Petrogenesis of Middle-Eocene granitoids and their Mafic microgranular enclaves in central Urmia-Dokhtar Magmatic Arc (Iran): Evidence for interaction between felsic and mafic magmas

Kazemi, Kazem; Kananian, Ali; Xiao, Yilin; Sarjoughian, Fatemeh

doi:10.1016/j.gsf.2018.04.006

Cited by 51 publications

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“…Eocene granitoids are widespread in the Buin Zahra–Saveh region of central part of UDMA (e.g., Kazemi et al, ; Rezaei‐Kahkhaei et al, ; Tabbakh Shabani, ). Kazemi et al () proposed that the Middle Eocene Haji Abad granitoids were emplaced in an arc‐related and active continental margin system in a pre‐plate collision setting and during flat or low angle subduction. The Eocene granitoids in the Gheshlagh–Aftabrow area, together with associated MMEs, are characterized by an enrichment in LILE (K and Rb) and Th, and a depletion in Nb, Ta, and Ti (Figure ), indicating arc‐related magmatism.…”

Section: Discussionmentioning

confidence: 99%

“…Volcanic activity in the belt started in the Palaeocene and reached a climax during the Eocene (e.g., Stöcklin, ; Zarasvandi, Liaghat, & Zentilli, ). Intrusions in the UDMA include granite, granodiorite, diorite, and tonalite that generally show calc‐alkaline, metaluminous, I‐type composition (e.g., Kananian, Sarjoughian, Nadimi, & Ahmadian, ; Kazemi, Kananian, Xiao, & Sarjoughian, ; Rezaei‐Kahkhaei, Galindo, Pankhurst, & Esmaeily, ; Sarjoughian et al, ; Sarjoughian & Kananian, ). The GAG exposed to the central UDMA consists of host granodiorite and associated mafic‐intermediate microgranular enclaves, which indicate magma mixing/mingling processes.…”

Section: Geological Settingmentioning

confidence: 99%

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Role of magma mixing in generating of the Gheshlagh–Aftabrow intrusions, SW Buin Zahra, Iran: Evidence for a juvenile origin from geochemical and Sr–Nd isotopic data

et al. 2018

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In this paper, we investigate host granodiorites and associated mafic microgranular enclaves (MMEs), including gabbroic to quartz diorite enclaves from the Middle Eocene Gheshlagh-Aftabrow granitoid, to assess magma mixing and crust-mantle interaction in the Urumieh-Dokhtar magmatic arc. The host granodiorites yield zircon U-Pb ages of ca. 40 Ma. Geochemical and bulk rock Nd-Sr isotopic modelling, together with the widespread occurrence of mafic microgranular enclaves with ellipsoidal and spherical shapes and chilled margins, K-feldspar and plagioclase megacrysts in the enclaves, and the presence of acicular apatite, ocellar quartz, plagioclase with oscillatory zoning and resorption surfaces, suggests that the mafic microgranular enclaves are globules of a more mafic magma derived from the mantle that was injected into and mixed/mingled with the magma derived from partial melting of a lower crust. Geochemically, the granitoid rocks are high-K calc-alkaline and metaluminous (A/CNK = 0.87-0.92) and belong to I-type suite. These granitoid host rocks have much higher SiO 2 (65.4-67.3 wt%) and relatively low Fe 2 O 3 (1.8-2.1 wt%) and MgO (1-1.58 wt%), so compared with the host rocks, the mafic microgranular enclaves have much lower SiO 2 contents (50.5-55 wt%), considerably higher Fe 2 O 3 (3.4-4.2 wt%) and MgO (3.9-4.8 wt%). Both the host intrusion and enclaves are enriched in LREE relative to HREEs (LREE/HREE = 3.1-4.1; (La/Yb) N = 2.1-4.1) and show slightly negative Eu anomalies (δEu = 0.75-0.90) and nearly flat HREE patterns ((Gd/Yb) N = 0.86-1.26). Analyses of Sr-Nd isotopes in the host granodiorites and associated enclaves show ( 87 Sr/ 86 Sr) i host = 0.705070-0.705174, εNd (t) host = 0.21-2.31, T DM1 host = 782-983 Ma, ( 87 Sr/ 86 Sr) i enclave = 0.704997-0.705170, εNd (t) enclave = 2.15-2.17, and T DM1 enclave = 874-980 Ma, indicating of juvenile nature for these granites. This characteristic together with similar trace-element compositions indicates intense magma mixing and a high degree of geochemical equilibration between the host granodiorites and their enclaves.A binary mixing model based on Sr-Nd isotopic compositions of the GAG indicates that rocks were mostly generated by mixing of 7-12% melts produced by partial melting of meta-igneous old lower crust rocks with 88-93% contribution of mantlederived juvenile basaltic magmas.The Gheshlagh-Aftabrow granodiorites (GAG) in central Urumieh-Dokhtar magmatic arc (UDMA) are characterized by the presence of mafic-intermediate microgranular enclaves (MMEs). In this paper, we present field relationships, petrographic descriptions, major-and trace-element compositional and textural disequilibrium features of some minerals (e.g., plagioclase), with geochemical and Rb-Sr isotopic data for the granodiorite hosts and associated MMEs of the Gheshlagh-Aftabrow intrusive rocks in order to unravel their respective source characteristics and petrogenesis and to contribute to a better understanding of magma mixing/mingling processes.

