Gang Yang , Juan Zhang , Hong-fu Zhang , An-Ping Chen , A-Bing Lin
{"title":"造山带陆壳向深部地幔的再循环:来自北秦岭造山带白花杂岩锆石U-Pb-Hf-O和全岩Mg-Fe同位素的约束","authors":"Gang Yang , Juan Zhang , Hong-fu Zhang , An-Ping Chen , A-Bing Lin","doi":"10.1016/j.chemgeo.2025.122982","DOIUrl":null,"url":null,"abstract":"<div><div>Mafic magmatism in the orogenic belt acts as an invaluable repository for exploring the intricate dynamics of crust-mantle interactions. It meticulously preserves measurable signatures of recycled oceanic lithosphere and subducted continental materials within the orogenic mantle domains. This study employs an integrated approach, combining zircon U-Pb-Hf-O isotopic analyses and whole-rock geochemistry to investigate the Baihua metamorphosed magmatic complex in the North Qinling orogen, with the aim of deciphering the crustal recycling mechanisms.</div><div>Zircon U-Pb dating indicates the emplacement of mafic magma occurred between 441.6 ± 2.9–428.3 ± 2.2 Ma. Amphibolites have arc-like trace element signatures, tholeiitic differentiation trends, and a dual-source origin from mantle-derived melts (ε<sub>Hf</sub>(t): +0.10 to +12, δ<sup>18</sup>O: 5.61 ± 0.05 ‰) and inherited crustal components (ε<sub>Hf</sub>(t): −10.9 to −8.6, δ<sup>18</sup>O: 5.75 ± 0.15 ‰), highlighting ancient crustal components in the mantle source. Their δ<sup>26</sup>Mg values range from −0.28 ± 0.01 ‰ to −0.12 ± 0.01 ‰, and δ<sup>56</sup>Fe values from 0.06 ± 0.02 ‰ to 0.31 ± 0.04 ‰, likely due to mid-lower continental crust involvement in the mantle source.</div><div>Mafic microgranular enclaves (MMEs) and host diorites also have arc-like trace element signatures but show calc-alkaline affinities. They have uniform ε<sub>Hf</sub>(t) values (−0.1 to +5.1) and δ<sup>18</sup>O values from 4.51 ‰ to 6.77 ‰, suggesting a cognate cumulate-residual melt relationship during magma evolution. Their δ<sup>26</sup>Mg values range from −0.66 ‰ to −0.17 ‰ and δ<sup>56</sup>Fe values from 0.11 ‰ to 0.17 ‰. Light δ<sup>26</sup>Mg values suggest carbonate metasomatism, and variable Fe isotope signatures are due to fractional crystallization of olivine, clinopyroxene and ilmenite.</div><div>Consequently, the ∼433 Ma mafic rock suite likely originated from lithospheric mantle metasomatized by ancient mid-lower crustal and carbonate-rich melts. These mafic rocks preserve a geochemical signature of continental crust recycled into the deep mantle.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"693 ","pages":"Article 122982"},"PeriodicalIF":3.6000,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Recycling of continental crust into the deep mantle in orogens: Constraints from zircon U-Pb-Hf-O and whole-rock Mg-Fe isotopes of Baihua complex, North Qinling Orogen\",\"authors\":\"Gang Yang , Juan Zhang , Hong-fu Zhang , An-Ping Chen , A-Bing Lin\",\"doi\":\"10.1016/j.chemgeo.2025.122982\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Mafic magmatism in the orogenic belt acts as an invaluable repository for exploring the intricate dynamics of crust-mantle interactions. It meticulously preserves measurable signatures of recycled oceanic lithosphere and subducted continental materials within the orogenic mantle domains. This study employs an integrated approach, combining zircon U-Pb-Hf-O isotopic analyses and whole-rock geochemistry to investigate the Baihua metamorphosed magmatic complex in the North Qinling orogen, with the aim of deciphering the crustal recycling mechanisms.</div><div>Zircon U-Pb dating indicates the emplacement of mafic magma occurred between 441.6 ± 2.9–428.3 ± 2.2 Ma. Amphibolites have arc-like trace element signatures, tholeiitic differentiation trends, and a dual-source origin from mantle-derived melts (ε<sub>Hf</sub>(t): +0.10 to +12, δ<sup>18</sup>O: 5.61 ± 0.05 ‰) and inherited crustal components (ε<sub>Hf</sub>(t): −10.9 to −8.6, δ<sup>18</sup>O: 5.75 ± 0.15 ‰), highlighting ancient crustal components in the mantle source. Their δ<sup>26</sup>Mg values range from −0.28 ± 0.01 ‰ to −0.12 ± 0.01 ‰, and δ<sup>56</sup>Fe values from 0.06 ± 0.02 ‰ to 0.31 ± 0.04 ‰, likely due to mid-lower continental crust involvement in the mantle source.