subduction

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1 - Geomorphological characteristics of raised beaches of south east of Iran
حسین Negaresh

Raised beaches has raising gradually since 30-50 thousands years ago, and the amountof raising has estimated 1-3 milimeters per year. These matchless beaches are observablefrom port of Jask to Gwater bay, and continue to after port of Karachi, and therate of raising inc More

Raised beaches has raising gradually since 30-50 thousands years ago, and the amountof raising has estimated 1-3 milimeters per year. These matchless beaches are observablefrom port of Jask to Gwater bay, and continue to after port of Karachi, and therate of raising increase from west to east. So that their height is about 1 meter in Jaskport, more than 100 meters in Chahbahar and Tis, and about 500 meters in Karachi ofPakistan.The Cause of raising beaches is related subduction and tectonic forces in this part ofIran beaches, that the amount of subduction is 5 centimeters per year and intensity ofraising in beach is very more than plain and Makran mountains. Since the subductionis active, the raising of beach is continuing yet, and beaches are uplifting steply.There is very reasons of prove raising beaches that will be point in later discussions. Manuscript profile

Open Access Article

2 - Distribution and geochemical variations among paleogene volcanic rocks from the north-central Lut block, eastern Iran
Saeed Saadat Charles Stern

The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary a More

The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary age. Peak volcanic activity took place in the north-central part of the Lut block during the Eocene, and then dramatically decreased, becoming more restricted to the eastern and western margins of the block during the late Miocene and Quaternary. There is also significant variation in chemistry between the Paleogene igneous rocks from the north-central part compared to the Neogene and Quaternary volcanic rocks from the western and eastern margins of the Lut block. The Neogene and Quaternary olivine basalts, which were erupted along both margins of the Lut block, are similar in trace element chemistry to the average composition of oceanic island basalt. In contrast, the Paleogene volcanic units of the north-central Lut block, which include basalts through rhyolites, follow both calc-alkaline and alkaline trends. Low TiO2 and high Ba/Nb and La/Nb ratios for both Paleogene basalts and andesitic samples from the north-central Lut block suggest affinities, at least for some of these samples, with convergent plate boundary arc magmas. LILE/HFSE ratios, interpreted as an indication of subduction signature, increase to the south-southwest of the central Lut block, where Neotethys oceanic crust was subducted beneath Iran in a northeastern direction from approximately Late Triassic to Late Oligocene time. We suggest that components derived from low angle subduction of this crust during the Mesozoic and early Tertiary were stored in the mantle lithosphere below the north-central Lut block until the Paleogene, when changing subduction geometry, associated with the collision of Arabia with Iran and the closing of Neotethys, caused hot asthenosphere to well up under the Lut block. This created the Eocene peak in volcanic activity, generating basalts from asthenospheric mixed with lithospheric melts, with both alkaline and calc-alkaline affinities. After this volcanism waned, becoming restricted during the Neogene to OIB-type alkaline basalts erupted through deep lithospheric structures along both the western and eastern margins of the Lut block. Manuscript profile

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3 - Geochemistry of the Paleocene Sediments from SW Ahar: Implications for Provenance, Tectonics and Source Rock Weathering
Nasser Ashrafi Behzad Hajalilou

The mineralogy and geochemistry of Paleocene shales and interbedded siltstones in the southwestern of Ahar town (NW Iran) were studied by optical microscopy, XRD, SEM, XRF, and ICP-MS techniques. The mineralogical composition, mainly characterized by calcite, quartz, fe More

The mineralogy and geochemistry of Paleocene shales and interbedded siltstones in the southwestern of Ahar town (NW Iran) were studied by optical microscopy, XRD, SEM, XRF, and ICP-MS techniques. The mineralogical composition, mainly characterized by calcite, quartz, feldspar, dolomite, muscovite, magnesiohornblende, chlorite, illite, montmorionite, palygorskite, and koninckite, suggests relatively fast erosion of the parent rocks and incipient metamorphism for the studied sediments. The values of weathering indices and the Index of Compositional Variability, as well the mineralogy of the sediments imply moderate weathering in the parent rocks and deposition as first cycle sediments. The shales exhibit higher Al2O3/TiO2 (≈21), La/Sc, and Th/Cr values corresponding to felsic and/or intermediate source rocks. The geochemical character of sediments including ∑REE=116 ppm, (La/Yb)N=8.3, (Eu/Eu)=0.78, and the immobile elemental ratios values suggest an immature continental arc setting. The typical shale and chondrite normalized REE patterns of the shales are comparable with continental arc terrigenous sediments and Andean-type andesites. The inferred tectonic setting for the studied shale is in agreement with the tectonic evolutionary history of NW Iran during the Upper Cretaceous-Upper Paleocene. According to the present data, we conclude that the ultimate provenance of the studied shale and its interbedded siltstone and thin detritic limestone was probably the Upper Cretaceous sediments with the geoenvironment of acidic to intermediate volcanic rocks and marl. Manuscript profile

