Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Analysis of sedimentary facies and depositional environment of the Aghajari Formation, north of Hosseinieh, Andimeshk, Khuzestan Province Analysis of sedimentary facies and depositional environment of the Aghajari Formation, north of Hosseinieh, Andimeshk, Khuzestan Province 1 26 242568 10.22071/gsj.2026.552988.2229 FA Mohammad Mallah Department of Geology, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran Behrouz Rafiei Department of Geology, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran 0000-0002-5384-7462 Hassan Mohseni Department of Geology, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran Journal Article 2025 10 14 This study aims to investigate the depositional environment of the Aghajari Formation (Upper Miocene-Pliocene) in the Hosseiniyeh area (Andimeshk). In this regard, three stratigraphic sections (Pa’alam, Khoshab, and Pirvali) were selected for study. The Aghajari Formation consists of sandstone, siltstone, mudstone, and shale, with a thickness exceeding 500 meters in the examined regions. Investigations in the field revealed 11 lithofacies, which include 6 sandstone facies (Sp/St/Sm/Sh/Sr/Sfl), 2 mudstone facies (Fm/Fl), 1 carbonate facies (bioclastic wackestone), 1 gray shale facies, and 1 skolithos ichnofacies. Evidence collected in the field suggests that the Pa’alam section exhibits characteristics of a deltaic environment, with delta-front facies containing sediments from the mouthbar, delta slope, and prodelta. In contrast, the deltatop facies includes deltaic channels and deltaic plains. This facies association constitutes the lower section of the Aghajari Formation. The upper part of the Aghajari Formation found in the Pa’alam section displays features typical of meandering rivers. The delta identified in the Pa’alam section is primarily river-influenced, with minimal tidal impact, where the maximum thickness of the tidal flat sediments reaches 2 meters. The two additional sections (Khoshab and Pirvali) were formed in a meandering river environment. This study aims to investigate the depositional environment of the Aghajari Formation (Upper Miocene-Pliocene) in the Hosseiniyeh area (Andimeshk). In this regard, three stratigraphic sections (Pa’alam, Khoshab, and Pirvali) were selected for study. The Aghajari Formation consists of sandstone, siltstone, mudstone, and shale, with a thickness exceeding 500 meters in the examined regions. Investigations in the field revealed 11 lithofacies, which include 6 sandstone facies (Sp/St/Sm/Sh/Sr/Sfl), 2 mudstone facies (Fm/Fl), 1 carbonate facies (bioclastic wackestone), 1 gray shale facies, and 1 skolithos ichnofacies. Evidence collected in the field suggests that the Pa’alam section exhibits characteristics of a deltaic environment, with delta-front facies containing sediments from the mouthbar, delta slope, and prodelta. In contrast, the deltatop facies includes deltaic channels and deltaic plains. This facies association constitutes the lower section of the Aghajari Formation. The upper part of the Aghajari Formation found in the Pa’alam section displays features typical of meandering rivers. The delta identified in the Pa’alam section is primarily river-influenced, with minimal tidal impact, where the maximum thickness of the tidal flat sediments reaches 2 meters. The two additional sections (Khoshab and Pirvali) were formed in a meandering river environment.

