Late quaternary to recent laminated sediments from the central and southern basins of the Caspian Sea
by
Ian Boomer
University of Newcastle, UK
Coauthors: Uli von Grafenstein (LSCE, Gif-sur-Yvette, France), François Guichard (LSCE, Gif-sur-Yvette, France), Andy Baker (University of Newcastle, UK), Sophie Bieda (CEREGE, Aix en Provence, France)

Short (<10m) cores have yielded late Quaternary to Recent laminated sediments from the deepest parts of the Caspian Sea (figure 1). Two cores in particular have been studied in some detail, one (SR9409-GS20) from the central basin at a depth of 479m and the other (SR9402-GS05) from the southern basin, depth 518m. Some of the physical properties of these sediments have been investigated (Chalié et al., 1997; Jelinowska et al., 1998). The laminations vary in thickness from sub-millimetre to 10 mm. The processes behind lamination formation are not yet clear (although they are believed to represent annual pairs). New, high-resolution, microfossil evidence (faunal, stable-isotope and geochemistry of the Ostracoda) combined with image analysis of the laminations indicates that the southern basin core (GS20) contains two types of deposition, the upper part (0-5.5m; age) is characterised by fine-scale laminae and a lower part (5.5-9.2m; age) with much coarser laminae. These physical observations are supported by distinct changes in the microfossil (and geochemical?) records. The ostracod faunal and stable-isotope evidence suggest that superimposed upon the observed laminations are a series of cycles, with a period of approx. 500 yrs, which we assume to be the result of changes in deep-water ventilation. From these records it may be possible to reconstruct detailed late Quaternary to Recent palaeoclimatic histories for the Caspian region.

Date received: May 13, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahi-89.