Feldspar, plagioclase

After the experiments, significant quantities of newly formed minerals were observed at the cold extremity of the tube, pointing to a fast material transport by diffusion from the hot to the cold end of the tube. The following spatial distribution of newly formed phases, reflecting the temperature profile, was observed in both runs (Fig. 8) quartz + K-feldspar + plagioclase + Mg-rich saponites (hot extremity) quartz + K-feldspar + plagioclase (middle of the tube) and alkaline or Ca-rich clays + quartz + plagioclase (cold extremity). The cation composition of the phyllosilicates was similar in both experiments. Some newly fonned quartz crystals... 

Suspended solid surfaces (particles or colloids) in waters play a prominent role in controlling the concentration of dissolved trace elements. Most of these elements are eliminated by sedimentation after incorporation on to or into particles, generally by complexation with the surface sites. The most common inorganic particles and colloids are non-clay silicates (quartz, potash feldspar, plagioclase, opaline silica (diatoms)) clays (illite, smectite) carbonates (calcite, dolomite) Fe-Mn oxides (goethite, magnetite) phosphates (apatite) sulfides (mackinawite). Particles and colloids in a water body may be classified as a function of their origin ... 

Feldspar plagioclases albite to anorthite NaAlSisOg (solid solution series) CaAlgSigOg... 

Bicarbonate-dominated water with TDI concentrations up to about 600 mg/1 has not passed evaporites, and the nature of the rocks interacted with can be deduced from the cations calcium-dominated HC03 water has passed limestone calcium- and magnesium-dominated HC03 water is produced by contact with dolomite sodium-dominated and potassium-rich HC03 waters have interacted with feldspar, plagioclase, and pyroxene contained in igneous or volcanic rocks. 

Feldspar Plagioclase feldspar NaAlSijOg to CaAl2Si208 (continuous series)... 

There is no proof, liowever, that the weathered material has derived from the exact parent rock given in the table. This may explain the excess in soil vol % quartz, which, assuming quartz is not dissolved or precipitated during soil formation and that volume and weight percents are roughly equal, should not exceed about (30/75) x 100 = 40 wt % of the soil. (Densities of quartz, K-feldspar, plagioclase feldspar, and kaolinite are alt 2.60 0.05 g/cm ). 

Figure 1335 Apparent K i values for Np(V) as a function of Eh with INp = 10 M. Sorbent sediments contained quartz, K-feldspar, plagioclase feldspar, kaolinite, muscovite, calcite, chlorite, and dolomite. Apparent Kj values from >10 to > lO, measured for Eh values below about 250 mV, reflect precipitation of Np(IV) solids rather than adsorption. Modified after Lieser and Mohlenweg, Neptunium in the hydrosphere and in the geosphere. Radiochim. Acta 43 27-35. Copyright 1988 by Oldenbourg Verlag GmbH. Used by permission.

Mudrocks from both types of basin are grey and calcitic, dominated by clay minerals and calcite, and 5-15% quartz, feldspar (plagioclase K-feldspar) and mica. They are largely hemipelagic and pelagic beds, but include some Bouma E intervals. Clay minerals are dominated by illite and chlorite, but mixed-layer illite/smectite, serpentine, corrensite and possibly kaolinite are present in some samples. Pyrite is ubiquitous. 

The Namorado Sandstone is composed of fine- to medium-grained, moderately to well sorted arkoses and subarkoses (Fig. 5). The main framework constituents are quartz, potassium feldspar, plagioclase and quartz-feldspar rich rock fragments, most of Plutonic origin. Although previous work indicated the predominance of K-feldspars (Carvalho, 1990 ... 

Fig. 6.110 Granite from Nadziejow nearNysa (Poland). Large biotite erys-tals seen in different eross sections, in the neighborhood of xenomorphie quartz grains and feldspars (plagioclases). Polaroidx...

N2.1.12.64) Porphyritic quartz latite, phenocrysts of K-feldspar, plagioclase, and quartz in a dark-red groundmass. Hawkes Porphyry Member, west side of Hawkes camp vaUey, southern Neptune Range. 

Microcrystalline to cryptocrystalline intergrowth of quartz, alkali feldspar, plagioclase, and pyroxene with minor amounts of glass, chlorophaeite, zeolite ( ), and chlorite, probably formed by devitrification of glass. 

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