Late Quaternary glacial history of the northern Antarctic Peninsula: Evidence from the Bellingshausen continental shelf

[摘要] Piston cores and Precision Depth Recorder (PDR) data collected from the western margin of the Northern Antarctic Peninsula were examined to reconstruct the late Wisconsinian glacial setting of this region and characterize the Holocene depositional setting. Evidence of subglacial scouring is restricted to the inner continental shelf, with the exception of the Adelaide-Biscoe Trough whose bed is scoured partially onto the outer shelf. Basal Tills were sampled on the inner shelf and from the Adelaide-Biscoe Trough. Transitional Glacial Marine sediments occur mostly in Marguerite Bay; whereas, modern diatomaceous muds occur almost directly on top of basal till in the Adelaide-Biscoe Trough. Terrigenous gravelly muds dominate the outer continental shelf. Petrogenic variability, pebble shape analyses and oxygen isotope data indicate that these sediments were deposited during the Holocene by icebergs. This glacial reconstruction places grounded ice in Marguerite Bay and the Adelaide-Biscoe Trough. Glacial ice retreated rapidly from the northern regions, while offshore of Marguerite Bay, an ice tongue slowly retreated. $sp{14}$C data indicate that an ice shelf in Marguerite Bay retreated after 12,430 ybp.

[发布机构] Rice University