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Rare earth elements (REE) and their relationships with biogenic silica (BSiO2), magnetic susceptibility, Al2O3 and Fe2O3 in Core DC-11 were analyzed to reveal sediment provenances and transport history by iceberg-current-atmosphere since 34 ka BP in the southeastern Scotia Sea, Antarctica. Temporal variation of REE is similar to that of Al2O3, indicating they mainly occur in terrigenous detritus and BSiO2 has obvious dilution effect on them. Sediments with high REE concentration, flat shale-normalized pattern, weak positive Eu anomaly, and high LaN/YbN ratio during the last glacial period indicated they are transferred from the Weddell Sea and eroded from the bordering lands with relatively old crust. The increases in magnetic susceptibility, ΔAl2O3, TFe2O3/Eu ratio indicated an enhanced input of dust from South America during this period. In early Deglaciation (19.6−14.1 ka BP), increasing Eu positive anomaly and lower LaN/YbN ratio indicated the southern branch of Antarctic Circumpolar Current (ACC) strengthened and contributed more sediments from the South Shetland Islands and Antarctic Peninsula due to the southward shifts of oceanic fronts, while decreasing magnetic susceptibility, ΔAl2O3, TFe2O3/Eu ratios showed rapid decrease in dust supply from South America. During the Antarctic Cold Reversal period (ACR, 14.1−12.9 ka BP), sediments from the South Shetland Islands and Antarctic Peninsula decreased sharply due to cold condition and weakened ACC branch, the weakest Eu positive anomaly and highest LaN/YbN ratio indicated that the sediments from the Weddell Sea dominated in the core again, and the peak of ice raft debris indicated ice rafting is vital or dominant agent. In the late Deglaciation (12.9−11.7 ka BP), the return of ACC branch to the South Shetland Islands and Antarctic Peninsula contributed more to the sediments in Core DC-11; in Holocene (11.7−0 ka BP), the ACC branch in the area between the South Shetland Islands and Antarctic Peninsula was generally enhanced, and its contribution to core sediments increased to be roughly equivalent to the amount of sediments from the Weddell Sea.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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