The carbon-cycle significance of soil carbonate fluxes is subject to large uncertainties because it is not clear precisely how much calcium is derived from atmospheric sources compared with that from the chemical weathering of silicate minerals. In the petrocalcic horizon (calcrete) of a Pleistocene soil from the USDA–SCS Desert Project area near Las Cruces, NM, approximately 1.5 g Ca=cm3 has b...

Introduction: Spinel minerals with 'normal' structure are common in extraterrestrial materials and can form via a large range of processes including nebular condensation, crystallization from liquid melts and sub-solidus metamor-phic reactions. Owing to their ability to accept a large range of cations in their crystal structures these minerals can be regarded as useful petrogenetic indicators w...

Dissolved water is known to dramatically enhance oxygen diffusion in silicate melts, glasses and minerals. A quantitative theory has been developed to explain this phenomenon by transport via molecular H2O diffusion [Y. Zhang, E.M. Stolper, G.J. Wasserburg, Diffusion of a multi-species component and its role in the diffusion of water and oxygen in silicates, Earth Planet. Sci. Lett., 103 (1991)...

Trace minerals are required for essentially all biochemical processes in the body. Many of these minerals are necessary for optimal growth, physiologic function, and productivity in animals. This paper focuses on 8 trace minerals: cobalt (Co), copper (Cu), iodine (I), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn). These trace minerals have been chosen because nutritio...

OBJECTIVE Objectives of this study were 1) to investigate the mineral intake by Chinese lactating women, 2) to explore the dietary source of minerals, and 3) the ratios between different dietary minerals. METHODS A total of 468 lactating women in 5-240 days post-partum participated in this study. Food intakes by participants were measured using one time of 24-hour dietary recall, and minerals...

Melt inclusions were studied in chrome diopside from the Inagli deposit of gemstones in the Inagli massif of alkaline ultrabasic rocks of potassic affinity in the northwestern Aldan shield, Yakutia, Russia. The chrome diopside is highly transparent and has an intense green color. Its Cr 2 O 3 content varies from 0.13 to 0.75 wt %. Primary and primary–secondary polyphase inclusions in chrome dio...

The purpose of this study is to understand mineral diagenesis authigenic mineral and the effect of climate on mineral of Pleistocene-Holocene sediment deposits in the Southern Kenya Rift. Lake Magadi unique geologic settings are characterized by extreme alkalinity and high silica activities. The mineralogical analysis was achieved by X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM...

Potato consumption provides significant dietary contributions to several essential minerals, but the effects of cultivar and planting site are not well-understood. The mineral content of 16 cultivars, grown at 5 locations, was measured using inductively coupled plasma-optical emission spectroscopy and evaluated on a per serving basis for percent recommended daily intake (% RDI), emphasizing som...

Differentiation in terrestrial planets is expected to include the formation of a metallic iron core. We predict the existence of terrestrial planets that have differentiated but have no metallic core, planets that are effectively a giant silicate mantle. We discuss two paths to forming a coreless terrestrial planet, whereby the oxidation state during planetary accretion and solidification will ...

We suggest that the partial pressure of carbon dioxide in the atmosphere is buffered, over geological time scales, by a negative feedback mechanism in which the rate of weathering of silicate minerals (followed by deposition of carbonate minerals) depends on surface temperature, and surface temperature, in turn, depends on carbon dioxide partial pressure through the greenhouse effect. Although ...