Abstracts

Preliminary results of research of modern remnants of /Pinus sylvestris/ in the Baikal region and ancient floods of the Lena River are discussed. The main zone of pine distribution in the eastern slope of Baikalsky

Mountains is 500-1100 meters above sea level. A similar situation characterizes the isolated or semi-isolated pine population in Ol’khon Island. An exception is represented by the high-altitude distribution of

pine in the western slope of Baikal Mountains - at the source of the Lena River. Here, at 1400-1450 meters above sea level pine of dwarf and common wood forms are found. One cannot exclude the

possibility that this population is an ancient isolate, a preserved genetic throwback to the most northern pine isolates of the Lena River in Central Yakutiya. Basis of such proposal is the geological and geomorphology specifics of the territory – first of all, the enormous size of alluvial fans of Rita, Pokoinitskaya, and Zavorotnaya Rivers. They do not correspond to present power of named rivers, and have no analogies in alluvial fans even of the biggest rivers of Lake Baikal. The thickness of Rita alluvial fan is close to the thickness of the world famous alluvial fan of the Sarydzhaz River in

Tian Shan – which is a misunderstood phenomenon even today. From the view point of the authors, this phenomenon can be explained only by gigantic ancient floods that periodically repeated along the Sarydzhaz and Lena River courses in the Pleistocene (Fig. 3). Powerful floods of the Lena are confirmed by the wide distribution there of permafrost (frozen water of ancient floods), and also 100-meter thickness of sand terrace in Bestyakh and in other similar areas where pine forests grow. Some geological markers show that in the past, the pine populations of the Lena and Barguzin basins could have formed a causeway through the Baikal – for that reason genetic evidence of this ancient connection could be found in Ol’khon Island. The most probable areas for locations of ancient remnants and isolates of pine is

the high-altitude zone of the Lena and Barguzin basins. There, it was very possible to avoid the floods’ impact during whole Quaternary.

Note. Abstracts are published in author's edition

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