In the proposed classification certain modifications are made in that of Bateman (2), 1 which relate it more closely to the rock cycle. It is a classification based on geochemical and petrologic concepts. Consideration is also given to the morphological characteristics such as structure, texture, and composition, as well as to the genetic relationships.Economic geology deals with the upper part of the lithosphere. Here the processes of differentiation and recombination form the various rocks, some of which have economically valuable constituents. In this work-rocks have been divided on the basis of their position at the time of formation, in relationship to the upper geospheres of the earth. If the rock or the valuable constituents of a rock are formed solely within the upper-most lithosphere it is endogenic in nature and belongs to the endogenic or major cycle. Those rocks that are formed by the involvement of the uppermost lithosphere with the atmosphere, hydrosphere or biosphere are exogenic in nature and belong to the exogenic or minor cycle.The endogenic cycle is subdivided into the magmatic (early and late),contact metasomatic, pegmatite, hydrothermal (cavity filling, metasomatic), metamorphic, and granitization deposits. The exogenic cycle is subdivided into surficial volcanic emanations, soils, water supply or resistate, hydrolyzate, oxidate, precipitate, evaporate, oxidation with super-gene enrichment and biolith (reduzate and incombustible).

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