Late Neogene structural inversion around the northern Gulf of Tonkin, Vietnam: Effects from right-lateral displacement across the Red River fault zone

Michael B.W. Fyhn, Phung V. Phach

    Research output: Contribution to journalArticleResearchpeer-review

    40 Citations (Scopus)

    Abstract

    Continental extrusion may take up much of the deformation involved in continental collisions. Major strike-slip zones accommodate the relative extrusion displacement and transfer deformation away from the collision front. The Red River fault zone (RRFZ) accommodated left- and right-lateral displacements when Indochina and South China were extruded during the Indian-Eurasian collision. The northern Song Hong basin onshore and offshore in the Gulf of Tonkin delineates the direct extension of the RRFZ and thus records detailed information on the collision-induced continental extrusion. We assess the rapidly evolving kinematics of the fault zone buried within the basin based on seismic analysis. Contrary to previous studies, we do not identify indications for latest Miocene left-lateral motion across the RRFZ. We tentatively consider the shift from left- to right-lateral motion to have occurred already during the middle Late Miocene as indicated by inversion of NE-SW-striking faults in the Bach Long Vi area. Right-lateral displacement terminated around the end of the Miocene in the Song Hong basin. However, continued inversion in the Bach Long Vi area and NNW-SSE-striking normal faulting suggests a stress regime compatible with right-lateral motion across the onshore part of the RRFZ continuing to the present. Inversion around the Bach Long Vi Island may have accommodated up to a few kilometers of right-lateral displacement between the Indochina and South China blocks. Comparable NE-SW-striking fault zones onshore may have accommodated a larger fraction of the right-lateral slip across the RRFZ, thus accounting for the restricted transfer of lateral displacement to the offshore basins.

    Original languageEnglish
    Pages (from-to)290-312
    Number of pages23
    JournalTectonics
    Volume34
    Issue number2
    DOIs
    Publication statusPublished - Feb 2015

    Keywords

    • marine seismics
    • plate tectonics
    • submarine tectonics and volcanism

    Programme Area

    • Programme Area 3: Energy Resources

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