http://www.gsjournal.ir/article_242568_24c89d1f4d190fbefcd2a8ed20b2c756.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Quantitative assessment of heterogeneity based on the Lorenz Coefficient and integrated analysis of petrophysical, microfacies, and diagenetic data of the Dariyan Formation, Central Persian Gulf Quantitative assessment of heterogeneity based on the Lorenz Coefficient and integrated analysis of petrophysical, microfacies, and diagenetic data of the Dariyan Formation, Central Persian Gulf 27 48 243333 10.22071/gsj.2026.541451.2221 FA Mahnaz Hosseinzadeh School of Geology, College of Sciences, University of Tehran, Tehran, Iran Vahid Tavakoli School of Geology, College of Sciences, University of Tehran, Tehran, Iran Nooshafarin Haghighat Geological Survey and Mineral Exploration of Iran, Shiraz, Iran Journal Article 2025 08 15 Heterogeneity in carbonate reservoirs is one of the key factors controlling reservoir quality and fluid flow. In this study, the heterogeneity of the Dariyan Formation in the Persian Gulf was evaluated using the Lorenz coefficient in combination with an integrated analysis of petrophysical and geological data. The study was conducted based on data from one well, incorporating quantitative interpretation of petrophysical logs, including gamma ray, bulk density, neutron porosity, sonic, and deep resistivity logs. In addition, 1093 thin sections from core samples were petrographically analyzed at the well scale to identify depositional facies, textures, microfacies characteristics, pore types, and dominant diagenetic processes. To quantitatively assess reservoir heterogeneity, the Lorenz coefficient was applied as a statistical index within depth intervals of 2 m. Lithological, textural, and facies-related heterogeneity in several intervals, shows a clear relationship with diagenetic trends. Increased heterogeneity is associated with reduction in average porosity and permeability, whereas diagenetic processes such as cementation and stylolitization locally reduce petrophysical heterogeneity. The findings provide a more detailed quantitative insight into intra-reservoir heterogeneity in the Dariyan Formation and highlight the applicability of the Lorenz coefficient for characterizing heterogeneity in carbonate reservoirs, with implications for improved reservoir modeling and production strategy optimization. Heterogeneity in carbonate reservoirs is one of the key factors controlling reservoir quality and fluid flow. In this study, the heterogeneity of the Dariyan Formation in the Persian Gulf was evaluated using the Lorenz coefficient in combination with an integrated analysis of petrophysical and geological data. The study was conducted based on data from one well, incorporating quantitative interpretation of petrophysical logs, including gamma ray, bulk density, neutron porosity, sonic, and deep resistivity logs. In addition, 1093 thin sections from core samples were petrographically analyzed at the well scale to identify depositional facies, textures, microfacies characteristics, pore types, and dominant diagenetic processes. To quantitatively assess reservoir heterogeneity, the Lorenz coefficient was applied as a statistical index within depth intervals of 2 m. Lithological, textural, and facies-related heterogeneity in several intervals, shows a clear relationship with diagenetic trends. Increased heterogeneity is associated with reduction in average porosity and permeability, whereas diagenetic processes such as cementation and stylolitization locally reduce petrophysical heterogeneity. The findings provide a more detailed quantitative insight into intra-reservoir heterogeneity in the Dariyan Formation and highlight the applicability of the Lorenz coefficient for characterizing heterogeneity in carbonate reservoirs, with implications for improved reservoir modeling and production strategy optimization.

http://www.gsjournal.ir/article_243333_5d9cd59a4828a4509e7ae432f137f245.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Investigation of sub-ichnofacies of the Nereites ichnofacies in the upper part of the Late Cretaceous flysch deposits in the Jolfa region, northwestern Iran, Alborz Basin Investigation of sub-ichnofacies of the Nereites ichnofacies in the upper part of the Late Cretaceous flysch deposits in the Jolfa region, northwestern Iran, Alborz Basin 49 66 242427 10.22071/gsj.2026.559536.2234 FA Samira Taghdisi Nikbakht Department of Geology, Faculty of Sciences, University of Gonabad, Gonabad, Iran Mahdi Badpa Department of Geology, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran Mir Amir Salahi Department of Biology, Faculty of Basic Science, University of Maragheh, Maragheh, Iran Yaghub Nasiri Department of Geology, Faculty of Sciences, University of Gonabad, Gonabad, Iran Journal Article 2025 11 13 A detailed study aimed at investigating the abundance of Late Cretaceous ichnofaunal assemblages in the Jolfa area, East Azerbaijan Province, indicates that these assemblages are reliable tools for interpreting the depositional environment of submarine fans. The types of trace fossils and their stratigraphic arrangement are related to favorable biotic zones; therefore, they are employed to infer information concerning the differentiation of sub-environments within the turbidite fan system, sedimentation rate, and substrate consistency. The proximal and axial parts of the sandy