Rock classification sedimentary rocks

The following sections briefly describe the three rock types. Sedimentary rocks are discussed in more detail with respect to their importance to fluid reservoir exploration (e.g. hydrocarbons, water) and their abtmdance on the earth s surface. A detailed classification of rocks and their abtmdances on... 

Feldspars are the most abundant minerals of igneous rocks, where their ubiquity and abundance of their components influence normative classifications. They are also abundant in gneisses, and may be observed in several facies of thermal and regional metamorphic regimes. Notwithstanding their alterability, they are ubiquitously present in sedimentary rocks, as authigenic and/or detritic phases. Only in carbonaceous sediments is their presence subordinate. 

In an exploration area in northern Peru, igneous rocks cover an area of several square km within a metamorphosed series of quartzites and limestones. The younger sequence consists of ignimbrites, tuffs and tuffites of approximately 1000 m thickness. The metamorphism produced skams, which are connected with the ore body. A porphyry Cu deposit occurs in the metamorphosed rocks and is characterised by intense hydrothermal alteration (quartz-kaolinite-sericite) which makes determination and classification of magmatic and sedimentary rocks at the surface very difficult. A zone of propylitic alteration can locally be followed up to 500 m into the andesitic-dioritic wall rocks. 

Folk, R. L., Andrews, P. B. Lewis, D. W. 1970. Detrital sedimentary rock classification and nomenclature for use in New Zealand. New Zealand Journal of Geology and Geophysics, 13, 937-968. 

This chapter will examine the ways in which major element data axe used in geochemistry. The discussion will be restricted to the ten elements traditionally listed as oxides in a major element chemical analysis — Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K and P. Geochemists make use of major element data in three principal ways — in rock classification, in the construction of variation diagrams and as a means of comparison with experimentally determined rock compositions, whose conditions of formation are known. Each of these uses will be discussed in a separate section of this chapter. In addition, major elements are used, often together with trace elements, in the identification of the original tectonic setting of igneous and some sedimentary rocks. This topic will be discussed in Chapter 5. 

Picard, M. D., 1971. Classification of fine-grained sedimentary rocks. J. Sed. Petrol. 41 179-195. Picard, M. D. L. R. High, 1972. Criteria for recognizing lacustrine rocks. In Rigby, J. K. W. K. Hamblin (eds.) Recognition of Ancient Sedimentary Environments. SEPM Special Publication No. 16, Tulsa 108-145. 

Clark, J.I., and Walker, B.F. 1977. A proposed scheme for classification and nomenclature for use in engineering description of Middle Eastern sedimentary rocks. Geotechnique, 27 93-99. 

Figure 2.5. Classification for intact sedimentary rock (modified from West 1995).

Coal has also been considered to be a metamorphic rock, which is the result of heat and pressure on organic sediments such as peat. However, the discussion in favor of coal as a sedimentary rock because most sedimentary rocks undergo some heat and pressure and the association of coal with typical sedimentary rocks and the mode of formation of coal usually keep low-grade coal in the sedimentary classification system. Anthracite, on the other hand, undergoes more heat and pressure and is associated with low-grade metamorphic rocks such as slate and quartzite. Subducted coal may become graphite in igneous rocks or even the carbonate-rich rocks (carbonatites). 

The sedimentary rocks consisting mainly of calcite crystals are processed by standard mining procedures and then subjected to grinding and classification. In addition to natural ground calcium carbonate (GCC), there also exists a chemically produced form known as precipitated calcium carbonate (PCC), which may be finer and of higher purity, but also more expensive than the natural one. 

In order to develop a classification for anisotropic rocks, the results of the studied rocks and a large number of data for metamorphic (shales, schists, gneisses, phyllites, marbles) and some sedimentary rocks were collected. 

Vein-like deposits were described as uranium deposits of uncertain genesis by Mathews etal Except for a small number of these deposits in sedimentary rocks, the group is subdivided into unconformity-related deposits and deposits of metamorphic rocks. In a more genetic classification of the major (Proterozoic) vein-like deposits of the world, Dahlkamp and Adams deciphered the relationship of diagcncsis, metamorphism, metasomatism and weathering on uranium concentrations in various host rocks. The result is a logical genetic explanation for the spectrum of vein-like deposits observed today. 

Jones C. A. A classification of uranium deposits in sedimentary rocks. In Preliminary classification of uranium deposits Mickle D. G. ed. Open-File Rep. U.S. Dep. Energy GJBX-63 (78), 1978, 1-15. 

Division of the minerals in soils into primary (i.e., inherited) and secondary minerals is by no means as easy as it might appear, since secondary minerals from a geological aspect may well be regarded as primary on a pedological basis—and sedimentary rocks introduce even greater complications. Fortunately, however, such a division is largely irrelevant for the present purpose, since the principles of classification should apply to all minerals irrespective of their origin. 

Bioliths are interpreted here in a more confined sense than in the definition and classification of Ehrenberg and Potonie who incorporated the term and concept when dealing with organogenic sedimentary rocks. 

Carbon and its Domestication Table 4.1. Classification of sedimentary rocks... 

Kimberlite in the Western Canadian Sedimentary Basin (WCSB) has been referred to as Class 2 kimberlite (Skinner Marsh 2004). A distinct classification is required because these bodies differ from the classical South African carrot-shaped vertical intrusions known as pipes , in that Class 2 kimberlites contain large volumes of volcaniclastic rocks deposited in shallow (<500 m in depth) saucer-shaped craters with feeder zones that are often difficult to locate. 

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