FAULT AND STRATIGRAPHIC CONTROLS ON VOLCANOGENIC MASSIVE SULFIDE DEPOSITS IN THE STRELLEY BELT, PILBARA CRATON, WESTERN-AUSTRALIA

Early Archaean, Fe-Zn-Cu volcanogenic massive sulphide deposits of the Strelley Belt, Pilbara Craton. occur at the top of a volcanic dominat ed sequence, at the interface of felsic volcanic rucks and siliceous l aminites, beneath an unconformity overlain by elastic sedimentary rock s. The structure of the Sulphur Springs and Kangaroo Caves VMS deposit s is relatively simple, with the present morphology reflecting origina l deposition rather than significant structural modification. The rock s have been tilted giving an oblique cross-sectional view of discordan t high-angle, deep penetrating faults in the footwall, which splay clo se to the zones of voltcanogenic massive sulphide mineralization. Faul ts do not extend far into the overlying sedimentary cover, indicating their syn-volcanic and syn-mineralization timing. Both the Sulphur Spr ings and Kangaroo Caves sulphide deposits are located within elevated grabens in a setting similar to massive sulphide mineralization in mod ern back-are environments. Mineralization at Sulphur Springs and Kanga roo Caves is located at the edge of the grabens, at the site of inters ecting syn-volcanic extensional faults. (C) 1998 Elsevier Science B.V.