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The Amargosa Project

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The project is located at an elevation of ~730 m above mean sea level and within the Basin and Range physiographic province (BR). The BR is composed of high relief mountains or foothills separated by low-lying valleys and salt flats. The salt flats of the Amargosa do not support plant life, but Phreatophytes (deeply rooted plants) occur on their edges and near the adjacent gravel-dominated alluvial fans. Iodine bush (Allenrolfea occidentalis) grows closet to the salt flats, while saltgrass (Distichlis stricta) and arrowweed (Pluchea sericea) occur more distal. The dominant species in the salt flat-proximal areas is honey mesquite (Prosopis juliflora) that occurs as large stands. Sacatone grass (Sporobolus airoides) and desert holly (Atriplex hymenelytra) intergrown with …show more content…

Miocene volcanic rocks that form the Timber Mountains and Oasis valley caldera complex border the basin to the north (Christiansen et al., 1977) and extend southward beneath the basin. Most of these volcanic rocks are silicic ignimbrites that are 9.5-16 Ma (Christiansen et al., 1977). These volcanic rocks are overlain by moderately to highly deformed siltstone, fanglomerates, tuff, and limestone that have been correlated to the Furnace Creek Formation of Death Valley (Hunt and Mabey, 1966; Naffe, 1973) which has been dated at 5.3 to 6.4 Ma (Fleck, 1970; Hay et al., 1986).
Pliocene to Pleistocene sediments composes the basin fill in the Amargosa desert, with most of the rocks comprising Mg-rich clay deposits of Pliocene age. The exposed parts of the Pliocene basin rocks are dominated by clays and carbonate rocks on the eastern part of the basin with comparatively few outcrops on the western part of the basin. Thickness of the Pliocene sequence may be 300 m thick in the Ash Meadows area (Naffe, 1963) and near the Amargosa project, and is estimated to be 2 to 4 Ma years

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