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Section: Discussionmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Role of magma mixing in generating of the Gheshlagh–Aftabrow intrusions, SW Buin Zahra, Iran: Evidence for a juvenile origin from geochemical and Sr–Nd isotopic data

et al. 2018

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“…This indicates that most of them are mainly derived from partial melting of juvenile mafic lower crust and mantle magma that could be contaminated with old crust (e.g., Jahn, Wu, & Chen, 2000;Wu et al, 2006). Based on the initial ratios of low to high 87 Sr/ 86 Sr (i) and positive to negative ϵNd(t), a mixture of two end members can be inferred for the UDMA intrusive rocks, that is, mixing depleted mantle and a juvenile lower crustal end members, which generated more evolved UDMA magmatism (e.g., Chekani Moghadam et al, 2018;Kazemi et al, 2019;Sarjoughian et al, 2018Sarjoughian et al, , 2019Shafaii Moghadam, Whitechurch, Rahgoshay, & Monsef, 2009;Yeganehfar, Ghorbani, Shinjo, & Ghaderi, 2013) 9e), mixing between mantle and juvenile crust-derived magmas can be the key role for UDMA magmatism. Furthermore, the intrusive rocks of the south-east of the UDMA have higher 87 Sr/ 86 Sr (i) , lower ϵNd (t) , and MgO values than the other parts of the UDMA, which indicates the higher crust component than the others parts.…”

Section: Comparison With Other Udma Intrusion Rocksmentioning

confidence: 99%

“…The study area is located in the central part of the UDMA. Other intrusive rocks in UDMA that have been compared with the other area include: North‐west of UDMA (NW): (1) Haji Abad granitoids from Kazemi, Kananian, Xiao, and Sarjoughian (2019); (2) Gheshlaghe‐Aftabrow intrusions from Kazemi, Kananian, Xiao, and Sarjoughian (2020); (3) Saveh magmatic complex from Nouri et al (2018). Center of UDMA: (4) Niyasar plutonic complex from Honarmand et al (2014); (5) Kuh‐e Dom granitoids from Kananian, Sarjoughian, Nadimi, Ahmadian, and Ling (2014); (6) Kajan subvolcanic rocks from Golkaram et al (2016); (7) Zafarghand complex from Sarjoughian, Lentz, Kananian, Ao, and Xiao (2018); (8) Marshenan granitoids from Sarjoughian, Azizi, Lentz, and Ling (2019); (9) Soheyle‐PaKuh granitoids from Sarjoughian et al (2020); (10) Nadoushan granitoids from Shahsavari Alavijeh, Rashidnejad‐Omran, Toksoy‐Koksal, Xu, and Ghalamghash (2019).…”

Section: Introductionmentioning

confidence: 99%

Juvenile crust and mantle sources for the Nasrand intrusive rocks, the central Urumieh–Dokhtar magmatic arc, Iran: Insights from elemental and isotopic geochemistry

et al. 2022

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The Oligocene Nasrand intrusive rocks (NIRs), located in the central part of the Urumieh–Dokhtar magmatic arc, are mainly composed of granite and subordinate diorite and gabbro. These rocks are characterized by the enrichment of light rare earth elements (LREEs), Nb‐Ta negative anomalies, and high LILE/HFSE, suggesting a subduction‐related origin. The felsic rocks with granite compositions have high SiO2 content (69.77–77.88 wt.%), low Mg# (0.02–0.43), low Nb/Ta, and Zr/Hf (Avg: 12.53, and 33.08, respectively). The initial 87Sr/86Sr ratio and εNd(t) values in felsic rocks range from 0.70577 to 0.70576 and 0.4 to −0.3, respectively. These data suggest that these felsic rocks originated from juvenile crust by heat rising from basaltic magmas in an orogenic setting. The mafic‐intermediate rocks and dikes are gabbro, gabbroic diorite, and monzodiorite, with low SiO2 content (48.08–56.11 wt.%) and high Mg# (0.37–0.68), with average ratios of Nb/Ta and Zr/Hf are 27.88 and 39.84, respectively. The initial 87Sr/86Sr ratio and εNd(t) values for mafic‐intermediate rocks and dikes are 0.70583 to 0.70476 and −0.1 to +2.6, respectively. These characteristics indicate magma from a mantle source that had undergone minor mixing with juvenile crust. It seems mantle‐derived juvenile magma underplating played an important role in the crustal growth in the Urumieh–Dokhtar magmatic belt during the Ediacaran to Early Cambrian, relative to other time frames.

