Strontium isotope geochemistry of barite mineralization at La Minita, S.W. Mexico

http://dx.doi.org/10.18268/BSGM1993v52n1a1

F. Ortigoza-Cruz¹; A. Changkakoti²; R.D. Morron³; J. Gray⁴

¹Zuloaga 380. Col. Los Angeles, Torreon. Coah CP. 2700, Mexico
²P. O. Box 6639.600 St. Kilda Road. Melbourne. Australia, 3004
³Department of Geology, University of Alberta, Edmonton. Canada T6G 2E3
⁴Department of Physics. University of Alberta, Edmonton, Canada T6G 2J1

Abstract

The La Minita Fe-Ba-Zn-Pb-Ag deposits are located in the Michoacan Province of Mexico. Previous fluid inclusion and stable isotope studies showed that these deposits were generated around submarine hot-springs issuing in a Cretaceous island-arc environment.

A strontium isotope study was carried out to determine the source of Sr and Ba. The ⁸⁷Sr/⁸⁶Srratios in barites, mafic volcanics, felsic volcanics and carbonates range from 0.70492 to 0.70535, 0.70451 to 0.70557, 0.70660 to 0.75709 and 0.70571 to 0.70685 respectively. The data suggest that both the volcanics and limestones were the sources of Sr in the mineralizing fluids. On the other hand, trachytes and rhyolites seem to be the most viable sources of Ba, with possible minor contributions from andesite. basalt and limestone.