273 research outputs found

    The geology of Mount Taftan stratovolcano, southeast of Iran

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    Mount Taftan is a double-peaked stratovolcano, located in southeast of Iran. This volcano constructed a number of calderas among which one of the most important is Anjerk. The magmas erupted from this multi-caldera complex range from andesi-basalt to dacite, but are dominated by andesite and dacite. Two terminal cones, Narkuh and Matherkuh, culminate at 4100m and 3950m, respectively. There are three evolutionary stages in the history of the volcanic complex (stage 1: Palaevolcanism, 6.95±0.72 Ma, stage 2: Mesovolcanism, 6.01±0.15Ma and stage 3: Neovolcanism, 0.71 ± 0.03 Ma). The eruptive products consist of lava flows, ignimbrites and pyroclastic rocks. The later include tuffs, nuees ardents, breccias and sometimes reworked as lahars. Textural and mineralogical data suggest that both magma mixing and fractional crystallization were involved in the generation of the andesites and dacites. The magmas erupted from this volcano show a calc-alkaline trend. The corresponding lavas are calk-alkaline with a potasic tendency

    Petrogenesis of the Lalezar granitoid intrusions (Kerman Province – Iran)

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    The Lalezar granitoids crop out within volcanic successions of the Urumieh-Dokhtar Magmatic Assemblage (UDMA). These granitoids have a range from gabbro-diorites to granites in composition. The mineral compositions of the most felsic rocks are characterized by the abundances of Na-plagioclase, quartz, alkali feldspar, biotite and hornblende. In the gabbro-diorite rocks, plagioclase (Ca-rich), hornblende, biotite and clinopyroxene are the most common minerals. Major element geochemical data show that the Lalezar granitoids are mostly metaluminous, although the most felsic members (granites) attain slightly peraluminous compositions and that they have features typical of high-K calc-alkaline rocks. In primitive mantle-normalized trace element spider diagrams, the analysed samples display strong enrichment in LILE compared to HFSE, accompanied by negative anomalies of Nb,Ta and Ti. REE chondrite-normalized plots show moderate LREE enrichment with slight to strong negative Eu anomalies. Rb–Sr geochronological data, mainly dependent on the Sr isotopic composition of biotite, was obtained in two samples and it points to 15-16 Ma. As a probable, age for the emplacement of the studied intrusives. Initial 87Sr/86Sr ratios and ƐNdi values range from 0.70495 to 0.70565 from +3.1 to +1.5 respectively, which fit into a supra-subduction mantle wedge source for the parental melts and indicates that, in general, crustal contribution for magma diversification was not relevant. Geochemical and isotopic evidence reveal that the Lalezar intrusions are cogenetic I-type granitoids which were generated in a continental arc setting, in agreement with models previously presented in the UDMA

    Geochemistry of granitoids of the Lalezar area (Kerman, Iran)

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    The Lalezar granitoids crop out within the Urumiyeh-Dokhtar Volcanic Belt (U-DVB) which is the largest volcanic belt in Central Iran. These granitoids intrude Eocene volcano-sedimentary rocks and range from gabbrodiorites to granites, with dominance of diorites and tonalites. The mineral composition of the most felsic rocks is characterized by the abundance of Na-plagioclase, quartz, alkali feldspar and biotite (and hornblende, in granodiorites and tonalites). In dioritic and gabbroic rocks, plagioclase (Ca-rich, in the most mafic lithologies), hornblende, biotite and clinopyroxene are the most common minerals, sometimes accompanied by orthopyroxene. Two kind of enclaves have been identified within the intrusive rocks: some display the same features of the andesitic country volcanic rocks, and therefore, are interpreted as xenoliths; others have mineral assemblages similar to those of the enclosing granitoid but with larger proportions of mafic minerals, which suggests that they can represent disrupted portions of sectors of the magma chamber where preferential settling of heavy minerals took place. Major element geochemical data show that the Lazelar granitoids are mostly metaluminous, although the most felsic members (granites) attain slightly peraluminous compositions, with A/CNK varying from 0.85 to 1.03. Harker diagrams show, in general, good linear correlations that agree with a genetic relationship between the different granitoids, through fractional crystallization of plagioclase, pyroxene, amphibole, oxide minerals and apatite. In primitive mantle-normalized trace element spiderdiagrams, the analysed samples display strong enrichment in LILE compared to HFSE (15.78≤ RbN/YN ≤ 81.96), accompanied by negative anomalies of Nb, Ta and Ti. REE chondrite-normalized plots show moderate LREE enrichment (3.32 ≤ LaN/LuN ≤ 6.36) and slight to strong negative Eu anomalies (0.46 ≤ Eu/Eu* ≤ 0.92). In conclusion, the petrographical and geochemical features show that the Lalezar intrusives fit into I-type granitoids, belong to the calc-alkaline series and probably have been generated in a continental arc setting, which agrees with models previously presented to the U-DVB

    Petrology, geochemistry and tectonomagmatic evolution of Hezar Igneous Complex (Rayen - south of Kerman - Iran): the first description of an arc remnant of the Neotethyan subduction zone

