مقالات

The Fadisheh granitoid body is located in the southwest of Neyshabour and northeast of Iran, into the Sabzevar zone and north of the Central Iran structureal zone. The composition of the study intusive bodies consist of gabbro, diorite, granodiorite, granite, and aplitic-pegmatitic dikes and the host of these rocks are Sabzevar ophiolitic suite. In the tectonomagmatic diagrams plot in the volcanic arc granitoid (VAG) field. These rocks are metaluminous and have calc-alkaline nature and are belong to I type granitoids. Previous age dating have reported ages for these rocks 67.5 Ma. In this study, dating studies with U-Pb method on zircon, represents the 48/81± 0/86 Ma (Lower Eocene-Ypresian stage). Th/U ratios of zircons consistent with a magmatic origin and thus show the crystallization age of these rocks. These different ages show different pulses of intusion magma in this area. Keywords :Diorite, Granite, Zircon U-Pb dating, Fadisheh, Neyshabour. ...

Binalood mountain range with a northwest-southeast trend is part of Alborz which is considered as a transitional zone between central Iran and Alborz. In order to study large benthic foraminifera(LBF), Marusk section is located 52 kilometers northwest of the city of Neyshabur has been ed. The systematic studies of large benthic foraminifera(LBF) were done based on their morphological and biometric characteristics and led to identifing 4 species belonging to genus nummulites including N.perforatus (de Montfort ),N. herbi, N. deshayesi D'archiac & Haime and N. biedai Schaub , And the three recent species have been reported for the first time in Iran. The Eocene deposits in this section 1008 meters was measured and consist of clastic-carbonate and volcanic sequences.. ...

Nowadays, interdisciplinary science have presented an effective potential in solving various problems by using theoretical foundations of the other science. Increasing of crop's quantification and qualification is one of the most important results of agricultural geology investigation. Less attention has been paid on systematic agricultural surveys on karst and non-karst geo- environments. In this study agricultural field of Mashhad and Kashmar as karst and non-karst plain respectively, have been studied. Correlation of karst agricultural geo-environment with non-karst agricultural geo-environment in the study area, is highly affected by climate factors and drought. With respect to inappropriate condition of pH and physicochemical parameters of soils in the study area, bioavailability of most of the micronutrients for crops is inadequate. ...

The fluvial deposits, Jurassic in age, rests nonconformably on older metamorphic rocks, in Hesar Sorkh village, SW of Mashhad. The course grain sediments are interbeded with sandstones (facies Sh), and mostly consist gravely facies, Gcm, Gci, Gmm and Gt. Identified architectural elements are SB, SG, DA and CH, that indicate a braided system precipitation. The gravely sediments are mainly orthoconglomerate polymict. The grains are mostly gravel in different sizes, and consist quartz and rock fragments (igneous, sedimentary, metamorphic) with high roundness. In some cases tectonic effect caused grains fractured or change their direction. Imbrication and graded bedding are the main fabric and sedimentary structures. Based on the paleoflow data, sediment was transported southwest in that time. ...

The studied area exposed in western Se-Changi,Lut Block, comprises of Eocene volcanoclastic and lavas which erupted in aerial to subaqueous environments. These rocks have different variations basic-intermediate to acidic in compositions including basalt,basaltic andesite, andesite, trachy andesite, dacite, trachydacite and rhyolite-ignimberite. The studied lavas display shoshonitic,calc-alkalineandhigh-Kcalc-alkaline magmatic trends. In the tectonomagmatic diagrams, they plot in the active continental margin and subduction zone. In REE patterns and spider diagrams, they show enrichment of LILEs and LREEs in relative to HREEand depletion in HFSEs. Thegeochemical evidences indicate that the source of the basic-intermediate lavas produced partial melting of a sub continental lithospheric mantle, which have been previously enriched by subduction components (melt, fluids). It seems that the primary and basic magmaemplaced into the continental crust and caused partial melting of it. These evidences indicate that the Eocene volcanism in the studied area occurs in a collision-extension to post-collision environment. ...

