Articles
Petrology (15562085)33(2)pp. 139-161
Abstract: Metabasites within the Jandaq Metamorphic Complex (JMC), Iran, offer valuable insights into the region’s magmatic and metamorphic history. Whole-rock geochemical data (major, trace, and rare earth elements) coupled with Sm-Nd isotopes were used to decipher the protolith origin and tectonic setting of formation of these metabasites. Our results demonstrate a predominantly ortho-amphibolitic nature for the JMC metabasites, with igneous protoliths ranging from basalt to andesite based on geochemical discrimination diagrams (Zr versus MgO and Sm/Nd). They exhibit geochemical affinities closer to enriched mid-oceanic ridge basalts (E-MORB) rather than normal MORB, implying a nascent oceanic basin within an intracontinental extensional setting. Trace element signatures (LILE enrichment, HFSE depletion) suggest a metasomatized subcontinental lithospheric mantle (SCLM) or a metasomatized lithospheric mantle beneath the oceanic crust as the parental magma source. Sm-Nd isotopic data suggest a potential plume source for the protoliths. These rocks were metamorphosed further by at least three metamorphic events: M1 (regional metamorphism, Barrovian-type; 616–687°C, 8–11 kbar), M2 (a brittle deformation event), and a later retrograde metamorphism (M3). These findings provide a comprehensive understanding of the geochemical characteristics, tectonic setting, and metamorphic evolution of JMC metabasites, shedding light on the geological history of the Jandaq region as a Paleo-Tethyan remnant. © Pleiades Publishing, Ltd. 2025.
Arian, H.,
Alaminia, Z.,
Ahmadi, H.,
Pour, A.B.,
Tabatabaei manesh, S.M.,
Lentz, D.R.,
Parsa, L. Remote Sensing Applications: Society and Environment (23529385)38
The demand for critical minerals is increasing swiftly as they are essential components for clean energy technologies. Nowadays, lithium (Li) is considered critical due to its wider use in various battery chemistries and the rapid growth of the electric vehicle industry. Pegmatites are considered one of the main sources of lithium worldwide. The pegmatite belt in Afghanistan, known for its enormous resources of critical metals, has recently emerged as an important region for lithium exploration. Multispectral remote sensing imagery is the only technique with large spatial coverage to map lithium-bearing pegmatites on a regional scale. In this study, ASTER and Sentinel 2MSI multispectral remote sensing imagery was used to map lithium-bearing pegmatites in the Tagablor pegmatite field in central Afghanistan. Various spectral mapping methods such as False Color Composite (FCC), Band Ratio (BR) and Spectral Angle Mapper (SAM) as well as supervised classification algorithms, i.e. Support Vector Machine (SVM), Minimum Distance (MD) and Maximum Likelihood (ML), were used to discriminate between altered minerals and lithologies as well as to identify areas with high potential for lithium-bearing pegmatites. Of the classification algorithms tested, SVM showed the highest efficiency in separating pegmatite bodies from their host rocks when applied to Sentinel 2 MSI data. The current study identified six promising pegmatite zones in the Tagablor pegmatite field, five of which were newly discovered and proposed for a comprehensive field campaign. In this study, an overall accuracy of 89 % was achieved in the detection of pegmatites and their surrounding formations, highlighting the potential of multispectral remote sensing for lithium exploration at a regional scale in arid and semi-arid regions. Further geochronological, geochemical and mineralogical investigations are recommended to better understand the age and mineralization potential of these pegmatites in the Tagablor pegmatite field, central Afghanistan. This study highlights the significant potential of multispectral remote sensing in mapping potential zones of critical minerals to enhance the sustainable utilization of minerals for green energy technologies in the future. © 2025 Elsevier B.V.
Journal of the Geological Society (2041479X)182(5)
This study explores the Oligocene–Miocene subduction-related plutonic rocks (OMPs) from the central Urumieh–Dokhtar Magmatic Arc (UDMA) in the centre of the Alpine–Himalayan Orogenic Belt (AHOB). OMPs range in composition from gabbro/diorite (c. 34–32 Ma) to tonalite (c. 20 Ma) with geochemical signatures of metaluminous calc-alkaline I-type granitoids. Geochemical analyses reveal enrichment in large ion lithophile elements and light rare earth elements relative to high-field-strength elements and heavy rare earth elements (LaN/YbN = 3.05–4.45). Mineral and whole-rock chemical variations reflect lower crust melting to crustal contamination over time, and magmatic chamber evolution. OMP chemical evolution can be attributed to two key factors: (1) incorporation of Th-rich sediment/crustal components from progressive lower crustal melting and (2) injection of fertile mantle melts altering magma chamber composition. These factors rendered the OMPs barren in Cu-mineralization but suggest a possible potential Cu mineralization in Miocene intrusive rocks, where the enriched mantle fluids, derived from the subducted slab, were more pronounced. This study proposed a geodynamic model to improve our understanding of the UDMA magmatic evolution. Comparison of subduction-related magmatism plutonic rocks from the central UDMA, southern Tibet and western Anatolia highlights the evolution of slab dynamics, crustal thickening and extensional processes in ‘Oligocene–Miocene’ magmatism during the eastward closure of Neotethys along the AHOB. © 2025 The Author(s). Published by The Geological Society of London. All rights, including for text and data mining (TDM), artificial intelligence (AI) training, and similar technologies, are reserved. For permissions: https://www.lyellcollection.org/publishing-hub/permissions-policy. Publishing disclaimer: https://www.lyellcollection.org/publishing-hub/publishing-ethics.
