Metallogenic provinces of the southwestern United States and northern Mexico

Some of the metallogenic provinces of the southwestern United States and northern Mexico are defined by the geographic distribution of sulfophile trace elements in more than 500 samples of chalcopyrite and sphalerite from 172 mining districts.Maps that show the geographic distribution of tin, silver, and the "combined metal content" in chalcopyrite, and of silver and the "combined metal content" in sphalerite, reveal three major belts of high trace-element content in the Southwest. These belts, which are here called the Eastern, Central, and Western metallogenic belts, are consistent in trend and position with a beltlike distribution of the major ore deposits of copper, gold, silver, and other metals. However, the deposits of a given metal tend to be concentrated in certain segments of the metallogenic belts; consequently, the metallogenic provinces, in the ordinary sense, are merely component parts of the larger beltlike features.The metallogenic belts also are generally consistent in position and trend with the major tectonic features, although they do not appear to be closely related in time. Hence, it is suggested that both the metallogenic belts and the major tectonic features are the effects of a more fundamental cause, which perhaps is a combination of compositional heterogeneities and associated physical discontinuities in the deep-seated source regions of the ores.