Composition, Geochronology and Geodynamic Implications of Igneous Rock

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Geochemistry and Geochronology".

Deadline for manuscript submissions: closed (1 July 2022) | Viewed by 18373

Special Issue Editors


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Guest Editor
V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, 630090 Novosibirsk, Russia
Interests: petrology; geochemistry; gabbro; granite; geodynamics; Central Asia

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Guest Editor
Geological Institute of the Siberian Branch of the Russian Academy of Sciences, Sakhyanova st. 6a, 670047 Ulan-Ude, Russia
Interests: petrology of granitoids; geochemistry of magmatic processes; geochronology and geodynamics of Central and Northeast Asia

Special Issue Information

Dear Colleagues,

Magmatism is a very important manifestation of deep activity of the Earth. Magmatism plays a pivotal role in the formation and evolution of the Earth’s crust. Thermodynamic and composition properties of magmas are caused by many factors, including temperature, pressure of generation, substrates, and fluid composition. Investigations in recent decades have allowed us to determine the magmatic series and magmatic formations related to different geodynamic settings. Nevertheless, the study of magmatic formations in orogenic belts has shown that they often have geochemical features of various geodynamic settings. Thus, it becomes obvious that the detailed study of magmatism history and evolution in a particular region is necessary to identify the patterns of endogenous activity and to reach comprehensive geodynamic conclusions. Such studies must be based on sufficient data about the geological position, composition, and geochronological age of igneous rocks. The presentation of the results of such studies is the main goal of this Special Issue. We invite a wide range of researchers of igneous rocks, manifesting in a variety of geodynamic settings, to participate in this Special Issue.

Dr. Sergei Khromykh
Dr. Andrei Tsygankov
Guest Editors

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Keywords

  • igneous rocks
  • geochemistry
  • Nd–Sr–Hf Isotopic data
  • U–Pb and Ar–Ar geochronology
  • geodynamic settings

Published Papers (11 papers)

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Editorial

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3 pages, 169 KiB  
Editorial
Editorial for Special Issue “Composition, Geochronology and Geodynamic Implications of Igneous Rock”
by Sergey V. Khromykh
Minerals 2023, 13(4), 463; https://0-doi-org.brum.beds.ac.uk/10.3390/min13040463 - 25 Mar 2023
Viewed by 825
Abstract
Magmatism is a very important manifestation of the deep activity of the Earth [...] Full article

