The Matchless Copper Deposit, South West Africa/Namibia: A Deformed and Metamorphosed Massive Sulfide Deposit

Matchless is one of a number of copper-zinc sulfide deposits associated with the Matchless amphibolite belt in the upper Proterozoic Damara orogen. Within the belt, amphibolite is interlayered with quartz-mica schist, believed to represent fiysch-type sediment deposited during the initial opening of a Damaran ocean. Two major deformation events involving isoclinal folding and thrusting are recognized. D1 produced apronounced layering which is everywhere parallel to the bedding. F2 folds deform the earlier S1 cleavage and layering. The dominant structure is an S2-spaced cleavage which strikes east-northeast and dips to the northwest. Major porphyroblastic mineral growth took place subsequent to D • at lower amphibolite facies metamorphic grade. A minor Da deformation event produced crenulation and fracture cleavages. The copper-zinc deposits occur within a stratiform zone of sulfide-bearing rocks. Massive sulfide ore occupies three shoots plunging northwest parallel to the F • fold axes. The footwall to the ore shoots consists of pyrite-bearing quartz-muscovite schist with interlayered bands of massive pyrite-quartz-muscovite rock and a distinctive biotite-bearing marker schist. In the hanging wall are chloritic schists, with variable proportions of quartz, ankerite, and calcic amphibole, bands of magnetite quartzite, and amphibolite