708
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
geomorphologic, and archaeologic work carried out in the foreland of the western Putoran
Plateau, in the western Byrranga Mountains, and on the Severnaya Zemlya Archipelago.
First results from permafrost deposits and ground ice bodies at the Labaz Lake have shown
that the last glaciation of the area predates the Middle Weichselian and that the East Siberian
anticyclon had gained in significance during Middle and Late Weichselian times, leading to a
distinctly higher continentality of the climate (Melles et aI., 1996; Derevyagin et aI., 1996;
Chizhov et aI., 1997). Evidence for a restricted ice advance during the Last Glacial Maximum
was also found on the Severnaya Zemlya Archipelago, based on geochronological and paleogeographic investigations (Bolshiyanov and Makeev, 1995).
A more detailed presentation and discussion of the permafrost development in the Labaz Lake
area, and its dependence on the Late Quaternary climatic history, is presented in this book by
Siegert et al. (this volume). The results support the suggestion that the last ice advance to the
central Taymyr lowland took place prior to the Middle Weichselian. The preservation of fossil
glacier ice in near-surface permafrost deposits evidence a strongly retarded deglaciation of this
territory with continuous, low-temperature permafrost. Climate warming during Middle
Weichselian interstadials and at the Pleistocene/Holocene transition led to distinct vegetation
changes and enhanced thermokarst processes, and subsequent peat accumulation. Following an
early Holocene climatic optimum, climatic deterioration since about 3 ka led to the drying of the
lakes and a gradual increase of permafrost aggregation. Additional information concerning the
latest Holocene climate and environment comes from the archaeological findings on the northern
Taymyr Peninsula (Pitul'ko, this volume). Limited information about the pre-Weichselian
history, in contrast, is available from the sampled permafrost deposits. Some data about the
fluctuations in relative sea level were obtained by ESR dating and lithostratigraphic studies of
marine deposits (Bolshiyanov and Molodkov, this volume).
Paleoenvironmental reconstructions by lake sediments
The sediment fill in lakes functions as one of the best natural data archives for
paleoenvironmental reconstructions because lakes act as sediment traps. Limnic sediments
generally represent more complete depositional sequences than other terrestrial deposits. With
multi-proxy data from lake sediments, complex information concerning the environmental
setting both in the catchment area and in the water column of lakes can be obtained. In addition,
detailed age determinations can often be achieved by radiocarbon dating of organic matter.
Hence, lake sediments may supply high-resolution reconstructions of the environmental
history, with good stratigraphic control.
Within the scope of the "Taymyr" Project, long sediment cores were recovered from the lakes
Lama (18.9 m), Pyassino (6.0 m), Kokora (5.2 m), Portnyagino (4.0 m), Taymyr (14.3 m),
Levinson-Lessing (22.4 m), Changeable (12.7 m), and Fjord (3.2 m). These lakes cover the
entire project study area (Figures 3 and 4). In the lakes Lama, Taymyr, and Levinson-Lessing,
in addition, the large-scale sediment architecture was investigated by sub-bottom profiling. With
the existing sample and data set, therefore, both spatial and temporal variations of the climatic
and environmental histories can be reconstructed.
The analytical work on the lake sediment cores is manifold, being used irregularly in
dependence on individual objectives and core qualities. Special emphasis is put on the sediment
chronology, sedimentology, palynology, micropaleontology, geochemistry, and mineralogy.
First results, obtained on sediment cores from the Lama Lake and the Levinson-Lessing Lake,
had shown that palynological analyses supply comprehensive information on the climatic
evolution and related vegetation history (Hahne and Melles, 1997) and that investigations of
lake sediment cores in the Taymyr region ideally complement investigations of permafrost
profiles and ground ice bodies on land (Melles et a!., 1996).
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
geomorphologic, and archaeologic work carried out in the foreland of the western Putoran
Plateau, in the western Byrranga Mountains, and on the Severnaya Zemlya Archipelago.
First results from permafrost deposits and ground ice bodies at the Labaz Lake have shown
that the last glaciation of the area predates the Middle Weichselian and that the East Siberian
anticyclon had gained in significance during Middle and Late Weichselian times, leading to a
distinctly higher continentality of the climate (Melles et aI., 1996; Derevyagin et aI., 1996;
Chizhov et aI., 1997). Evidence for a restricted ice advance during the Last Glacial Maximum
was also found on the Severnaya Zemlya Archipelago, based on geochronological and paleogeographic investigations (Bolshiyanov and Makeev, 1995).
A more detailed presentation and discussion of the permafrost development in the Labaz Lake
area, and its dependence on the Late Quaternary climatic history, is presented in this book by
Siegert et al. (this volume). The results support the suggestion that the last ice advance to the
central Taymyr lowland took place prior to the Middle Weichselian. The preservation of fossil
glacier ice in near-surface permafrost deposits evidence a strongly retarded deglaciation of this
territory with continuous, low-temperature permafrost. Climate warming during Middle
Weichselian interstadials and at the Pleistocene/Holocene transition led to distinct vegetation
changes and enhanced thermokarst processes, and subsequent peat accumulation. Following an
early Holocene climatic optimum, climatic deterioration since about 3 ka led to the drying of the
lakes and a gradual increase of permafrost aggregation. Additional information concerning the
latest Holocene climate and environment comes from the archaeological findings on the northern
Taymyr Peninsula (Pitul'ko, this volume). Limited information about the pre-Weichselian
history, in contrast, is available from the sampled permafrost deposits. Some data about the
fluctuations in relative sea level were obtained by ESR dating and lithostratigraphic studies of
marine deposits (Bolshiyanov and Molodkov, this volume).
Paleoenvironmental reconstructions by lake sediments
The sediment fill in lakes functions as one of the best natural data archives for
paleoenvironmental reconstructions because lakes act as sediment traps. Limnic sediments
generally represent more complete depositional sequences than other terrestrial deposits. With
multi-proxy data from lake sediments, complex information concerning the environmental
setting both in the catchment area and in the water column of lakes can be obtained. In addition,
detailed age determinations can often be achieved by radiocarbon dating of organic matter.
Hence, lake sediments may supply high-resolution reconstructions of the environmental
history, with good stratigraphic control.
Within the scope of the "Taymyr" Project, long sediment cores were recovered from the lakes
Lama (18.9 m), Pyassino (6.0 m), Kokora (5.2 m), Portnyagino (4.0 m), Taymyr (14.3 m),
Levinson-Lessing (22.4 m), Changeable (12.7 m), and Fjord (3.2 m). These lakes cover the
entire project study area (Figures 3 and 4). In the lakes Lama, Taymyr, and Levinson-Lessing,
in addition, the large-scale sediment architecture was investigated by sub-bottom profiling. With
the existing sample and data set, therefore, both spatial and temporal variations of the climatic
and environmental histories can be reconstructed.
The analytical work on the lake sediment cores is manifold, being used irregularly in
dependence on individual objectives and core qualities. Special emphasis is put on the sediment
chronology, sedimentology, palynology, micropaleontology, geochemistry, and mineralogy.
First results, obtained on sediment cores from the Lama Lake and the Levinson-Lessing Lake,
had shown that palynological analyses supply comprehensive information on the climatic
evolution and related vegetation history (Hahne and Melles, 1997) and that investigations of
lake sediment cores in the Taymyr region ideally complement investigations of permafrost
profiles and ground ice bodies on land (Melles et a!., 1996).