Glacigenic and associated marine sediments in the Weddell Sea, fjords of Spitsbergen and the Barents Sea: A review
1984; Elsevier BV; Volume: 57; Issue: 1-4 Linguagem: Inglês
10.1016/0025-3227(84)90195-6
ISSN1872-6151
Autores Tópico(s)Arctic and Antarctic ice dynamics
ResumoStudies of glacigenic and associated marine sediments in the Weddell Sea, fjords of Spitsbergen and Barents Sea show that during periods of limited glacial coverage (interstadials) large amounts of material may be brought into the sea, mainly by meltwater. The major load is deposited relatively close to the icefront (<10 km) at a rate of 5–10 cm yr−1. At times of maximum glacial extent, grounded ice extends onto the shelf with the shelf edge as the outer limit, and land and inner shelf areas are eroded. Main glacial depositional sites are then the outer shelf and shelf edge. The sedimentary environment outside an ice shelf is characterized by low clastic supply, mainly deposited from icebergs. Due to low turbidity and a supply of nutrient-rich water, biogenic matter accumulates, leading to a glaciomarine sequence rich in bioclastics. Sea-level lowering results in grounding and seaward expansion of the ice shelf. Subsequent eustatic rise causes the grounded ice to float. Deglaciation and sea-level rise reduces clastic input to the shelves. Glacial sediments are reworked, and carbonates may accumulate, forming tillite-carbonate sequence (e.g. Late Precambrian). Break-up of marine ice sheets such as the Barents Sea ice sheet seems to have taken place stepwise, in response to eustatic rise and climatic changes.
Referência(s)