Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Harry, D.L. Articles by Huerta, A. Search for Related Content GeoRef GeoRef Citation

Early Paleozoic transform-margin structure beneath the Mississippi coastal plain, southeast United States

¹ Department of Geological Sciences, University of Alabama, Box 870338, Tuscaloosa, Alabama 35487-0338, USA

A geophysical transect across the central Gulf of Mexico coastal plain shows that the early Paleozoic continental margin of southern Laurentia is preserved in a nearly pristine state beneath younger strata that were emplaced during the late Paleozoic Ouachita orogeny and formation of the modern Gulf of Mexico coastal plain. The thickness of the crystalline crust decreases abruptly across the margin over a distance of 50 km, from 35 km beneath the Black Warrior foreland basin to 10 km beneath the Ouachita fold-and-thrust belt. This abrupt decrease in crustal thickness is similar to modern transform margins, but very different from most rifted margins, which display much more gradual transitions in crustal thickness. The geophysical data indicate an absence of synrift intrusive and volcanic rocks, underplated mafic rocks at the base of the crust, and abnormally thick oceanic crust adjacent to the margin. The lack of these features is also characteristic of modern transform margins. Combined with transects across the margin farther west, the data confirm previous suggestions that the central Gulf of Mexico coastal plain overlies an 800-km-long transform segment of the late Proterozoic–early Paleozoic southern Laurentian continental margin that extends continuously from western Arkansas to southeast Alabama.

Key Words: Gulf of Mexico • North America • rifting • Ouachita orogeny

This article has been cited by other articles:

				K. Mickus, R. J. Stern, G.R. Keller, and E. Y. Anthony Potential field evidence for a volcanic rifted margin along the Texas Gulf Coast Geology, May 1, 2009; 37(5): 387 - 390. [Abstract] [Full Text] [PDF]