Minor minerals

The vein is composed of rhythmic banding of quartz layers and fine-grained sulfides such as argentite, acanthite, sphalerite, galena, pyrite and chalcopyrite, and elec-trum. The principal gangue minerals are quartz, calcite, adularia and interstratified chlorite/smectite. Minor minerals are inesite, johansenite, xonotlite and sericite. These gangue minerals except for quartz, adularia, calcite and sericite are not found in the wall rocks. 

Dominant gangue minerals are quartz, muscovite, chlorite, actinolite, hornblende, epidote, and biotite (Table 2.22). Minor minerals are rutile, illite, sphene, and glauco-phane. It is interesting to note that silicate minerals such as chlorite, epidote, pumpellyite, and albite are common and actinolite has been reported from the basalt near the Ainai Kuroko deposits (Shikazono et al., 1995) and they are also common in the basic schist which host the Motoyama Kuno deposits (Yui, 1983). 

Galena, tetrahedrite-tennantite, mawsonite and native silver occur in the copper rich ores but not in ordinary pyritic ores and copper rich ores most commonly occur as offshoots, tongues and veins in the deformed deposits. This suggests that these minor minerals formed during the metamorphic deformation stage accompanied by recrystallization. 

Major mineral phases identified in the DTMF included several aluminosilicates, quartz, gypsum and hydrobasaluminite. Minor mineral phases identified included ferrihydrite, gersdoffite (NiCoAsS), sulfide phases, and several carbonates. 

Polished thin sections of the host mineralized granite, SB-2671, and pegmatite with minor mineralization, SB-2670B, were selected for U-Th-Pb chemical monazite dating using to the method of Montel etal. (1996). 

Quantitative determination of the major and minor minerals In geological materials Is commonly attempted by x-ray diffraction (XRD) techniques. Mineralogists use a variety of sophisticated and often tedious procedures to obtain semlquantltatlve estimates of the minerals In a solid sample. The mineralogist knows that XRD Intensities depend on the quantity of each mineral component In the sample even through expressions for conversion of signal Intensity to quantitative analysis often are unknown or difficult to determine. Serious difficulties caused by variables such as particle size, crystallinity, and orientation make quantification of many sample types Impractical. Because of a lack of suitable standards, these difficulties are particularly manifest for clay minerals. Nevertheless, XRD remains the most generally used method for quan-... 

Our current estimate for the quantitative mineral composition of the entire oil shale sample based on all 10 clusters Is presented In Table VII. These estimates are consistent with the qualitative XRD results of Table I. Because they are subject to several sources of uncertainty, It Is Impractical to assign error bounds at this time. These Include uncertainty In values of chemical elements for test vectors, problems In Identifying minor mineral components In the clusters, uncertainty In the relative concentrations of each element, and uncertainty In the organic content of each sample. 

Minor minerals were not detected as their concentration the samples was below the detection limits for XRD. 

Studies of the sorption of natural radionuclides from groundwater have established that minor minerals, such as clays coating the fractures in crystalline rock and Fe- and Mn-oxyhydroxides, are important sinks for radionuclides. For example, investigations carried out at the Aspo facility (Smellie Karlsson 1999) showed qualitatively that rare earth elements (REEs), Sc, Th, U, Ra, and Ba have been scavenged by Fe-oxyhydroxide and calcite precipitates,... 

The winonaites are compositionally similar to silicate inclusions in some IAB irons (described below). They have chondritic compositions, and relict chondrules have been found in some meteorites. They consist of olivine, pyroxenes, plagioclase, metal, troilite, and other minor minerals (Benedix et al., 1998), and most have been recrystallized. Like the acapulcoites, they have experienced only small degrees of melting. 

The second book is devoted to what he calls the minor minerals, under which he includes mercury and its ores, sulphur, antimony, marcasites containing metals, vitriol, alum, arsenic, orpiment, and realgar, common salt and other salts, calamine, zaffre, ocher, Armenian bole, emery, borax, lapis lazuli, rock crystal and glass. 

The kerogenic material present in the Green River shale which is of Eocene Age is bound to a mineral matrix composed of carbonates, quartz, clays, and other minor minerals. The isolation of this organic material can, therefore, be carried out in two ways. 

Table III. Major and Minor Minerals Determined by X-ray Diffraction Analysis of Sediments and Low-Temperature Ash of Coal ...

Tyler G, Olsson T (2001) Plant uptake of major and minor mineral elements as influenced by soil acidity and hming. Plant Soil 230 307-321... 

Since oil shale is fine-grained and typically does not contain any trace element-loaded minor minerals such as allanite or zircon, inhomogeneity of the pulverized sample is not likely. Table II shows analytical results for rubidium and strontium on different 0.500-g splits (16) and 300-/xg replicates (21), For most of the elements studied, homogeneity is retained down to the SOO-fig sample sizes. 

Chemically, nearly all the minerals are tungstates. In the group of the minor minerals, two exceptions exist (1) tungstenite— which is a sulfide, and (2) tungstite— which is an oxide hydrate. 

Minor Minerals. Chemical as well as physical and mineralogical properties of these minerals are summarized in Table 2.7. 

Analysis of lunar rocks returned by Apollo astronauts reveals the presence of three major minerals, which occur in concentrations of more than 10 percent in some rocks an equal number of minor minerals, which occur in concentrations of 1 and 10 percent and a somewhat larger number of minerals that occur in only very small quantities, always less than 1 percent. The chart on pages 223-224 lists these minerals. Many of these minerals occur in more than one form. For example, the various forms of pyroxene differ in what cation is present (iron, magnesium, and/or calcium). Enstatite, one form of pyroxene, has the formula MgSiOs wollastonite is CaSi03 and hedenbergite is CaFeSi206. 

There is no visual or chemical distinction between the two different types of magnesite. Examination of the magnesite under an electron microscope reveals individual magnesite crystals in the 1- to 5-p.m range, with minor minerals present in the nodules being dolomite, quartz, clays, and iron and manganese oxides. 

It has long been known that most or all of the important major and minor mineral nutrients may escape in appreciable amounts from the roots under many conditions of plant growth and climatic changes. As much as 5-25% of some elements or substances may under extreme conditions escape to the soil, and under normal conditions at least trace amounts may leave the root more or less regularly. This includes arftmonia, nitrites and nitrates (Wilson, 1943). 

The SEM-AIA categories listed in Table IV consist of 15 individual mineral categories This number of minerals is about double that determined by standard XRD or IR techniques, which are generally limited to the determination of no more than seven major minerals (J ) The SEM-AIA technique, then, is more sensitive to minor mineral consonants than these more traditional techniques Also, it is considerably more flexible in that a novel mineral can be introduced into the analysis very easily and without the need for calibration data, unlike these other techniques. 

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