A model takes on the quality of theory when it abstracts from raw data the facts that its inventor perceives to be fundamental and controlling, and puts these into relation to each other in ways that were not understood before—thereby generating predictions of surprising new facts. Geochemical modeling has become a popular and useful tool for a wide number of applications from research on the f...

Polluted white dwarfs that have accreted planetary material provide a unique opportunity to probe the geology of exoplanetary systems. However, nature bodies which pollute is not well understood: are they small asteroids, minor planets, or even terrestrial planets? We present novel method infer pollutant masses from detections Ni, Cr and Si. During core--mantle differentiation, these elements e...

The Earth formed through accretion of planetesimals in 1–100 million years. Planetesimal impacts induce degassing, melting, and vaporization during accretion. The impact degassing, as well as the gravitational capture of the surrounding solar nebula gas, formed the proto-atmosphere on a growing Earth. The impact of heating and the blanketing effect of the proto-atmosphere resulted in the meltin...

-Multivariate statistical analyses of geochemical, mineralogical, and cation-exchange capacity (CEC) data from a Venezuelan oil well were used to construct a model which relates elemental concentrations to mineral abundances. An r-mode factor analysis showed that most of the variance could be accounted for by four independent factors and that these factors were related to individual mineral com...

In this study two small, but genetically related iron carbonate deposits Mačje Jame and Vranjski Potok, south west of Busovača (MBSM), located in the pre-Devonian metamorphic complex were investigated in detail. Analyses of the main chemical components, trace elements, REE, isotope composition of C, O, S, 87Sr/86Sr ratio of rhyolite, plot of REE normalized to CI chondrites and a microscopic stu...

The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical baseand precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment quality are res...

have continued to use the same analytical system (that is, the same sample preparation and decomposition methods, with atomic absorption spectroscopy as the final determination step) to determine 13 elements in stream and lake sediments collected for the RGS program. In the early 1980s, simultaneous determination of 30 elements or more by inductively coupled plasma emission spectroscopy (ICP-ES...