Reference : Hydrological instability during the Last Interglacial in central Asia: a new diatom o...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Earth sciences & physical geography
Hydrological instability during the Last Interglacial in central Asia: a new diatom oxygen isotope record from Lake Baikal
Mackay, Anson []
Swann, Georges []
Fagel, Nathalie mailto [Université de Liège - ULiège > Département de géologie > Argiles, géochimie et environnements sédimentaires >]
Fietz, Suzanne []
Leng, Melanie []
Morley, David []
Quaternary Science Reviews
[en] lake ; baikal ; climate ; interglacial ; diatom
[en] 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 (d18Odiatom)
spanning c. 127.5e115 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 d18Odiatom values, with a pacing of approximately
1.26 0.3 ka, similar to fluctuations of within lake productivity. Fluctuations in d18Odiatom 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 d18Odiatom 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 d18Odiatom 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.
Commission européenne : Direction générale de la Recherche

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