Research

Jump to: Editorial

19 pages, 7459 KiB  
Article
Hydro-Volcanism in the Longgang Volcanic Field, Northeast China: Insights from Topography, Stratigraphy, Granulometry and Microtexture of Xidadianzi Maar Volcano
by Bo Zhao, Debing Xu, Zhida Bai and Zhengquan Chen
Minerals 2022, 12(9), 1113; https://0-doi-org.brum.beds.ac.uk/10.3390/min12091113 - 31 Aug 2022
Cited by 1 | Viewed by 1631
Abstract
Hydro-volcanism in the Longgang volcanic field (LVF) of Northeast China has produced a dozen maars with features of complex sequences. To better understand the formation mechanism of maar volcanos in the LVF, this study focuses on the Xidadianzi (XDDZ) maar volcano, located in [...] Read more.
Hydro-volcanism in the Longgang volcanic field (LVF) of Northeast China has produced a dozen maars with features of complex sequences. To better understand the formation mechanism of maar volcanos in the LVF, this study focuses on the Xidadianzi (XDDZ) maar volcano, located in the Jinchuan valley of the LVF. Based on detailed stratigraphy analysis, 14C geochronology, grain-size distribution, and scanning electron microscopy (SEM) analysis, the eruptive sequence of the XDDZ volcano, including the South Crater and the North Crater, was constructed. The whole sequence was formed after four eruptive phases, including a wet phreatomagmatic eruption, an explosive magmatic eruption, a dry and hot phreatomagmatic eruption, and a small explosive magmatic eruption. 14C geochronology indicates that the formation age of XDDZ is 15,900 ± 70 years, BP. Topographic and stratigraphic characteristics show that the landforms of two craters were damaged and buried because of the destruction of lava flows and agricultural modification. The NE- trending fissure in the hard rock area is thought to participate in the formation of the XDDZ maar volcano. Full article
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21 pages, 10109 KiB  
Article
Early Triassic Monzonite–Granite Series in Eastern Kazakhstan as a Reflection of Siberian Large Igneous Province Activity
by Sergey V. Khromykh, Pavel D. Kotler, Anna V. Kulikova, Dina V. Semenova, Kamil R. Minnebaev, Bulat I. Gareev, Georgii A. Batalin, Tatiana N. Antsiferova, Ekaterina A. Il’icheva and Alexey S. Volosov
Minerals 2022, 12(9), 1101; https://0-doi-org.brum.beds.ac.uk/10.3390/min12091101 - 29 Aug 2022
Cited by 2 | Viewed by 1933
Abstract
We provide the results of studying the internal structure and composition of the rocks of the Semeitau and Delbegetei massifs located in Eastern Kazakhstan. It was previously believed that these massifs have different ages and were formed in different geodynamic settings. The U-Pb [...] Read more.
We provide the results of studying the internal structure and composition of the rocks of the Semeitau and Delbegetei massifs located in Eastern Kazakhstan. It was previously believed that these massifs have different ages and were formed in different geodynamic settings. The U-Pb zircon age from the monzonites and quartz monzonites was determined to be 249 ± 2 Ma, which showed the same Early Triassic age of the massifs. Both massifs are composed of rocks of the same monzonite–granite series of rocks with a significant proportion of high-silica rocks (leucocratic granites). Intermediate rocks are formed due to the differentiation of subalkaline mafic magmas, and the felsic rocks (rhyolites and granites) are the result of partial melting of crustal substrates. The massif formation model assumes the intrusion of mafic magmas into the crust, their differentiation and mixing with crustal melts, and then the intrusion of various rocks into the upper crustal levels. Analysis of the geological position, age and composition of the rocks allows us to conclude that the Semeitau and Delbegetei massifs were formed in an intraplate geodynamic setting. The activity of the mantle plume is the most probable reason for their formation. The Semeitau and Delbegetei massifs can be included in the southern part of the range of the Early Triassic Siberian Large Igneous Province. Full article
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20 pages, 5197 KiB  
Article
Petrogenesis and Tectonic Implication of the Hongtaiping High-Mg Diorite in the Wangqing Area, NE China: Constraints from Geochronology, Geochemistry and Hf Isotopes
by Siyu Lu, Yunsheng Ren, Qun Yang, Yujie Hao and Xuan Zhao
Minerals 2022, 12(8), 1002; https://0-doi-org.brum.beds.ac.uk/10.3390/min12081002 - 08 Aug 2022
Cited by 2 | Viewed by 1351
Abstract
This study presents new data from zircon U–Pb dating and Hf isotope analysis, as well as whole-rock major- and trace-element compositions of the Hongtaiping high-Mg diorite in the Wangqing area of Yanbian, NE China. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) zircon [...] Read more.
