tailieunhanh - Tectonic evolution of the Red river basin and adjacent area (Vietnam) in Cenozoic era

This paper, we will clarify this problem by analyzing tectonic events observed in seismic sections of the RRB and structural-tectonic data collected from numerous field trips and outcrops surounding Tonkin Gulf and some islands. | Vietnam Journal of Marine Science and Technology 2023 23 4 345 359 Vietnam Academy of Science and Technology Vietnam Journal of Marine Science and Technology journal homepage jmst Tectonic evolution of the Red river basin and adjacent area Vietnam in Cenozoic era Phung Van Phach1 2 Le Duc Anh1 Nguyen Thi Hong Hanh2 3 V. V. Golozubov4 Kasatkin4 S. 1 Institute of Marine Geology and Geophysics VAST Vietnam 2 Graduate University of Science and Technology VAST Vietnam 3 Colledge of Oceanic and Atmospheric Sciences Ocean University of China Qingdao China 4 Far East Geological Institute FEGI FEB RAS Russia Received 17 July 2023 Accepted 23 September 2023 ABSTRACT Based on the structural and tectonophysic analysis of data collected from outcrops around Tonkin Gulf and the results of analysis of seismic sections of the Red River basin the four main successive tectonic phases with specific paleostress fields since the beginning of the Cenozoic era have been established. The first middle Eocene-early Miocene 45 My tectonic phase with sub-latitudinal compression and sub- longitudinal extension was accompanied by large-scale sinistral displacement of the Red river fault the extension centers of the Red river basin and seafloor spreading of East Vietnam Sea. The second middle-late of middle Miocene My tectonic phase with sub-longitudinal compression and sub-latitudinal extension has created a local depocenter N-S orientation right-lateral strike-slip of the Red river fault and first inversion of the basin. The third late Miocene My BP tectonic phase with NE-SW compression has caused a strong inversion in the Red river basin with strong uplift of some blocks and significant shrinkage of the RRB up to 15 20 . The fourth Quaternary-to-Recent tectonic phase with NW- SE compression and NE-SW extension appears in an appearance of the hydraulic system offset the recent grabens of NW-SE direction the earthquakes and GPS data. Formation and