Open Access Article

4 - Petrogenesis of mantle peridotites from the South of Jazmourian, Makran accretionary prism, Iran
Mohammad Elyas Moslempour Morteza Khalatbari-Jafari Tomoaki Morishita Habib Biabangard

Mantle peridotites exposed in south Jazmourian comprise of lherzolite and porphyroclastic Cpx-bearing harzburgite in the lower part with chromitite lenses in the upper parts. Petrography and microprobe studies shows evidence of melt-peridotite interactions; post melting More

Mantle peridotites exposed in south Jazmourian comprise of lherzolite and porphyroclastic Cpx-bearing harzburgite in the lower part with chromitite lenses in the upper parts. Petrography and microprobe studies shows evidence of melt-peridotite interactions; post melting processes and subsolidus interactions, which has been associated with appearance of two generations of deformed primary pyroxene-olivine and fine-grained pyroxene-olivine-amphibole neoblasts. Second generation of minerals formed as inclusion, interstitial and fine-grain. These two groups of minerals have different geochemical characteristics, So that, the first group are comparable with abyssal peridotites and second group are comparable to suprasubduction (SSZ) peridotites. Thus, the chemical compositions of different generations minerals show different petrogenesis for ultramafic rocks in south Jazmourian. Whole rock chemical data indicate south Jazmourian peridotites have a depleted MORB mantle source which undergoing 10-20% partial melting. Thus this peridotites have experienced multistage evolution and show characteristics of the abyssal environment to suprasubduction zone. We are belived that peridotites transition from the abyssal environment to suprasubduction and affected by fluids derived from the subducted slab.  Manuscript profile

Open Access Article

5 - Role of supra-subduction zone ophiolites in the tectonic evolution of the southeastern Zagros Orogenic Belt, Iran
Ramin Arfania

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6 - Constraints on the Petrogenesis of Nosrat-Abad Ophiolite Extrusives, SE Iran
Mohammad Elyas Moslempour Morteza Khalatbari-Jafari Rahim Dabiri Sara Shahdadi

Nosrat-Abad ophiolitic extrusive sequence, located in the Sistan Suture Zone, in south eastern Iran. The extrusive sequence, contains pillow lava, sheet flow and related volcanic-clastic breccias which have undergone low-grade metamorphism. This association shows calc a More

Nosrat-Abad ophiolitic extrusive sequence, located in the Sistan Suture Zone, in south eastern Iran. The extrusive sequence, contains pillow lava, sheet flow and related volcanic-clastic breccias which have undergone low-grade metamorphism. This association shows calc alkaline to tholeiitic affinities. Interpretation of the geochemical data and behavior of the elements in different diagrams reveals two distinct domains in the Nosrat-abad ophiolitic extrusive sequence. The sheet flows are depleted in HFSE similar to those of SSZ. However, the enrichment of the pillow lavas in LILE could be attributed to an enriched mantle source or melting of metasomatized sediments above the subducted slab. It appears that two subduction components (fluids-melt), caused the diversity seen in the chemical composition of the study rocks. The MORB to subduction chemical characteristics of the Nosrat-Abad ophiolitic extrusive sequence could be explained by a shift in the tectonic settings from the mid-ocean ridge to the marginal basin in Sistan during the Late Cretaceous period. Manuscript profile

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7 - The study of geochemistry and petrogensis of the Hasansalaran granitoids (SE Saqqez)
علی Pournouroz M.H Emami S.J SHikh-Zakariaei

Hasansalaran granitoid is located in structural Sanandaj–Sirjan zone. This granitoid share towparts: a) northern part, b) southern part, northern part is composed of biotite and hornblandgranite, granodiorite and tonalite. In this Granitoid, ther are microgranular More

Hasansalaran granitoid is located in structural Sanandaj–Sirjan zone. This granitoid share towparts: a) northern part, b) southern part, northern part is composed of biotite and hornblandgranite, granodiorite and tonalite. In this Granitoid, ther are microgranular enclaves that arecomposed of quartzdiorite and tonalite and they have circular or ellipsoidal shapes. These rockshave granular, porphyritic and graphic texture and secondary textures are kataclastic and milonitic texture.Southern part composed of alkali feldspar granite, alkali syenite and quartz syenite that theyhave show granular matrix and pertite.The northern parts of Hasansalaran granitoid share all the geochemical features common toI – type granites. these granites are related with active continental margin zone. Southern partsare A – type and related with rifts. According to isotopic study Southern parts are older thanNorthern parts. Variation of major and trace elements shows magmatic differentiation, somewhat crustal contamination in northern part of studies area. Manuscript profile

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8 - Petrology and contact metamorphism of Salafchegan quartz diorite intrusion
Mahbobe Nazari Shahriar Keshtgar

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9 - Tsunami Propagation in Arabian Sea and Its Effect on Dwarka City of Gujarat, India
Vikram M. Patel H.S Patel A.P Singh

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