GEOLOGY, URANIUM DEPOSITS, AND URANIUM FAVORABILITY OF THE HARTFORD HILL RHYOLI7.E AND TRUCKEE FORMATION, SOUTHWESTERN WASHOE COUNTY, NEVADA, AND EASTERN LASSEN COUNTY, CALIFORNIA

摘要

The Hartford Hill Rhyolite and the overlying Truckee Formation arc host for several uranium deposits found in an area extending from Long Valley (Lassen Co., California) eastward to the Virginia Mountains (Washoe Co., Nevada) and from Seven Lakes Mountain on the north to Hungry Valley on the south.nThe Hartford Hill Rhyolite is a scries of ash-flow sheets that range in age from late Oligocene to early Miocene. This scries at¬tains a maximum stratigraphic thickness of approximately 4,000 ft. The formation is divided into seven ash-flow tuff cooling units and avalanche deposits, which range in composition from rhyolite to andesite.nThe Truckee Formation is a sequence of alternating lacustrine, fluviatile, and volcanic rocks of Pliocene, age, which attains a thickness in excess of 3,000 ft.