¹⁰Be and ¹⁰Be^/9Be in glaciomarine sediments of Ross Sea, Antarctica: implications for mid-late Quaternary paleoenvironmental changes

This study documents the variation of Be isotopes (Be-10 and Be-9) and their ratio (Be-10/Be-9) from a Ross Sea sediment core (LC42) with relation to mid to late Pleistocene geomagnetic and paleoclimatic changes. Significant changes in Be isotope concentration are observed during pre and post-Mid-Pleistocene Transition (MPT) periods. The Be-10 concentration and Be-10/Be-9 ratio show a gradual decrease during the late Matuyama Chron, suggesting a relative increase in geomagnetic intensity. The overproduction episode associated with the Matuyama-Brunhes Boundary (MBB) does not show any pre- MBB precursor event. The progressively decreasing trend observed in Be-10 and Be-10/Be-9 ratio records from 1 to 0.8 Ma, with minimum values at around 0.8 Ma, suggests a relatively open sea condition during the early part of MPT and an extended glacial condition around MIS 22. The Be-10 and Be-10/Be-9 ratios are approximately constant during the pre-Mid Bruhnes Event (MBE) period and show a gradual increase after the MBE, indicating a climatic transition from colder (pre-MBE) to relatively warmer (post-MBE) conditions.