INTRODUCTION The fate of various metals, including chromium, nickel, copper, manganese, mercury, cadmium, and lead, and metalloids, including arsenic, antimony, and selenium, in the natural environment is of great concern (Adriano, 1986; 1992), particularly near former mine sites, dumps, tailing piles, and impoundments, but also in urban areas and industrial centers. Soil, sediment, water, and ...

Haynes, F.M., 1984. A geochemical model for sulfide paragenesis and zoning in the Cu-Fe--As--S system (Tsumeb, South West Africa/Namibia). Chem. Geol., 47: 183--190. The Cu-bearing hypogene mineralization at Tsumeb, South West Africa/Namibia, is interpreted to have resulted from the interaction of hot circulating Cu-rich saline solutions and host dQlomites. Fluids attending formation of the mai...

We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarseto medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated wi...

This autobiography covers the past 55 years of my research in geochemistry. I try to show how chemical principles can be applied to a wide variety of geological problems, ranging from iron sulfide mineralogy, to carbonate chemistry in the oceans, to silicate mineral surface chemistry during weathering, to biogeochemical changes during early diagenesis, to plants and weathering, to models for th...

Marine hydrothermal microorganisms respond rapidly to changes in the concentrations and availability of metals within their environment. Hyperthermophilic archaea appear to possess novel mechanisms for metal detoxification, dissimilatory metal reduction and metal assimilation that may be absent in their mesophilic and bacterial counterparts. For example, tungsten was found in high concentration...

Joegoldsteinite, a new sulfide mineral of end-member formula MnCr2S4, was discovered in the Social Circle IVA iron meteorite. It is a thiospinel, the Mn analog of daubréelite (FeCr2S4), and a new member of the linnaeite group. Tiny grains of joegoldsteinite were also identified in the Indarch EH4 enstatite chondrite. The chemical composition of the Social Circle sample determined by electron mi...

The crystal structure of the mineral lautite (copper arsenic sulfide), CuAsS, previously described as either centrosymmetric [Pnma; Marumo & Nowacki (1964 ▶). Schweiz. Miner. Petro. Mitt.44, 439-454] or noncentrosymmetric [Pna2(1); Craig & Stephenson (1965 ▶). Acta Cryst.19, 543-547], was reinvestigated by means of single-crystal X-ray diffraction. The centrosymmetric structural model reported ...

Extremely light and highly variable δ60Ni values have been observed in komatiite-associated magmatic sulfides recent studies. In this study, we examine the mechanisms of Ni isotope fractionation between silicate sulfide liquids Hart Fe-Ni-Cu-sulfide system. We assess petrogenetic significance these using concentration data. The bulk rock varies from 774 to 2690 ppm komatiite samples with no min...

In environments isolated from solar radiation, diverse microbial populations and ecosystems are sustained by the chemical energy supplied from Earth!s interior. The most outstanding example is a deep-sea hydrothermal vent, which discharges enormous amounts of reductive energy in the form of reduced sulfur compounds, H2, CH4, and reduced metals during magma degassing and hydrothermal reactions w...