Host rock Geochemistry
Ternary Plot of SiO2/20 vs. Fe2O3 vs. MgO . The Metasedimentary/Metavolcaniclastic Rocks of the Jowett and Broadview Formations Plot in Group 1, and the Intrusive Rocks (I-1 and I-2) Plot in group 2.
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Host Rock Geochemistry: The host rocks at Thor are a series of Lower Paleozoic-age metasediments and metavolcaniclastic rocks that were deposed in an ocean that flanked the west side of ancestral North America. The rocks are mainly greywackes as well as volcaniclastic sediments that indicate there was active volcanicism in the sedimentary basin. The succession of rocks was folded into a major feature called the Silver Cup Anticline during a continental collision that trends northwesterly through the Silver Cup Mining District. These rocks have been subjected to extensive geochemical anlysis at Thor, primarily to ascertain alteration related to the I-1 intrusive body. |
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HREE Analysis
Some insight into the origin and associations of rocks can be gained by understanding the levels of trace elements found in various rock units. The host rocks at Thor include metasediments and metavolcaniclastics, and have very distinctive HREE profiles characterized by depletion of niobium, tantalum, phosphorus and titanium, and enrichment in potassium and lead. These rocks have different HREE profiles from the I-1 and I-2 rocks. |
HREE plot Showing the Typical Profile for the Unaltered Metasediments/Metavolcaniclastics at Thor. These Rocks are Characterized by Marked Depletions and Enrichments of Elements Not Seen in the I-1 and I-2 Rocks.
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