Quaternary Record of Paleoenvironmental Conditions in the Antarctic zone in Southwest Pacific sector of the Southern Ocean: Preliminary results

Abstract

Three cores (RS15-LC42, RS15-LC47, RS15-LC48) were retrieved in Southern Ocean in close proximity to the Ross Sea shelf in January, 2015 from the Korean RVIB Araon. The cores are generally composed of alternating massive light gray sandy mud and laminated greenish gray diatomaceous mud. Intermittent existence of IRDs on the whole core indicates that ice rafting contributed substantially to sediment deposition. Overall sediments include the traces of bioturbation. They contain diatoms and foraminifera, although diatoms are by far the dominant fossil present. Although study site is located near the late Cenozoic volcanic centers of Adare Peninsula and the Balleny islands, there is little evidence of volcanic contribution to the sediment. The chronology was roughly constructed based on paleomagnetism data by comparing with marine magnetic anomalies. Magnetic susceptibility (MS), concentrations of total organic carbon (TOC), biogenic opal, and CaCO₃, and grain size were measured at 1 - 5 cm intervals. Concentration of cosmogenic nuclide ¹⁰Be was measured at 30cm interval. Oxygen isotopic composition of foramiinifera were analyzed. Here we present initial results from this core sediment.