system in the studied section contain assemblages characterized by low diversity and low bioturbation intensity, which are mostly dominated by post-depositional trace fossil suites. However, the distal parts show an increase in both diversity and bioturbation intensity, displaying pre-depositional trace fossil assemblages. The identified ichnofossil assemblages in the studied section correspond to the Nereites ichnofacies. Five sub-ichnofacies of the Nereites ichnofacies were recognized in the studied deposits, which may indicate a trend toward increasing water depth. These include: (1) Ophiomorpha rudis sub-ichnofacies, (2) mixed Ophiomorpha rudis–Paleodictyon sub-ichnofacies, (3) Paleodictyon sub-ichnofacies, (4) mixed Nereites–Paleodictyon sub-ichnofacies, and (5) Nereites sub-ichnofacies. A detailed study aimed at investigating the abundance of Late Cretaceous ichnofaunal assemblages in the Jolfa area, East Azerbaijan Province, indicates that these assemblages are reliable tools for interpreting the depositional environment of submarine fans. The types of trace fossils and their stratigraphic arrangement are related to favorable biotic zones; therefore, they are employed to infer information concerning the differentiation of sub-environments within the turbidite fan system, sedimentation rate, and substrate consistency. The proximal and axial parts of the sandy system in the studied section contain assemblages characterized by low diversity and low bioturbation intensity, which are mostly dominated by post-depositional trace fossil suites. However, the distal parts show an increase in both diversity and bioturbation intensity, displaying pre-depositional trace fossil assemblages. The identified ichnofossil assemblages in the studied section correspond to the Nereites ichnofacies. Five sub-ichnofacies of the Nereites ichnofacies were recognized in the studied deposits, which may indicate a trend toward increasing water depth. These include: (1) Ophiomorpha rudis sub-ichnofacies, (2) mixed Ophiomorpha rudis–Paleodictyon sub-ichnofacies, (3) Paleodictyon sub-ichnofacies, (4) mixed Nereites–Paleodictyon sub-ichnofacies, and (5) Nereites sub-ichnofacies.

http://www.gsjournal.ir/article_242427_431af639284677b503945fd6857d074d.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Magma evolution and physicochemical conditions of the Ghohroud granitoid complex on mineral chemistry and thermobarometric data Magma evolution and physicochemical conditions of the Ghohroud granitoid complex on mineral chemistry and thermobarometric data 67 84 243726 10.22071/gsj.2026.533389.2209 FA Tayebeh Khaksar Department of Petrology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran Fariba Jamshidi Department of Geology, Payame Noor University, Tehran, Iran Journal Article 2025 07 14 The Ghohroud granitoid complex, located southwest of Kashan in the central part of the Urumieh–Dokhtar Magmatic Arc (UDMA), mainly consists of granodiorite–tonalite rocks hosting mafic microgranular enclaves (MMEs) with compositions ranging from gabbrodiorite to tonalite. The main mineral assemblage includes amphibole, biotite, plagioclase, and alkali feldspar. Mineral chemistry indicates that plagioclase is andesine, amphiboles are Mg-rich hornblende, and biotites are also magnesium-rich. Amphiboles show relatively high Fe³⁺/(Fe³⁺ + Fe²⁺) ratios, while magmatic ones are characterized by low total Al and Fe/(Fe + Mg) ratios, suggesting crystallization under moderately oxidizing conditions. Oxygen fugacity (ƒO₂), calculated relative to the nickel–nickel oxide (NNO) buffer, ranges from 10⁻12 to 10⁻14 bar (ΔNNO +1.23) in tonalitic samples, and from 10⁻14 to 10⁻16 bar (ΔNNO +0.34) in granodioritic rocks and their associated enclaves. Thermobarometric calculations based on calcic amphiboles yield maximum pressures of about 4.39 kbar at 800 °C for tonalites, and around 3.89 kbar at 750 °C for granodiorites and their enclaves, corresponding to amphibole crystallization depths around ~12-16 km. Primary biotites in the Ghohroud granitoids crystallized slightly later, at 690–784 °C (average ~712 °C). The Ghohroud granitoid complex, located southwest of Kashan in the central part of the Urumieh–Dokhtar Magmatic Arc (UDMA), mainly consists of granodiorite–tonalite rocks hosting mafic microgranular enclaves (MMEs) with compositions ranging from gabbrodiorite to tonalite. The main mineral assemblage includes amphibole, biotite, plagioclase, and alkali feldspar. Mineral chemistry indicates that plagioclase is andesine, amphiboles are Mg-rich hornblende, and biotites are also magnesium-rich. Amphiboles show relatively high Fe³⁺/(Fe³⁺ + Fe²⁺) ratios, while magmatic ones are characterized by low total Al and Fe/(Fe + Mg) ratios, suggesting crystallization under moderately oxidizing conditions. Oxygen fugacity (ƒO₂), calculated relative to the nickel–nickel oxide (NNO) buffer, ranges from 10⁻12 to 10⁻14 bar (ΔNNO +1.23) in tonalitic samples, and from 10⁻14 to 10⁻16 bar (ΔNNO +0.34) in granodioritic rocks and their associated enclaves. Thermobarometric calculations based on calcic amphiboles yield maximum pressures of about 4.39 kbar at 800 °C for tonalites, and around 3.89 kbar at 750 °C for granodiorites and their enclaves, corresponding to amphibole crystallization depths around ~12-16 km. Primary biotites in the Ghohroud granitoids crystallized slightly later, at 690–784 °C (average ~712 °C).

