Geopersia
Volume:13 Issue: 1, Winter-Spring 2023

In mechanized tunneling, TBM performance prediction is vital to estimate the time and cost of the project.Therefore, calculating the performance parameters is so important. The utilization coefficient depends onmanagement parameters, personal ability, logistic utility and equipment, tunnel characteristics, objectivesand geological conditions. Although in each of the main models same as CSM, NTNU and QTBM, thespecific parameters used to estimate the utilization coefficient, the effect of management factor andinteractions and overlapping factors not considered. On the other hand, many parameters have a severedependence on each other and may simultaneously affect the performance of the TBM. Therefore, theinteraction matrix can be used to evaluate the interaction of parameters on each other and on TBMperformance. The effect of 18 parameters on the utilization coefficient was evaluated by the matrix methodin Karaj water conveyance tunnel. The interactions of these parameters show that the lack of utility servicesand shift change have the most significant impact on TBM performance. By recording the actual delays ineach parts of tunnel, the downtime index (DTI) is obtained; this index has a direct relationship with tunnelboring time and is inversely related to TBM performance

The Gol-e-Gohar iron deposit in the Sanandaj-Sirjan zone of south-western Iran comprises six majorore bodies. The largest deposit is Gol-e-Gohar No. 3 (Gohar-Zamin) with about 643 Mt @ 53.1% Fe.Magnetite is formed in massive and brecciated shapes. Gol-e-Gohar magnetite contains Mg, Ca, and Siup to the percent range, V and Ti in the 100s ppm level, and low Cr, Co, Ni in the tens of ppm range,typical of Kiruna mineralization (especially Bafq mining district). But Chador-Malu magnetite is formedat a higher temperature than Gol-e-Gohar magnetite, therefore, hydrothermal high-T nature (magmatic ore-forming fluids), which are related to felsic magmatism (host meta-granites), and both of them are attributed to the Early Paleozoic. The oxygen isotope composition of magnetite is 4.9 ± 0.7‰ δ18 O (n = 9) and the iron isotope composition is 0.49 ± 0.05‰ δ56 Fe (n =17). These data suggest that the magnetite ore formed from a magmatic- hydrothermal (high-T) fluid in equilibrium with a granitic source. The Gol-e-Gohar iron ore district shows several similarities to the Bafq mining district, located about 400 km to the north, and seems to be a disrupted member of theKashmar-Kerman arc. Finally, according to the mentioned evidence and comparison of Gol-e-Gohar iron deposit with global samples, the genesis of mineralization in this deposit is most similar to Kiruna- type (Kiruna-type magnetite ± apatite mineralization).

Shadan gold (+copper) deposit in the Lut block, east of Iran, comprises Eocene to Oligocene intrusive and subvolcanic rocks with intermediate to felsic composition, which have intruded into Eocene volcanic- pyroclastic rocks. Shadan intrusive rocks range from granodiorite, quartz monzonite, and diorite to micro-gabbrodiorite. Geochemical data indicate that Shadan intrusive rocks are I-type, metaluminous to peraluminous, belonging to the calc-alkaline to high-potassic calc-alkaline magmatic series. Rare earth elements (REE) and trace elements patterns of Shadan rocks display enrichment in light rare earth elements (LREE) and large ion lithophile elements (LILE) relative to heavy rare earth elements (HREE) and high field strength elements (HFSE). The main hydrothermal alteration types contain quartz-carbonate, propylitic, argillic, phyllic and potassic, which affected the rocks in varying degrees. According to tectonomagmatic discrimination diagrams, all rock samples display evidence of a volcanic arc, which was formed at an active continental margin. Based on Nb/Y vs. Rb/Y ratio, Shadan rock samples experienced subduction zone enrichment and crustal contamination. According to Nb/Zr vs. Nb/Ba ratio, source region of the Shadan intrusive and subvolcanic rocks are attributed to the subcontinental lithosphere source. Th/Yb versus Nb/Yb diagram shows a separation between Shadan samples and MORB-OIB arrays,possibly due to crustal contamination and the mobility of Th during subduction. La vs. La/Yb ratio reveals that partial melting played a significant role in the formation of Shadan rocks.

Acoustic emission is a high-frequency elastic signal that is generated and emitted by a material when it is loaded. Transient elastic waves are created by the release of energy in the sources in the material. Acoustic emission test is one of the methods of non-destructive tests. These waves are emitted in the material and can be received by acoustic emission sensors. Acoustic emission method can monitor the solids’ fracturing process during a period of time, and this method is extensively used in studying the fracturing process and inspections. In the present study, tensile splitting and uniaxial compressive tests were done on concrete sample accompanied by AE (acoustic emission) monitoring. The chart of AE parameters were analyzed; the parameters include energy, energy cumulative values as well as amplitude values, duration, average frequency, rise angle, b-value, and improved b-value relative to the stress applied to the specimens during the loading time. Based on the results, most of the crack growth signals in tensile splitting tests were tensile crack signals, and there are fewer shear crack signals; however, in uniaxial compressive tests, there were more shear cracks. Moreover, the b(Ib)-values can be used for predicting damages in large scales during the fracturing process in specimens, based on AE parameters.