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    The Hezar Igneous Complex (HIC) in the south-eastern part of Urumieh-Dokhtar magmatic arc, is the most prominent magmatic feature in the Kerman Porphyry Copper Belt, that understanding magmatic evolution of which may shed light on the tectonomagmatic development of this less-studied part of an important magmatic arc in the Neotethys realm. The HIC has been developed in the the intersection of the N-S striking Sabzevaran fault and the NW-SE striking Rafsanjan-Rayen fault. It is indicated that the possible place of the conduit and vent is in Jalas Mountain which has been splitted later by the Sabzevaran fault into Minor and Major Jalas. The current summit had been constructed by ascending magma chamber under the HIC that constitutes the Kamali Mountain at the south of the summit. Some plutonic rocks of the HIC are exposed at Kamali Mountain. The subalkaline rocks of this complex mainly are composed of different pyroclastic and lava flow rocks, acidic to basic in composition, showing the evidences of fractional crystallization and mineral segregation. Sequential explosive and effusive eruptions with Strombolian to Vulcanian types are evident in the successive volcanic layers. The compositional trend shows the melting of spinel lherzolite, not garnet lherzolite. The subduction-related mechanism of the magma genesis has been indicated by IAB nature of the magma formation in geochemical diagrams.publishe

    Stock assessment of the bony fishes of Golestan province

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    Total catches of bony fishes in the coastal of south Caspian Sea have been ended to 1554 ton in 1382. The catch of common carp Cyprinus carpio as a one of important commercial species has been lower than others species such as mahisephid, kolmeie and kafal. From commercial catch point of view, the catch of kolmeie is not very important, so that its catch was included only 2% of total bony fish catch in three provinces which are located in south of Caspian sea . In spite of lower common carp catch, in comparison with total bony fish catch in Golestan province more thanb70% catch was belong to Common carp. The higher catch kolmeie among three provinces was related to Guilan with 46% of total catches. Seasonal changes of common carp catch showed maximum and minimum catch were in April 83 and December 82 respectively. The most of (CPUE) was in April 83 and September, October 82. The trend of kolmeie catch showed low fluctuation. Three age groups were specified in kolmeie age composition high and low percent observed in 2 and 3 age groups respectively. Result of biometric information common carp showed most of catch was under standard fisheries catch

    Single subunit degradation of WIZ, a lenalidomide- and pomalidomide dependent substrate of E3 ubiquitin ligase CRL4^(CRBN)

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    Immunomodulators (IMiDs) are an effective class of drugs used to treat blood cancers. IMiDs are believed to work by recruiting protein targets containing a β-hairpin motif for ubiquitination by E3 ubiquitin ligase complexes composed of cereblon (CRBN), Cullin-4a (CUL4a), DNA Damage Binding protein-1 (DDB1), and Ring Box-1 (RBX1). The ubiquitinated protein is subsequently degraded by the proteasome. By characterizing the repertoire of proteins that show an increased physical association with CRBN after IMiD treatment, we identified a novel IMiD substrate, Widely Interspaced Zinc Finger Motifs (WIZ). WIZ contains a C2H2 zinc finger domain, like several other substrates that were previously characterized. We demonstrate that IMiDs stabilize physical association of WIZ with CRBN, deplete WIZ steady state protein levels in a way that is dependent on E3 ligase activity, and enhance the rate of its degradation. Notably, proteins that assemble with WIZ are co-recruited to CRBN by IMiDs but are not degraded, illustrating the potential of targeted protein degradation to eliminate individual subunits of a protein complex. These findings suggest that systematic characterization of the full repertoire of proteins that are targeted for degradation by IMiD compounds will be required to better understand their biological effects

    Left atrial drainage of the right superior vena cava: A case report

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    An isolated right superior vena cava (RSVC) draining into the left atrium represents a very rare congenital malformation, especially in the absence of a partial anomalous pulmonary venous return. This condition leads to hypoxemia, cyanosis, and clubbing without any other signs of heart defects. We describe an 8-year-old girl, who was referred to our hospital due to unexplained cyanosis. Segmental approach in transthoracic echocardiography showed left atrial drainage of the RSVC, which was subsequently confirmed by contrast echocardiography and angiography. Surgical repair via trans-section and anastomosis of the superior vena cava to the right atrium was performed to prevent the complications of right-to-left shunting and cyanosis. During a 4-year follow-up, the patient remained in very good clinical status and her serial echocardiography was normal except for very mild left atrial and left ventricular enlargement. © 2018, Tehran Heart Center. All rights reserved

    Left atrial drainage of the right superior vena cava: A case report

    Get PDF
    An isolated right superior vena cava (RSVC) draining into the left atrium represents a very rare congenital malformation, especially in the absence of a partial anomalous pulmonary venous return. This condition leads to hypoxemia, cyanosis, and clubbing without any other signs of heart defects. We describe an 8-year-old girl, who was referred to our hospital due to unexplained cyanosis. Segmental approach in transthoracic echocardiography showed left atrial drainage of the RSVC, which was subsequently confirmed by contrast echocardiography and angiography. Surgical repair via trans-section and anastomosis of the superior vena cava to the right atrium was performed to prevent the complications of right-to-left shunting and cyanosis. During a 4-year follow-up, the patient remained in very good clinical status and her serial echocardiography was normal except for very mild left atrial and left ventricular enlargement. © 2018, Tehran Heart Center. All rights reserved
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