Trace element signatures of mantle xenoliths along an east-west transect extending from the Sierra Nevada to the Colorado Plateau were investigated in this study. Those beneath the Sierra Nevada are highly enriched in fluid-mobile elements (Cs, Pb, U, and Sr) and, in particular, are characterized by low U/Pb and high Sr/Nd. These signatures imply that aqueous fluids derived by dehydration of se...

Uranium is an alpha-emitting, radioactive, heavy metal that occurs naturally in nearly all rocks and soils. Twenty-two isotopic forms of uranium have been identified, mainly associated with nuclear reactor operations or high-energy physics experiments; the most prevalent isotopes found in the environment are the three naturally-occurring isotopes: U, U, and U. Most uranium isotopes undergo deca...

[1] Abstract: We propose that across-arc differences in the geochemistry of Izu-Bonin arc magmas are controlled by the addition of fertile-slab fluids to depleted mantle at the volcanic front, and residual-slab fluids to fertile mantle in the back arc without slab melting or contemporaneous back arc spreading. The arc consists of a volcanic front, an extensional zone, and seamount chains (the W...

At Long Valley (LV) model Sr isotope phenocryst ages and absolute U–Pb zircon ages from precaldera Glass Mountain (GM) and caldera-related Bishop Tuff (BT) rhyolites show that these crystals track >1 Myr of evolution of a voluminous rhyolite magmatic system. In detail, strong disparities between the different age populations complicate ideas for a unified model for rhyolite generation, differen...

Introduction: Road dust is a group of solid particles that are presented in the urban areas and are originated from both natural and human-induced sources. This study aims to determine concentrations of heavy metals in urban dusts in Behbahan to identify their natural or anthropogenic sources. Materials and Methods: In this study, a total of 20 samples were collected from main roads with diffe...

A transmission electron microscope (TEM) study of Paleoproterozoic zircon that has experienced ultra-high temperature (UHT) metamorphism at ca. 570 Ma in the Kerala Khondalite Belt (KKB), southern India, documents the occurrence of metallic Pb nanospheres. These results permit comparison with a previous report from UHT zircon in Enderby Land, Antarctica, and allow further constraints to be plac...

BACKGROUND More than 60,000,000 Bangladeshis are drinking water with unsafe concentrations of one or more elements. OBJECTIVES Our aims in this study were to evaluate and improve the drinking water testing and treatment plans for western Bangladesh. METHODS We sampled groundwater from four neighborhoods in western Bangladesh to determine the distributions of arsenic, boron, barium, chromium...