Geochemistry and Petrogenesis of lower to middle Paleozoic alkaline lamprophyre dikes of Hour Village, north east of Kerman


Department of Geology, School of Sciences, University of Tehran, Tehran, Iran


In the northeast of Kerman toward Ravar around Hour village, a series of rocks in the form of dike have been penetrated into the Lower-Middle Paleozoic Formations. The color of these rocks is dark with non-equigranular texture resulted from large phenocrysts of brown amphibole and pyroxene set in a fine grain groundmass. The existing phenocrysts, according to their abundance, are consist of calcic amphiboles, clinopyroxene and pseudomorphosed olivines. The main characteristics of lamprophyric rocks are non equigranular texture as well as mafic minerals. The normativre results indicate the occurrence of leucite and nepheline and the lack of quartz. According to mineralogical and geochemicai studies, these rocks are classified as alkaline Lamprophyres and are probably comptonite. The average contents of Al2O3, K2O, MgO, Na2O, SiO2 and TiO2 are (12/92, 2/64, 9/98, 1/29, 39/35 and 3/44 ) Wt% respectively, in all samples the amount of K2O is over that of Na2O and the K2O/Na2O ratio is more than one which indicating the potassic nature of these rocks. All samples show enrichment in lithophile elements in spider diagrams and are plotted in intracontinental extension environment in tectonic discriminate diagrams. As the spider diagrams show the lamprophyres studied are enriched in HFSE and volatiles. Generally, these lamprophyres are derived from enriched garnet lherzolite mantle under low degree (%2 to %5) of partial melting.