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The Mohorovičić discontinuity, often known as the Moho, marks the boundary separating the Earth's crust from the mantle. Techniques such as isostatic-gravity and seismic methods can be used to determine this division. The Moho marks the boundary between the continental and oceanic crust and the upper mantle. Simply put, the Moho acts as a physical/chemical boundary between the mantle and the crust and causes significant changes in geophysical properties such as seismic wave velocity, density, pressure, and temperature (Mooney and Masters, 1998; Martinck, 1994; Bagherbandi, 2011 and Dashtbazi et al., 2023). An accurate and high resolution Moho depth model in fields such as geodesy, geology, geophysics, geodynamic modeling, seismic risk assessment, stress field modeling caused by mantle convection (Li et al., 2018; Behr et al., 2022; Singh and Yadav, 2023; Heilman and Becker, 2022; Hashima et al., 2016; Eshagh et al., 2020; Eshagh, 2015 and Gido et al., 2019), and understanding seismic source mechanisms is important, among other applications (Gido et al., 2019 and Dashtbazi et al., 2023). Furthermore, a reliable Moho model can reveal details of crustal structure that provide valuable insights into the complexities of deeper mantle layers; related to the calculations and detailed examination of gravity, geothermal, geomagnetic models (Stalk et al., 2013). Although there are several Moho models, their accuracy and resolution are insufficient in the complex tectonic geometry of the Makran subduction zone (Brizi et al., 2021 and Heilman and Becker, 2022), because these zones show a complex Moho configuration (Shad Manaman et al., 1390; Taghizadeh Farhamand et al., 2015 and Dashtbazi et al., 2023). As a result, the existing models lack the necessary accuracy for the Makran subduction zone, a region approximately 1000 km long located in southeast Iran and southwest Pakistan (Byrne et al., 1992; Shad Manaman et al., 1390, Penney et al., 2017; Dashtbazi et al., 1398; Dashtbazi. et al., 2023). In geophysical and geodetic studies, hybrid methods are mainly used to determine the Moho depth when seismic data with appropriate distribution and abundance are not available. These techniques include the Parker-Oldenberg method and the Wenning-Mines-Moritz method. In an effort to strengthen the existing Moho depth models in the Makran subduction zone, two distinct models named BC and SC through the integration of gravity (VMM) and seismic (CRUST1.0) data, which are processed through the Butterworth filter, spectral combination approaches and the least squares technique, was developed (Bagherbandi, 2011 and Dashtbazi et al., 2023). The resulting models provide a resolution of 5' x 5' degrees of arc, corresponding to a grid size of 9 x 9 km (Dashtbazi et al., 2023). The accuracy of these models was evaluated against four separate regional and local models. The resulting RMS values were 5.28, 1.55, 4.18, and 1.27 km for the BC model and 5.59, 1.17, 3.74, and 3.04 km for the SC model. Also, the Moho depth model obtained for the west Makran region in Iran significantly improved the accuracy and resolution of the Moho depth models in the studied area. The SC Moho model exhibits improved RMS metrics compared to the combined BC model, so we recommend it as the first priority. While the Moho depth models in our research really bring significant improvements to the existing models of the Makran subduction Moho zone, the integration of more detailed seismic data with SC and BC Moho models can improve the developed model for the Makran subduction zone. In the end, we suggest that a similar approach be adopted for the analysis of the Moho model in the eastern Makran region in Pakistan, which allows a comparative evaluation of the Moho depth and structure between the western and eastern parts in order to obtain a better picture of the Moho depth model of the Makran subduction zone. [ABSTRACT FROM AUTHOR]

Zarrin granitoid, with mostly metaluminous to slightly peraluminous, and I-type composition, outcropped in Yazd block, Central Iran. The U-Pb SHRIMP zircon age from Zarrin granitoid yields 557-567 Ma age consistent with the Late Neoproterozoic-Early Cambrian ‘Cadomian’ plutonism at northern margin of Gondwana supercontinent. The chondrite and primitive mantle normalized trace elements patterns show light rare earth elements (LREE) enrichment relative to heavy rare earth elements (HREE) and enrichment of large ion lithophile elements (LILE) relative to high field strength elements (HFSE), accompanied by negative anomalies in Nb, Ti, and Eu consistent with arc-related magmatism, associated with subduction of Proto-Tethys oceanic crust beneath the northern margin of Gondwana. Geochronological and geochemical data including inherited zircon age suggest the Zarrin granitoid originated from partial melting of relatively younger mafic crust and point to the existence of hidden PaleoproterozoicMesoproterozoic rocks in the lower continental crust of Iran. [ABSTRACT FROM AUTHOR]

Chamatoo intrusive body with monzonite to granite composition located south of Amlash city and east of Guilan in the Western Alborz. Petrographically, the Chamatoo intrusive body is mostly made of alkali feldspars and plagioclase with biotite, pyroxene, opaque minerals, and different textures from granular to porphyry granular as the main textures and perthitic, graphic, poikilitic as the accessory textures. In the chondrite-normalized spider diagram, the granitoid rocks display subparallel, linear and homogeneous REE profiles with LILE enrichment as well as Ta and Ti negative anomalies. In addition, all samples have the characteristics of WPG. Overall, the Chamatoo body was formed during the subduction of the oceanic crust of the Southern Caspian Sea and owing to the activity of an subducted mid oceanic ridge towards south, in an extensional regime above the supra-subduction zone a Slab Window was formed. Finally, Slab Window tectonic regime caused the rise of asthenosphere and the alkaline OIB magmatism in the region, followed by the generation of A1- type granite and the per-alkaline Chamatoo granitoid from fractional crystallization of OIB magma source. [ABSTRACT FROM AUTHOR]

In the north of Torud and the eastern part of the Trood- Chah Shirin magmatic arc, the Late Eocene- Early Oligocene subvolcanic rocks with andesite, trachyandesite and dacite composition intruded the Eocene volcanic- pyroclastic sequence. Mineralogically, they are dominated by plagioclase, hornblende, biotite, quartz and magnetite with microlithic porphyry and hyallomicrolithic porphyric textures. Plagioclase with polysynthetic twinning and oscillatory zoning is the most abundant mineral that sometimes having sieve texture, dissolution, and corroded margins. Biotite and amphibole phenocrysts are idiomorphs to subidiomprph with opacitic margins. Quartz phenocrysts sometimes have corrosion gulf. Microscopic evidence, including non- equilibrium textures (oscillatory zoning and sieve texture of plagioclases), dissolution, and corrosion of crystals point to assimilation and magmatic contamination. The geochemical signatures of the rocks studied including enrichment in LILEs (especially Rb, K, Th) and LREEs relative to HREEs and HFSEs (Ta, Nb, Ti), a calcalkaline affinity and their position on discrimination tectonomagmatic diagrams, display that these rocks derived from a subduction- related environment. These mentioned signatures with a differentiated pattern of rare earth elements without Eu anomaly, depletion in Y and Yb, and high ratio of Sr/Y and La/Yb show these rocks belong to high silica adakites. The parent magma of adakitic rocks in this region originated from partial melting of subducted oceanic crust (in garnet stability depth) associated with fractional crystallization and assimilation processes. [ABSTRACT FROM AUTHOR]