El yacimiento Matahambre (Pinar del Río, Cuba): estructura y mineralogía

Abstract

The Matahambre ore deposit has two types of mineralization: a stratiform mineralization (with Pb-Zn) hosted in black shales, and a vein mineralization (with Cu), hosted in the sandstones of the Lower Jurassic San Cayetano formation. In addition to chalcopyrite, pyrite, sphalerite and Co-Ni sulfoarsenides, minor amounts of Bi-, Ag-, and Pb-selenides and tellurides are common in the vein mineralization. Contrastingly, the stratiform mineralization display a zonal structure: pyite is the dominant sulphide at lower part, and sphalerita and galena at the upper part. In the lower part, sphalerite and other sulphides display evidences to have been replaced by pyrite and chalcopyrite, thus indicating the replacement of a low temperature mineralization by another formed at higher temperature. A sedex model is proposed for these mineralizations, based on the extensional geodynamic setting of the series, the association of stratiform facies with exhalative roots and the association with sedimentary sequences rich in black shales. The whole is deformed by thrusting, possibly caused by reactivation of normal faults in the basin.