Land Subsidence due to the groundwater over-exploitation is a significant problem in some areas which experience urbanization and expansion of agriculture and industry. In this study, the land subsidence of the Aliabad plain of Iran has been modeled using the artificial neural network (ANN) method. In this regard, a multi-layer perceptron has been used to model the land subsidence measured from Sentinel-1 images from 2015 to 2016. Groundwater dropdown, the thickness of alluvial sediments, the aquifer sediments' transmissivity, and elasticity modulus have been considered as four ANN model’s inputs variables and land subsidence as a single output. The results show that the ANN model has the ability to predict Aliabad subsidence with good accuracy (R2 = 0.74, R=0.94, RMSE= 0.02 m, MSE = 0.0006). Then a sensitivity analysis was performed in order to determine the impact of input parameters and the results indicate groundwater fluctuations as the most effective one. Model validation was achieved by comparing the ANN results with the calculated land deformation by DInSAR technique. An unused dataset including the four specified input parameters have been used, to assess the generalization of the ANN model. The model produces a proper prediction of land deformation with the new dataset.

Groundwater is an important water supply for irrigation and drinking purposes in semi-arid regions. In the Garmsar Plain, Iran, groundwater has severely deteriorated during recent years due to human activities and environmental changes. Hence, the main purpose of the current research is to investigate the chemical processes that control hydrochemistry and assess the groundwater quality to determine its suitability for irrigation and drinking uses and potential human health risks. Analysis results of the groundwater samples revealed that the most common water type is the sodium chloride type (82%) in the Garmsar Plain, followed by the mixed Ca-Mg-Cl type (18%). The main processes that contribute to groundwater chemistry are the dissolution along the flow path, evaporation, rock water interaction, ion exchange, and the mixing processes. According to the Irrigation Water Quality Index (IWQI), 51% of samples represent a severe restriction category and the remaining 49% constitute a high restriction class which reveals moderate to high salt tolerance, indicating that salt plants under some irrigation conditions can be cultivated in the Garmsar Plain. Based on human health considerations, 33%, 31%, 46%, 44%, 95%, and 77% of the groundwater samples are classified as poor water because of their high concentrations of Ca2+, Mg2+, Na+, HCO3-, Cl-, and SO42-, respectively. Drinking this water may cause a risk to human health, therefore management strategies are required for sustainable groundwater quality protection in the Garmsar Plain before using it for irrigation and drinking purposes.

Microcracks play an essential role in controlling rocks’ physical and mechanical properties and thus are a vast research subject in engineering geology. The present study aimed to investigate microcracks developed in granitoids. Thermal shock at four temperatures of 250, 450, 650, and 850℃ was applied to induce microcrack in granitoids. The rate of microcracks development and their effect on the physical properties of the rocks were assessed using the measurement of the P-waves velocity and capillary water absorption test. Both tests showed that the thermal shock, even in one cycle, has developed micro cracks. Moreover, the increased rate in effective porosity and total porosity of granitoids due to the growth of microcracks would estimate by the capillary water absorption test. This study showed that microcracks development directly relates to the increase in temperature at the thermal shock. The capillary water absorption test could measure the granitoids porosity as well as the water absorption and retention in the induced microcracks. These two tests could investigate microcracks development from two different points of view. The p-wave velocity estimates the propagation of different types of microcracks, while the capillary absorption test evaluates the connected microcracks. The effective porosity differently affects the rock mass efficiency in varied projects. Finally, total porosity and effective porosity are developed independently of each other through thermal-induced micro-cracks.

In northwest of the Takestan area (NW Iran), as a part of the western Alborz mountain belt, various plutonic (monzodiorite, quartz monzonite, granite, and alkali granite), volcanic (andesite, basalt, basaltic andesite, rhyolite, and dacite) and pyroclastic rocks (tuff, agglomerate, and ignimbrite) are hosted of Eocene age. Electron probe micro analyzing (EPMA) on clinopyroxene, orthopyroxene, biotite, and amphibole show that they are diopside to augite (Mg# = 0.6-0.8), enstatite (Mg# = 0.63-0.68), annite to phlogopite (Fe# = 0.15 - 0.3) and pargasite (Mg# = 0.6 - 0.8), respectively. The plagioclases havedifferent compositions with normal chemical zoning  from labradorite (in the basalts, An% = 40 - 60) to andesine (in the monzodiorite, An% = 27 - 50) to oligoclase (in the other rocks, An% = 13 - 38). All minerals are primary magmatic except for the alkali granite biotites that have low Ti contents whichindicate that they formed by re-equilibrium with a hydrothermal fluid. Chemical compositions of the clinopyroxene, biotite, and amphibole reveal that they crystallized from calc-alkaline magmas formed by subduction of Neo-Tethys oceanic crust beneath the Iran micro-plate. Geothermometry calculations based on the mineral compositions indicate ca. 880 to 980 °C for the basalts, 800 to 850 °C for the andesite and the dacite, 750 to 820 °C for the monzodiorites and the quartz monzonite, and 520 to 670 °C for the alkali granite. High Al contents of the plagioclases from the quartz monzonite and monzodiorite as well as Fe+3 contents of the biotites from the alkali granite show that they formed from oxidized magmas that were suitable for Cu porphyry systems. Propylitic and argillic alteration zones in the area confirm it.

