Biological productivity and glaciomarine sedimentation in the Central Basin of the northwestern Ross Sea since the last glacial maximum

Abstract

This study documents multi-proxy data representing surface water productivity and AMS 14C dates of box (BC3) and gravity (GC2) cores in the Central Basin of the northwestern Ross Sea. Based on AMS 14C dates, a comparison of sediment properties between BC3 and GC2 reveals that BC3 records the complete Holocene (i.e., interglacial) history, which is correlated to the uppermost part of GC2. The lithostratigraphic succession of GC2 consists of the repetition of contrasting layers distinguished by the productivity proxies. In contrast to the uppermost sediment layer (i.e., interglacial), the subsurface sediment layer (i.e., deglacial) is distinctly characterized by very high biogenic components. Such pronounced biogenic remnants in the deglacial sediments are not explained exclusively by in situ enhanced productivity in the surface water. Our results, thus, suggest that eroded and reworked shelf sediments from a previous interglacial period enriched in biogenic components by the advancing ice sheet might be transported through the melt-water plumes from the grounding line to the Central Basin, to provide high geochemical properties of deglacial sediments. Thus, growth and retreat of the grounded ice sheet played an important role in glaciomarine sedimentation change in the Central Basin of the northwestern Ross Sea.