ZTEM airborne electromagnetic surveys over the Copaquire porphyry deposit, in northern Chile, were designed to map its alteration and structure due resistivity contrasts, to depth, based on successful applications of the method in north America. ZTEM is an airborne variant of the AFMAG passive EM method whose source fields are related to world-wide thunderstorm activity. The ZTEM results over Copaquire appear to map the resistive potassic alteration associated with known Marta and Cerro Moly porphyries, below the surficial secondary enrichment layer and extending to depth. These are in turn surrounded by more conductive, barren pyrite-rich phyllic and propyllitic alteration. Over the other two known mineralized prospects, at Sulfato North and South, the ZTEM results are different, with more resistive rocks at surface becoming more conductive at depth – perhaps reflecting a different geologic setting. Overall, these results are consistent with ZTEM results obtained over other, similar calc-alkalyne porphyry systems and also agree with the known geology.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error