Reconstructing the oxygen depth profile in the Arabian Sea during the last glacial period

A total of six core sites of western Arabian Sea were selected to form a depth transect with water depths ranging from 600 to 3650 m, in order to reconstruct the oxygen depth profile in the Arabian Sea during the last glacial period. Four RC27 cores were sampled from the Lamont-Doherty Core Repository, and two TN041/047 cores were sampled from the Woods Hole Oceanographic Institution (WHOI) Seafloor Samples Repository. Sampling intervals were every 5 or 10 cm. All cores were dated to last ~30 thousand years. All samples were first freeze-dried, then wet-sieved to > 63 µm fraction with de-ionized water, and oven-dried at 45°C. Benthic foraminifera Cibicidoides spp. and Globobulimina affinis were picked from the > 212 µm fraction. Photos of benthic foraminifera were taken using a Scanning Electron Microscope (SEM) (Hitachi model TM3000) at WHOI. Benthic surface porosity was determined from the SEM photos. Benthic foraminifera carbon and oxygen isotopic analyses were made using a Finnigan MAT253 mass spectrometer at WHOI.本研究选取阿拉伯海西部共6处核心站位，构建水深范围为600至3650米的断面剖面，旨在重建末次冰期阿拉伯海的氧气深度剖面。4个RC27岩芯采自拉蒙特-多赫蒂岩芯库（Lamont-Doherty Core Repository），2个TN041/047岩芯采自伍兹霍尔海洋研究所（Woods Hole Oceanographic Institution, WHOI）海底样品库。采样间隔为每5厘米或10厘米。所有岩芯的定年结果均对应约3万年的沉积序列。所有样品首先经冷冻干燥处理，随后用去离子水湿筛至粒径大于63微米的组分，再于45℃下烘箱烘干。从粒径大于212微米的组分中挑取底栖有孔虫Cibicidoides spp.与Globobulimina affinis。在WHOI使用日立TM3000型扫描电子显微镜（Scanning Electron Microscope, SEM）拍摄底栖有孔虫的显微照片，并据此测定其表层孔隙度。底栖有孔虫的碳、氧同位素分析采用Finnigan MAT253质谱仪于WHOI完成。