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“…Mafic microgranular enclaves (MMEs) are common in granitic or dioritic rocks. Through the study of host rocks and MMEs, information about the composition of deep crustal materials, interaction between the crust and mantle and exchange of energy can be revealed, which potentially provides new constraints for the genesis, mineralization and tectonic setting of rocks (Perugini et al 2003;Zhao et al 2010;Liu et al 2017;Wang et al 2017;Plail et al 2018;Kazemi et al 2019). Therefore, the study of host rocks and MMEs has attracted extensive attention from geologists.…”

Section: Introductionmentioning

confidence: 99%

Geochemical characteristics of the Nyemo intrusion and crust–mantle interactions in southern Gangdese, Tibet

et al. 2020

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The Gangdese magmatic belt across the southern Tibetan Plateau is juxtaposed with the Indus–Yurlung Zangbo suture zone (IYS), and many mafic microgranular enclaves (MMEs) are exposed in the belt, thus providing a window for observing deep crust–mantle processes related to the Indo-Asian collision. The Nyemo intrusion is located in the middle part of the Gangdese magmatic belt and comprises host diorites with abundant MMEs. Compared with other parts of the Gangdese magmatic belt, the host rock of the Nyemo intrusion has a mineral composition similar to that of the MME, although differences are observed in chemical contents. To explore the genetic type of the MMEs and the deep processes of the Gangdese magmatic belt, the Nyemo intrusion is selected as the research object for this paper. Here, we report zircon U–Pb geochronological and whole-rock geochemical data for host diorites and MMEs, and electron probe data for hornblendes in diorites and MMEs, and combine mineralogy, petrology, petrogeochemistry and isotope geochemistry analyses. Research has shown that diorites in the Nyemo intrusion belong to the medium-K, metaluminous series. The light rare earth elements (LREEs) and heavy rare earth elements (HREEs) are significantly fractionated, and the LREE/HREE values are 5.77–7.71. The (87Sr/86Sr)i values of the diorites range from 0.704260 to 0.704287, and the εNd(t) values are from 3.73 to 4.17. The MMEs in the Nyemo intrusion have a limited range of SiO2 contents, are calc-alkaline with metaluminous affinity, and have relatively high contents of MgO (4.34–5.00 wt %) with Mg# (Mg2+/Mg2+ + Fe2+) values of 42.36–43.53, which is close to that of evolved basic magma. The contents of REEs vary from 108.87 to 120.59 ppm and show obvious Eu anomalies. The (87Sr/86Sr)i values of the MMEs range from 0.704680 to 0.704704, and the εNd(t) values are 0.35–3.74. The crystallization temperature of the hornblende in the diorite is 820 °C, the formation depth is 5.39 km, the oxygen fugacity is ΔNNO + 0.88 and the water content is 5.95 %. The crystallization temperature of the hornblende in the MMEs is 880 °C, the formation depth is 12.18 km, the oxygen fugacity is ΔNNO + 0.38 and the water content is 8.27 %. The Nyemo MMEs are formed by magma mingling, and originate from the partial melting of the depleted mantle, while the host diorite originates from partial melting of the juvenile crust with the addition of mantle material. The formation of the Gangdese magmatic belt is related to the Indo-Asian continental collision. The break-off of the subducted Neo-Tethyan oceanic plate triggered partial melting of the asthenosphere, which resulted in accumulation of the basaltic magma and then caused the partial melting of the juvenile crust with the addition of mantle material, thus forming a variety of granitic rocks and the large Gangdese magmatic belt.

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Petrogenesis of Middle-Eocene granitoids and their Mafic microgranular enclaves in central Urmia-Dokhtar Magmatic Arc (Iran): Evidence for interaction between felsic and mafic magmas

Cited by 51 publications

References 135 publications

Role of magma mixing in generating of the Gheshlagh–Aftabrow intrusions, SW Buin Zahra, Iran: Evidence for a juvenile origin from geochemical and Sr–Nd isotopic data

Role of magma mixing in generating of the Gheshlagh–Aftabrow intrusions, SW Buin Zahra, Iran: Evidence for a juvenile origin from geochemical and Sr–Nd isotopic data

Juvenile crust and mantle sources for the Nasrand intrusive rocks, the central Urumieh–Dokhtar magmatic arc, Iran: Insights from elemental and isotopic geochemistry

Geochemical characteristics of the Nyemo intrusion and crust–mantle interactions in southern Gangdese, Tibet

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