Basalt from Louisiana continental shelf
A basalt outcrop was discovered on Alderdice Bank on the outer Louisiana continental shelf. The basalt shows an age of 76.8 ± 3.3 × 106 years. Textural, mineralogical, and chemical characteristics indicate that it is an alkali basalt of shallow intrusive origin. It was probably brought to the seafloor by salt tectonics and exposed due to salt dissolution.
An accurate account of the Mesozoic geologic history of the Gulf of Mexico must consider the apparent consanguinity of all magmatic rocks of the region, including the Alderdice Bank basalt, and the apparent basinward decrease in age of magmatic activities.
KeywordsChemical Characteristic Continental Shelf Geologic History Magmatic Rock Magmatic Activity
Unable to display preview. Download preview PDF.
- Winkler, H. G. F., 1979. Petrogenesis of metamorphic rocks. Springer-Verlag, New York, 348 p.Google Scholar
- Spencer, A. B., 1969. Alkalic igneous rocks of the Balcones province, Texas. Journal of Petrology, v. 10, pp. 272–306.Google Scholar
- Scott, R. B., 1981. Geochemistry of igneous rocks in Deep Sea Drilling Project Hole 465A, Hess Rise: significance to ocean plateau petrology and evolution. In: Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, D.C., v. 62, pp. 955–960.Google Scholar
- Bass, M. N., Moberly, R., Rhodes, J. M., Shih, C., and Church, S. E., 1973. Volcanic rocks cored in the Central Pacific, Leg 17. Deep Sea Drilling Project. In: E. L. Winterer and others (eds.), Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, D.C., v. 17, pp. 429–466.Google Scholar
- Hunter, B. E., and Davies, D. K., 1979. Distribution of volcanic sediments in the Gulf Coastal Province—significance to petroleum geology. Gulf Coast Association of Geological Societies Transactions, v. 29, pp. 147–155.Google Scholar
- Zartman, R. E., Brock, M. R., Heyl, A. V., and Thomas, M. M., 1967. K-Ar and Rb-Sr ages of some alkali intrusive rocks from central and eastern United States. American Journal of Science, v. 265, pp. 848–870.Google Scholar
- Baldwin, O. D., and Adams, J. A. S., 1971. K40/Ar40 ages of the alkalic igneous rocks of the Balcones fault trend of Texas. The Texas Journal of Science, v. 22, pp. 223–231.Google Scholar
- Burke, W. H., Otto, J. B., and Denison, R. E., 1969. Potassium-argon dating of basaltic rocks. Journal of Geophysical Research, v. 74, pp. 1082–1086.Google Scholar
- Braunstein, J., and McMichael, C. E., 1976. Door Point: a buried volcano in southeast Louisiana. Gulf Coast Association of Geological Societies Transactions, v. 26, pp. 79–80.Google Scholar
- Nettleton, L. L., 1934. Fluid mechanics of salt domes. American Association of Petrologists Bulletin, v. 18, pp. 1175–1204.Google Scholar
- Rezak, R., and Bright, T. J., 1981. Northern Gulf of Mexico topographic features study. Final Report, Bureau of Land Management, Contract AA551-Ct8-35, v. 3, pp. 99–127.Google Scholar
- Rezak, R., and Bright, T. J., 1981. Seafloor instability of East Flower Garden, northwest Gulf of Mexico. Geo-Marine Letters, v. 1, pp. 97–103.Google Scholar
- Buffler, R. T., Watkins, J. S., Schaub, F. J., and Worzel, J. L., 1980. Structure and early geologic history of the deep central Gulf of Mexico basin, In: R. H. Pilger (ed.), The Origin of the Gulf of Mexico and the opening of the central North Atlantic Ocean. Proceedings of a Symposium at Louisiana State University, Baton Rouge, La., March 3–5, 1980.Google Scholar