Petrology (15562085)31(4)pp. 459-474
Abstract: A Permian-Triassic lamprophyric magmatism has developed as dyke and subvolcanic intrusions in the northeast of Isfahan Province, in Central Iran, where is so-called the Chahriseh-Bagherabad area. These rocks mainly consist of olivine, pyroxene, amphibole, and biotite as major minerals and apatite, biotite, muscovite, and opaque as minor minerals with porphyritic texture and with felsic xenoliths and xenocrysts. The Chahriseh-Bagherabad lamprophyres (CBL) magma has undergone significant crustal contamination and fractional crystallization. Based on whole rock geochemistry, these rocks belong to alkaline lamprophyres, derived from a low degree (less than 5%) partial melting of an amphibole-garnet lherzolite mantle and enriched by the lithospheric mantle in the source region. Their 87Sr/86Sr (0.70435–0.70696) and 143Nd/144Nd (0.51260–0.51276) values were supported by an enriched mantle source of the EMІI-type that has been contaminated by the continental upper crust. Thus, the CBL samples are alkaline rock formed by tensional intraplate magmatism in a Paleo-Tethyan subduction zone in the lower Paleozoic to late Permian in which metasomatism and mantle enrichment occurred. The lamprophyres magmas ascend due to tensional stress during rotation and displacement of the central-eastern Iranian microcontinent. © 2023, Pleiades Publishing, Ltd.
Ahmadi-bonakdar s., S.,
Tabatabaei manesh, S.M.,
Nadimi, A.,
Mirlohi a., A.,
Santos j.f., J.F.,
Parfenova o.v., Geotectonics (15561976)56(6)pp. 791-809
Abstract: The Golpayegan metamorphic complex is located in the Sanandaj-Sirjan Zone, Iran. This complex consists of various metamorphic rocks including schists, marbles, slates, gneisses, and amphibolites, most of them have Neoproterozoic age. The presence of structures such as sigma fabrics, boudinage, folded boudinage and interfering fold patterns indicates the occurrence of more than two deformation phases in the Golpayegan metamorphic complex. The measurement of strain intensity in the folds indicated deep immersion of structures and old Precambrian settings that had been influenced by orogenic events in the Neoproterozoic. These deformed rocks were exposed during extensional movements and, subsequently, sheared. The results based on field works shown geochemical relations and initial εNd(600 Ma) values of amphibolites in three sampling points located in Golpayegan region manifested that the protolith of the first (a') and second (b') sampling points had mantle origin (ortho-amphibolite), whilst protolith of the third (c') sampling point had sedimentary origin (para-amphibolite). Geochemically, the Golpayegan ortho-amphibolites showed sub-alkaline basalt-basaltic andesite compositions of tholeiitic affinity. The negative anomalies of Nb and Ti relative to Pb, La, and Ce in the primitive mantle-normalized spider-diagram and εNd(600 Ma) values revealed the subduction environment for ortho-amphibolites. The ortho-amphibolites exhibited the intermediate chemistry between the normal mid-ocean ridge basalt and island-arc tholeiitic basalt. Enrichment in large ion lithophile elements (LILE), light rare earth elements (LREE), and relative depletion in high field strength elements (HFSE) suggest the back-arc basin setting for the Golpayegan ortho-amphibolites. The primitive magma of the ortho-amphibolites was produced by 8–20% melting of spinel lherzolite. According to the Neoproterozoic age of the Golpayegan ortho-amphibolites and their relationship with the Golpayegan granitic gneiss (596‒578 Ma), it shows that they can be related to the Cadomian back-arc basin in the north of Peri-Gondwana at the Neoproterozoic. The high values of 87Sr/86Sr (0.708450‒0.714986) interpreted as result of seawater hydrothermal alteration. © 2022, Pleiades Publishing, Inc.