This study presents new data from zircon U–Pb dating and Hf isotope analysis, as well as whole-rock major- and trace-element compositions of the Hongtaiping high-Mg diorite in the Wangqing area of Yanbian, NE China. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) zircon U–Pb dating gives an eruption age of ca. 267 Ma for the high-Mg diorite. These samples have MgO contents of 13.30% to 16.58% and high transition metal element concentrations, classified as sanukite. Their rare earth element (REE) contents range from 45.2 to 68.4 ppm and are characterized by slightly positive Eu anomalies (Eu/Eu* = 1.08–1.17). They show enrichment in light REEs (LREEs) and depletion in heavy REEs (HREEs), with LREE/HREE ratios = 6.54–6.97 and (La/Yb)N values = 7.24–8.08. The Hongtaiping high-Mg diorite is enriched in Rb, U, K, and Sr, but depleted in Th, Nb, and Ta. High MgO contents, Mg# values, and transition metal element concentrations imply that the magma experienced insignificant crystallization fractionation and crustal contamination. Relatively homogenous positive Hf isotopic values indicate that the original magma was generated by the partial melting of a depleted mantle wedge that was metasomatized by subducting slab fluids. The magma was generated by the moderate degree partial melting (20%–30%) of a garnet lherzolite source. Combined with previous studies, this shows that the high-Mg diorite was formed by the northward subduction of the Paleo-Asian oceanic plate during the Middle Permian. Full article
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17 pages, 5139 KiB  
Article
Allanite in Variscan Post-Collisional Lamprophyre Dykes from Les Guilleries (NE Iberia) as a Part of Rare Earth Elements Recycling in Collisional Orogens
by Esteban Mellado, Mercè Corbella and Andrew Kylander-Clark
Minerals 2022, 12(8), 954; https://0-doi-org.brum.beds.ac.uk/10.3390/min12080954 - 28 Jul 2022
Cited by 1 | Viewed by 1931
Abstract
Recent studies of Late Permian calc-alkaline lamprophyre dykes located in the Les Guilleries Paleozoic massif of the Catalan Coastal Range have revealed that allanite is present as the main REE-bearing accessory phase, which is the object of this study. The lamprophyre dykes are [...] Read more.
Recent studies of Late Permian calc-alkaline lamprophyre dykes located in the Les Guilleries Paleozoic massif of the Catalan Coastal Range have revealed that allanite is present as the main REE-bearing accessory phase, which is the object of this study. The lamprophyre dykes are amphibole–plagioclase-dominated spessartites with a wide variety of accessory phases, including titanite, ilmenite, allanite, fluorapatite, spinel, zircon, and sulfides, and show complex alteration textures related to secondary albite, chlorite, epidote, titanite and calcite. The allanite crystal composition, analyzed by SEM-EPMA and LA-ICP-MS, evidences the solid solution between epidote and allanite with a ferriallanite component, similar to what is found in Variscan post-collisional granitoids from western Europe. However, heterogeneity in crystal shapes, sizes, type of zoning, dissolution embayment textures, growth of epidote coronas, mineral paragenesis, and the unique geochemical characteristics of allanite crystals suggest multiple crystallization events. At least two types of allanite–epidote composite grains have been identified: allanite Type I, with regular allanite–epidote core-to-rim zoning and a secondary allanite rim; and allanite Type II, with anhedral allanite cores surrounded by epidote coronas. Additionally, irregular zoning, complex dissolution textures and REE redistribution suggest the occurrence of deuteric and/or post-magmatic processes, which are also common in Variscan post-collisional plutons from the Catalan Coastal Range and nearby Paleozoic massifs. Multivariate statistical analyses of major elements in allanite–epidote composite grains show a relationship between major textural and geochemical variations for three out of ten principal components, mainly related to cationic substitutions between ferriallanite-(Ce) and epidote, but also involving Mn and Ti(REE3+ + Fe2+ + Ti4+ + Mg2+ + Mn2+ = Al3+ + Ca2+ + Fe3+). The allanite U-Pb-Th- weighted mean age of 265 ± 15 Ma (MSWD = 0.57) is roughly similar to the age of emplacement of the lamprophyres in the upper crust in the mid–late Permian, and coincides with the period following the main tectonometamorphic and magmatic events of the post-collisional evolution in the Catalan Coastal Range. Th/U and La/Sm ratios suggest a metamorphic origin for most allanite grains, but a combination of metamorphic processes prior to partial melting, early–late magmatic crystallization, and/or post-magmatic hydrothermal processes is the most plausible explanation to account for the diversity of allanite grains in Les Guilleries lamprophyres. Full article
