S Nasiri Bezenjani; M Boomeri; H Biabangard; M Abdollahy
Abstract
Distinct cathodoluminescence (CL) properties of certain minerals such as quartz allow rapid identification of the different mineral constituents and their distribution within rocks using CL microscopy. Quartz is not only one of the main mineral in felsic intrusive rocks associated with porphyry copper ...
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Distinct cathodoluminescence (CL) properties of certain minerals such as quartz allow rapid identification of the different mineral constituents and their distribution within rocks using CL microscopy. Quartz is not only one of the main mineral in felsic intrusive rocks associated with porphyry copper deposits, but is the most abundant hydrothermal mineral in potassic and phyllic alterations. Although the study of the quartz in Back Scattered Electrons (BSE) images is useful but study of quartz by Scanning Electron Microscope- Cathodoluminescence (SEM-CL) revealed many textures (zoning, healed microfractures and cobweb textures) that cannot be observed in backscattered electrons images. The observed zonations reflect chemical and/or physical changes during growth in the precipitation environment (i.e. concentric zonation). Healed microfractures and cobweb textures are present in some of the quartz grains. The main purpose of this study is investigation of quartz textures and generations by SEM-CL in potassic and phyllic zones of the Sarcheshmeh porphyry copper ore deposit. Investigation of quartz using SEM-CL in the deposit revealed different generations of quartz (in phenocrysts and veins) that have been precipitated under different conditions. Quartz in the studied samples predominantly exhibits blue luminescence.
M Afarin; M Boomeri; A Mahboubi; M Gorgij; M.A Hamzeh
Abstract
In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis ...
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In this study, geochemical and sedimentological assessment was carried out on mudstone and sandstone deposits of Eastern coasts of Chabahar. Fifty samples were taken from five sectione of Tiss, Ramin, Lipar, Gorankesh and Garindar estuary and subjected to grain size analysis and chemical analysis using XRF and ICP AES methods. Positive sorting and skewness (with the frequency of fine grain particles) of samples indicate deposition in a low energy environment. Plotting geochemical data of major elements from Late Miocene- Pleistocene age 10 mudstone and sandstone samples in east coasts of Chabahar in Makran zone, on siliciclastic rocks classification diagrams, showed that the sandstones are wacky and Mudstones are shale. The mean calculated chemical indexes of alteration (CIA) and weathering (CIW) for siliciclastic sediments, confirm low level weathering of source rocks of this sediments. The average index of combinational variety (ICV) for the studied sediments was 1.57, which indicates that these deposits have a moderate chemical maturity and are derived from the first cycle of sediments. Distribution pattern of rare earth elements on spider diagrams shows the enrichment of light rare earth elements (LRRE) relative to heavy rare earth elements (HRRE) in the rocks. High ratios of LILE/HFSE and LRRE/HRRE in the rock samples and similarity of their chemical composition with subduction zone facies, indicates that siliciclastics of Chabahar coasts have formed in a subduction zone. The diagrams of tectonic setting associated with patterns of multivariate charts also shows that the studied rocks have been developed in an active continental margin.
A Zahedi; M Boomeri
Abstract
The Panah-Kuh skarn is situated in 50km NW of Taft City in Yazd province. Inrtusion of granodioritic stock into the calcareous-dolomitic rocks of Permian Jamal Formation led to formation of calcic and magnesian skarns. The REE patterns of skarns and its forming garnets show Eu/Eu* and Ce/Ce*ratios increase ...
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The Panah-Kuh skarn is situated in 50km NW of Taft City in Yazd province. Inrtusion of granodioritic stock into the calcareous-dolomitic rocks of Permian Jamal Formation led to formation of calcic and magnesian skarns. The REE patterns of skarns and its forming garnets show Eu/Eu* and Ce/Ce*ratios increase with increasing of ∑REE, implying that skarn forming fluids were dominantly of magmatic origin, whereas (Pr/Yb)cn ratio decrease almost with increasing of ∑REE that implying the magmatic fluids granitoid-derived had not much REE during the Panah-Kuh skarn formation. Based on the fluid inclusion data from garnet, fluid temperature and salinity in the prograde stage vary between 308-380oC and 12.6-23.8 wt.% NaCl equivalent, respectively. Inclusion fluids in the calcite had lower temperature (T<280°C) and fluid salinity decline to 3.5 wt.% NaCl equivalent. Mixing and dilution of early magmatic fluids with external fluids (e.g., meteoric waters) caused a decrease in fluid temperature and salinity in latest stage of the skarn formation. Therefore, both REEs and fluid inclusions data suggest the dominant role of magmatic water in the formation of Panah-Kuh skarn.
