A Preliminary Study of Magnetic Proxies for the Late Quaternary Paleoclimate Using Gravity Cores From Lake Hovsgol, Northern Mongolia

Lake Hovsgol (50°30'~51°35'N, 100°15'~100°40'E) in northern Mongolia is the second largest and deepwater basin within the Baikal rift system, which is affected dominantly by East Asian Winter Monsoon. Lake Hovsgol is 135 km long, average 20 km wide, and has a maximum depth of 262 m. Lake Hovsgol sediments are potentially excellent paleoclimate recorders due to their altitude of 1645 m above sea level (about 1100 m higher than Lake Baikal) and minimal human influence. Recent studies reported magnetic susceptibility data along with detailed sedimentologic, absolute age-dating, and paleontologic data from Lake Hovsgol (Prokopenko et al., 2005; Hovsgol Drilling Project Group, 2007). Although magnetic susceptibility is one of the useful parameters for analyzing climatic change recorded by lake sediment, loess and paleosol around the world, other enviromagnetic parameters (e.g., frequency- dependent susceptibility, isothermal remanent magnetization, anhysteretic remanent magnetization, and bivariate ratios) can be more sensitive to climatic change in some cases. The aims of this study are to find the optimal magnetoclimate proxies for Lake Hovsgol sediments and to provide high resolution paleoclimate change model in the study area. We have measured various magnetic parameters representing magnetic composition, concentration, and granulometry of seven gravity cores from Lake Hovsgol. Preliminary correlations of magnetic properties with other paleoclimate proxies (e.g., lithology, AMS radiocarbon ages, sedimentary structure, and diatom analysis) yield three paleoenvironmental units that span about 20000 years: Last Glacial Maximum, Deglacial, and Holocene. Ongoing analytical work will further provide high resolution records for abrupt paleoclimate change within the units.