Rocks classification

The chemical classification and nomenclature of volcanic rocks usmg the total alkalis versus silica (TAS) diagram of Le Maitrc et al, (1989). Q. = normative quartz 01 = normative olivine. 

Platting coordinates expressed as Si02, (Na20+K20) for the field boundaries of the toul alkalis versus silica diagram of Le Maitre et aL (1989). 

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Abstract Chronological studies of kimberlite-host rocks in the diamondiferous Buffalo Head Hills kimberlite field of north-central Alberta facilitate new interpretation of the nature, timing and sequence of kimberlite eruptions in northern Alberta. Three different emplacement episodes are recognized in association with volcanic and intrusive activity Late Cretaceous ( 88-81 Ma) Smoky Group equivalent intra- and extra-crater facies, Late Cretaceous and Paleocene ( 81 and 64 Ma) intrusion of sills or dykes, and Paleocene ( 60 Ma) Paskapoo Formation equivalent intra-crater facies. These specific periods of magmatism correspond to characteristic intra-field features such as spatial distribution, rock classification and diamond content. 

Plutonic rock classification by petrologic means is a simple procedure involving the use of Streckeisen ternary diagrams. Unfortunately, classification suffers from modal estimation errors involving visual estimates, or representativity issues from point counts or image analysis procedures applied to thin sections or slabs of insufficient size. 

In contrast, volcanic rock classification by petrologic means is generally difficult because complete crystallization is not achieved, making it impossible to use the modal rock petrography as a classification criterion. As a result, classification of volcanic rocks has historically relied on lithogeochemistry, and the most successful approaches have employed conserved, trace element concentration ratios. These have been used as proxies for petrology to empirically classify volcanic rocks. Unfortunately, these trace elements are imperfect proxies for rock... 

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. 

Thermal conductivities were measured and modelled from reference values of the thermal conductivity of different minerals and from the mineral composition of all Aspd samples in the SKB SICADA database. The thermal conductivity database has been analysed in terms of frequency, type of distribution, spatial distribution, variogram analyses, etc. The data have also been analysed according to the different rock types. However, there are uncertainties relating to the rock classification, mainly due to problems in distinguishing between the Aspo diorite and Avro granite, but also because different classification systems have been used. 

Here we present, based on the chemical rock classification introduced in Section 1.3.2, typical cases of how major and trace elements contained in normal rocks are dispersed in the surrounding ecosystem. The different compartments studied are (A) the solid parts of the soil column, (B) the meteoric water that percolates through the soil and is later collected as ground water, emerging in springs, and (C) plants growing in the soil, in cases where data are available (cf. Fig. 2). In the last chapter on contaminated... 

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. 

Basalt classification using the Ne-Di-Ot-Hy-Q diagram Granite classification using the Ab-An-Or diagram Volcanic and plutonic rock classification using Q (F )- ANOR... 

Engineering requirements require rock classifications to apportion them on their properties pertinent to engineering needs. Some engineering classifications e.g. those of the International Association of Engineering Geology (lAEG 1981) and theBS 5930 1981 classifications have been formulated to meet this necessity. The BS 5930 1981 classifications for the three different rock types are as shown in Tables 2.10, 2.11 and 2.12. 

Engineering requirements require rock classifications to recognize and apportion them on quantifiable physical properties. Intact rockhas been classified on mechanical properties suchas strength and compressibility thus giving an indication of its engineering utility. One such classification of intact rocks is as shown in Figures 2.4, 2.5 and 2.6. 

Rock classification tests Saturation moisture content (alteration index)... 

Barton et al. (1975) pointed out that Bieniawski (1974), in his analysis of tunnel support, more or less ignored the roughness of joints, the frictional strength of the joint fillings and the rock load. They, therefore, proposed the concept of rock mass quality, Q, which could be used as a means of rock classification for tunnel support (Table 9.6). They defined the rock mass quality in terms of six parameters ... 

Barton, N. 1988. Rock mass classification and tunnel reinforcement selection using the Q-system. Proceedings Symposium on Rock Classification for Engineering Purposes, American Society for Testing Materials, Special Technical Publication 984, Philadelphia, 59-88. 

Exploratory Drifts provide basic rockmass parameters, which are used for rock classification. Drifts are also useful for insitu rock mechanic tests to determine mechanical characteristics of rockmass (Plate 12). 

To fulfill the aim of the study, some physical properties of the samples including dry density and effective porosity were determined in accordance with ISRM (1981) (Table 1). According to the rocks classification based on dry density and porosity suggested by Anon (1979), dl of the samples were classified as to have moderate density... 

Except of normal provisions, here supply two postulates If no any explanations, the working face will go on normally During excavation process, if the rock classification keep invariability, the measuring station will also keep sameness. 

Xing Nianxin and Xu Fan 1986. Surrounding rock classification and design in tunnel engineering. Chinese Journal of Rock Mechanics and Engineering, 4 33-50. 

Surrounding rock classification Elastic modulus (lO MPa) Deformation modulus (lO MPa) Poisson s ratio Density (kN/m ) Compression stress (MPa)... 

On the whole, the mountain along the tailrace tunnel is high, and the mountain slope is stable. The tailrace tunnel is buried deeply in the slightly weathered-fresh granite, except inlet/outlet tunnel. The surrounding rock is integral structure, except the fault areas. The excavation reveals the surrounding rock classification class I 13.88%, class 11 41.65%, class III 36.82%, and class IV 7.65%. 

The parameters of materials adopted for calculation are shown in Table 3. The control case results of different surrounding rock classification are shown in Table 4. 

Table 4. Control case results of different smroimding rock classification. ...

Streckeisen, A.L. lUGS Subcommission on the Systematics of Igneous Rocks. Classification and Nomenclature of Volcanic Rocks, Lamprophyres, Carbonatites and Melilite Rocks. Recommendations and Suggestions. Neues Jahrbuch fur Mineralogie, Abhandlungen, 141 (1978) 1-14. 

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