XVI INQUA Congress

Paper No. 17
Presentation Time: 1:30 PM-4:30 PM

NEW DATING OF EUROPEAN ICE SHEETS IMPROVES THE QUATERNARY OF THE RHINE REGION


THOME, Karl N., Ruhr-University Bochum, Institute of Geology, Mineralogy and Geophysics, Universitätsstrasse, Bochum, D-44780, Germany, clausthome@web.de

Deep sea sediments are dated by linear interpolation (IMBRIE et al. 1984:274) because they are believed to have not settled. But a remarkable settlement can be proofed safely by the comparison of layer thickness. So dating by linear interpolation is false (THOME 1997 - 2002b). The wrong dating of stage 5 (Eemian interglacial) with 125 kyr seemed to be confirmed erroneously by independent dating of an interglacial in coral reefs with a real age of 125 kyr. SHACKLETON & OPDYKE 1973:46: "This well dated episode remains the most important calibration point...". But interglacials of 125 kyr belong to stage 7. Regarding the settlement it becomes clear, that there are confused stage 5 (80 kyr) with stage 7 (125 kyr). Other fictitious confirmations are based on unsafe age estimations in recent ice sheets. The theory of Milankovich: ..."Ice age cycles, which occur at essentially the same frequency (every 100 000 years or so) as changes in the shape of the Earth`orbit" SCHRAG 2002:23 (also IMBRIE et al. 1984:269) connects wrong dated records of disqualified cores with unsafe orbital constructions. The development of ice sheets was ruled by other factors.

Reconstruction of the settlement enables the election of a core without severe sediment disturbances: V28-239. Its record, "based on oxygen isotope data from marine fossils that reflect the size of continental ice sheets" (SCHRAG 2002:23) is proportional to the known sequence of European ice sheets.

An application to the Rhine region shows more details: The largest sheets touched the Lower Rhine in the stages 22 (850 kyr), 16 (550 kyr) and 12 (300 kyr). In different stages ice sheets had different size and duration. Crustal movement, river erosion and volcanism were mobilized most in the stages 22 and 16, less in 12, still less in the other. Overridden sheets are distinguishable.

SHACKLETON NJ, OPDYKE ND (1973) Quaternary Research 3:39-55 IMBRIE J, HAYS JD, MARTINSON DG et al. (1984) NATO ASI Series C Vol. 126 pp 269-305 SCHRAG DP (2000) Nature 404:23 THOME KN (1997) Springer Berlin Heidelberg New York ISBN 3-540-62932-7 pp 25-26, 41-55, 69-111, 188-209 --(2000) Decheniana (Bonn) 153:241-259 ISSN 0366-872 X --(2001) DGG14:211-212 ISSN 1616-0606, ISBN 3-932537-14-9 --(2002a) Terra Nostra 2002/6:364-374 DEUQUA ISSN 0946-8978 --(2002b) GeoArchaeoRhein 4 Münster ISBN 3-8258-6009-4

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