Document Type : Original Research Paper
Authors
1 M. Sc., Geological Survey and Mineral Exploration of Iran, Southeast Branch, Kerman, Iran
2 Assistant Professor, Department of Mining Engineering, Higher Education Complex of Zarand, Shahid Bahonar University of Kerman, Kerman, Iran
3 Professor, Department of Mining Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
Abstract
Volcanic, sub-volcanic (dyke) and pyroclastic (agglomerate and tuff) rocks of Eocene age are located in the Kalmard block in the north and northeast of Kerman City. Petrographically, the lavas are basalt, andesite, rhyodacite and rhyolite, whereas the dykes and pyroclastic rocks are andesite and crystal tuff in composition respectively. The porphyritic, microlitic-porphyritic and trachytic are the main textures and mineralogically consist of plagioclase± quartz± K-feldspar ± biotite± amphibole± clinopyroxene± olivine+ opaque minerals. Plagioclases show evidences of disequilibrium textures such as sieve texture, resorption and zoning; whereas quartzes have resorbed margins, and amphiboles and biotites are only slightly opacitized. These textures can be resulted from magma mingling, PH2O variations, and decompression with minor loss of temperature during magmatic ascent. Geochemical studies revealed that the volcanic rocks belong to a sub-alkaline magmatic series with calc-alkaline nature. Furthermore, acidic volcanic rocks are metaluminous to peraluminous and show characteristics of I-type granitoids. The trace element discrimination diagrams along with chondrite-normalized rare earth element patterns show that the igneous rocks formed in an active continental arc environment.
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