STRUCTURAL FRAMEWORK OF THE AG-HG DEPOSIT OF IMITER (ANTI-ATLAS, MOROCCO) - METALLOGENIC INFERENCES

Imiter Ag-Hg deposit is constituted of a lot of gashes opened mainly i n a black shale level regionally associated with greywacke formations which are attributed to Upper Proterozoic (PII). Folding of the series during the main Pan-African orogenic phase develops hecto- to kilomet ric reclined to recumbent folds with axial plane cleavage. The black s chists appear to be situated at the top of the formation and were depo sited at the foot of a continental slope. They show, in the neighbouri ng of the mine of Imiter, a complex faulted-contact with the late Prec ambrian formations (PIII) which are mainly volcanics. Structural analy sis of fracturing, particularly in the quarry of the mine, shows that the Imiter fault zone played first mainly as an extensional fault-zone (NNW-SSE extension) which then evolved toward a sinistral-extensive m ovement (NW-SE extension) during the emplacement of PIII volcanics. Hy drothermal mobilization of sulphides and hydraulic fracturing took pla ce during the activity of this complex wrench and flexure zone. This c an be related to the late post collisional stage of Pan-African orogen y. Cementation which makes the native Ag deposit is a later event.