Hydrological instability during the Last Interglacial in central Asia: A new diatom oxygen isotope record from Lake Baikal

Anson W. Mackay, George E.A. Swann, Nathalie Fagel, Susanne Fietz, Melanie J. Leng, David Morley, Patrick Rioual, Pavel Tarasov

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    14 Citations (Scopus)

    Abstract

    Last Interglacial variability is commonly used as an analogue for variability in a future, warmer world. Pervasive cycles are increasingly apparent in Last Interglacial archives, although studies in continental regions are under-represented. Here we provide a new isotopic record of diatom silica (δ 18 O diatom ) spanning c. 127.5-115 ka BP from Lake Baikal in central Asia. Peak rain-fed discharge occurred c. 125.4 ka BP, shortly after July insolation maximum and initiation of Siberian soil development. Between 127 and 119.7 ka BP there are six marked fluctuations in δ 18 O diatom values, with a pacing of approximately 1.26 ± 0.3 ka, similar to fluctuations of within lake productivity. Fluctuations in δ 18 O diatom values show good agreement with patterns in Atlantic meridional overturning circulation (AMOC), supporting hypothesis of strong teleconnections via theWesterlies between the North Atlantic and central Asia. Two periods of low δ 18 O diatom values are especially notable. The earliest between c. 126.5 and 126 ka BP is concurrent with the final stages of the Heinrich 11. The second between 120.5 and 119.7 ka BP is also concurrent with an increase in ice-rafted debris in the North Atlantic. Aquatic productivity in Lake Baikal increased between 119.7 and 117.4 ka BP before declining to the top of the record (115 ka BP) concomitant with a shift to predominately cool steppe catchment vegetation. However, isotopic composition of discharge into Lake Baikal provides evidence for strong penetration of Westerlies into central Asia during the latter stages of the Last Interglacial. Variability in δ 18 O diatom values was compared between the Last Interglacial and the Holocene. Millennial-scale variability was significantly more stable during the Last Interglacial, possibly linked to diminished influence of freshwater discharge on AMOC during periods of higher, global mean temperatures. © 2012 Elsevier Ltd.
    Original languageEnglish
    Pages (from-to)45-54
    JournalQuaternary Science Reviews
    Volume66
    DOIs
    Publication statusPublished - 1 Jan 2013

    Keywords

    • Amoc
    • Bond events
    • Lake Baikal
    • Last Interglacial

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