http://www.gsjournal.ir/article_243726_449505b903518cccd18d726bebd91719.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Mineral chemistry, thermobarometry, and petrogenesis of igneous rocks from the Negisan area, east of Rudbar, Kerman province, Iran Mineral chemistry, thermobarometry, and petrogenesis of igneous rocks from the Negisan area, east of Rudbar, Kerman province, Iran 85 102 242745 10.22071/gsj.2026.561524.2236 FA Mehrnaz Zaifi Department of Geology, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Hormozgan, Iran Gholamreza Ghadami Department of Geology, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Hormozgan, Iran 0000-0003-3190-1242 Mohammad Poosti Department of Geology, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Hormozgan, Iran 0000-0003-2424-2189 Mohammad Fadaeian Department of Geology, Faculty of Sciences, Payame Noor University, Tehran, Iran 0000-0003-1747-212X Journal Article 2025 11 22 This study investigates the mineral chemistry, thermobarometric conditions, and petrogenetic evolution of Quaternary basaltic and olivine–basaltic lava flows exposed in the Negisan area, located in the southeastern segment of the Urumieh–Dokhtar Magmatic Arc (UDMA) and within the Dehaj–Sarduiyeh Magmatic Belt (DSMB). These volcanic units consist predominantly of porphyritic to glomeroporphyritic basalts characterized by phenocrysts of plagioclase (bytownite–labradorite), clinopyroxene (diopside–augite), and olivine (chrysolite), set within a microcrystalline to hyalomicrolitic groundmass. Comprehensive petrographic analysis reveals the pervasive presence of disequilibrium textures, including sieve-textured plagioclase and embayed olivine, indicative of dynamic open-system magmatic evolution. Quantitative major-element data obtained by electron probe microanalysis (EPMA) offer robust constraints on the physicochemical conditions of mineral crystallization. Clinopyroxene compositions correspond to an alkaline magma affinity and plot within the within-plate basalt tectonomagmatic field. Single-mineral thermobarometric calculations using clinopyroxene chemistry yield crystallization temperatures of 1160–1200 °C and pressures of 2–5 kbar, corresponding to mid- to upper-crustal magma storage depths (~7–18 km), under oxidizing and water-rich magmatic conditions. Systematic compositional contrasts between the olivine basalts (less evolved) and basalts (more evolved) demonstrate that fractional crystallization was the dominant differentiation mechanism. Nonetheless, petrographic evidence for magma mixing indicates that open-system recharge and interaction were also essential in magma evolution. These findings collectively support a model in which Negisan mafic volcanism represents late-stage, post-collisional magmatic activity associated with extensional tectonics following the final closure of the Neo-Tethys Ocean beneath the Central Iran microplate. The integration of petrography, mineral chemistry, and thermobarometry provides new insights into the magmatic plumbing system and geodynamic evolution of the southeastern UDMA. This study investigates the mineral chemistry, thermobarometric conditions, and petrogenetic evolution of Quaternary basaltic and olivine–basaltic lava flows exposed in the Negisan area, located in the southeastern segment of the Urumieh–Dokhtar Magmatic Arc (UDMA) and within the Dehaj–Sarduiyeh Magmatic Belt (DSMB). These volcanic units consist predominantly of porphyritic to glomeroporphyritic basalts characterized by phenocrysts of plagioclase (bytownite–labradorite), clinopyroxene (diopside–augite), and olivine (chrysolite), set within a microcrystalline to hyalomicrolitic groundmass. Comprehensive petrographic analysis reveals the pervasive presence of disequilibrium textures, including sieve-textured plagioclase and embayed olivine, indicative of dynamic open-system magmatic evolution. Quantitative major-element data obtained by electron probe microanalysis (EPMA) offer robust constraints on the physicochemical conditions of mineral crystallization. Clinopyroxene compositions correspond to an alkaline magma affinity and plot within the within-plate basalt tectonomagmatic field. Single-mineral thermobarometric calculations using clinopyroxene chemistry yield crystallization temperatures of 1160–1200 °C and pressures of 2–5 kbar, corresponding to mid- to upper-crustal magma storage depths (~7–18 km), under oxidizing and water-rich magmatic conditions. Systematic compositional contrasts between the olivine basalts (less evolved) and basalts (more evolved) demonstrate that fractional crystallization was the dominant differentiation mechanism. Nonetheless, petrographic evidence for magma mixing indicates that open-system recharge and interaction were also essential in magma evolution. These findings collectively support a model in which Negisan mafic volcanism represents late-stage, post-collisional magmatic activity associated with extensional tectonics following the final closure of the Neo-Tethys Ocean beneath the Central Iran microplate. The integration of petrography, mineral chemistry, and thermobarometry provides new insights into the magmatic plumbing system and geodynamic evolution of the southeastern UDMA.

