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Geochemistry of late Cenozoic sediments from Lake Baikal, Siberia: Inferences on linkage of tectonics, climate and depositional environment
Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
Manuscript (Other academic)
URN: urn:nbn:se:uu:diva-92131OAI: oai:DiVA.org:uu-92131DiVA: diva2:165100
Available from: 2004-09-10 Created: 2004-09-10 Last updated: 2010-01-13Bibliographically approved
In thesis
1. Late Cenozoic Geoarchives from Lake Baikal, Siberia
Open this publication in new window or tab >>Late Cenozoic Geoarchives from Lake Baikal, Siberia
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Three long sediment cores (BDP-98 – 600 m, BDP-96 – 200 m and BDP-93 – 100 m) drilled in Lake Baikal (Siberia) have been studied with the aims of establishing an absolute chronology and reconstructing paleoclimatic and paleoenvironmental changes in the region. The location of the lake at relatively high latitude and continental interior and a thick continuous sedimentary archive that developed in a rift system tectonic setting provide unique material for this investigation. The cosmogenic isotope 10Be was used for dating and the results indicate time spans of 8 (+0.8\-0.6) Myr for BDP-98, 5.5 (±0.13) Myr for BDP-96 and >0.7 Myr for BDP-93. Two major sedimentary facies (deltaic and hemipelagic) are distinguished by textural geochemical and mineralogical data. Detrital mineral composition suggests negligible change in provenance during the period studied. Formation of authigenic minerals, such as framboidal pyrite, vivianite and siderite, reflects variable environmental conditions in the lake and climate change in the region. Biogenic silica content shows climatic influence, which is modified by the supply of detrital material and postdepositional alterations. 10Be dating, combined with lithological analysis of the sediments, makes it possible to place temporal constrains on climate cooling at the Miocene/Pliocene boundary (5 Myr ago) and at the Early/Late Pliocene boundary (3.6 Myr ago) as well as the beginning of the northern hemisphere glaciation at about 2.5–2.6 Myr ago. The regional east-west tectonic extension of south-east Asia, related to Tibetan Plateau uplift, was confined in the Baikal area to between about 7 and 5 Myr ago, with a rifting rate calculated at 7 mm year-1. Furthermore, the 10Be data suggest that geomagnetic field intensity strengthened around the Miocene/Pliocene boundary.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 64 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 1013
Quaternary geology, Lake Baikal, Be-10 isotope, chronology, paleoclimate, tectonics, geomagnetic field, cosmic rays, Kvartärgeologi
National Category
urn:nbn:se:uu:diva-4552 (URN)91-554-6037-2 (ISBN)
Public defence
2004-10-01, Hambergsalen, Geocentrum, Villavägen 16, Uppsala, 10:00
Available from: 2004-09-10 Created: 2004-09-10Bibliographically approved

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