Gold mineralization in the Proterozoic Bleida ophiolite, Anti-Atlas, Morocco
-
Published:January 01, 2008
Abstract
The newly discovered (1998) West Bleida gold mineralization (3 tonnes metal Au) lies west of the main Moroccan Bleida copper deposit (1981–1991) in the central Anti-Atlas (southern Morocco). It is hosted by metamorphosed and deformed mafic to intermediate volcanic rocks that are part of the Neoproterozoic tholeiitic volcanosedimentary series forming the stratigraphically upper part of the Bou Azzer ophiolite sequence. Strong sericitization and local silicification are associated with mineralization. These altered rocks represent a proximal hydrothermal alteration halo around the West Bleida ore zones. Normative chlorite characterizes the metamorphic assemblage away from the ore zones. Gold mineralization primarily occurs...
Figures & Tables
Contents
The Boundaries of the West African Craton

The boundaries of rigid cratons can be affected by subsequent orogenic events, leading to ‘metacratonic’ characteristics not often properly recognized and still poorly understood. Major lithospheric thickening is absent and early events such as ophiolites are preserved; however, metacratonic boundaries are affected by major shear zones, abundant magmatism and mineralizations, and local high-pressure metamorphism.
West Africa, marked by the large Eburnian (c. 2 Ga) West African craton, the absence of Mesoproterozoic events, the major Pan-African (0.9–0.55 Ga) mobile belts that generated the Peri-Gondawanan terranes, and the weaker but enlightening Variscan and Alpine orogenies, is an excellent place for tackling this promising concept of metacratonization.
The papers in this book consider most of the West African craton boundaries, from the reworking of the Palaeoproterozoic terranes, through the Pan-African encircling terranes, the late Neoproterozoic-early Palaeozoic extension period and the Peri-Gondwanan terranes, the Variscan imprint to the current situation.