Quick Search:    advanced search

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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 Wawrzyniec, T. Articles by Axen, G. J. Search for Related Content GeoRef GeoRef Citation

Correlations between fluid composition and deep-seated structural style in the footwall of the Simplon low-angle normal fault, Switzerland

¹ Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-1116, USA
² Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA

Structural and fluid-inclusion analyses reveal a correlated change in structural style and fluid composition along strike in footwall mylonites of the Simplon low-angle normal fault of Switzerland. In the south, early postmylonitic structures are semibrittle shears and brittle faults; synkinematic fluid inclusions within the faults contain a carbonic component, whereas those in the shears lack CO₂. To the north, early postmylonitic structures are extension veins and kinkbands and synkinematic fluid inclusions are aqueous. Entrapment conditions for all fluid inclusions are estimated to be >500 °C and >5 kbar. We speculate that different wetting characteristics of carbonic versus aqueous fluids influenced the mechanical behavior of the rocks. Nonwetting carbonic fluids locally increased fluid pressure and induced brittle failure, resulting in development of abundant, closely spaced brittle faults. In areas lacking carbonic fluids, ductile deformation continued to lower pressures and temperatures.

This article has been cited by other articles:

				E. F. Baxter and D. J. DePaolo Field measurement of high temperature bulk reaction rates II: Interpretation of results from a field site near Simplon Pass, Switzerland Am J Sci, June 1, 2002; 302(6): 465 - 516. [Abstract] [Full Text] [PDF]

				J. A. Miller, I. S. Buick, I. Cartwright, and A. Barnicoat Fluid processes during the exhumation of high-P metamorphic belts Mineralogical Magazine, February 1, 2002; 66(1): 93 - 119. [Abstract] [Full Text] [PDF]