Response of Long Lake sediments to Antarctic climate: A perspective gained from sedimentary organic geochemistry and particle size analysis

Mahesh, B.S.; Warrier, Anish Kumar; Mohan, Rahul; Tiwari, Manish; Babu, Anila; Chandran, Aswathi; Asthana, Rajesh; Ravindra, Rasik

doi:10.1016/j.polar.2015.09.004

Cited by 23 publications

(8 citation statements)

References 49 publications

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“…The East Antarctic coast is marked by a discontinuous mountain chain that can be traced intermittently all along the coast from 75 0 45′ E longitudes to 15 0 West longitudes, running nearly parallel to the coast line. There are some low lying, ice free areas in the coastal Antarctica such as the Schirmacher Oasis, Larsemann Hills, Vestfold Hills, Bunger Hills etc., that have been studied in detail for Late Pleistocene (~ 0.12 My) and Holocene glacial History [1][2][3][4][5][6][7][8][9][10][11][12] These oases are distinguished from nunataks by the process of ablation. While most nunataks are located in the accumulation zone of glaciers and are kept free of ice by the strong winds, the oases are separated from the ice sheet by a distinct ablation zone.…”

Section: Ice Free Areas Of East Antarcticamentioning

confidence: 99%

“…These results are in conformity with results of other studies, as documented above. Further, the geochemical proxies (TC%, TN%, C/N ratios, δ 13 C and δ 15 N) along with the physical proxies (grain size: sand-silt-clay) for three different periglacial lakes viz., Long Lake, Zub Lake and Sandy Lake [1][2][3] spanning the glacial-interglacial variations (spanning up to 43 cal ka BP). These studies presents the evolution of lake through reconstruction of productivity patterns, source of organic matter and the hydrological processes through grain size variation complimenting the environmental magnetism records from the same lakes [5,6].…”

Section: Deglaciation Historymentioning

confidence: 99%

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Geomorphological Insight of Some Ice Free Areas of Eastern Antarctica

Ravindra¹,

Mahesh²,

Mohan³

2021

Glaciers and the Polar Environment

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The Schirmacher Oasis and Larsemann Hills are among the few significant ice free areas of East Antarctica that are conspicuous due to presence of more than a hundred melt water lakes each, preserving the signatures of climatic variation and deglaciation history since Last Glacial Maximum (19 to 24 ky BP) and beyond. There are evidences, recorded in the lake sediments of low lying Larsemann Hills, of marine transgression due to variation in sea level, isostatic upliftment and close vicinity of the Hills to the marine environment. The Schirmacher Oasis, on the other hand has preserved various landforms-both erosional and depositional- typical of a periglacial environment along with proglacial lakes (incorporating signals of ice-sheet dynamics) and epishelf lakes (signatures of marine influence) .

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Section: Ice Free Areas Of East Antarcticamentioning

confidence: 99%

Section: Deglaciation Historymentioning

confidence: 99%

Geomorphological Insight of Some Ice Free Areas of Eastern Antarctica

Ravindra¹,

Mahesh²,

Mohan³

2021

Glaciers and the Polar Environment

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“…Although the region falls on the coastal part of East Antarctica, the width of the ice shelf is~100 km, which prevents the salty marine waters from entering the region (Laybourn-Parry and Wadham 2014). The air temperature fluctuates between 0.7 and 8.2°C during summer (December-January), and from − 16.3 to − 35.5°C during winter with August being the coldest (Lal 2006;Mahesh et al 2015). The southeasterly winds blow at an average speed of 9.3 m s −1 and 6.2-7.2 m s −1 in the winter and summer seasons respectively (Soni et al 2017).…”

Section: Study Areamentioning

confidence: 99%

Magnetic properties of surface sediments in Schirmacher Oasis, East Antarctica: spatial distribution and controlling factors