</div><div>Mafic microgranular enclaves (MMEs) and host diorites also have arc-like trace element signatures but show calc-alkaline affinities. They have uniform ε<sub>Hf</sub>(t) values (−0.1 to +5.1) and δ<sup>18</sup>O values from 4.51 ‰ to 6.77 ‰, suggesting a cognate cumulate-residual melt relationship during magma evolution. Their δ<sup>26</sup>Mg values range from −0.66 ‰ to −0.17 ‰ and δ<sup>56</sup>Fe values from 0.11 ‰ to 0.17 ‰. Light δ<sup>26</sup>Mg values suggest carbonate metasomatism, and variable Fe isotope signatures are due to fractional crystallization of olivine, clinopyroxene and ilmenite.</div><div>Consequently, the ∼433 Ma mafic rock suite likely originated from lithospheric mantle metasomatized by ancient mid-lower crustal and carbonate-rich melts. These mafic rocks preserve a geochemical signature of continental crust recycled into the deep mantle.</div></div>\",\"PeriodicalId\":9847,\"journal\":{\"name\":\"Chemical Geology\",\"volume\":\"693 \",\"pages\":\"Article 122982\"},\"PeriodicalIF\":3.6000,\"publicationDate\":\"2025-07-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Chemical Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0009254125003729\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0009254125003729","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Recycling of continental crust into the deep mantle in orogens: Constraints from zircon U-Pb-Hf-O and whole-rock Mg-Fe isotopes of Baihua complex, North Qinling Orogen
Mafic magmatism in the orogenic belt acts as an invaluable repository for exploring the intricate dynamics of crust-mantle interactions. It meticulously preserves measurable signatures of recycled oceanic lithosphere and subducted continental materials within the orogenic mantle domains. This study employs an integrated approach, combining zircon U-Pb-Hf-O isotopic analyses and whole-rock geochemistry to investigate the Baihua metamorphosed magmatic complex in the North Qinling orogen, with the aim of deciphering the crustal recycling mechanisms.
Zircon U-Pb dating indicates the emplacement of mafic magma occurred between 441.6 ± 2.9–428.3 ± 2.2 Ma. Amphibolites have arc-like trace element signatures, tholeiitic differentiation trends, and a dual-source origin from mantle-derived melts (εHf(t): +0.10 to +12, δ18O: 5.61 ± 0.05 ‰) and inherited crustal components (εHf(t): −10.9 to −8.6, δ18O: 5.75 ± 0.15 ‰), highlighting ancient crustal components in the mantle source. Their δ26Mg values range from −0.28 ± 0.01 ‰ to −0.12 ± 0.01 ‰, and δ56Fe values from 0.06 ± 0.02 ‰ to 0.31 ± 0.04 ‰, likely due to mid-lower continental crust involvement in the mantle source.
Mafic microgranular enclaves (MMEs) and host diorites also have arc-like trace element signatures but show calc-alkaline affinities. They have uniform εHf(t) values (−0.1 to +5.1) and δ18O values from 4.51 ‰ to 6.77 ‰, suggesting a cognate cumulate-residual melt relationship during magma evolution. Their δ26Mg values range from −0.66 ‰ to −0.17 ‰ and δ56Fe values from 0.11 ‰ to 0.17 ‰. Light δ26Mg values suggest carbonate metasomatism, and variable Fe isotope signatures are due to fractional crystallization of olivine, clinopyroxene and ilmenite.
Consequently, the ∼433 Ma mafic rock suite likely originated from lithospheric mantle metasomatized by ancient mid-lower crustal and carbonate-rich melts. These mafic rocks preserve a geochemical signature of continental crust recycled into the deep mantle.
期刊介绍:
Chemical Geology is an international journal that publishes original research papers on isotopic and elemental geochemistry, geochronology and cosmochemistry.
The Journal focuses on chemical processes in igneous, metamorphic, and sedimentary petrology, low- and high-temperature aqueous solutions, biogeochemistry, the environment and cosmochemistry.
Papers that are field, experimentally, or computationally based are appropriate if they are of broad international interest. The Journal generally does not publish papers that are primarily of regional or local interest, or which are primarily focused on remediation and applied geochemistry.
The Journal also welcomes innovative papers dealing with significant analytical advances that are of wide interest in the community and extend significantly beyond the scope of what would be included in the methods section of a standard research paper.