Temporal and spatial heterogeneity of the Ailaoshan–Song Ma–Song Chay ophiolitic mélange, and its significance on the evolution of Paleo-Tethys

• Autorzy: Lin Wei , Liu Fei , Wang Ying , Meng Lingtong , Faure Michel , Chu Yang , Nguyen Vuong Van , Wu Qinying , We Wei , Thu Hoai Luong Thi , Vu Tich Van
• Konferencja: Western Tethys meets Eastern Tethys - geodynamical, palaeoceanographical and palaeobiogeographical events : Second Symposium of the International Geoscience Programme IGCP 710 : 28th August - 3rd September, 2023, Kraków, Poland : abstract book
• Języki publikacji: EN

Abstrakty

EN

The ophiolite is the direct evidence to restore the oceanic evolution, and it is used to identify the convergence boundary of the plates. Compared with ophiolite, ophiolitic mélange, especially its matrix, contains more information about the evolution of ocean. The evolution of eastern Paleo-Tethys, between the South China and Indochina blocks, recorded the whole process of rifting from Gondwana and their northward migration and convergence. To understand the tectonic implications from matrix of ophiolitic mélange, the Mesozoic Paleo-Tethys Ailaoshan–Song Ma–Song Chay suture zone located in the North Vietnam–Southeast Yunnan region acts as an ideal study area. Based on the structural geology, we reviewed previous zircon U-Pb dating and Lu-Hf isotopic analyses on the detrital zircon from the Ailaoshan–Song Ma–Song Chay ophiolitic mélange. Accordingly, we subdivide the matrix of these ophiolitic mélange into four parts (M1, M2, M3, and M4; Fig. 1). M1 is mainly located in the middle segment of the Ailaoshan–Song Ma belt. It shows age peaks of 440 Ma and 960 Ma with εHf(t) values of −19.6 ~ +10.3. M2 is mainly located in the NW segment of the Ailaoshan–Song Ma belt, showing a dominant age peak of ~260 Ma. Particularly, it has εHf(t) values of −28.9 ~ +8.1. M3 is mainly located in the SE segment of the Ailaoshan–Song Ma belt, showing the peaks at ~250 Ma, 440 Ma, and 960 Ma with εHf(t) values of −21.9 ~ +10.1. M4 is mainly located in the Song Chay belt, showing the peaks at ~310 Ma, 470 Ma, 610 Ma, 770 Ma, and 965 Ma with εHf(t) values of −28.2 ~ +10.8. The geochronological data of the detrital zircon from the matrix of the Ailaoshan– Song Ma–Song Chay ophiolitic mélange zone, documents a temporal heterogeneity between the M1, M2, M3, and M4 units, which formed at 310–270 Ma, 265–250 Ma, 245–240 Ma, and 310–255 Ma, respectively. The different components and provenances of each unit reflect a strike-parallel heterogeneity (Fig. 1). The M1 unit was mainly sourced from the Paleozoic sedimentary rocks of the Indochina Block (IB). The main provenance for the M2 unit is Emeishan Large Igneous Province (ELIP). The magmatic arc developed in the IB provided the materials for the M3 unit, and the detrital materials of the M4 were mainly sourced from the South China Block (SCB) (Fig. 1). The Cenozoic strike-slip deformation led to an inverted geometry of the M1, M2, and M3 units, accounting for a strike-perpendicular heterogeneity straight to the strike of the orogenic belt. The temporal, strike-parallel, and strike-perpendicular heterogeneity help us to decipher the tempo-spatial evolution of the Paleo-Tethys. The M1, M2, M3, and M4 units contain information from different evolutionary stages, likely recording the comprehensive history of the ancient oceanic basin. Importantly, our results demonstrate that both the active continental margin of the IB and the passive continental margin of the SCB acted as provenance sources that supplied significant amount of detrital material in the ophiolitic mélange matrix, indicating that the Paleo-Tethys Ocean was a “narrow” or “limited” ocean rather than the archipelagic ocean proposed before.

Słowa kluczowe

EN

Tethys; heterogeneity; Vietnam

PL

tetyda; Wietnam; niejednorodność

• Wydawca: Wydawnictwa AGH ; Stowarzyszenie Naukowe im. Stanisława Staszica
• Czasopismo: Geotourism / Geoturystyka
• Rocznik: 2023
• Tom: nr 1-2 (72-73)
• Strony: 42--43
• Opis fizyczny: rys.

Twórcy

autor

Lin Wei

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

Liu Fei

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
• Wuhan Center of China Geological Survey (Central South China Innovation Center for Geosciences), Wuhan 430205, China

autor

Wang Ying

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

Meng Lingtong

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

Faure Michel

• Institut des Sciences de la Terre d’Orléans, UMR CNRS 7327, Université d’Orléans, 45067 Orléans Cedex 2, France

autor

Chu Yang

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

Nguyen Vuong Van

• University of Science, Vietnam National University, Hanoi, Viet Nam

autor

Wu Qinying

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

We Wei

• State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Innovation Academy of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
• College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

autor

Thu Hoai Luong Thi

• University of Science, Vietnam National University, Hanoi, Viet Nam

autor

Vu Tich Van

• University of Science, Vietnam National University, Hanoi, Viet Nam

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).