20 Petrology, Structural Geology, Geophysics, and Economic Geology

Wednesday, 2 May 2001
1:00 PM - 5:00 PM

THE STUDY OF FUILD INCLUSIONS OF THE IMITER SILVER DEPOSIT (SAGHRO ORIENTAL, ANTI-ATLAS, MOROCCO)

Paper number: 20-4
Program: Technical Sessions
Time: 4:30 PM – 4:45 PM

Authors

Abstract

The microthermometric study of the Imiter silver deposit (Saghro oriental, Anti-Atlas, Morocco) shows the existence of tow geotherms. The precocious geotherm F1 is characterized by the circulation of aqua-carbonic fluid of high temperature (>300°C) and a of a weak salinity. This fluid becomes more and more aqueous with decreasing temperature and then undegroes a dilution phenomena. It could probably belong to the structural-metamorphic hydrothermal remobilization stage of the lower PII sandstone series host rock with a preconcentration of silver. The late hydrothermal geotherm F2 is characterized by the circulation of aqueous fluid of a moderate temperature (T=180°C) and a higher salinity (Na, K, Mg, Fe…). It reveals a leaking of the different lower PII and/or upper PII magmatic bodies, and it is the potential responsible of the Imiter silverous mineralisation. A geothermic model was proposed: the Imiter silverous fluids are plugged by the variations of water/rock ratio in the PII metamorphic shales. A comparison was determined with the Zgounder deposit, located at the West of Imiter deposit, because of the similarity between the two deposits.