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The Crust and Mantle of the Earth: Abstract
The accumulated geophysical data for the Gulf of Mexico, combined with the known geology, make a number of maps possible which serve to define the modern geosyncline and provide some evidence as to its inception. The velocities and depths of interfaces observed in seismic reflection and refraction profiles may be tied to layers of rock, and the gravity and magnetic data assist in determining the tectonic framework. The inception of the geosyncline appears to be related to widespread collapse in Triassic time; this had been preceded by deposition of Paleozoic sediments and the possible extension Gulfward of the Appalachian orogeny. The problems dealt with are (1) the shallow Jurassic and Cretaceous aspect of the Gulf, (2) the widespread extent of the salt and the resultant domes, (3) the lateral or wrench faults and the restoration of transposed elements, (4) the pattern of shifting depocenters, (5) the tremendous acceleration of depositional rates in Tertiary time culminating in the rapid present day rate of 24.4 cm/century determined by Hardin and Hardin, (6) the engimatic Atlantic trench, (7) the unexpected axial directions of magnetic anomalies and (8) the intermediate (between continent and ocean) depth of the Gulf Moho. The combined result of the complex history is a Mesozoic and Cenozoic geosyncline with a sedimentary thickness of perhaps 60,000 feet. The final problem is why this great prism of rocks does not fold into a mountain range after exceeding the accepted depth limit for other geossynclines.
Acknowledgments and Associated Footnotes
1 Sinclair, Tulsa
Copyright © 2006 by the Tulsa Geological Society