Inherited minerals

In Table 3, susceptibility to weathering increases down the list as fewer silicon-oxygen bonds need to be broken to release silicate. Consequently, quartz and feldspars especially, but also mica in temperate soils, are common inherited minerals in the coarse particle size fractions of soil (the silt and sand fractions, 0.002-2 mm). The amphiboles, pyroxenes, and olivine are much more easily weathered. Thus, soils derived from parent material with rock containing a predominance of framework silicates e.g. granite, sandstone) tend to be more sandy, while those derived from rocks containing the more easily weathered minerals tend to be more clayey. 

These five groups are inherited from the soil s parent material and are considered easily weatherable minerals when clay-sized. Inherited minerals that are more resistant to weathering in the clay fraction include ... 

Interstratified or intermixed layer silicates, vermiculite (M+(Mg,Fe)s(Si4-n, Aln)0iq(0H)2) and the hydrous (slightly weathered) micas. The M+ represents an exchangeable cation. Whether the minerals of this category are inherited from the parent material or are secondary products derived from inherited minerals is uncertain in many cases. 

The remaining categories of Table 7.5 contain secondary (soil-formed) minerals resulting from the weathering of primary minerals from soil parent materials. By the time these stages of weathering are reached, inherited minerals in the clay fraction have either disappeared or are present in only minor amounts. 

The inorganic component of soil is dominated by four elements O, Si, Al, and Fe (Jackson, 1964). Together with Mg, Ca, Na, and K they constitute 99% of the soil mineral matter (see Table 8-2). Minerals in soil are divided into primary and secondary minerals. Primary minerals, which occur in igneous, metamorphic, and sedimentary rocks, are inherited by soil... 

Grustal reservoirs are also variable in Gl-isotope compositions (Figs. 1-6) due to fractionation of the Gl-isotope compositions inherited from their mantle source through fluid-mineral reactions, incorporation of G1 derived from the oceans and fractionation within fluid reservoirs by diffusion (see below). For example, the oceanic crust is enriched in Gl (and pore fluids depleted in Gl) through reaction of seawater with basaltic crust derived from the depleted mantle (Fig. 1 Magenheim et al. 1995). Undoubtedly, future investigations of Gl-isotopes in whole rocks and mineral separates will address the Gl-isotope compositions of these reservoirs and their evolution. 

CAIs are composed of a variety of minerals, primarily hibonite, perovskite, melilite, spinel, aluminum- and titanium-rich diopside, anorthite, forsterite, and occasionally corundum or grossite. They also show significant enrichments in refractory trace elements. CAIs exhibit a host of isotopic anomalies inherited from incorporated presolar grains or from the early nebula itself. 

Ma (Fig. 9.16). The 40Ar-jyAr ages appear to be considerably older, but are compromised by the presence of trapped 40Ar from the Martian atmosphere and possibly inherited radio-genic Ar as well. In contrast to the mineral (internal) isochrons, whole-rock Rb- Sr and Pb-Pb isochrons for shergottites suggest a much older age of-4.1 Ga (Bouvier et al., 2008). Most workers interpret this age to reflect planetary differentiation that established mantle... 

The problem is certainly more complex at conditions of low temperature and pressure where thermal energy is low and slight fluctuations in configurational energy can probably provide metastable crystallization as experienced often in the laboratory. However, we will retain the general principle that authigenic minerals will more closely represent equilibrium phases than will detrital minerals inherited from other geological cycles. 

In metamorphosed sedimentary rocks, arsenic tends to occur in oxide and sulfide minerals (Bebout et al., 1999), 69-70. Many metamorphic rocks simply inherit their arsenic from their precursor rocks. That is, unless arsenic-rich metamorphic fluids are introduced, quartzites metamorphosed from low-arsenic quartz-rich sandstones and marbles metamorphosed from low-arsenic limestones should have relatively little arsenic. In contrast, shales often contain more arsenic than sandstones and limestones (Table 3.23). Therefore, slates and phyllites that form from the metamorphism of shales should inherit at least some of the arsenic (Table 3.24). 

Vitamin D deficiency remains the most common cause of rickets and osteomalacia in the world, with the exception of the United States and the Scandinavian countries where most dairy products are supplemented with this vitamin. This deficiency can be caused either by dietary habits or by insufficient exposure to ultraviolet light. The same type of symptoms can be observed when there is interruption of the normal vitamin D metabolic pathways due to a number of liver and/or kidney diseases. In addition, a number of inherited factors can lead to different types of vitamin D resistance which require massive supplements of vitamin D and/or minerals. Extensive reviews have been published depicting both the clinical features and their most likely causes, as well as the possible treatments of the different types of clinical disorders resulting from vitamin D deficiencies [113-117], The newly defined role for l,25(OH)2D3 upon the hematopoietic system could also have clinical relevance in bone disorders such as osteoporosis where patients have been shown to possess abnormal T-cell subsets [118]. 

Soil samples were air dried and prepared for lead isotope analysis using 50-100 mg of the <0.2-mm size fraction. Sulfides, Fe-hydroxides, and other secondary minerals in the Penobscot Formation can be used to monitor the composition of labile Pb and provide the means to discriminate labile (anthropogenic) lead from lead inherited from the parent rocks and sulfides (e.g., Ayuso and Foley, 2008). A cool mild acid leach (1,5N HC1 + 3N HNO3) was used to attack the secondary minerals. This solution likely reflects the labile Pb (e.g., Erel et al., 1997) captured in the Fe-hydroxide, carbonate, or organic materials, or other secondary minerals (clays). These minerals can contain lead, arsenic, and other elements derived from outside of the watershed. Mixed solutions of HF—HN03 were used for final dissolution of the residual fractions. Table 12.2 summarizes the Pb-isotopic data for the leach fractions of the soil horizons (together with Pb and As contents) Table 12.3 shows equivalent data for the residues. 

On the basis of analyses of bulk CAIs or separated minerals, the inheritance of 0-rich condensates from supemovae appears plausible. However, the magnitude of the isotopic difference between the putative dust and gas reservoirs is a free parameter, so that the model has no predictive power. Furthermore, the observed oxygen isotope anomalies in presolar oxide grains are best understood as resulting from processing in red giant stars, and do not show 0-excesses. 

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