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Rhyolite was mined there starting 11,500 years ago. [32] Tons of rhyolite were traded across the Delmarva Peninsula, [32] because the rhyolite kept a sharp point when knapped and was used to make spear points and arrowheads. [33] Obsidian is usually of rhyolitic composition, and it has been used for tools since prehistoric times. [34]
Rhyolite is a ghost town in Nye County, in the U.S. state of Nevada. It is in the Bullfrog Hills , about 120 miles (190 km) northwest of Las Vegas , near the eastern boundary of Death Valley National Park .
The mechanical properties of the rhyolite on Mount Kineo exhibits the physical properties of flint and was used extensively by indigenous peoples to make arrowheads and implements and thus, has often been referred to as "Kineo flint" in literature; but this term misleads by implication that the rhyolite is a cryptocrystalline form of the ...
The ancient Ballena River brought rhyolite-gravel, or "Poway" clasts, from a region in present-day Sonora, Mexico to the Pacific Ocean. Its sediments deposited into an alluvial fan –submarine canyon–submarine fan complex extending for miles offshore.
Aquacade, previously designated Rhyolite, was a class of SIGINT spy satellites operated by the National Reconnaissance Office for the United States Central Intelligence Agency. The National Security Agency (NSA) was also reportedly involved. [ 1 ]
Llanite is a porphyritic rhyolite with distinctive phenocrysts of blue quartz (a rare quartz color) and perthitic feldspar (light grayish-orangeish). The brown, fine-grained groundmass consists of very small quartz, feldspar, and biotite mica crystals.
Accessory minerals like pyroxenes provide insight to the history of the magma. The formation of dacite provides a great deal of information about the connection between oceanic crust and continental crust. It provides a model for the generation of felsic, buoyant, perennial rock from a mafic, dense, short-lived one.
Additional rhyolite flows may have erupted along the incipient ring-fault, [18] but the pre-collapse rhyolite history likely spans no more than ~70 kyr. [34] Another pre-collapse unit is the 60 to 70 m (200 to 230 ft)-thick Junction Butte Basalt on the northeastern margin of the plateau, [18] dated at 2.16 ± 0.04 million years. [35]