Holocene climate variability from the lake sediment core in Schirmacher Oasis region, East Antarctica: Multiproxy approach

TitleHolocene climate variability from the lake sediment core in Schirmacher Oasis region, East Antarctica: Multiproxy approach
Publication TypeJournal Article
Year of Publication2016
AuthorsGovil, P, Mazumder, A, Asthana, R, Tiwari, A, Mishra, R
JournalQuaternary International
Volume425
Pagination453 - 463
ISSN1040-6182
KeywordsFreshwater lakes
Abstract

Abstract A 1.62 m sediment core was retrieved from one of the landlocked freshwater lakes (L-6) in the Schirmacher Oasis (SO), East Antarctica during the 24th Indian Antarctic Expedition (2004–2006). The sediment core samples were analyzed for Total Organic Carbon (TOC), Biogenic Silica (BSi), grain size and elemental concentration ratios (Mg/Ca and Mn/Fe). The sediment core represents the time period of last ∼11.6 cal ka \{BP\} as ascertained by \{AMS\} 14C radiocarbon dates. The sedimentation accumulation rate variation of ∼13.6 cm/ka from ∼11.6 to ∼10 cal ka \{BP\} reveals a warm phase followed by a low sedimentation accumulation rate of ∼2.9 cm/ka from ∼10 ka \{BP\} to ∼3.1 ka BP, indicating a cold period in the region. The sedimentation accumulation rate again increased from ∼3.1 cal ka \{BP\} to recent with a maximum of ∼88 cm/ka which reveals the initiation of glacier retreat or ice-free conditions in the study area. The Total Organic Carbon (TOC) is <2% from ∼10 to ∼3.1 cal ka \{BP\} indicating a prolonged colder phase in the study area. However, elevated TOC, \{BSi\} and Mg/Ca ratio since ∼3.1 cal ka \{BP\} to recent points indicates towards ice-free conditions (continental ice sheet retreat) and subsequently high productivity in the region. Moreover, the productivity was higher at the Pleistocene–Holocene boundary as evidenced by the Mg/CA, Mn/Fe ratio and Biogenic Silica (BSi). The present study identified a colder phase (or re-advancement of continental ice sheet) during the early to mid-Holocene and initiation of ice-free or continental ice-sheet retreat during the late Holocene and their implications on the productivity changes.

URLhttp://www.sciencedirect.com/science/article/pii/S1040618216304293
DOI10.1016/j.quaint.2016.09.032