DBPapers
DOI: 10.5593/SGEM2014/B42/S19.072

THE AGE MODEL SEDIMENTATION IN LAKE SHIRA (KHAKASIA, RUSSIA) USING VARVES COUNTING AND RADIOCARBON DETERMINATIONS

A. Darin, I. Kalugin, N. Maksimova, T. Markovitch, Y. Rakshun, D. Rogozin, D. Sorokoletov, F. Darin
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-16-2 / ISSN 1314-2704, June 19-25, 2014, Book 4 ,Vol. 2, 545-550 pp

ABSTRACT
Meromictic Shira Lake is situated in the semi-arid climatic area of South Siberia. The
lake has a size of 5 × 9 km and a maximum depth of 24 m. A sediment column of 155
cm in length was retrieved in the deepest part of the lake. The sediment has thin
laminated structure, where black clay carbonate organic-bearing layers are coupled with
white organic free ones. Thickness of coupled rhythms varied from 2 mm in the
uppermost 20 cm of core to 0.4 mm close to the bottom. For calculation of the layers
were used pictures of wet core, optical thin sections and geochemical indicators,
marking each annual layer. For dating the depth of the core were used AMS data 14C
content, the activity of 137Cs and 210Pb. Comparison of age model, obtained by counting annual layers with radiocarbon data, showed that the «reservoir effect» in Lake Shira is equal 1275 years. Radiocarbon data reduction by this amount gives a good coincidence all results.

Keywords: Shira Lake, bottom sediments, annually laminated layers, varves, scanning microanalysis, synchrotron radiation.