The present study aimed to investigate the biostratigraphic studies of Hasan Abad section (two sections), located in the southeast of Birjand in the east of Iran. The thickness of the first section of Hasan Abad is 74 meters, and the second section is 62 meters thick, including conglomerate, sandstone, calcareous sandstone, sandy limestone, limestone, and nummulitic limestone. The base of these sections is overlaid on the ophiolites, and their tops are erodedIn total, 21 genera and 29 species of benthic foraminifera were identified in the first section, and four biozones were consequently determined. These biozones included the Daviensina sp. interval zone, Alveolina ellipsoidalis interval zone, Nummulites globulus interval zone and Nummulites subramondi interval zone. In the second section, 16 genera and 21 species were identified, and three biozones were introduced based on the identified foraminifera, including Kathina selveri interval zone, Alveolina ellipsoidalis interval zone and Nummulites globulus interval zone. According to the identified biozones and foraminiferal assemblages, the age of the studied sequence was speculated to be the first section of Hasan Abad, Thanetian? - Early Cuisian and in the second section the Thanetian -Early Cuisian. Two new species of the Ornatorotaliidae family, Granorotalia sublobata and Ornatorotalia granum, are the first records from the east of Iran.

The Kalateh-Naser area is located in the northeast of the Lut block (Eastern Iran). The rock units of the region generally include Cretaceous limestone units and metamorphosed carbonate rocks. Intrusive rocks emplaced in the study area are mainly composed of quartz monzonite, monzodiorite, quartz diorite, and granodiorite. These rocks are typically I-type with strongly metaluminous signatures. Dating using the zircon U-Pb method on two intrusive rocks revealed ages between 104.23 ± 0.85 Ma and 102.13 ± 0.91 Ma. Rb-Sr and Sm-Nd isotopic data yield mantle derived magma modified by the addition of crustal materials, as shown by initial 87Sr/86Sr ratios (0.7049 - 0.7051) and 143Nd/144Nd ratios (0.512697 - 0.512796). The geochemical compositions indicate enrichment of LILE compared to HFSE with (La/Yb)N values of 2.61–8.43. The LREE versus HREE ratios, as well as depletion of Nb, Ta and Ti elements in these intrusive rocks represent the characteristics of the rocks belonging to the subduction zone. The subduction characteristics of these rocks can be attributed to the subduction inherited in this part of eastern Iran. The whole-rock geochemistry combined with the Nd and Sr isotopic data and similar ages suggest that quartz monzonite and granodiorite are more likely co-magmatic and fall in VAG category. Comparing isotopic composition variations of the Kalateh-Naser rocks with other intrusive rocks from the Lut block, indicates a heterogeneous mantle beneath the Lut block and different amount of the metasomatized mantle source in eastern Iran.

The mining district of Batouri is located in the southeastern part of Cameroon and constitutes an integral part of the Adamaoua-Yadé domain of the Pan-African fold belt. This work aimed to highlight the structural and petrographic markers that characterize the auriferous shear zone. The investigations show that the rocks of the Batouri area suffered a ductile-brittle shear deformation in three directions (E-W, NE-SW, and NW-SE). These shear directions constitute the local extension of the Demza and the Balche shear zones of the Poli group, and the central Cameroon shear zone. Within these shear bands, the S n schistosity and tension cracks present a sigmoidal geometry, which is justified by a variation in the direction and dip of the schistosity planes and veins. This shear zone displays a finite local extension (NNW-SSE) generated by an ENE-WSW compression. Intense shearing is observed within gold- bearing monzogranites and syenogranites. The gold mineralization is controlled by three main vein directions (NNW-SSE, E-W and NE-SW), which are closely associated with silicification, sulfidation, and K-alteration of the host granitoids.

In this research, the biostratigraphy of the Dalichai Formation in the Bar and Sarmeran sections at theBinalud Mountains has been studied with special emphasis on the most abundant ammonite family(Phylloceratidae family). The Dalichai Formation is mostly composed of marl, shale, siltstone, nodularmarly limestone and limestone. In this study, by studying 219 specimens taken from the Bar andSarmeran sections, ammonites belonging to 11 species, 4 Genus and 1 subgenus of the Phylloceratidaefamily have been identified. Based on the research completed, it is possible to consider an age equivalentto the Middle to Late Jurassic for the examined sequence of the Dalichai Formation in the Bar andSarmeran sections. Paleobiogeographically, the existing ammonite fauna are closely related to the sub-Mediterranean Province of the northwestern Tethys. The Zigzag Zone of the Early Bathonian and theBimammatum and Planula Zones of the Late Oxfordian have been recognized.