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© Springer Nature Switzerland AG 2020
P. S. Goel et al. (eds.), Climate Change and the White World,
https://doi.org/10.1007/978-3-030-21679-5_4
Glacial Sediments of Schirmacher Oasis,
East Antarctica and their Characteristics
Rasik Ravindra
Abstract Schirmacher Oasis in Central Dronning Maud Land of East Antarctica
represents a polar and periglacial environment that exhibits large accumulation of
unconsolidated sediments as moraines and debris dropped by retreating ice sheet
and admixture of sand-silt-clay deposited by the melt water channels. Study involved
collection of sediments from various depositional environments for analyses. The
sand-silt-clay ratios determined from these samples show that the sand percentage
is varying between 71% and 95.22%, silt percentage varies between 3.06% and
15.54% and the clay percentage falls within 1.72–13.46% range indicating that the
sand constitutes major part of the soil while clay fraction is generally negligible to
minimum. It is in the vertical sections of some lake margins that fine lamiae of clay
are seen. The organic carbon content and the inorganic carbon, as also the variation
in the CaCO 3 in the samples is very low. The sediments indicate a quartzose provenance and abundance of heavy minerals. Glacial till around Maitri were mapped on
1:1000 scale to understand the depositional history of sediments. The samples collected from each level were analysed for Accelerated Mass Spectrometer (AMS)
dating. The results indicate four distinct surfaces of these deposits between the
Priyadarshini Lake (towards north) and the area in the immediate vicinity of Maitri
Station deposited between the span of 4702 and 8942 years BP. The surface textures
and the morphological features on the quartz grains further indicate differential
transportation, essentially by the glacial agency as the angularities of the edges are
still preserved and the sub-rounding to rounding of the grains, typical of the fluvial
action, is present only in case of channel deposits. Periods of residency of the grains
for long span of time is shown by the engraved features on the surfaces of the quartz
grains.
Keywords Schirmacher Oasis · Glacial and periglacial environment ·
Sedimentation history
R. Ravindra (*)
National Centre for Polar and Ocean Research, Vasco da Gama, Goa, India
© Springer Nature Switzerland AG 2020
P. S. Goel et al. (eds.), Climate Change and the White World,
https://doi.org/10.1007/978-3-030-21679-5_4
Glacial Sediments of Schirmacher Oasis,
East Antarctica and their Characteristics
Rasik Ravindra
Abstract Schirmacher Oasis in Central Dronning Maud Land of East Antarctica
represents a polar and periglacial environment that exhibits large accumulation of
unconsolidated sediments as moraines and debris dropped by retreating ice sheet
and admixture of sand-silt-clay deposited by the melt water channels. Study involved
collection of sediments from various depositional environments for analyses. The
sand-silt-clay ratios determined from these samples show that the sand percentage
is varying between 71% and 95.22%, silt percentage varies between 3.06% and
15.54% and the clay percentage falls within 1.72–13.46% range indicating that the
sand constitutes major part of the soil while clay fraction is generally negligible to
minimum. It is in the vertical sections of some lake margins that fine lamiae of clay
are seen. The organic carbon content and the inorganic carbon, as also the variation
in the CaCO 3 in the samples is very low. The sediments indicate a quartzose provenance and abundance of heavy minerals. Glacial till around Maitri were mapped on
1:1000 scale to understand the depositional history of sediments. The samples collected from each level were analysed for Accelerated Mass Spectrometer (AMS)
dating. The results indicate four distinct surfaces of these deposits between the
Priyadarshini Lake (towards north) and the area in the immediate vicinity of Maitri
Station deposited between the span of 4702 and 8942 years BP. The surface textures
and the morphological features on the quartz grains further indicate differential
transportation, essentially by the glacial agency as the angularities of the edges are
still preserved and the sub-rounding to rounding of the grains, typical of the fluvial
action, is present only in case of channel deposits. Periods of residency of the grains
for long span of time is shown by the engraved features on the surfaces of the quartz
grains.
Keywords Schirmacher Oasis · Glacial and periglacial environment ·
Sedimentation history
R. Ravindra (*)
National Centre for Polar and Ocean Research, Vasco da Gama, Goa, India