacia zone (ca. 131.2-129.1 ka BP) indicates summer dryness and mild winter conditions during the initial warming, (II) the Quercus-Ulmus zone (ca. 129.1-127.2 ka BP) occurred during warm and humid climate conditions with enhanced evaporation, (III) the Carpinus zone (ca. 127.2-124.1 ka BP) suggest increasingly cooler and wetter conditions, and (IV) the expansion of Pinus at ~124.1 ka BP marks the onset of a colder/drier environment that extended into the interval of global ice growth. Pollen data suggest migration of thermophilous trees from refugial areas at the beginning of the last interglacial. Analogous to the current interglacial, the migration documents a time lag between the onset of climatic amelioration and the establishment of an oak steppe-forest, spanning 2.1 ka. Hence, the major difference between the last interglacial compared to the current interglacial (Holocene) is the abundance of Pinus as well as the decrease of deciduous broad-leaved trees, indicating higher continentality during the last interglacial. Finally, our results demonstrate intra-interglacial variability in the low mid-latitudes and suggest a close connection with the high-frequency climate variability recorded in Greenland ice cores.