File(s) not publicly available
Evidence from diatoms for Holocene climate fluctuation along the East Antarctic margin
journal contribution
posted on 2023-05-16, 13:02 authored by Fiona TaylorFiona Taylor, Andrew McMinnAndrew McMinnDiatom assemblages in two Holocene sediment cores (GC1 and GC2) from the Mac. Robertson Shelf, East Antarctica, are compared with modern sedimentary diatom assemblages from the same area. Open marine deposition commenced in Iceberg Alley (GC1), on the outer continental shelf, >10.7 adj. 14C kyr BP. Chaetoceros resting spores, which may indicate water-column stabilization from melting glacial and/or sea ice or the maximum summer sea-ice retreat, dominate the diatom assemblage. Approximately 7.5 adj. 14C kyr BP, a sea-ice diatom assemblage was deposited. This assemblage is similar to that being deposited in the surface sediments of the Mac. Robertson Shelf today and suggests that perennial sea ice has persisted in the vicinity of Iceberg Alley since that time. Interbedded within the sea-ice assemblage, however, are Corethron-rich sediment layers that suggest mid- to late-Holocene high-productivity events associated with a climatic optimum. The diatom record from Nielsen Basin (GC2), on the inner continental shelf, is relatively uniform compared to that in GC1. Glacial ice was present over the region c. >5.6 adj. 14C kyr BP and a dissolution diatom assemblage was deposited beneath it. Following ice retreat, an ice-edge diatom assemblage was deposited briefly before sea-ice conditions similar to that on the continental shelf today developed. There is no evidence in GC2 for the mid- to late-Holocene high-productivity events identified in GC1.
History
Publication title
The HoloceneVolume
11Issue
4Pagination
455-466ISSN
0959-6836Department/School
Institute for Marine and Antarctic StudiesPublisher
Arnold, Hodder Headline PlcPlace of publication
LondonRepository Status
- Restricted