Milankovitch cyclicity and sea-level change in the Late Eocene-Early Oligocene interval: evidence for rapid and extensive Antarctic glaciation at 33.5 Ma? (abstract of paper presented at EUG XI, Strasbourg, France, 8-12 April 2001)


Gale, A., Pälike, H., Hardenbol, J., Huggett, J., Laurie, E. and Skipper, J. (2001) Milankovitch cyclicity and sea-level change in the Late Eocene-Early Oligocene interval: evidence for rapid and extensive Antarctic glaciation at 33.5 Ma? (abstract of paper presented at EUG XI, Strasbourg, France, 8-12 April 2001) Journal of Conference Abstracts, 6, (1), p.100.

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Description/Abstract

We have studied an expanded succession of coastal marine, estuarine and lacustrine sediments of Late Eocene-Early Oligocene age in the Isle of Wight southern England. In this succession, a strong Milankovitch signal (406, 100, 40 and weaker 20Ka) is recorded from the relative abundance of neoformed illite and illite-smectite, which formed in soils by seasonal wetting and drying. The orbital timescale is calibrated using magnetostratigraphic, and to a lesser extent, biostratigraphic data. Combined orbital calibration and sequence stratigraphic analysis allows us to identify the major control on sea-level as the 406Ka long eccentricity cycle, which caused sea-level to fluctuate by 10-15 m. These values have been determined from the amount of incision at observed at sequence boundaries on a regional scale. Minor sea-level changes of 1-3 m were controlled by obliquity. The position of the Early Oligocene heavy ?18O event can be inferred in the Isle of Wight from its magnetostratigraphic proxy (base of chron 13n). We have determined the sea-level fall at this level to be approximately 12 m, close in magnitude to drops associated with the preceding 3 Late Eocene 406 Ka sequences. This evidence does not support recent estimates of a 50-90 m sea-level fall within the Early Oligocene based on the calculation that a significant part of the oxygen isotope event was caused by rapid Antarctic ice buildup. Rather, orbitally driven sealevel changes throughout the Late Eocene-Early Oligocene, although probably glacioeustatic in origin, remained of similar magnitude.

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ePrint ID: 41869
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2001Published
Date Deposited: 16 Oct 2006
Last Modified: 16 Apr 2017 18:57
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/41869

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