مجله یافته های نوین زمین شناسی کاربردی
پیاپی 17 (بهار و تابستان 1394)

Combinations of geological, geomorphic, aeromagnetic and remote sensing data used to clarify the extent and nature of terminations of the Taleqan Fault in south Central Alborz. The Taleqan fault is cut by three transverse basement faults that are different in nature and age. Geological evidence along the Karaj Valley shows that N-S transverse faulting although influenced the Eocene sedimentation in the Taleqan Fault hanging wall. The western termination of the Taleqan Fault is hidden under alluvial fan deposits that showing evidence of Quaternary deformation. Several lineaments mapped in these Quaternary deposits that illustrate a horsetail fault system for the western termination of the Taleqan Fault. Geomorphic study in this area (Af, Hi, Vf, Smf) show high tectonic activity (Iat: class 2). The eastern termination of the Taleqan Fault linked with a Mesozoic rift-margin transfer fault. The western portion of the fault i.e. from the Karaj Valley to west is tectonically active that poses major seismic hazard to the Tehran, Karaj, Taleqan and Hashtgerd.

Today, to understand the geomechanical properties, many tests have been developed and used, which are presented in different standards. Four recognized method for evaluating abrasivity of rocks offered that is Rock Abrasivity Index (RAI), Cerchar Abrasivity Index (CAI), Shimazaki Abrasivity Factor (F- Abrasivity) and Bit Wear Index (BWI) methods. The Cerchar test a useful test for excavating projects. But a few works on it, and still unknown than other geotechnical tests such as direct shear, triaxial and …. In this study, along with introduction of this test, we measured the cerchar index and subsequent that estimation of hardness (resistance to scratching or cutting) of conglomerate samples taken over the course of Golab 2 water tunnel from BH - II3 borehole. Based on the results of this test, CAI values calculated for the sandstone 3.48, for limestone 3.5 and cement matrix of samples is 1.. According to cerchar classification is classified as moderate to very abrasive and by Michalakopoulos et al. also placed in the category of medium abrasive to abrasive

Because of its abundance of land and water, Khouzestan has long been one of Iran's most productive agricultural provinces. Individual farmers have been effectively managing these resources to serve their short-term economic purposes. However, no long-range management plan has existed for groundwater. This thesis presents the results of a mathematical groundwater model developed for the ghale khawje plain in the Khouzestan province, employing conceptual groundwater modelling approach. For this purpose, Groundwater Modelling Software (GMS7.1) was used which supports the MODFLOW-2000 code. For modeling the Source/Sink Coverage,Recharge Coverage, Extraction Coverageand Soil Coverage were considered.The model was calibrated against the historical and observed water level data for period 2010 to 2011 in the non-steady state and verified for period 2011 to 2012. The results of applying this model to conditions in the study area provide a guide for managing groundwater resources in future. Selected water-management alternatives for the study area were evaluated with the aid of the ground-water flow.for coping with water shortage in the study area, feasibility of underground dam was assessed. After selecting the effecting parameters, they were surveyed in the plain by building associated layers and appropriated sites were determined by overlay method in GISenvironment. Then, based on simulation of groundwater model, the best place was selected.The proposed model was implemented for the conditions of drought and groundwater dam This study shows that underground dams may be a very useful instrument to substantially increase the available storageAnd reduce the negative balance in the ghale khawje plain aquifer.

Karaj Formation overlies unconformably on the Upper Cretaceous carbonate sediments and is overlain by the Oligocene molassic sediments of the Lower Red Formation, in the Ashtian area, Central Iran. In this area, Karaj Formation includes of volcanic (andesite and basalt), pyroclastics rocks and intercalations of carbonate and sandstone. It is divided to five lithozones that includ E1-E5 units. Only E5 unit contains various larger benthic and small foraminifera. In order to biostratigraphy of E5, one stratigraphic section was surveyed and sampled in north of Ashtian. In this section, thickness of E5 unit is 610 m. Study of this section led to identification 10 genera and16 species. The age of the E5 unit in the studied section is assigned to the Middle Eocene (Lutetian). E5 unit is equivalent with Upper TuffMember at type section of Karaj Formation in west of Challus valley, Alborz Basin, and upper part of Pabdeh and Jahrum Formations in Zagros Basin.

