Publication Date:
1981-01-01
Description:
Present-day sedimentary environments in the eastern Weddell Sea confirm low clastic sediment input from wide (〉 100 km) ice shelves. Mainly bioclastic sediments are formedin situon the inner and shallow central-shelf areas (250 to 350 m water depth), with sedimentation rates probably 〈 0.01 m ka−3. Ice-rafted debris (IRD) is mainly deposited on the outer shelf and upper continental slope, with a sedimentation rate of 0.02 to 0.07 m ka−3. The coarse-grained texture of these deposits is caused by removal of finer grades in suspension during settling of IRD sediments. Overconsolidated till was deposited 〈 31 ka BP during expansion of grounded ice to the shelf break. Subsequent eustatic rise caused grounded ice to float. Frozen-on sediments melted out of the base of the ice, depositing soft pebbly mud above the till. Marine conditions similar to present-day conditions were found for the interval 30 to 40 ka BP.IRD variation is an indicator of ice-shelf coverage and changes in relative sea-level, and is, in low latitudes, probably inversely related to the degree of ice cover.
Print ISSN:
0260-3055
Electronic ISSN:
1727-5644
Topics:
Geography
,
Geosciences
