Provenance and temporal variability of ice rafted debris in the Indian sector of the Southern Ocean during the last 22,000 years

Journal of Earth system science

A Sahana1¹  Meloth Thamban1¹  M C Manoj1¹  Rahul Mohan1¹  Kotha Mahender2² 

[1]National Centre for Antarctic and Ocean Research, Headland Sada, Goa 403 804, India.$$

[2]Department of Earth Science, Goa University, Taleigao Plateau, Goa 403 206, India.$$

关键词: Ice rafted debris;    provenance;    last glacial maximum;    Southern Ocean.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Ice rafted debris (IRD) records were studied in two sediment cores (SK200/22a and SK200/27) from the sub-Antarctic and Polar frontal regime of the Indian sector of Southern Ocean for their distribution and provenance during the last 22,000 years. The IRD fraction consists of quartz and lithic grains, with the lithic grains dominated by volcaniclastic materials. IRD content was high at marine isotope stage 2 but decreased dramatically to near absence at the Termination 1 and the Holocene. The concentration of IRD at glacial section of the core SK200/27 was nearly twice that of SK200/22a. Moreover, IRD were more abundant at the last glacial maxima (LGM) in SK200/27 with its peak abundance proceeding by nearly two millennia than at SK200/22a. It appears that an intensification of Antarctic glaciation combined with a northward migration of the Polar Front during LGM promoted high IRD flux at SK200/27 and subsequent deglacial warming have influenced the IRD supply at SK200/22a. Quartz and lithic grains may have derived from two different sources, the former transported from the Antarctic mainland, while the latter from the islands of volcanic origin from Southern Ocean. Sea-ice, influenced by the Antarctic Circumpolar Current is suggested to be a dominant mechanism for the distribution of lithic IRD in the region.

【 授权许可】

Unknown