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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 68 (1984)

Issue: 4. (April)

First Page: 525

Last Page: 525

Title: Gulf of Mexico Plate Reconstruction by Palinspastic Restoration of Extended Continental Crust: ABSTRACT

Author(s): Dale S. Sawyer

Abstract:

A number of recently published Gulf of Mexico plate reconstructions are strikingly dissimilar. There are no sea floor magnetic lineations, and the sizes and shapes of the continental blocks are not well-defined. Perhaps the only common feature of the several reconstructions is that they ignore the role of continental crust extension during rifting.

In this study, total tectonic subsidence analysis was used to estimate the mount of crust extension in the Gulf of Mexico to determine its effects on the proposed plate reconstructions. This involves the calculation and mapping of the sediment-unloaded basement depth from observations of the basement depth, water depth, and sediment compaction properties. The well-known depth-age relation for oceanic crust and a model for the subsidence of extended continental crust allowed within the limits of available data the identification and mapping of crust type and the amount of extension of transitional crust.

The zone of extended continental crust under the northern margin of the Gulf is extraordinarily wide, more than 800 km (500 mi) in a cross section through east Texas. The zone of extended crust to the south is much narrower, about 150 km (90 mi) on the margin of the Yucatan Block. Palinspastic restoration shows that the total 950 km (590 mi) of extended and thinned continental crust corresponds to 490 km (300 mi) of continental crust of original thickness. Therefore 460 km (280 mi) of crustal extension occurred during rifting and prior to ocean crust formation. The 460 km (280 mi) of extension along this cross section, and the results of similar calculations on other cross sections, must be accounted for properly when reconstructing the prerift configuration of the Gulf of Mexico.

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