We compare the sediment magnetic properties of two lakes in Schirmacher Oasis, East Antarctica and discuss the intensity of pedogenesis during the Late Quaternary. The magnetic minerals are land-derived with no obliteration of the signal due to bacterial or anthropogenic sources. The magnetic grains of Lake L-49 are much smaller in size compared to Lake Sandy's (low ratio values of IRM20mT/ARM and S20 ). The iron oxide minerals in Lake Sandy's sediments are coarse stable single domain (SSD) and multi-domain (MD) grains with the SSD concentration increasing during the Holocene. Percentage frequency-dependent susceptibility, a marker for pedogenic iron oxide minerals shows a similar trend for Lake Sandy, with the values remaining low during the Last Glacial Stage (LGS) and increasing towards the Holocene. Such a pattern is not observed in the sediments of Lake L-49. Principal Component Analysis reveals a relatively stronger intensity of pedogenesis in the Lake Sandy catchment during the deglaciation. From the data, we observe that even though pedogenesis is active, the intensity is not strong enough to form superparamagnetic (SP) grains. The peaks in χfd for both the lakes show a direct relationship with Antarctic Isotope Maximum events recorded in an ice-core data suggesting that χfd can be used as a proxy for paleo-pedogenesis in Antarctica.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science
- Earth and Planetary Sciences(all)