Sharon Creek Formation
tSharon Creek Formation
The Sharon Creek Formation is the oldest rock unit found at Thor, and consists of shales and siltstones (pelitic rocks) that weather into recessive areas. The rock unit is highly fissile and is generally found under the Thor epithermal deposit. The formation is believed to host hydrocarbons that have been thermally altered in proximity to the epithermal deposit and the prospective porphyry target.
Carbon and oxygen isotope chemistry has shown that the carbonaceous zones around the epithermal deposit have identical composition. The carbonaceous zones are important at Thor because they can be mapped using both ground and aeromagnetic geophysical surveys. The recently completed MT survey has provided evidence of a large 'donut' of conductive material that surrounds the porphyry target. This is interpreted to mean that the porphyry target has intruded into the Sharon Creek Formation and converted the organic material into conductive carbonaceous material.