The Role of Manganese As a Controller of Gold Mineralization/Introduction

The San José de Las Malezas deposit is located within the Structural-Facial Zone (S.F.Z.) "Zaza", in the province of Villa Clara in Central Cuba. This S.F.Z. is composed of (i) a volcano-sedimentary complex of Lower Cretaceous age (Turonian) located to the South, (ii) the Ochoa Formation composed of limestones and marls of the Eocene in discordant contact to the North, and (iii) the Zurrapandilla Complex, composed of diabasic porphyries, spilites, gabbro diabase, gabbro diabase porphyries, and other gabbroic rocks that cut both described complexes (Cabrera and Tolkunov, 1979). Within the S.F.Z. "Zaza" and in tectonic contact with the volcano-sedimentary complex are serpentinitic bodies, that form a large massif with an east-west massif. These intrusions form part of the Central Cuban Ophiolitic Belt of the Upper Cretaceous, and they are commonly interpreted as the remains of an ancient oceanic crust.

These serpentinites are massive, crushed, light green rocks, with a reticular structure due to the uneven distribution of chrysolite and antigorite, and the presence of metallic minerals, such as magnetite, chromite and spinel. This mineralogical composition, suggests that the original rock was a harzburgite, however the original texture has been completely erased. The serpentinites are frequently cut by diabasic, microdiabasic and porphyritic diabasic dikes from the Zurrapandilla Complex.

A more detailed geological description of the region and the outcrop, including maps and cross-sections, appears elsewhere (Valls Álvarez, 1995a)

In this paper we will study the formation and evolution of manganese minerals within these serpentinites and their relationship with gold mineralization.