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25 pages, 65426 KiB  
Article
Petrogenesis and Tectonic Implications of the Triassic Granitoids in the Ela Mountain Area of the East Kunlun Orogenic Belt
by Zhongcui Pan, Fengyue Sun, Zhichao Cong, Nan Tian, Wei Xin, Li Wang, Yajing Zhang and Dongqian Wu
Minerals 2022, 12(7), 880; https://0-doi-org.brum.beds.ac.uk/10.3390/min12070880 - 13 Jul 2022
Cited by 6 | Viewed by 1560
Abstract
The East Kunlun Orogenic Belt is located in the western part of the Central Orogenic Belt of China, with a large number of Triassic igneous rocks parallel to the Paleo-Tethys ophiolite belt, which provides a large amount of geological information for the tectonic [...] Read more.
The East Kunlun Orogenic Belt is located in the western part of the Central Orogenic Belt of China, with a large number of Triassic igneous rocks parallel to the Paleo-Tethys ophiolite belt, which provides a large amount of geological information for the tectonic evolution of the Paleo-Tethys Ocean. The granitoids studied in this paper are located in the Ela Mountain area in the eastern part of the East Kunlun Orogenic Belt. Zircon U-Pb dating results show that these different types of granitoids were crystallized in the Triassic. The 247.5 Ma porphyritic granites from Zairiri (ZRR) displayed calc-alkaline I-type granite affinities, with the zircon εHf(t) values being mainly positive (−0.5 to + 3.8, TDM2 of 1309–1031 Ma), indicating that they are derived from the partial melting of the juvenile crust and mixed with ancient crustal components. The 236.8 Ma Henqionggou (HQG) granodiorites and 237.5 Ma Daheba (DHB) granodiorites are high-K calc-alkaline I-type granite, and both have mafic microgranular enclaves (MMEs), showing higher and more varied Mg# (39.73–62.73), combined with their negative Hf isotopes (εHf(t) = −2.6 to −1.6, TDM2 = 1430–1369 Ma), suggesting that their primary magmas were the products of partial melting of the Mesoproterozoic lower crust that mixed with mantle-derived rocks. The 236.4 Ma DHB porphyritic diorites showed characteristics of high-K calc-alkaline I-type granitoids, with moderate SiO2 contents, medium Mg# values (40.41–40.65), with the Hf isotopes (εHf(t) = −2.9 to −0.5; TDM2 = 1451–1298 Ma) indistinguishably relative to contemporaneous host granodiorites and MMEs. The petrographic and geochemical characteristics indicate that the porphyritic diorites are the product of well-mixed magma derived from the Mesoproterozoic lower crust and lithospheric mantle. Based on the results of this paper and previous data, the chronology framework of Late Permian–Triassic magmatic rocks in the eastern part of the East Kunlun Orogenic Belt was constructed, and the magmatic activities in this area were divided into three peak periods, with each peak representing an extensional event in a particular tectonic setting, for example, P1 (slab roll-back in subduction period; 254–246 Ma), P2 (slab break-off in transition period of subduction and collision; 244–232 Ma), P3 (delamination after collision; 230–218 Ma). Full article
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17 pages, 4985 KiB  
Article
Petrogenesis and Geological Significance of the Quartz Monzonites in the Jinling Area, Western Shandong Province
by Zhao-Lu Zhang, Chao Zhang, Ye Li, Lu-Yuan Wang, Ji-Lei Gao, Ming Ma and Ya-Dong Li
Minerals 2022, 12(6), 771; https://0-doi-org.brum.beds.ac.uk/10.3390/min12060771 - 17 Jun 2022
Cited by 3 | Viewed by 1592
Abstract
Jinling complex pluton is a key part of the Mesozoic magmatic belt in the eastern North China Craton. However, its petrogenesis is still being debated. The Jinling complex, mainly composed of biotite diorites, hornblende diorite, augite diorites, (quartz) monzonites, and quartz diorites, is [...] Read more.
Jinling complex pluton is a key part of the Mesozoic magmatic belt in the eastern North China Craton. However, its petrogenesis is still being debated. The Jinling complex, mainly composed of biotite diorites, hornblende diorite, augite diorites, (quartz) monzonites, and quartz diorites, is outcropped in Huashan and Heitieshan. This paper studies the zircon geochronology, zircon Hf isotope, and Sr-Nd-Pb isotope of quartz monzonites. The samples have high contents of Cr, Ni, V, Al2O3, Ba, Sr, and are enriched in LREEs, LILEs (K, Ba, Sr), depleted in HREEs, and HFSEs (Nb, Ta, Ti). The samples with captured zircons of ~2.5 Ga yield a weighted mean age of ~127 Ma, and the zircons have negative values of εHf(t) from −3.2 to −9.4 while the ratios of 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb 37.75~38.15, 15.41~15.43, 17.59~17.98, respectively. The ratios of Th/U are from 3.77 to 3.82, while the values of μ and ω are 9.18 and from 35.72 to 36.15. Meanwhile, the ratios of 87Sr/86Sr are higher than the ones of the mantle. Geochemical and isotopic features indicate that the quartz monzonites derived from the subcontinental lithospheric mantle that probably assimilated ancient NCC upper crust materials (~15–20%) during the magma ascent in a lithospheric extension setting. Full article
