Sergey K. Krivonogov

Predictability of biomass burning in response to climate changes

Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.

Radiocarbon chronology of the late Pleistocene-Holocene paleogeographic events in lake Baikal region (Siberia)

New radiocarbon dates obtained from Late Pleistocene and Holocene deposits of the southern, eastern, and northern shores of Lake Baikal in 1995-2001 are presented, and the most important results of paleoenvironmental studies based on (super 14) C data are discussed. The following paleogeographic events were verified with the help of (super 14) C dating: 1) first Late Pleistocene glaciation (Early Zyryan); 2) Middle Zyryan interstadial; 3) loess formation during the Late Zyryan (Sartan) deglaciation; 4) warm and cold events in the Late Glacial; and 5) vegetation changes and forest successions during the Late Glacial and Holocene.

Pollen Record from the Chivyrkui Bay Outcrop on the Eastern Shore of Lake Baikal since the Late Glacial

Bogs have formed on the shore of Chivyrkui Bay near Svyatoy Nose Peninsula on the eastern shore of Lake Baikal. Two sediment columns were taken from the outcrop of one of bogs (53°39′N, 109°12′E) to investigate the vegetation history of the eastern shore area of Lake Baikal. The forests around the bog are composed mainly of Pinus sylvestris, Pinus sibirica, Larix sibirica, and Abies sibirica. The results of a palynological study of the cores with 14 radio-carbon dates revealed the following vegetation history since the late glacial. The late glacial and early Holocene vegetation from 12000 to 9000 14C years BP was a shrub tundra with spruce and birch trees, thickets of dwarf birch and alder, and herbs such as Gramineae and Artemisia. Between 9000 and 8000 14C years BP, spruce forests expanded in the area, accompanied by some fir and pine, indicating the initial development of the dark taiga. Pine trees gradually increased after 8000 14C years BP and then started a dramatic increase, to become dominant in 6000 14C years BP in the dark taiga forests. The vegetation from 6000 14C years BP to the present was mainly composed of pines (Pinus sylvestris and P. sibirica) and birch, accompanied by spruce, fir, and larch.

Lake Hovsgol in the Late Pleistocene and Holocene: On-Land Geological Evidence for a Change in Its Level

We present geomorphological and sedimentological evidence for a change in the level of Lake Hovsgol during the second half of the late Pleistocene and Holocene. Both transgressive and regressive stages of lake evolution have been deduced from a study of lacustrine, river, slope, and glacial sediments and landforms. The events which caused the lake level to rise took place in the Karginian,* late Sartanian, early Holocene, and recent time, and were a result of warming periods. The lowering of the level resulted from periods of glaciation and the middle Holocene arid stage.

Extent of the Aral Sea Drop in the Middle Age

The landlocked Aral Sea, which is dying off at present (Fig. 1), was a widespread weaksalty basin with abundant life at least in the 1960s. Then its level started to drop rapidly, the area of the lake decreased to a quarter of its former size, and its volume was reduced tenfold. The ecological crisis of the Aral Sea is considered to be the effect of excessive water intake from the feeding tributaries, Amu Darya and Syr Darya, for irrigation. Did a similar catastrophe occur in the past, or is it an exclusively anthropogenic phe� nomenon.

Geomorphological Development of the Tunka Depression in the Baikal Rift Zone in Siberia, Russia

There is no large lake, such as Lake Baikal or Lake Hovsgol, in the Tunka depression now, but it is one of the depressions of the Baikal rift zone. The bottom of the depression is formed of Miocene to Holocene rocks set on Precambrian and Paleozoic rocks, which mainly crop out in mountains north and south of the depression. In Miocene times, lacustrine sediments were formed and basaltic lava flows erupted. However, in the Pliocene and Pleistocene, fluvial or fluvioglacial sediments were formed. Therefore, it is assumed that the development of the Tunka depression is different from that of Lake Baikal and Lake Hovsgol. The difference has to do with the outflow of water via the Irkut river during the Phocene, Pleistocene, and Holocene. In the Phocene, any large lake apparently disappeared, because the sediments are composed of coarse sand and pebbles produced by the rivers. In the Pleistocene, many gravel beds were formed by fluvial and fluvioglacial processes, and, especially in the middle Pleistocene, water probably flowed out of Lake Baikal to the Irkut river via the Kultuk vafley (Kononov and Mats 1986; Mats et al. 2000).

Uranium in Saline Lakes of Mongolia and Adjacent Areas

1 Introduction Increasing demand for uranium raw materials for the nuclear industry has stimulated interest in non-traditional sources,including hydromineral ones[Qin,2009].Those are saline lakes located in the uranium ore districts.Accumulation of uranium in such lakes results from the leaching of uranium from the rocks by surface and ground

The Main Factors of Uranium Accumulation in the Ishim Plain Saline Lakes (Western Siberia)

Hydrochemical analysis of the high-salinity lakes in the Ishim Plain (>250–300 g/L) located at the border with the Northern Kazakhstan uranium ore province is performed. The studies have shown that the main factor of concentration and redistribution of uranium in the lake basins of the Ishim Plain are the processes of intense salt deflation causing sanding of lakes and uranium depletion in the near-surface layer of the bottom deposits. The correlation between the hydroxide forms of uranium binding in the bottom lacustrine deposits of the Ishim Plain and the coffinite composition of the Semizbai deposit makes it possible to consider this province to be promising for the discovery of hydromineral uranium deposits.