Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting
To better understand geodynamic implications for the transition from adakitic to non-adakitic magmatism in a continental collision setting, an integrated study including zircon U–Pb ages and whole-rock geochemistry was performed for the Gahai and Erhai granitoid intrusions within the Qilian Block. T...
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Frontiers Media S.A.
2022-07-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.967003/full |
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| author | Jiao-Long Zhao Wan-Feng Chen Jin-Rong Wang Qing-Yan Tang Er-Teng Wang Yi-Qiao Fu |
| author_facet | Jiao-Long Zhao Wan-Feng Chen Jin-Rong Wang Qing-Yan Tang Er-Teng Wang Yi-Qiao Fu |
| author_sort | Jiao-Long Zhao |
| collection | DOAJ |
| description | To better understand geodynamic implications for the transition from adakitic to non-adakitic magmatism in a continental collision setting, an integrated study including zircon U–Pb ages and whole-rock geochemistry was performed for the Gahai and Erhai granitoid intrusions within the Qilian Block. The ca. 450–428 Ma Gahai biotite granite and Erhai muscovite-bearing granite are peraluminous S-type granites with adakitic geochemical characteristics, and have low Mg# (41.2–31.7) and εNd(t) (−10.8 to −6.5) values with two–stage Nd model ages of 2.05–1.72 Ga, implying their derivation almost entirely from an ancient crustal source under a thickened lower crust condition. The geochemical characteristics of the granites indicate that the Gahai and Erhai S-type granites were derived from partial melting of meta-greywacke and meta-pelite sources, respectively. In comparison, the ca. 415 Ma Gahai granodiorite belongs to metaluminous I-type granitoid and has low Sr/Y ratios as well as high Y and heavy rare Earth element (REE) concentrations, with nearly flat heavy REE patterns, implying a shallow source region. The granodiorites were most likely generated by partial melting of a K-rich basaltic magma source, with some contributions from mantle-derived melts. Synthesized data from this and previous studies suggest that the ca. 450–415 Ma Gahai and Erhai granitoids within the Qilian Block were generated in a post-collisional extensional regime triggered by the break-off of the northward subducting South Qilian Ocean slab beneath the Qilian Block. The geochemical transition from adakitic to non-adakitic intermediate-acidic magmas indicated that the thickened continental crust of the Qilian Block had experienced significant extension and thinning after ca. 420 Ma. |
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| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-10T09:31:19Z |
| publishDate | 2022-07-01 |
| publisher | Frontiers Media S.A. |
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| spelling | doaj.art-b0f0e84bd03e446f8944bfdcd62e17922022-12-22T01:54:20ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-07-011010.3389/feart.2022.967003967003Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional settingJiao-Long ZhaoWan-Feng ChenJin-Rong WangQing-Yan TangEr-Teng WangYi-Qiao FuTo better understand geodynamic implications for the transition from adakitic to non-adakitic magmatism in a continental collision setting, an integrated study including zircon U–Pb ages and whole-rock geochemistry was performed for the Gahai and Erhai granitoid intrusions within the Qilian Block. The ca. 450–428 Ma Gahai biotite granite and Erhai muscovite-bearing granite are peraluminous S-type granites with adakitic geochemical characteristics, and have low Mg# (41.2–31.7) and εNd(t) (−10.8 to −6.5) values with two–stage Nd model ages of 2.05–1.72 Ga, implying their derivation almost entirely from an ancient crustal source under a thickened lower crust condition. The geochemical characteristics of the granites indicate that the Gahai and Erhai S-type granites were derived from partial melting of meta-greywacke and meta-pelite sources, respectively. In comparison, the ca. 415 Ma Gahai granodiorite belongs to metaluminous I-type granitoid and has low Sr/Y ratios as well as high Y and heavy rare Earth element (REE) concentrations, with nearly flat heavy REE patterns, implying a shallow source region. The granodiorites were most likely generated by partial melting of a K-rich basaltic magma source, with some contributions from mantle-derived melts. Synthesized data from this and previous studies suggest that the ca. 450–415 Ma Gahai and Erhai granitoids within the Qilian Block were generated in a post-collisional extensional regime triggered by the break-off of the northward subducting South Qilian Ocean slab beneath the Qilian Block. The geochemical transition from adakitic to non-adakitic intermediate-acidic magmas indicated that the thickened continental crust of the Qilian Block had experienced significant extension and thinning after ca. 420 Ma.https://www.frontiersin.org/articles/10.3389/feart.2022.967003/fullearly-middle paleozoic magmatismadakitic S-type granitenon-adakitic I-type granodioriteslab break-offqilian block |
| spellingShingle | Jiao-Long Zhao Wan-Feng Chen Jin-Rong Wang Qing-Yan Tang Er-Teng Wang Yi-Qiao Fu Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting Frontiers in Earth Science early-middle paleozoic magmatism adakitic S-type granite non-adakitic I-type granodiorite slab break-off qilian block |
| title | Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting |
| title_full | Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting |
| title_fullStr | Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting |
| title_full_unstemmed | Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting |
| title_short | Petrogenesis of early–middle paleozoic granitoids in the qilianblock, northwest China: Insight into the transition from adakitic to non-adakitic magmatism in a post-collisional extensional setting |
| title_sort | petrogenesis of early middle paleozoic granitoids in the qilianblock northwest china insight into the transition from adakitic to non adakitic magmatism in a post collisional extensional setting |
| topic | early-middle paleozoic magmatism adakitic S-type granite non-adakitic I-type granodiorite slab break-off qilian block |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.967003/full |
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