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13 pages, 3462 KiB  
Article
Closure of the Eastern Paleo-Asian Ocean: Constraints from the Age and Geochemistry of Early Permian Zhaojinggou Pluton in Inner Mongolia (North China)
by Guang-Yao Li, Liang Qiu, Zhi-Dan Li, Lei Gao, Chao Fu, Jia-Ying Wang, Qi Zhang, Jia-Run Tu and Teng-Fei Ge
Minerals 2022, 12(6), 738; https://0-doi-org.brum.beds.ac.uk/10.3390/min12060738 - 09 Jun 2022
Cited by 2 | Viewed by 1417
Abstract
The closing time of the Paleo-Asian Ocean and the tectonic evolution of the northern margin of the North China Craton are still controversial. The geochronology and geochemistry of the Zhaojinggou monzogranite pluton provide new constraints on the late Paleozoic tectonic evolution and the [...] Read more.
The closing time of the Paleo-Asian Ocean and the tectonic evolution of the northern margin of the North China Craton are still controversial. The geochronology and geochemistry of the Zhaojinggou monzogranite pluton provide new constraints on the late Paleozoic tectonic evolution and the closure time of the Paleo-Asian Ocean in the southern Central Asian Orogenic Belt (CAOB). The monzogranite yielded a zircon U-Pb age of 286.7 ± 1.2 Ma. Due to the characteristics of low–moderate Mg# values (25.87–39.21), low Fe2O3T values (1.13–1.72), and A/CNK > 1, we show that the pluton is weak peraluminous, high in potassium calc–alkaline series, and displays the feature of S-type granite. The total REE content is low, the distribution curve is right dipping, and the LREE is enriched; the δEu average value is 1.32 (1.11–1.54). The granite presents relatively high (87Sr/86Sr)i values of 0.712345–0.713723, low εNd(t) values of −8.89–−8.21 (an average value of −8.56), and a TDM2 of 1718–1773 Ma. Furthermore, the zircon in situ Hf isotopic analysis shows 176Hf/177Hf ratios of 0.282342 to 0.282614, low εHf(t) values of −9.27–0.38 (mean −4.74), and a TDM2 of 1275–1887 Ma. Additionally, high field strength elements such as Nb, Ta, and Ti are depleted, and large ion lithophile elements, e.g., Rb, Ba, K, and Sr, are enriched. The above features of the Zhaojinggou monzogranite indicate that the pluton was derived from late Paleoproterozoic to Mesoproterozoic lower crustal mafic materials. By discussing the genesis and tectonic implications of the pluton massif, we propose that the Zhaojinggou monzogranite represents a magmatic event caused by the crustal–mantle interaction during the southward subduction of the eastern Paleo-Asian Ocean in the northern margin of the North China Craton during the Early Permian. Full article
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19 pages, 9835 KiB  
Article
Petrogenesis of Early Cretaceous High-Mg Adakitic Pluton in the North Lhasa Block, Tibet Plateau: Implications for the Tethyan Orogeny
by Qian-Ru Xiao, Yong-Feng Wei, Zhong-Yuan Liu, Fu-Hao Xiong, Lei Fan, Jian-Xin Wu and Han Zhao
Minerals 2022, 12(2), 213; https://0-doi-org.brum.beds.ac.uk/10.3390/min12020213 - 07 Feb 2022
Cited by 2 | Viewed by 1312
Abstract
Late Mesozoic igneous rocks from the north Lhasa block record the Neo-Tethyan orogeny in the southern Tibet Plateau. This study presents geochronological and geochemical data of Bieruozecuo quartz diorite pluton in the northern margin of the Lhasa block to constrain its petrogenesis and [...] Read more.
Late Mesozoic igneous rocks from the north Lhasa block record the Neo-Tethyan orogeny in the southern Tibet Plateau. This study presents geochronological and geochemical data of Bieruozecuo quartz diorite pluton in the northern margin of the Lhasa block to constrain its petrogenesis and tectonic implications. The LA–ICP–MS zircon U–Pb geochronology of quartz diorites shows that the emplacement occurs at ca. 114–116 Ma, belonging to the products of Early Cretaceous magmatic activities. The high concentrations of TiO2, MgO, and MnO, together with SiO2 vs. K2O and A/NK vs. A/CNK diagrams, all suggest that the Bieruozecuo quartz diorites are meta-aluminous and high-potassium calc-alkaline rocks. Their high Sr and low Y and Yb contents, as well as high Sr/Y and La/Yb ratios, are consistent with the typical adakitic rocks. The REE patterns show a large distribution of compositions, which have LREE, while HREE are buffered, along with large ratios of (La/Yb)N, as well as high values of K2O/Na2O, Mg#, Cr, and Ni, all of which imply the partial melting of a delaminated lower crust, without obvious fractional crystallization during the magma ascending and emplacement. This study suggests that, with the closure of the Bangonghu–Nujiang Tethys Ocean Basin, the post-collisional extension of the north Lhasa block will have started no later than ca. 114–116 Ma. Combined with the previous studies, our new data demonstrates that the partial melting of the delaminated lower crust, in a post-collisional setting, may be the main mechanism responsible for the ca. 116–82 Ma adakitic magmatism in the north Lhasa block. Full article