et al. 2020

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Purpose We investigated the magnetic properties (abundance, grain size, and mineralogy) of iron oxides present in Lake L-55 sediments, Schirmacher Oasis, East Antarctica, with an aim to understand their spatial distribution and the underlying mechanisms that control their formation and distribution. Methods Twenty-five surficial sediments retrieved from different parts of Lake L-55 were subjected to the entire range of environmental magnetic (magnetic susceptibility, anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM)) measurements (at different field strengths). Inter-parametric ratios (χARM/SIRM, χARM/χlf, χARM/χfd, IRM20 mT/SIRM, IRM20 mT/ARM, S-ratio, L-ratio) provided insights into the magnetic properties (abundance, grain size, and mineralogy of iron oxides). Scanning electron microscopic-energy dispersive X-ray spectroscopic (SEM-EDS) analysis was performed on magnetic extracts from a few sediments. Besides, organic matter (%) was also calculated for the sediment samples. Principal component analysis was performed to gain information on the presence of different components and their relative dominance. Results The iron oxides are strongly magnetic (high values of concentration-dependent parameters). The principal iron oxide is magnetite (S-ratio > 0.90) which is coarse-grained (multi-domain (MD) and stable single-domain (SSD) grains), and there is no influence of authigenic greigite, bacterial magnetite, and anthropogenic magnetite. The mineralogy is confirmed by SEM-EDS data. The iron oxides are of different grain sizes, and their contribution is in the order of MD > SSD > SP as shown by the principal component analysis. Pedogenic iron oxide minerals seem to be present in the samples whose formation is due to the oxidation of magnetite into hematite. However, they are of SSD size and not SP, suggesting that the intensity of pedogenesis is not sufficient to form SP grains. Conclusion The iron oxide minerals are mainly terrigenous, and the biogenic activity within the lake is not sufficient to modify the ferrimagnetic minerals. Spatial distribution patterns suggest the non-uniform distribution of magnetite/titanomagnetite of varying sizes in the lake basin which is transported by both melt water streams and winds.

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“…Little is known about sediment deposited in polar lacustrine environments; in particular, evidence is lacking on bedrock release, transport processes and ultimate sedimentation (Mahesh et al 2015). Although much of the Antarctic continent is covered with ice, some locations, such as the archipelago of the South Shetlands, contain freshwater lakes.…”

Section: Introductionmentioning

confidence: 99%

“…Sediment deposited in lakes of the peripheral zones of Antarctica represent a great potential to understand different sedimentary processes under harsh climatic conditions (Mahesh et al 2015). Sediment is brought into the lake basin by release from bedrock; glacial, aqueous and aeolian transport; shoreline erosion and mass movement.…”

Section: Introductionmentioning

confidence: 99%

Provenance, transport and diagenesis of sediment in polar areas: a case study in Profound Lake, King George Island, Antarctica

et al. 2018

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Detailed scanning electron microscopy (SEM) micro-texture and mineralogical analysis of lacustrine sediment recovered from Profound Lake (also known as Uruguay Lake), Antarctica, was conducted in the foreland area of the Collins Glacier, King George Island. Very coarse and coarse sand grade size fractions (2 mm -600 μm) were examined with SEM/ energy dispersive spectrometry, while the total sand fraction and fines (silt + clay) were examined using x-ray diffraction to determine relationships to source rock, weathering and transport history and long-term clay mineral weathering, all of which are poorly understood in polar areas. The mineralogy of these sediments was compared with petrographical information of the country rock to identify potential detrital sources. The association of recovered detrital minerals, sometimes strongly pre-weathered, supports release from source rock of basaltic and andesitic compositions. The micro-texture analysis of quartz, magnetite and various plagioclase grains show micro-features that reveal a complex weathering-diagenesis history tentatively extending into the Paleogene. The bedrock was eroded mostly by glacial processes and mechanical action presumed to result from glacial crushing. Alteration minerals, likely the product of pre-weathering, are probably sourced from weathered bedrock during contact with the sub-aerial atmosphere prior to entrainment. However, amorphous silica precipitation indicates weathering subsequent to glacial erosion from the source bedrock. Cracks of variable dimensions are mostly characteristic of either frost weathering or glacial transport, and involve mechanical and chemical processes.

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Response of Long Lake sediments to Antarctic climate: A perspective gained from sedimentary organic geochemistry and particle size analysis

Cited by 23 publications

References 49 publications

Geomorphological Insight of Some Ice Free Areas of Eastern Antarctica

Geomorphological Insight of Some Ice Free Areas of Eastern Antarctica

Magnetic properties of surface sediments in Schirmacher Oasis, East Antarctica: spatial distribution and controlling factors

Provenance, transport and diagenesis of sediment in polar areas: a case study in Profound Lake, King George Island, Antarctica

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