«Red-colored» Pliocene soils of linear levelling surfaces in Western Cisbaikalia (Russia)

Abstract

This paper presents a comparative assessment of «red-coloured» Pliocene soils studied at the well-known paleontological sites of Tologoi and Udunga (Transbaikalia) and new objects - the sections of the Mikhailovka and Kholmushino quarries (Western Cisbaikalia). Studies of Pliocene sediments and soils in Baikal Siberia have quite a long history. «Red» Pliocene soils are sporadically found within the Baikal rift zone and on the Siberian platform - on fragments of the near-valley levelling surface at elevations of 70-120 m above the edge of the Angara River and its tributaries. A comparative assessment of the studied sections with similar age and morphology of the deposits of Transbaikalia showed that the deposits differ quite significantly in the content of rock-forming oxides. In particular, in the sediments of Western Cisbaikalia, a higher content of silicon oxide and a lower content of sesquioxides are observed, which might be evidence of worse conditions for heat and moisture supply in this region. An excess of the Clarke values characterizes the rare-earth elemental composition of the Pliocene deposits of Transbaikalia for La, Ce, Nd, Yb, while the deposits of the Western Cisbaikalia contain these elements in amounts lower than those of the Clarke ones.