Epigenetic, low-temperature, carbonate-hosted Pb-Zn-Cu-Ba-F-Sr deposits in Mexico: A Mississippi Valley-type classification
Por:
Tritila J., Levresse G., Corona-Esquivel R., Banks D.A., Lamadrid H., Bourdet J., Pinto-Linares P.J.
Publicada:
1 ene 2007
Categoría:
Geology
Resumen:
The low-temperature epigenetic and stratabound Pb-Zn-Cu-Ba-F-Sr-bearing ore deposits enclosed within sedimentary columns historically have been major sources of metals. Exploration companies still find these deposits to be a profitable exploration target due to their simple mineralogy as well as the large tonnage that can present, always considering the mineral districts as a whole. In northeastern Mexico, several nonmagmatic, low-temperature Pb-Zn-F-Ba deposits have been systematically considered as magmatic-related (skarns, high- temperature replacement deposits, epithermal deposits, etc.). Recently, these deposits have been restudied and placed within a scenario of deep fluid circulation of basinal brines through the Mesozoic sedimentary series, enriched in Ba, F, and metals during fluid flow and water-rock interactions. These fluids gave rise to a series of strata- bound epigenetic ore deposits scattered throughout the whole Mesozoic carbonate platform and can be shown to be unrelated to any period of magmatism. There is no intense alteration to the host rocks. Commonly there is a close association with organic matter, either liquid hydrocarbons or bitumen; they have a very simple mineralogy of barite, celestine, fluorite, sphalerite, galena, and have low formation temperatures (90-105 °C) combined with variable salinities. These characteristics make these deposits similar to the Mississippi Valley-type deposits, possibly most similar to the Alpine-Appalachian subtype. ©2007 The Geological Society of America.
Filiaciones:
Centro de Geociencias, Campus U.N.A.M.-Juriquilla, Universidad Nacional Autónoma de México (UNAM), Carr. Qro-SLP, Santiago de Querétaro 76230, Mexico
Museo de Geología-Instituto de Geología, Universidad Nacional Autónoma de México (UNAM), J. Torres Bodet No. 176, Col. Sta Maria de La Ribera México D.F. 06400, Mexico
School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
UMR 7566 G2R-CREGU, Université H. Poincaré, B.P. 239, Vandoeuvre-lès-Nancy 54506, France
Instituto Potosino de Ciencia y Tecnología (IPICYT), Depto. Geología Económica, Camino a la Presa San José 2055, Col. Lomas CP. 78216, San Luis Potosí, S.L.P., Mexico
|