Evolution of fluid sources during the neogene exhumation of the Sierra Almagrera (Betics, Spain)

Abstract

In the Sierra Almagrera, the N-S striking Palomares fault separated an uplifted block to the East (Booth-Rea et al., 2004) where Fe-Ba-Pb-Cu-Zn-(Ag) mineralizations led to the development of a mining district. To the West, the basement is buried below Neogene sediments locally presenting silicification and stratabound ore deposits Fe-Ba-Pb-(Ag) (Morales-Ruano, 1994). The question related to the orographic evolution of the wedge is addressed in this work: Did basinal and meteoric fluids from the sierras have circulated within the crust and interacted with deeper crustal fluids related to the metamorphism, volcanism and hydrothermal events? Answers are given by the study of fluid inclusions (FI) trapped within several vein generations of different minerals such as quartz, siderite barite and calcite, related to different stages of exhumation. Fluids are identified by microthermometry, Raman spectroscopy and halogens characterization.