Petrology
Mostafa Delkhah; Habib Biabangard; Hamedreza Soloki
Abstract
Zardkuh igneous complex is located in 35 km Southeast of Iranshahr and is geologically situated flysh zone and the Sistan-suture zone. Rock units in the area are Ophilitic rocks (upper Cretaceous), Eocene flysh and Oligomiocene intrusive and extrusive rocks (Zardkuh igneous complex). Patterns of minor ...
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Zardkuh igneous complex is located in 35 km Southeast of Iranshahr and is geologically situated flysh zone and the Sistan-suture zone. Rock units in the area are Ophilitic rocks (upper Cretaceous), Eocene flysh and Oligomiocene intrusive and extrusive rocks (Zardkuh igneous complex). Patterns of minor and rare earth elements normalized to Primitive mantle and Chonderit show low enrichment to LREE such as La, Ce and Sm than to HREE such as Ho, Yb, Tb and Lu. The dip of digram is soft to HREE and in the extrusive rocks is low increased. . it is thought that the constituent magma of these rocks from the mantle wedge above the subduction plate, which is usually affected by the fluids released from the subducted plate and its elements (including Silica, potassium and sodium) can produce such magma. So these rocks are related to magmatism and subduction Neo-Tehyan oceanic between Lut and Sistan blocks.
Petrology
Mahnoush Bahjati; A. Ahmadi; Habib Biabangard
Abstract
The volcanic rocks of Kuleh sangi-Malek siah kuh igneous complex consist of alkalibasalt, basalt, basaltic andesite, andesite, dacite and trachyte. In the SiO2 versus K2O diagram, the basaltic samples are plotted in the shoshonitic field and the subalkaline samples are plotted in the medium K calc alkaline ...
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The volcanic rocks of Kuleh sangi-Malek siah kuh igneous complex consist of alkalibasalt, basalt, basaltic andesite, andesite, dacite and trachyte. In the SiO2 versus K2O diagram, the basaltic samples are plotted in the shoshonitic field and the subalkaline samples are plotted in the medium K calc alkaline series field. The average La/Yb, Rb/Zr and Cs/Hf ratios in basalts are 7, 47 and 63 times those of N-MORB, respectively. Considerable enrichment of LILEs, LREEs and relative depletion of HREEs indicate that the magmas originated from a mantle source more enriched than that of OIB, where phlogopite and garnet are stable. Using non-modal batch melting model, the compositions of the mafic samples are mainly consistent with about 5% melting of a phlogopite-bearing and garnet-bearing lherzolite with a mixture of about 80% and 20%, respectively. AFC models using Pb versus Ce/Pb and Rb versus K/Rb, show that the fractionated samples have undergone simultaneous crustal assimilation and fractional crystallization. It seems that the assimilation and the fractionation had been taken place with the same rate. Depletion in Y and elevated ratio of Sr/Y of fractionated rocks in addition to Rb/Nb ratio more than 8, could be considered as evidence for crustal assimilation.
Petrology
Habib Biabangard; Farzad Molazadebravate
Abstract
Kuh-Som, KuhzaBozorg and KuhzaKochak volcanic cones are located in the southeastern of Bam and northwest of Bazman cites. From the perspective geology these cones are belong to the Iranian central zone and south-eastern edge of Lut block. These cones are composed of extrusive igneous rocks such as basalt, ...
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Kuh-Som, KuhzaBozorg and KuhzaKochak volcanic cones are located in the southeastern of Bam and northwest of Bazman cites. From the perspective geology these cones are belong to the Iranian central zone and south-eastern edge of Lut block. These cones are composed of extrusive igneous rocks such as basalt, olivine basalt, andesite and basaltic andesite, and are predominant trachytic texture. Plagioclase, pyroxene and olivine are main minerals. Pyroclastic deposits, lapilli, tuff, ash and volcanic bombs, along with lava flows are main construction volcanic cones. These volcanoes are monogenitic and limited eruption. Based on type material that construction cone of the volcanoes, it seems they are among between Hawaii to Strambolian volcanoes. These rocks shows enrichment to LILE relative to HREE (Ce / Yb= 33-45) , high ratio Zr / Y (33.4), enrichment to LILE and negative anomaly from Ni, Cr and nearly Eu that reveals these rocks related to Calc-alkaline magmatism. In spider diagrams of trace elements and rare earth elements that normalized to Chondrites and primitive mantle show light rare earth elements enriched more than high rare earth elements and show pattern similar to affiliate subduction zones. Geochemical characteristics such as ratio of La / Yb 8/6 to 7/13, low Rb content with the tectonic setting discrimination diagrams indicate that they are related to subduction environments and low tendency to intapalate zone. Source of magma that formed these volcanoes resulted from melting of a garnet Lherzolite at depth of 100 to 110 Km. Tectonomagmatic diagrams shows these rocks dependence on of continental subduction environments to show slightly into the intraplate zone, so that it seems the volcanic cones of them related to the Makran and Oman subduction and related to Makran- Chaghy magmatic arc.
H. Biabangard; A. Moradian
Abstract
Taftan Volcano in southeast of Iran, Sistan and Baluchestan Province, is located in 45 km north of Khash city and about 100 km south to southeast of Zahedan at the terminal of Nehbandan-Khash flysch and north Makran zones. No Volcano-stratygraphic studies have been carried out around Taftan volcano. ...
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Taftan Volcano in southeast of Iran, Sistan and Baluchestan Province, is located in 45 km north of Khash city and about 100 km south to southeast of Zahedan at the terminal of Nehbandan-Khash flysch and north Makran zones. No Volcano-stratygraphic studies have been carried out around Taftan volcano. Taftan volcano can be classified into three groups from stratigraphic point of view: pre, syn and post volcanic deposits. The first group has formed the basement of Taftan and consists mostly of sandstones, shale, limestones and marl (flysch facies), colored melange complex, ultramafic rocks (preidotites), mafic rocks (gabbros and basalts), pelagic limestones, radiolarites and low metamorphic rocks, (metagreywackes, slates, phylites and schists). Second group has volcanoclastic and lava flows that form the main body of the volcano and third group includes alterations along with reworked product of Taftan. Our studies revealed that Taftan volcano has more than five eruptions stages including olivine basalte lava flows, Anjerk crater, Jamchen crater, Anar mount, principal peaks, eruption related to before and final stages of eruptions.
H. Biabangard; A. Moradian; Y. Bavali
Abstract
Taftan is a stratovolcano, located to the SE of Zahedan, eastern Iran. Due to the highlands of the volcano, a microclimate is created in the region where precipitation provides some water in the arid region that the volcano is located. Field studies and chemical analyses of thirteen mine springs from ...
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Taftan is a stratovolcano, located to the SE of Zahedan, eastern Iran. Due to the highlands of the volcano, a microclimate is created in the region where precipitation provides some water in the arid region that the volcano is located. Field studies and chemical analyses of thirteen mine springs from western flanks of the volcano indicate that springwater in Taftan is somehow related to volcanic rocks. Based on hydrogeochemical analyses, significant variation in Mg2+(2-150), Ca2+(11-465), Na+(10.5-444), K+(1.5-330), SO42-(8-1050), HCO3-(0-353.8), NO3-(1.1-58.6), Cl-(10.65-1520) and mole fraction of SiO2(6.11-182.87) all in mg/L is affected by the chemical composition of volcanic rocks. Since springwater in Taftan shows significant compositional variation, it is concluded that the springs originated mainly due to precipitation, affected by water-rock interaction to some extent. However, a few springs show characteristic of juvenile water and some may have a mixture of juvenile and meteoric water.