Recent geological studies show that lithosphere has been evolving in time and place. Hence, finding out the direction of paleostresses of great importance to interpret the emergence of structures and the processes of deformation (Alimi, 2014). Binalood Mountains also have formed a mountain range with northwest-west and southeast-east (NWW-SEE) trend in the north east of Iran and south of Mashhad. The study area is a part of the northern edge of the Binalood mountain range in northeastern Iran and west of Mashhad, which includes a metamorphic complex of the Permian age, Dehnoo granitoid masses (G1) with the upper Triassic age and basal conglomerate of Shemshak formation of the Jurassic age. After studies of fragile structures (faults and slip lines), two NW-SE and NE-SW stress trends were resulted in metamorphic rocks by the Permian age and granitoid masses dates back to the upper Triassic age, which were obtained by analyzing the existing structures of the stress field change NW-SE to NE-SW. Also, a NE-SW stress trend was obtained in the Shemshak basal conglomerate by the Jurassic age. As a result, the NE-SW field is related to the period after the upper Triassic, which effect is also seen in the form of a change in the field of stress in the metamorphic rocks and granitoid masses. According to studies (Alawi, 1991) (Rahimi and Ghaemi, 2014), the northern-southern stress field in the late Triassic has occurred as a result of the closure of Paleolithic in Binalood concurrent with the Paleo-Tethys event and the northeast - southwest stress field has occurred simultaneous with the Neo-Tethys closure and the middle and late Alpine events. This change in the direction of the stress field is also seen in the study area. ...

The Tirgan Formation (Barremian - Aptian) is exposed In the north-east of Iran and in the Kopet Dagh mountains. One stratigraphic section in this formation to 45m thickness was measured. Based on study of 38 thin sections, 13 carbonate facies and 3 siliciclastic facies have been identified. This formation is deposited in a homoclinal carbonate ramp in open marine, shoal, lagoon and tidal flat environments. Sea level changes during Barremian - Aptian time led to form two larg scale depositional sequences in this section That Tirgan formation successitaia has one second type sequence boundary (SB2) and are first type sequence boundary(SB1). This present data can help in reconstruction of tectonic history of the area during this time

Satellite imagery processing was performed due to detecting, extracting and analyzing fracture systems in Khorasan-e-Shomali region. As well as fractal studies and applying statistical parameters such as density, Length density and Intersection points density of fractures based on fractures map producing by remote sensing data was done in order to recognition of state of structural evolution and introducing probable areas in the region which has higher tension. The outcome of these processing indicated that total fractures of this region have a main direction in WNW-ESE. Statistical studies and structural analysis in Khorasan-e-Shomali represent existence of numerous fractural systems in different area which could form by various mechanisms in different times. These studies could be a basis for modeling the fracture pattern and predicting the effective flow fluids in mineralization, water and hydrocarbons resources in the region. ...

The study area is located in an ophiolite complex at North West of Sabzevar. In fact, Sabzevar is a part of ophiolite zone that stretches east to south. The rocks in the area containing peridotites (Dunite, Harzburgite and Lherzolite), were formed in the Upper Cretaceous. In addition, volcanic rocks on Cenozoic era are observed in this area that consists mainly of basaltic Andesites that are associated with Dacite in some areas. The objective of this study was to evaluate mineralization of nickel and associated elements. According to studies, amount of nickel in chromite host rock is more than chromite ore. Also, the amount of sulfur in the host rocks is far more than chromite ore. It seems, due to high oxygen fugacity, index of sulfide in this type of rock is less and the amount of nickel in the form of Sulphide is less in chromite ore. Due to lack of sulfur and copper, the possibility of the presence of PPGE elements is low. Of course, hydrothermal mineralization is observed sporadically within veins and fractures. High amount of sulfur and copper is observed in the microscopic studies and this indicates possible presence of pentlandite in the area under study. By analyzing this type of samples of chromite mines in the region, a small amount of sulfur was observed. Given the small amount of sulfur in most samples in the area, presence of PPGE elements in the study area is impossible. Nickel minerals were observed in electron microscope studies. ...

The reality of seismic hazard in each region is assessed on the basis of determining the level of seismic risk in it. We consider the central part of the Alpine-Himalayan Belt composed by the Caucasus, Alburz, and Kopet Dag mountain systems with a goal to recognize seismogenic nodes capable of M6 and M7 earthquakes. Intersections of the fault zones - nodes - characterized by geological and geophysical parameters are viewed as objects of recognition. For the M6 we consider each mountain system separately; for the M7 we've taken the region as a whole. As a result of recognition, the loci of seismogenic nodes prone to M 6 and M7 earthquakes were determined within the central segment of the Alpine-Himalayan belt and the high seismic potential of the region was established. Seismogenic nodes are characterized by the increased contrast of the neotectonic movements and enhanced tectonic fragmentation. ...