Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran
The study area is located in Ardabil province in the northeast of Meshkinshahr city. More than 200 small and large Eocene-age dykes form outcrops in this area. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U–Pb zircon analyses yield a consistent age of 44.3 ± 1.8 Ma for the...
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MDPI AG
2022-02-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/3/309 |
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| author | Mohammad Fadaeian Ahmad Jahangiri Songjian Ao Amin Allah Kamali Wenjiao Xiao |
| author_facet | Mohammad Fadaeian Ahmad Jahangiri Songjian Ao Amin Allah Kamali Wenjiao Xiao |
| author_sort | Mohammad Fadaeian |
| collection | DOAJ |
| description | The study area is located in Ardabil province in the northeast of Meshkinshahr city. More than 200 small and large Eocene-age dykes form outcrops in this area. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U–Pb zircon analyses yield a consistent age of 44.3 ± 1.8 Ma for the dyke swarms. These dykes include tephritic, andesitic and basaltic compositions, and show enrichment in LREEs (relative to HREEs) and are characterized by enrichment in LILEs and depletion in HFSEs. Petrological observations, along with major, rare earth and trace elements geochemistry, suggest that the dykes have a shoshonitic signature. All the rocks are highly enriched in incompatible trace elements and have variable Sr–Nd isotopes. Enrichment in incompatible elements and other geochemical features for the dyke swarm rocks suggest that a metasomatized subcontinental lithospheric mantle is the magma source. The negative Nb–Ta–Ti anomalies in the rocks are comparable with the features of subduction-related magmatism and contamination with ancient crustal components. The radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr isotopic values of the rocks imply the involvement of slab terrigenous sediments and/or a continental lithosphere. Isotopically, the volcanic rocks exhibit a binary trend, representing 1–5% mixing between the primary mantle and sediment melts. Our melting models suggest that there are residual garnet + spinel in the source, which are incompatible with the partial melting of amphibole- and/or phlogopite-bearing lherzolites. The geochronological, geochemical and isotopic data for the northeast Meshkinshahr dyke swarms suggest that these Late Eocene magmas were derived from a small degree of partial melting of a subduction-metasomatized lithospheric mantle source in a post-collisional setting. |
| first_indexed | 2024-03-09T13:14:05Z |
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| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T13:14:05Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-f02f8e8ae1f941cca8131f7e2d6cd3292023-11-30T21:38:19ZengMDPI AGMinerals2075-163X2022-02-0112330910.3390/min12030309Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW IranMohammad Fadaeian0Ahmad Jahangiri1Songjian Ao2Amin Allah Kamali3Wenjiao Xiao4Department of Geology, Payame Noor University, Tehran 19395, IranDepartment of Geology, University of Tabriz, Tabriz 51664, IranState Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, ChinaResearch Center for Conservation of Culture Relics (RCCCR), Research Institute of Cultural Heritage and Tourism, Tehran 11456, IranState Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, ChinaThe study area is located in Ardabil province in the northeast of Meshkinshahr city. More than 200 small and large Eocene-age dykes form outcrops in this area. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U–Pb zircon analyses yield a consistent age of 44.3 ± 1.8 Ma for the dyke swarms. These dykes include tephritic, andesitic and basaltic compositions, and show enrichment in LREEs (relative to HREEs) and are characterized by enrichment in LILEs and depletion in HFSEs. Petrological observations, along with major, rare earth and trace elements geochemistry, suggest that the dykes have a shoshonitic signature. All the rocks are highly enriched in incompatible trace elements and have variable Sr–Nd isotopes. Enrichment in incompatible elements and other geochemical features for the dyke swarm rocks suggest that a metasomatized subcontinental lithospheric mantle is the magma source. The negative Nb–Ta–Ti anomalies in the rocks are comparable with the features of subduction-related magmatism and contamination with ancient crustal components. The radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr isotopic values of the rocks imply the involvement of slab terrigenous sediments and/or a continental lithosphere. Isotopically, the volcanic rocks exhibit a binary trend, representing 1–5% mixing between the primary mantle and sediment melts. Our melting models suggest that there are residual garnet + spinel in the source, which are incompatible with the partial melting of amphibole- and/or phlogopite-bearing lherzolites. The geochronological, geochemical and isotopic data for the northeast Meshkinshahr dyke swarms suggest that these Late Eocene magmas were derived from a small degree of partial melting of a subduction-metasomatized lithospheric mantle source in a post-collisional setting.https://www.mdpi.com/2075-163X/12/3/309dyke swarmsgeochemistryshoshoniteSr-Nd isotopeU-Pb zircon datingpost collisional magmatism |
| spellingShingle | Mohammad Fadaeian Ahmad Jahangiri Songjian Ao Amin Allah Kamali Wenjiao Xiao Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran Minerals dyke swarms geochemistry shoshonite Sr-Nd isotope U-Pb zircon dating post collisional magmatism |
| title | Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran |
| title_full | Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran |
| title_fullStr | Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran |
| title_full_unstemmed | Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran |
| title_short | Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran |
| title_sort | geochemistry and petrogenesis of shoshonitic dyke swarm in the northeast of meshkinshahr nw iran |
| topic | dyke swarms geochemistry shoshonite Sr-Nd isotope U-Pb zircon dating post collisional magmatism |
| url | https://www.mdpi.com/2075-163X/12/3/309 |
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