Impact of Antarctic climate during the Late Quaternary: Records from Zub Lake sedimentary archives from Schirmacher Hills, East Antarctica
2019
Mahesh, Badanal Siddaiah | Warrier, Anish Kumar | Mohan, Rahul | Tiwari, Manish
The Antarctic continental margin is marked with ice-free areas which are host to numerous freshwater lakes. These lacustrine systems are rich in sedimentary deposits which archive in them the regional and general climatic variations. These lakes respond to the seasonal variations in climate over glacial-interglacial timescales and can be inferred from the sedimentary proxies. In this study, a 79-cm-long radiocarbon dated sediment core retrieved from a peri-glacial lake is analysed for elementary (Cₒᵣg%, Nₒᵣg%), isotopic (δ¹³COM, δ¹⁵NOM) and particle size (sand, silt, clay). The radiocarbon dated sections (0–65 cm) extends up to 43 kyr BP. The time-series of sedimentary organic matter (OM) proxies (Cₒᵣg ~ 3.5 ± 3%, C/Nₐₜₒₘᵢc ᵣₐₜᵢₒ ~ 11 ± 3 and δ¹³COM ~ −14 ± 4‰) indicate that the OM in this lake sedimentary record is an admixture of terrestrial and lacustrine biomass. Distinctly higher (lower) values during the Holocene (LGM) suggests presence of terrestrial and aquatic (aquatic) biomass indicating ice-free (ice-cover) and warm (cold) Holocene (glacial) conditions which would result in an increased (decreased) lake-productivity and fluvial (wind) input of sand and clay (silt). Higher sand content (~30, ~24 and ~15 kyr BP), silt content (~24 kyr BP), Cₒᵣg and Nₒᵣg (~24 kyr BP) within the Last Glacial Stage (LGS) indicates intermittent warming period in coherence with the Antarctic Isotope Maximum (AIM). The transition in values (Cₒᵣg, Nₒᵣg, C/N ratio, δ¹³COM, sand content) starting at 16.6 kyr BP closely following Antarctic deglaciation to reach Holocene optimum values at 11.3 kyr BP documents the influence of Antarctic climate on regional areas.
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