Baft ophiolitic melange, as a part of ophiolitic melange belt of the Central Iran, is adjacent to Urumieh-Dokhtar magmatic assemblage in the north and Sanandaj-Sirjan metamorphic zone in the south. The ophiolitic complex has been emplaced in the Late Cretaceous time as a result of closure of Nain-Baft oceanic basin. The gabbros are the main constituent of the complex and occur as large intrusive bodies showing isotropic and rarely layered structures with hypidiomorphic granular to pegmatitic textures. The color index varies from melanocratic to lesser extent mesocratic and leucocratic. Geochemical studies reveal that gabbros are tholeiitic to calc-alkaline, low-Ti in nature and show similarity to N-MORB. The chondrite-normalized rare earth elements patterns are almost flat with slight enrichment in LREEs relative to HREEs which indicates a similarity in their origin. It seems that gabbros were derived from a depleted refractory mantle source in a subduction zone setting.

Andalusite shows at least two oriented growth phase in regional and contact metamorphic rocks of Hamadan. in regional metamorphic rocks Andalusite are oriented along South East trend and in metamorphic these are orinted along North-East trend. Syn-tectonic Andalusite porphyroblast has been Boudined affected by layer parallel extension and even formed interesting structure (for example porphyroclast) by non coaxial deformation in this part. In Hamadan metamorphic rocks that are near the Alvand granitoid, an appropriate sites for nucleation of sillimanite is highly variable. One of nucleation sites is growth of sillimanite within the andalusite porphyroblast. Sillimanite, often formed within the twining and along crystal fractures in the andalusite. Some of the sillimanite are defromed and folded. Deformed sillimanite show effect of non-coaxial deformation in this area. Formed sillimanite within the andalusite indicate deformation at elevated temperatures in this area and Even after the formation of sillimanite, tectonic forces have been presence and caused their deformation in this region.

Volcanic rocks of the Chuopanan area are a part of the Yazd block (central Iran) and they include lava and pyroclastic rocks. These rocks belong to the Eocene and predominate volcanic rocks in this area are andesite that represent the NE-SW trend along the fault. pyroxene is the most significant mafic mineral of these rocks. These are as partly altered phenocrysts. Chemical compositions of clinopyroxene in these rocks range from diopside to augite. The mineral chemistry of clinopyroxene and field relationship and petrography evidence indicate that the composition of magma forming have the calc-alkaline affinity and belong to volcanic arc field. Aluminium supplies in octahedral and tetrahedral positions shows that the mineral was crystallized in low pressure in hydrous magma. Ferric Iron is related to the high oxygen fugacity content environment.

The study area is located in 9 km south of Germi city and 52 km north of Ardabil Province. From Structurally point of view this area is a part of south Talesh Zone. The volcanic rocks are mostly basaltic in composition with prismatic structure. Minerals of olivine, plagioclase, clinopyroxene and minor minerals such as titanomagnetite are formed the rocks. By the way calcite, sericite and chlorite with a lesser amount of idengsite are secondary minerals. Investigates show that phenocrysts of feldspar are mostly labradorite in composition and clinopyroxenes in studied rocks located in augite domain. Clinopyroxenes and olivines are originated from alkaline magma that belong to back-arc- basin magmatism. Thermobarometry of clinopiroxenes show that these minerals are crystallized from magma at ~5 Kbar pressure and 1000 C. Chlorite as a secondary mineral in these rocks generally are located in diabanit domain.and from geochemically point of view and zonation including two alteration stages that indicator of variety of factors in produce of secondary minerals.

Haram- Abad river basin (area = 2965 Km2) is an elongated basin located in south of Hamedan Province and occurs in the Sanandaj- Sirjan structural zone. 1392 km2 of this region is located in the western Malayer plain. Five lithofaceis were recognized in the river sediments: Gms, Gm, Sh, Sl and Fm and Fr. The river sediments are very poorly sorted, positively skewed and platykurtic. Four discontinuities were recognized in in the downstream decrease in the gravel percent. They occur as a result of the entrance of side-channel sediment sources (i.e. alluvial fan, tributaries and colluviums) to the main-river channel. Increase in the gravel percent is less significant (3-8%) in those tributaries with lower slope and slate and schist lithology than the tributaries with higher slope and granite and limestone lithology (25-32%). This shows the provenance lithology is also important in the downstream fining trend of the studied river.