Greenstone belts are zones of metamorphic and volcanic rocks that occur within ancient (Archean) formations dominated by granite and gneiss. They are common to most of the cratons in the world and are often associated with world-class gold deposits. The most important greenstone belt in the Pan Amazon is Barama-Mazaruni supergroup, which occurs as a non-contiguous band of rocks in Eastern Venezuela and Guyana, then reappears in Suriname and French Guiana and then further south in Amapá. Altogether, this geological formation covers about 13 million hectares (32 million acres). Top: The greenstone belt of the Guiana Shield is a discontinuous band of ultramafic volcanic rocks located within the Archean and Proterozoic formations of the Amazon Craton. They are the source of the extraordinarily rich gold deposits along the northern coast of the South American continent. Bottom: Annual rates of deforestation on wildcat mining landscapes in the jurisdictions of the Guiana Coast. Data sources: Gomez Tania et al (2019) and RAISG (2022). Venezuela Apparently, the richest portion of this geological province is in the Venezuelan state of Bolivar where small-scale placer mining began in the 1930s. The spike in gold prices in 1980 motivated thousands of adventurers to migrate into the region to work the surface (saprolite) gold deposits using hydraulic mining techniques. Most settled near two frontier towns: El Callão in the North and Las Claritas in the South. The wildcat miners shared these landscapes with three state-owned concessions that were created in the 1970s to exploit the richest and…This article was originally published on Mongabay
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