Recent drilling in Lake Hovsgol,NW Mongolia,recovered a sedimentary sequence with a base age of 1 cal Ma from the second-largest lake in the Baikal Rift Zone.Because of the small catchment,Hovsgol basin has elevated sensitivity to regional changes in the effective moisture,as seen from variable drill core lithologies and sediment fades.Here we discuss the work in progress on the regional Pleistocene paleoclimate synthesis based on the three key sediment sections from the Baikal Rift Zone.The section at Academician Ridge of Lake Baikal(53.7°N,drill cores BDP-96 and BDP-98) represents an area where Pleistocene sedimentation rates remained remarkably stable at ca.(4+2) cm·ka~(-1).Stable depositional setting allowed the development of the robust BDP-96 age model derived from orbital tuning of the cycles of biogenic silica content in sediments,which reflect past changes in diatom productivity.245 km SW,drill core BDP-99(52°N) has the best-resolved Baikal palynological record,more representative of regional vegetation than the pollen record of BDP-96.Despite the variable glacial-interglacial sedimentation rates at the BDP-99 site,this record can be closely correlated to BDP-96 using basin-wide diatom biostratigraphy.Some300 kilometers further southwest,Lake Hovsgol sediment section(HDP-04 drill core,51°N) consists of calcareous sediments with episodic deposition of carbonate-free diatomaceous layers during the past interglacials.HDP-04 is correlated to the BDP-96 via organic carbon-based productivity indices and the apparent diatom biostratigraphic ties between the basins.We show the relationship between productivity cycles in Lake Baikal and vegetation changes on land during three last interglacials.Productive diatom flora expanded in the lake at the time of the expansion of conifer forests in the Baikal region:durations of the intervals of high BioSi production(accumulation) match the duration of regional forest phases,as seen in the best-resolved records.We discuss repetitive patterns in the records of total organic carbon(TOC),total nitrogen(TN) and δ~(13) C_(org) in the parallel Lake Hovsgol in Lake Baikal sedimentary records,which reflect past changes in productivity and in the isotopic composition of the carbon pool of both lakes during the past 1 Ma.We show how productivity proxy signals may be used for distinguishing past glacials and interglacials and for constructing the age model for the HDP-04 sediment section.Finally,we discuss the results of the first quantitative reconstructions of regional climate during MIS 1,MIS 5e,and MIS 11 based on Lake Baikal palynological records in the context of mid-Pleistocene evolution of global climate and compare these reconstructions with the responses in the productivity proxy records. Recent drilling in Lake Hovsgol, NW Mongolia, recovered a sedimentary sequence with a base age of 1 cal Ma from the second-largest lake in the Baikal Rift Zone. Failure of the small catchment, Hovsgol basin has elevated sensitivity to regional changes in the effective moisture, as seen from variable drill core lithologies and sediment fades. Here we discuss the work in progress on the regional Pleistocene paleoclimate synthesis based on the three key sediment sections from the Baikal Rift Zone. The section at Academician Ridge of Lake Baikal (53.7 ° N, drill cores BDP-96 and BDP-98 represent an area where Pleistocene sedimentation rates are remarkably stable at ca. (4 + 2) cm · ka -1. Stable depositional setting allowed the development of the robust BDP- 96 age model derived from orbital tuning of the cycles of biogenic silica content in sediments, which reflect past changes in diatom productivity. 245 km SW, drill core BDP-99 (52 ° N) has the best-resolved Baikal palynological record, more represe ntative of regional vegetation than the pollen record of BDP-96. Expite the variable glacial-interglacial sedimentation rates at the BDP-99 site, this record can be closely correlated to BDP-96 using basin-wide diatom biostratigraphy. Home 300 kilometers further southwest, Lake Hovsgol sediment section (HDP-04 drill core, 51 ° N) consists of calcareous sediments with episodic deposition of carbonate-free diatomaceous layers during the past interglacials. HDP-04 is correlated to the BPC-96 via organic carbon-based productivity indices and the apparent diatom biostratigraphic ties between the basins.We show the relationship between productivity cycles in Lake Baikal and vegetation changes on land during three last interglacials.Productive diatom flora expanded in the lake at the time of the expansion of conifer forests in the Baikal region : durations of the intervals of high BioSi production (accumulation) match the duration of regional forest phases, as seen in the best-resolved records.We discuss repetitive patterns in the records of total organic carbon (TOC), total nitrogen (TN) and δ ~ (13) C_ (org) in the parallel Lake Hovsgol in Lake Baikal sedimentary records, which reflect past changes in productivity and in the isotopic composition of the carbon pool of both lakes during the past 1 Ma.We ​​show how productivity proxy signals may be used for distinguishing past glacials and interglacials and for constructing the age model for the HDP-04 sediment section. Finally, we discuss the results of the first quantitative reconstructions of regional climate during MIS 1, MIS 5e, and MIS 11 based on Lake Baikal palynological records in the context of mid-Pleistocene evolution of global climate and compare these reconstructions with the responses in the productivity proxy records.