Environmental Changes and Geomorphological Factors Influencing the Sediment Flux to a Coastal Lake Spanning the Deglacial- Early Holocene Period in East Antarctica

The geomorphological settings of the lakes in the coastal oases of East Antarctica play a significant role in the lake’s response to the local and regional environment. A 63-cm radiocarbon-dated sediment core spanning between 18.7 and 7.2 cal ka BP was retrieved from Discussion Lake, Larsemann Hills...

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Bibliographic Details
Published in:Journal of the Geological Society of India 2022-07, Vol.98 (7), p.911-916
Main Authors: Mahesh, B. S., Mello, Cheryl Noronha E. D., Nair, Abhilash, Warrier, Anish Kumar, Mohan, Rahul
Format: Article
Language:English
Subjects:
Clay
Deposition
Earth and Environmental Science
Earth Sciences
Environmental changes
Environmental conditions
Fractions
Geology
Geomorphology
Grain size
Holocene
Hydrogeology
Ice
Ice cover
Lake ice
Lakes
Meltwater
Oases
Organic matter
Original Article
Radiocarbon dating
Sand
Sediment
Sediment transport
Sediments
Silt
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Summary:The geomorphological settings of the lakes in the coastal oases of East Antarctica play a significant role in the lake’s response to the local and regional environment. A 63-cm radiocarbon-dated sediment core spanning between 18.7 and 7.2 cal ka BP was retrieved from Discussion Lake, Larsemann Hills of East Antarctica in order to understand the pathways of sediment transport and deposition and the mechanisms involved in response to changing environmental settings. This was achieved by analyzing the sedimentary sequence of this coastal lake for its grain size (sand-silt-clay) and organic matter content variations. Two cluster zones were identified viz., LZ1 (18.7 to 8.2 cal ka BP) and LZ2 (8.2 to 7.7 cal ka BP). LZ1 was dominated by fine-grained sediments (clay-silt), indicating wind and low meltwater influx influenced deposition of higher silt content. In addition, the lake during this period was in a moated or partially ice-free phases. On the other hand, coarser grains (sand) were predominant in LZ2 suggesting increased flux of the meltwater to the ice-free lake. Thus, the distinct shift in the sedimentary grains fractions (finer-to-coarser), indicated a change in environmental conditions of the lacustrine system, i.e., from an ice-covered lake to an ice-free lake in response to the regional warming trends and local geomorphological features. Furthermore, the environmental conditions, proximity of the lakes to coast or the ice-sheet, elevation and area, defines the sedimentological characteristics of the lake.
ISSN:0016-7622
0974-6889
DOI:10.1007/s12594-022-2094-y