METALLOGENIC AND TECTONOMAGMATIC EVOLUTION OF MEXICO DURING THE MESOZOIC: A REVIEW AND NEW INSIGHTS
Nearly all of the Mesozoic VMS deposits respond to the Kuroko-type model, and most of them occur in volcanosedimentary sequences close to terrane boundaries, especially along those of the southern Guerrero composite terrane (GCT) and mostly within it. However, new evidence suggests that they occur within the Sierra Madre terrane as well. This is compatible with their formation in back-arc settings between volcanic arcs, epicontinental seas and positive lands of eastern Mexico, or within juvenile and slightly evolved arcs. Contrastingly, no VMS deposits are known to occur in the northern half of the GCT, as the widespread extensional unroofing in the south did not seemingly propagate northwards. An important feature for the metallogeny of the Late Cretaceous and the Cenozoic is that the reactivation of crustal-scale discontinuities controlled the emplacement of shallow intrusives, volcanism, and also hydrothermal fluids from magmatic, meteoric or basinal sources. Thus, ore deposits of either the magmatic continental or the sedimentary-diagenetic realms were bound to such control despite being mutually exclusive realms.