M Refoseh; A Shaker Ardakani; H Ranjbar
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 ...
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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.
A. M. Ali Khasi; M. Hosseini Barzi; M. Shadan
Abstract
Determination of sedimentary environment, provenance and tectonic setting of Ab-Haji Formation sandstones (Lower Jurassic) have been carried out in Cheshmeh Bakhshi and Sartakht-e-Shotoran sections which are located in Kalmard Block. Facies analysis of sedimentary facies in mentioned sections implies ...
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Determination of sedimentary environment, provenance and tectonic setting of Ab-Haji Formation sandstones (Lower Jurassic) have been carried out in Cheshmeh Bakhshi and Sartakht-e-Shotoran sections which are located in Kalmard Block. Facies analysis of sedimentary facies in mentioned sections implies three clastic faceis associations including delta plain, delta front and prodelta and two carbonate facies, relevant to bar. The obtained results from modal analysis and geochemical data point to cratonic tectonic setting and presence of qurtzose rocks in the source area in the course of recycling processes. Moereover, using the tectonic discrimination diagrams suggest that Ab-Haji sandstones have been deposited in a passive continental margin. The calculated chemical index of alteration (CIA) and the plagioclase index of alteration (PIA), based on major element oxides, denote moderate to intense weathering in the hinterland. This consequence is conformed with the modal analysis and petrographic evidence referring to humid and semi-humid climate.
