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Leaf physiognomy provides estimates of environmental parameters, including mean annual enthalpy, which is a thermodynamic parameter of the atmosphere that varies with altitude. Analyses of 12 mid-Miocene floras from western [...]

Models for extension-related magmatism based on decompression melting of asthenospheric mantle poorly simulate fluxes and bulk compositions of magmas produced during early stages of continental extension. For the Great Basin of western North America, it is proposed that magmatism proceeded in two stages, the first involving melting of lithospheric mantle sources between 40 and '5 million years ago (Ma), followed (since '5 Ma) by melting of upwelling asthenospheric mantle in areas where extension has exceeded about 100 percent. This transition in magma sources is diachronous, depending on initial variations in lithosphere thickness and on rates of lithospheric thinning., Magmatism associated with lithospheric extension has been attributed to partial melting of ascending hot mantle material. Such a mechanism reasonably accounts for many aspects of magma production in regions of [...]

The mineralogy and fossil assemblages of lake beds currently provide the only tool for deciphering pre-Mid-Wisconsin paleoclimatic conditions in the Great Basin. Calcitic veins, which mark the sites of paleoground-water [...]

Pre-Mesozoic Palinspastic Reconstruction of the Eastern Great Basin (Western United States) THE GREAT BASIN OF THE WESTERN UNITED STATES (FIG. 1) is a classic area for geological research both for [...]