Vietnam Academy of Science and Technology

Project's information

Project's title	Studying to determine the structural features, magmatic activity, and crust evolution of the continental margin of Southeast Vietnam based on the interpretation of seismic, gravity, and magnetic data
Project’s code	VAST06.01/21-22
Research hosting institution	Institute of Marine Geology and Geophysics
Project leader’s name	Nguyen Nhu Trung
Project duration	01/01/2021 - 31/12/2022
Project’s budget	600 million VND
Classify	Grade A
Goal and objectives of the project	Unraveling structural features, intrusive magmatic activity - eruption and the Earth crust evolution in the continental margin of Southeast Vietnam
Main results	Theoretical results: - The project has built a set of atlas of crustal structural elements in the southeast region of the East Vietnam Sea at the scale of 1:500,000, including a map of sedimentary basement depth; an Earth crust thickness map; a map of the fault system; a map of magma system intruding and erupting; a map of the earth's crust structure; Model of crustal evolution; and two profiles of the earth's crust structure. - Based on the obtained research results, the structural features of the earth's crust have been determined and classified into five structural domains, including stretching continental crust, with a crystalline crust thickness of 20-24 km; The strong stretching continental crust, with a crystalline crust thickness of 15-20 km; The thinly beveled continental crust, with a crystalline crust thickness of 10-15 km; Ultrathin crust (Continental - Oceanic transitional crust), with a crystalline crust thickness of 6-10 km; And oceanic crust, with a basalt crust thickness of 4-6 km. - Research results have determined that magmatic activity post-East Sea rifting occurs quite strongly in the South East Sea of Vietnam. - Proposing a model of sea opening of the Southwest sub-basin in the form of a symmetrical propagating extension crust. The continental margin of eastern Vietnam belongs to the rich volcanic rift continental margin. Applied results: Determining the model of the Earth's crust structure and the characteristics of magma activity post-rift is essential in forecasting, prospecting, and exploring for oil, gas, gas hydrate, and solid minerals.
Novelty and actuality and scientific meaningfulness of the results	- Proposing a complex of methods for interpreting gravity data with high efficiency and reliability in studying the structure of the Earth's crust. - For the first time, specific criteria of deep structural features were proposed to build a map of the crust structure for the East Sea, including five structural regions: stretching continental crust, firm stretching continental crust, thin-beveled continental crust, ultrathin crust (continent-oceanic transition crust) and oceanic crust. - Proposing a model of the sea opening of the Southwest sub-basin under the symmetrical propagating extension crust model and continental margin of East Vietnam belongs to volcanic-rich spreading continental margin sea.
Products of the project	- Scientific papers in referred journals (list): + Trung Nguyen Nhu, Nam Bui Van & Kha Tran Van (2023) Three-dimensional direct gravity inversion for Moho and basement depths of the Tuchinh-Vungmay basin, offshore southeast Vietnam, incorporating a lithosphere thermal gravity anomaly correction, Geocarto International, 38:1, DOI: 10.1080/10106049.2023.2178522. + Trung Nhu Nguyen, Kha Van Tran, Nam Van Bui, 2022. Efcient setup of initial model for solving 2D gravity anomaly inverse problem based on the normalized full gradient method. Marine Geophysical Research (2022) 43:39 https://doi.org/10.1007/s11001-022-09504-x (thuộc danh mục SCI) + Nguyen Nhu Trung, Tran Van Kha, Bui Van Nam, 2022. Determination of vertical derivative of gravity anomalous by upward continuation and Taylor series transform methods: application to the Southwest sub-basin of the East Vietnam Sea. Vietnam Journal of Marine Science and Technology 2022, 22(2) 1–10. + Nguyen Nhu Trung, Tran Van Kha, Bui Van Nam, 2021. Determine the initial model for solving 2D gravity anomaly inversion problem by normalized full gradient method. Proceedings of the 14th SEGJ International Symposium, https://doi.org/10.1190/segj2021-038.1 - Technological products: 1) Basement depth map (1:500,000 scale); 2) Map of the distribution of intrusive and erupting magma systems (scale 1:500,000); 3) Earth crust thickness map (scale 1:500,000); 4) Map of fault system (scale 1:500,000); 5) Two crustal structure profiles (1:500,000 scale); 6) Deep crust structure map and crustal evolution model, scale 1:500,000.
Research area	- General Department of Geology and Natural Resources of Vietnam, Ministry of Natural Resources and Environment; - General Administration of Seas and Islands, Ministry of Natural Resources and Environment; - Petroleum Corporation.
Recommendations	The research content of the topic should be extended to apply to the entire East Sea region.
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