Geology and gravity modeling of the Logrosán Sn–(W) ore deposits (Central Iberian Zone, Spain)

Abstract

Sn–(W) granite-hosted ore deposits are characterized by the occurrence of pegmatites, stockworks and quartz veins within a granitic cupola and its surrounding host-rocks. A regional exploration tool for these deposits consists of targeting syn- to late-orogenic specialized S-type hidden shallow granites by geophysical methods. However, gravity as a tool for “brownfield type” exploration in a mature granite-related ore setting has not been widely used. The Logrosán area (Central Iberian Zone) provides a perfect case scenario with Sn–W endo- and exogranitic ore deposits within a relatively small-scale realm. We suggest that the understanding of the subsurface of the Logrosán area provides a key tool to develop a more comprehensive geological and metallogenic model for the ore deposits. In addition, a better explanation for the mineral evolution and the Sn–W ore precipitation can be achieved, by comparing the chemical and textural features of ores from several of the Logrosán deposits. Field gravity and geologic data allowed the modeling of the hidden granite bodies. Combining this information with detailed mineralogical, geochemical data and ore deposit modeling has allowed a definition of targets for probable new Sn–(W) deposits, all within a few kilometers of the main intrusion center.