Major Elements Abundance in the Kalam Lavas
Abstract
Andesite and salic eraptives of calc-alkaline affinity in the Kalam volcanic zone constitute the upper part of the ‘Kohistan sequence’ (Tahirkheli et al., 1979) developed in the western branch of the Himalayan syntaxis between 71 oE and 75o E. The sequence is interpreted as a complete cross section of a mature island arc formed by subduction during Mesozoic in the southern part of the Neotethys and obducted onto the Indian plate in Upper Cretaceous time (Bard et al., 1980). The Kohistan sequence includes a thick complex of amphibolites, hypersthene gabbros, pyroxene diorites, hornblende diorites, gmnodiorites, metasediments and volcanic rocks. The potential usefulness of the geochemical parameters of the extrusive rocks from the Kalam area, Swat as tectonic fingerprints and gentic indicators is discussed in this paper. There is a close correspondence between the available petrochemical indices of genetic significance of the studied suite to the calc-alkaline volcanic in western and southwestern Pacific regions, which substantiates earlier to worker’s designation of an Island arc environment in the Kohistan Himalaya during Mesozoic time.
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