Kimberlite exploration at Serra da Canastra province, Brazil

Abstract

Kimberlite and lamproite pipes are the only economically significant source rocks forming primary diamond deposits. Brazil, the world’s seventh largest diamond producer, has all of its production from alluvial deposits. The quest for a primary deposit has continued over several decades with very few positive results. To that end, airborne magnetic data from the Serra da Canastra diamondiferous province was used to identify kimberlite signatures. Serra da Canastra is located in the central portion of the Brazilian province in a low-magnetic-latitude region. The main tectonic feature of the area is a northwest-southeast major crustal fracture zone that extends for more than [Formula: see text] within the territory. The interpretation strategy was based on joint analysis of analytic signal and Euler deconvolution. A selected kimberlite target should typically have a roughly circular analytic signal anomaly coincident with a depth [Formula: see text] and structural [Formula: see text] constrained Euler solution. The proposed approach led to recognition of previously known pipes and generation of new targets. Ground geologic, geophysical, and geochemical follow-up surveys are necessary to test these selected targets.