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15 pages, 4673 KiB  
Article
Redetermination of the Zalantun Group in the ARong Qi Area of Da Hinggan Mountains (Northeastern China): Evidence from Petrology, Geochronology and Geochemistry
by Datian Wu, Zhumin Li, Junchao Lv, Jia Xu and Guanglong Shu
Minerals 2022, 12(2), 197; https://0-doi-org.brum.beds.ac.uk/10.3390/min12020197 - 03 Feb 2022
Cited by 2 | Viewed by 1338
Abstract
The Da Hinggan Mountains are an important area in the tectonic evolution of the Central Asian Orogenic Belt (CAOB), and there are disputes over the closure time of the Paleo-Asian Ocean and the amalgamation spatiotemporal relationship between the Ergun-Hinggan Massif and the Songnun [...] Read more.
The Da Hinggan Mountains are an important area in the tectonic evolution of the Central Asian Orogenic Belt (CAOB), and there are disputes over the closure time of the Paleo-Asian Ocean and the amalgamation spatiotemporal relationship between the Ergun-Hinggan Massif and the Songnun Massif. The geochronology and geochemistry of the Late Cambrian-Late Silurian volcanic rock assemblages in the ARong Qi area at the eastern margin of the Da Hinggan Mountains are studied in this paper. The results suggest that the U-Pb zircon ages of the Late Cambrian, Late Ordovician and Late Silurian volcanic rock assemblages are 507.5 ± 1.0 Ma, 456.2 ± 1.0 Ma, 446.1 ± 0.95 Ma and 423.3 ± 1.4 Ma, respectively. The Late Cambrian-Late Silurian volcanic rocks are quasi-aluminous-peraluminous, belonging to calc-alkaline-shoshonite series, which is rich in HREE but has insignificant europium anomalies. There are abundant large ion lithophile elements (LILE) in the rock, and remarkable Nb, Ta and Ti negative anomalies. The previous data and the current study indicate that a continental margin arc tectonic setting existed in the ARong Qi-Zalantun region during the Early Paleozoic, which is inferred to be the product of the subduction-accretion-amalgamation of the plates along the eastern margin of the Ergun Massif during the Early Paleozoic. Full article
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21 pages, 16015 KiB  
Article
Geochemical Insights from Clinopyroxene Phenocrysts into the Magma Evolution of an Alkaline Magmatic System from the Sanshui Basin, South China
by Peijia Chen, Nianqiao Fang and Xiaobo Yuan
Minerals 2021, 11(11), 1295; https://0-doi-org.brum.beds.ac.uk/10.3390/min11111295 - 22 Nov 2021
Cited by 10 | Viewed by 2223
Abstract
The Sanshui Basin is located at the northern continental margin of the South China Sea and characterized by a continental rift basin. The bimodal volcanic rocks in Sanshui Basin record the early Cenozoic magmatic activity in the South China Block, but the magmatic [...] Read more.
The Sanshui Basin is located at the northern continental margin of the South China Sea and characterized by a continental rift basin. The bimodal volcanic rocks in Sanshui Basin record the early Cenozoic magmatic activity in the South China Block, but the magmatic evolution that produced the bimodal volcanic rocks is poorly understood. Clinopyroxenes in bimodal volcanic rocks in the Sanshui Basin provide an opportunity to investigate magma during magma ascent. In this work, we classified nine types of clinopyroxene phenocrysts according to composition and texture in cogenetic basalt-trachyandesite-comenditic trachyte, while the composition of unzoned clinopyroxene have an evolution sequence of diopside-hedenbergite-aegirine along with an increase in trace element contents with a decrease of Mg#, indicating that the genesis of clinopyroxene was dominated by fractional crystallization in a closed magma system. However, the clinopyroxenes with reversed zoning and multiple zoning record the process of magma mixing and recharge indicating an open magma system. While fractional crystallization is the dominant process, magma mixing, recharge, and crystal settling were also found to influence magma evolution. Thermobarometric calculations showed that clinopyroxene crystallized a several structural levels in the crust during magma ascent. In this study, we established a magma plumbing system that provides new constraints for the magma evolution in the Sanshui Basin. Full article
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