The last 500 million years of the strontium-isotope record are shown to correlate significantly with the concurrent record of isotopic fractionation between inorganic and organic carbon after the effects of recycled sediment are removed from the strontium signal. The correlation is shown to result from the common dependence of both signals on weathering and magmatic processes. Because the long-...

The Yellowstone Plateau volcanic field is one of the largest centers exchange time to form zoned zircons is between a few hundred and a few thousand years, which reflects the residence time of lowO of rhyolitic magmatism on Earth. Major caldera-forming eruptions are followed by unusual lowO rhyolites. New oxygen isotope, magmas after formation and before eruption. petrologic and geochemical dat...

Introduction: It is well known that shergottites have a large variation of rare earth elements (REEs) abundance patterns and isotopic compositions. Jones [1] and Borg and Draper [2] suggest that light REEs (LREEs)-enriched shergottites resulted from mixing of a LREEs-enriched component with their parental magma. The LREEsenriched component is thought to be either Martian crust [1] or a KREEP-li...

Diverse explanations exist for the large-volume catastrophic eruptions that formed the Bishop Tuff of Long Valley in eastern California, the Bandelier Tuff in New Mexico, and the tuffs of Yellowstone, Montana, USA.These eruptions are among the largest on Earth within the last 2 Myr. A common factor in recently proposed petrogenetic scenarios for each system is multistage processing, in which a ...

Despite an apparent north/south topographic dichotomy that formed >4.0 Ga, the young Martian meteorites (<2.4 Ga) and first-order remote sensing observations revealed a surface of Mars is uniformly basaltic. This simplistic vision has been challenged by discovery brecciated meteorite additional spacecraft data all point to presence alkaline igneous rocks, thereby demonstrating unexpected divers...

The Erongo subvolcanic center in Namibia is the largest composite, bimodal complex in the Mesozoic Etendeka igneous province of Namibia. This study of 40Ar/39Ar and high spatial resolution U^Pb zircon dating demonstrates that emplacement of the various igneous units at Erongo took place within a time span equivalent to or shorter than geochronologically resolvable age differences (ca. 2 Ma), an...