Geology of the Fe-Pb-Ag "Mina Rica" deposit, Pulpí (Almería, Spain)

Abstract

The “Mina Rica” (the Rich Mine), located in the district of Pilar de Jaravía, in the municipality of Pulpi (Almería province, Spain), has become internationally renowned for the great geode of selenite gypsum discovered in its interior. The ore deposit is located in a NE-SW dextral shear band, affected by a system of NNE-SSW sinistral faults. The deposit is composed of two hectometric blocks of weakly deformed rocks with a pod shape, which are constituted by a folded and faulted alternation of limestone and dolomites, and to a lesser amount, gypsum and phyllites, all with a general NNESSW orientation and strong dipping to the W. In the time sequence of the mineral phases present in the “Mina Rica” we can distinguish a first stratabound, mineralization of iron carbonates that fossilizes the Serravallian age deformation. Baryte mineralization is associated with the Tortonian movements and celestine mineralization with the Messinian ones. Gypsum, which crystallized at a temperature of below 25ºC, was the last major sulphated mineral phase to be formed, and this took place after the Pliocene vertical replays. Moreover, this study – the cartographic underpinning of which has served as the basis for the recovery and musealization of the mine – has enabled us to discover the enormous potential that the “Mina Rica” has as a centre for geological and geo-mining practical teaching, beyond the indisputable lure of its Great Geode. We foresee that the results presented in this study will be the basis for the use of the “Mina Rica” as an educational tool to help train future generations of geologists and mining engineers.