Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau
Abstract The possibility that the Proto‐Tethys Ocean may have undergone intra‐oceanic subduction during ocean closure remains poorly constrained due to a lack of geological evidence for a mature intra‐oceanic arc. Here we present new geochemical and geochronological data for potential arc‐related vo...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2024-03-01
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| Series: | Earth and Space Science |
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| Online Access: | https://doi.org/10.1029/2023EA002985 |
| _version_ | 1797218190529396736 |
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| author | Changlei Fu Zhen Yan Jonathan C. Aitchison Wenjiao Xiao Solomon Buckman Bingzhang Wang |
| author_facet | Changlei Fu Zhen Yan Jonathan C. Aitchison Wenjiao Xiao Solomon Buckman Bingzhang Wang |
| author_sort | Changlei Fu |
| collection | DOAJ |
| description | Abstract The possibility that the Proto‐Tethys Ocean may have undergone intra‐oceanic subduction during ocean closure remains poorly constrained due to a lack of geological evidence for a mature intra‐oceanic arc. Here we present new geochemical and geochronological data for potential arc‐related volcanic rocks adjacent to the accretionary complex and forearc basin in the North Qaidam collisional belt, northern Tibetan Plateau. The volcanic rocks are dominated by foliated basalt, andesite, tuff, and minor dacite with zircon U‐Pb ages ranging from 517 to 497 Ma. They show distinctive geochemical characteristics and can be subdivided into three groups: island‐arc intermediate‐basic volcanic rocks, back‐arc basin basalts (BABB), and dacites with intra‐oceanic arc affinity. The island‐arc volcanic rocks have variable εNd(t) values (+1.6 to +7.5) that decrease northward and were generated by partial melting of depleted mantle wedge modified by hydrous fluid and sediment melt. The BABBs have high εNd(t) values (+5.3 to +6.6) and formed through the melting of MORB‐like mantle, whereas the nearby dacites have positive εNd(t) values (+1.9 to +3.6) similar to the surrounding island‐arc volcanic rocks and were derived from partial melting of intra‐oceanic arc crust as a result of BABB underplating. Integrated analysis of the spatial‐temporal distribution of these volcanic rocks and the reconstructed intra‐oceanic arc‐trench system confirms the existence of the earliest Phanerozoic intra‐oceanic arc formed in response to north‐directed intra‐oceanic subduction. This unrecognized subduction of the Proto‐Tethys Ocean in the North Qaidam belt initiated at ca. 530 Ma, matured ca. 520 Ma, and terminated by ca. 480 Ma. |
| first_indexed | 2024-04-24T12:13:49Z |
| format | Article |
| id | doaj.art-a71ae9aacffc4fce8dd1c9099e84dd05 |
| institution | Directory Open Access Journal |
| issn | 2333-5084 |
| language | English |
| last_indexed | 2024-04-24T12:13:49Z |
| publishDate | 2024-03-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Earth and Space Science |
| spelling | doaj.art-a71ae9aacffc4fce8dd1c9099e84dd052024-04-08T08:47:01ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842024-03-01113n/an/a10.1029/2023EA002985Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan PlateauChanglei Fu0Zhen Yan1Jonathan C. Aitchison2Wenjiao Xiao3Solomon Buckman4Bingzhang Wang5SinoProbe Laboratory Institute of Geology Chinese Academy of Geological Sciences Beijing ChinaSinoProbe Laboratory Institute of Geology Chinese Academy of Geological Sciences Beijing ChinaSchool of Earth and Environmental Sciences University of Queensland St Lucia QLD AustraliaXinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi ChinaGeoQuEST Research Centre School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW AustraliaBureau of Geological Exploration and Development of Qinghai Province Xining ChinaAbstract The possibility that the Proto‐Tethys Ocean may have undergone intra‐oceanic subduction during ocean closure remains poorly constrained due to a lack of geological evidence for a mature intra‐oceanic arc. Here we present new geochemical and geochronological data for potential arc‐related volcanic rocks adjacent to the accretionary complex and forearc basin in the North Qaidam collisional belt, northern Tibetan Plateau. The volcanic rocks are dominated by foliated basalt, andesite, tuff, and minor dacite with zircon U‐Pb ages ranging from 517 to 497 Ma. They show distinctive geochemical characteristics and can be subdivided into three groups: island‐arc intermediate‐basic volcanic rocks, back‐arc basin basalts (BABB), and dacites with intra‐oceanic arc affinity. The island‐arc volcanic rocks have variable εNd(t) values (+1.6 to +7.5) that decrease northward and were generated by partial melting of depleted mantle wedge modified by hydrous fluid and sediment melt. The BABBs have high εNd(t) values (+5.3 to +6.6) and formed through the melting of MORB‐like mantle, whereas the nearby dacites have positive εNd(t) values (+1.9 to +3.6) similar to the surrounding island‐arc volcanic rocks and were derived from partial melting of intra‐oceanic arc crust as a result of BABB underplating. Integrated analysis of the spatial‐temporal distribution of these volcanic rocks and the reconstructed intra‐oceanic arc‐trench system confirms the existence of the earliest Phanerozoic intra‐oceanic arc formed in response to north‐directed intra‐oceanic subduction. This unrecognized subduction of the Proto‐Tethys Ocean in the North Qaidam belt initiated at ca. 530 Ma, matured ca. 520 Ma, and terminated by ca. 480 Ma.https://doi.org/10.1029/2023EA002985intra‐oceanic arcintra‐oceanic subductionsubduction polarityProto‐Tethys OceanNorth Qaidam collisional belt |
| spellingShingle | Changlei Fu Zhen Yan Jonathan C. Aitchison Wenjiao Xiao Solomon Buckman Bingzhang Wang Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau Earth and Space Science intra‐oceanic arc intra‐oceanic subduction subduction polarity Proto‐Tethys Ocean North Qaidam collisional belt |
| title | Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau |
| title_full | Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau |
| title_fullStr | Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau |
| title_full_unstemmed | Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau |
| title_short | Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau |
| title_sort | subduction within the proto tethys ocean revealed by recognition of the earliest phanerozoic intra oceanic arc northern tibetan plateau |
| topic | intra‐oceanic arc intra‐oceanic subduction subduction polarity Proto‐Tethys Ocean North Qaidam collisional belt |
| url | https://doi.org/10.1029/2023EA002985 |
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