Geology of Mauritania ore. A Neoproterozoic carbonate unit, part of a synformal nappe overturned in the Paleozoic, now forms a major copper deposit 250 kilometers northeast of Nouakchott in the Mauritanides Belt. The one kilometer, 250 meter wide deposit spans the West and East Moghrein Guelb hills. Forty meters below the deposit is a secondary deposit of cuprite, azurite, malachite and tenorite, with an additional 2.25% copper, some gold and sulfide mineralization including cubanite, chalcopyrite, pyrrohitite and aresnopyrite. In the 2000s, mining at the site had mostly ceased except for gold mining in the tailings pile. Gypsum is extracted from the N'Drahamcha quarry,
Carbonate-hosted lead-zinc ore deposits brines (10-30 wt.% NaCl equivalent) with pH's of 4.5-5 (buffered by host carbonates). This hydrothermal fluid may or may not carry the required sulfur to form sulfide minerals. Mobile hydrocarbons may have played a role in delivering reduced sulfur to certain MVT systems, while methane and other organic matter can potentially reduce sulfate carried by an acidic fluid. The ore fluid is suspected to be derived from clastic red bed sequences (potential metal source) that contain evaporites (potential sulfur source). Two potential transportation mechanisms for the metal-bearing ore fluid have been proposed. The first involves compaction of sediments in basins