Ba [sbnd]Hg deposits in the Espadáan ranges (Iberian Chain, Eastern Spain): an example of Cretaceous fluid circulation and Alpine overprinting

Abstract

In the Espadán Ranges, two hydrothermal events with different fluid chemistry and temperature have been identified. A highsalinity (15 to 22 wt.% eq. NaCl) and moderate to high temperature (140–180 °C) fluid flowed during Santonian times through deep, listric faults that developed during a tectonically extensional period. Barite and Hg Sb Cu Ag sulfosalt vein type mineralizations formed due to the mixing between these hot brines and sulfate-rich waters. During the Alpine compression, a second fluid of lower salinity (5 wt.% eq. NaCl) and higher temperatures (up to 240 °C) flowed through the preexisting faults, oxidizing the hypogene sulfosalt paragenesis. The presence of powder-like cinnabar, Cu carbonates and iron oxides would be related to the oxidation of the primary sulfides during the second fluid flow event.