http://www.gsjournal.ir/article_242745_199812b842e69685be6a4ed7f2c3b8c5.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Source and evolution of ore-forming fluids in the Bafq district iron oxide–apatite deposits, Central Iran: insights from pyrite sulfur isotope and magnetite oxygen isotope ratios Source and evolution of ore-forming fluids in the Bafq district iron oxide–apatite deposits, Central Iran: insights from pyrite sulfur isotope and magnetite oxygen isotope ratios 103 122 245167 10.22071/gsj.2026.578346.2247 FA Mobina Esmaeili Zeini Department of Mineral and Ground Water Resources, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran 0009-0006-8706-1579 Saeid Alirezaei Department of Mineral and Ground Water Resources, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran 0000-0002-6344-3111 Amir Morteza Azimzadeh Department of Civil, Environmental and Natural Resources Engineering, Division of Geosciences and Environmental Engineering, Luleå University of Technology, Luleå, Sweden Journal Article 2026 03 22 Despite sharing several key features, the iron oxide–apatite deposits of the Bafq district, Central Iran, display variations in host rocks, wall rock alteration, and ore texture/mineralogy, and geochemical attributes, reflecting the complexity of the ore forming processes and the ore fluid sources. Here, oxygen and sulfur isotope composition of magnetite and pyrite, respectively, from various massive, vein-type, breccia, banded, and cumulate ores are used to investigate the source and evolution of the ore-forming fluids in the Bafq district iron deposits. The δ¹⁸O values of magnetite from Chadormalu, Gazestan, Mishdovan, Lak-e-Siah, and Se-Chahun deposits range from +0.7‰ to +8.2‰. Massive and vein-type magnetites exhibit lower δ¹⁸O values, between 0.7-4.4‰, consistent with crystallization from high-temperature magmatic fluids. The δ¹⁸O value of +3.9‰ for the banded ore at Mishdovan, interbedded with pyroclastic materials, indicates a significant contribution from high-temperature magmatic fluids. Magnetite from the cumulate ore in Chadormalu, yielded δ¹⁸O value at +2.5‰ implying formation under high-temperature magmatic conditions. In contrast, the higher δ¹⁸O values (up to +8‰) for magnetite from the Gazestan and Lak-e-Siah banded ore suggest deposition from non-magmatic fluids, compatible with a sedimentary–diagenetic origin or sub-seafloor replacement. The δ³⁴S values for pyrite from massive, brecciated, and vein-type ores range widely from +4‰ to +30‰, indicating the involvement of variable, dominantly nonmagmatic, sulfur sources. The broad ranges of oxygen and sulfur isotopic compositions suggest a multi-stage evolutionary model for mineralization, with contributions from both magmatic and non-magmatic fluid sources. This is supported by the fluid inclusion data, where wide ranges of fluid salinity and homogenization temperature are reported from various IOA deposits in the Bafq district, and even in individual deposits. Despite sharing several key features, the iron oxide–apatite deposits of the Bafq district, Central Iran, display variations in host rocks, wall rock alteration, and ore texture/mineralogy, and geochemical attributes, reflecting the complexity of the ore forming processes and the ore fluid sources. Here, oxygen and sulfur isotope composition of magnetite and pyrite, respectively, from various massive, vein-type, breccia, banded, and cumulate ores are used to investigate the source and evolution of the ore-forming fluids in the Bafq district iron deposits. The δ¹⁸O values of magnetite from Chadormalu, Gazestan, Mishdovan, Lak-e-Siah, and Se-Chahun deposits range from +0.7‰ to +8.2‰. Massive and vein-type magnetites exhibit lower δ¹⁸O values, between 0.7-4.4‰, consistent with crystallization from high-temperature magmatic fluids. The δ¹⁸O value of +3.9‰ for the banded ore at