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A study of the ages of the Precambrian of Texas

Wasserburg, G. J. and Wetherill, G. W. and Silver, L. T. and Flawn, P. T. (1962) A study of the ages of the Precambrian of Texas. Journal of Geophysical Research, 67 (10). pp. 4021-4047. ISSN 0148-0227. doi:10.1029/JZ067i010p04021.

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Age determinations using the Sr^(87)-Rb^(87), Ar^(40)-K^(40), and Pb-U methods were made on samples of muscovite, biotite, amphibole, microcline, and zircon from igneous and metamorphic rocks from the Franklin Mountains, Hueco Mountains, Pump Station Hills, and Carrizo and Van Horn Mountains. In addition ages were determined on a number of basement cores from Texas and New Mexico. The results show that a belt of rocks of varied lithology extending from El Paso to east of the Llano uplift are all of the same age. The general age by the strontium and argon methods is 1000 to 1090 m.y.; and by the lead-uranium method on zircons it is 1150 to 1200 m.y. This event is in the same time band as the ‘Grenville’ orogeny in Canada and the northeastern United States and possibly should be considered part of the general ‘Grenville’ episode. All the data now available indicate that the orogenic event at about 1000 to 1200 m.y. is the most widespread and pervasive episode of Precambrian orogeny on the North American continent for which adequate evidence has been presented. At least one and probably two older periods of igneous activity and metamorphism occurring at 1250 and 1400 m.y. are found in the northern regions of the Texas Precambrian basement. No evidence was found for any igneous event between the early Paleozoic and the 1000-m.y. episode.

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Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1962 by the American Geophysical Union. Manuscript received May 7, 1962; revised June 19, 1962. We should like to acknowledge the help of Robert L. Harbour of the U.S. Geological Survey, who generously aided us in our collecting trip to the Franklin Mountain area. Some of the core samples were made available to us through the kindness of Dr. R. G. Swanson of the Shell Oil Company, Dr. Milton Williams of the Humble Oil and Refining Company, and Dr. James F. Johnson of the Sinclair Oil Company. We should particularly like to thank Professor Manuel Bass, whose enthusiastic interest encouraged this work and who gave freely of his time and knowledge in discussing the problems. This work was supported by the National Science Foundation grants NSF-G19084 and NSF-G15945, and the Atomic Energy Commission contract AT(11-1)-208.
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Atomic Energy CommissionAT(11-1)-208
Issue or Number:10
Record Number:CaltechAUTHORS:20131211-090759937
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Official Citation:Wasserburg, G. J., G. W. Wetherill, L. T. Silver, and P. T. Flawn (1962), A study of the ages of the Precambrian of Texas, J. Geophys. Res., 67(10), 4021–4047, doi:10.1029/JZ067i010p04021
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42946
Deposited By: Tony Diaz
Deposited On:17 Dec 2013 00:07
Last Modified:10 Nov 2021 16:30

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