AN INTEGRATED PETROLEUM EVALUATION OF NORTHEASTERN NEVADA
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AN INTEGRATED PETROLEUM EVALUATION OF NORTHEASTERN NEVADA
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CRETACEOUS BASIC PLUTONIC ROCKS The compositional variation in plutons of Cretaceous age is quite narrow in comparison to that of Jurassic age intrusives. Most of the Cretaceous rocks are granodioritic to monzonitic in composition with very little diorite or quartz diorite phase. In the Eureka district, a Late Cretaceous quartz diorite stock is present at Ruby Hill and is dated at 62 +/- 12 Ma. The Enright Hill pluton in the Mountain City Quadrangle is a small quartz diorite pluton, with minor potassium feldspar, sanidine, hornblende with diopside cores, brown biotite, and accessory zircon and apatite. It has been dated as 110.9 +/- 1 Ma (in Coats, 1985). |
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