Mishdovan, interbedded with pyroclastic materials, indicates a significant contribution from high-temperature magmatic fluids. Magnetite from the cumulate ore in Chadormalu, yielded δ¹⁸O value at +2.5‰ implying formation under high-temperature magmatic conditions. In contrast, the higher δ¹⁸O values (up to +8‰) for magnetite from the Gazestan and Lak-e-Siah banded ore suggest deposition from non-magmatic fluids, compatible with a sedimentary–diagenetic origin or sub-seafloor replacement. The δ³⁴S values for pyrite from massive, brecciated, and vein-type ores range widely from +4‰ to +30‰, indicating the involvement of variable, dominantly nonmagmatic, sulfur sources. The broad ranges of oxygen and sulfur isotopic compositions suggest a multi-stage evolutionary model for mineralization, with contributions from both magmatic and non-magmatic fluid sources. This is supported by the fluid inclusion data, where wide ranges of fluid salinity and homogenization temperature are reported from various IOA deposits in the Bafq district, and even in individual deposits.

http://www.gsjournal.ir/article_245167_cb1b428ab0db0863d8633973e72926be.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Stability analysis and support system design for the lower headrace tunnel bifurcation at the Rudbar pumped storage power plant Stability analysis and support system design for the lower headrace tunnel bifurcation at the Rudbar pumped storage power plant 123 148 243525 10.22071/gsj.2026.537222.2213 FA Masoud Heidari Department of Engineering Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran Mohammad Hossein Jowkar Department of Engineering Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran Mashallah Khamehchiyan Department of Engineering Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran Mohsen Sharifi Boroujerdi Mahab Ghods Consulting Engineers Company, Tehran, Iran Journal Article 2025 07 26 Pumped storage power plants play a crucial role in balancing electricity supply and demand during peak periods. Given the structural complexity of underground facilities and the potential risks of design oversights, this study evaluates the structural stability of the lower headrace tunnel bifurcation at the Rudbar Pumped Storage Power Plant in Lorestan, Iran. A multi-method approach was employed, integrating empirical classification systems (Q, RMR, RMi, GSI, and Protodiakonov coefficient) with 3D numerical modeling using FLAC3D software. Initial results indicated that the underground opening is marginally stable with a low factor of safety (FOS), necessitating the installation of a support system. Upon implementing the designed support system comprising 10 cm of reinforced shotcrete (steel grid) and 2 meter long fully grouted anchors in a 2×2 m pattern the internal forces were analyzed. The efficiency of the system was verified using capacity diagrams and Sakurai’s hazard level criteria, ensuring an FOS of over 1.5. Furthermore, the Ground Reaction Curve (GRC) and Longitudinal Deformation Profile (LDP) confirmed the elastoplastic behavior of the rock mass. Based on these analyses, an optimal excavation step of 2 meters (full-face) is recommended for ensuring the long-term stability of the tunnel bifurcation. Pumped storage power plants play a crucial role in balancing electricity supply and demand during peak periods. Given the structural complexity of underground facilities and the potential risks of design oversights, this study evaluates the structural stability of the lower headrace tunnel bifurcation at the Rudbar Pumped Storage Power Plant in Lorestan, Iran. A multi-method approach was employed, integrating empirical classification systems (Q, RMR, RMi, GSI, and Protodiakonov coefficient) with 3D numerical modeling using FLAC3D software. Initial results indicated that the underground opening is marginally stable with a low factor of safety (FOS), necessitating the installation of a support system. Upon implementing the designed support system comprising 10 cm of reinforced shotcrete (steel grid) and 2 meter long fully grouted anchors in a 2×2 m pattern the internal forces were analyzed. The efficiency of the system was verified using capacity diagrams and Sakurai’s hazard level criteria, ensuring an FOS of over 1.5. Furthermore, the Ground Reaction Curve (GRC) and Longitudinal Deformation Profile (LDP) confirmed the elastoplastic behavior of the rock mass. Based on these analyses, an optimal excavation step of 2 meters (full-face) is recommended for ensuring the long-term stability of the tunnel bifurcation.

