Paleoclimatic interpretation of the late Quaternary by sedimentary facies modelling of the bottom sediments in Lake Hovsgol of northern Mongolia

Lake Hovsgol is located in Asian continental interior and occupies one of series of Cenozoic rift basins which comprise the Baikal Rift Zone. In this study, we studied the change of paleoclimate and paleoenvironment of late Quaternary through the classification of sediment facies using the HS-11(117 cm) from the depth 120 m, and HS-12(82.5 cm) cores from the depth 180 m, which were obtained at the north of Lake Hovsgol. The various sedimentary analysis like mineral composition and grain size analysis were conducted and the age was deducted by the analysis of radiocarbon dating. Sand and mud rhythmite (Sr) facies occurs in the lowest of HS-12 core and it was formed at the Last Glacial Maxium. This facies shows rhythmites composed of sand and muds, and it contains many ostracods microfossils. Weakly laminated sandy mud (Swl) facies which was formed at the deglacial time was discovered at both cores and was interpreted that it was deposited at the similar sedimentary environment although these facies were deposited at the different period and the different depths of the lake. Weakly laminated mud (Mwl) facies of HS-12 core was deposited at the deglacial time along the continuous rising of the lake level so this facies had a fining-upward feature. The Holocene weakly laminated mud (Mld) facies of HS-11 is faintly laminated and composed of diatom and elastic mud which is found in the lower part. Structureless mud (Md) facies was observed at the uppermost part in the both cores, and sedimentary structures were formed by slow sedimentation and they were disturbed later by bioturbation.