Bulletin of the United States Geological SurveyThe Survey, 1956 - Geology |
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Common terms and phrases
abnormal radioactivity abundant adit Alboroto rhyolite alkali feldspar alkalic igneous rocks alkalic rocks amphibole amphibolite anatase apatite biotite breccia veins brookite Cambrian carbonate rock carbonate veins cerium cerium group chlorite Dubois east erosion surface exposed exposures fine-grained foliation fragments gabbro Geol goethite Gunnison County hematite Hill composite stock Hunter igneous rocks Iron Hill Iron Hill carbonate Iron Hill complex Iron Hill composite Iron Hill stock iron oxides jasper Jurassic Larsen Little Johnnie claims Little Johnnie vein locality magnetite map area pl metarhyolite porphyry miles millimeters mineralized shear zones Morrison formation niobium perovskite phenocrysts porphyry potash feldspar Powderhorn district pre-Cambrian pre-Cambrian rocks probably prospect pit pyrite pyroxenite quartz quartz-biotite schist quartzite radioactivity rare-earth metals rare-earth-bearing apatite rhyolite sandstone schist specimens sphalerite strike syenite thin section ThO2 thorite thorite or thorogummite thorium deposits thorium-bearing veins thorogummite titanium U. S. Geological Survey uranium vein containing veinlets volcanic rocks wall rock