http://www.gsjournal.ir/article_243525_907a1f3d7f1401c79c072507cc3d9919.pdf

Geological Survey of Iran Scientific Quarterly Journal of Geosciences 1023-7429 36 2 2026 06 22 Physics-informed neural networks for GPS velocity field interpolation in the Alborz tectonic region Physics-informed neural networks for GPS velocity field interpolation in the Alborz tectonic region 149 170 242428 10.22071/gsj.2026.553765.2232 FA Asghar Rastbood Department of Surveying Engineering, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran 0000-0001-6767-3101 Nima Jahanghiri Department of Surveying Engineering, Ahar Azad University, Ahar, Iran 0009-0009-9139-5864 Ebrahim Aghazadeh Chakherlou Department of Surveying Engineering, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran 0009-0004-3301-6145 Journal Article 2025 11 10 The interpolation of GPS velocity vectors into continuous fields represents a significant challenge in geodesy and geophysics. Conventional methods, such as the elastic Green's function proposed by Sandwell and Wessel (2016), face limitations in modeling complex phenomena and accounting for data uncertainties. This paper investigates the application of Physics-Informed Neural Networks as a powerful alternative to these classical methods. In this study, a PINN model was implemented that directly incorporates the governing equations of elasticity into the Neural Network's loss function. The model was trained on GPS data from 89 stations across the Alborz Tectonic Region in the oblique collision zone of the Arabia-Eurasia tectonic plates. Results demonstrate that the proposed model can successfully reconstruct the velocity field with acceptable accuracy, achieving RMSE values of approximately 0.68 mm/yr and 0.99 mm/yr for the east and north components, respectively. The method offers several advantages, including high flexibility in modeling complex physics, the capability to integrate diverse data types, and automatic consideration of observational uncertainties. Although the computational time of this approach is longer compared to classical methods, its inherent ability to overcome the limitations of traditional techniques makes it a promising candidate for the next generation of geodynamic data processing tools. The interpolation of GPS velocity vectors into continuous fields represents a significant challenge in geodesy and geophysics. Conventional methods, such as the elastic Green's function proposed by Sandwell and Wessel (2016), face limitations in modeling complex phenomena and accounting for data uncertainties. This paper investigates the application of Physics-Informed Neural Networks as a powerful alternative to these classical methods. In this study, a PINN model was implemented that directly incorporates the governing equations of elasticity into the Neural Network's loss function. The model was trained on GPS data from 89 stations across the Alborz Tectonic Region in the oblique collision zone of the Arabia-Eurasia tectonic plates. Results demonstrate that the proposed model can successfully reconstruct the velocity field with acceptable accuracy, achieving RMSE values of approximately 0.68 mm/yr and 0.99 mm/yr for the east and north components, respectively. The method offers several advantages, including high flexibility in modeling complex physics, the capability to integrate diverse data types, and automatic consideration of observational uncertainties. Although the computational time of this approach is longer compared to classical methods, its inherent ability to overcome the limitations of traditional techniques makes it a promising candidate for the next generation of geodynamic data processing tools.

http://www.gsjournal.ir/article_242428_4f9f57eee5fac96575b611accc2332ed.pdf