Tectonic evolution of the southern part of Central Viet Nam and the adjacent area

Abstract

Interpretations of seismic, gravity and magnetic anomalies and structural data on the coastal zone of southern part of Central Viet Nam (SCVN) and the adjacent Tertiary basins suggest several phases in the tectonic evolution of the study region since the Late Cretaceous to Quaternary. In this paper, we try to clarify the tectonic evolution of SCVN and the adjacent continental margin. The Cretaceous – Paleocene tectonic phase commenced after cessation of the West Pacific plutonic magmatic activity that produced numerous diabases and aplite dykes of mainly sub-meridian orientation. It was characterized by N–S compression and E–W extension. The geomorphology and geology ofSE Asiawere considerably changed during the Neotectonic phases caused by collision between the Indian plate and the Eurasian continent. Two tectonic phases – Early and Late Neotectonic – are separated by a regional unconformity represented by a boundary surface between below strongly deformed strata (synrift) and above less deformed formations (post-rift). The Early Neotectonic phase was related to the left-lateral movement of the Red River Fault Zone (RRFZ) and includes two tectonic sub-phases: Eocene – Oligocene (NW–SE compression), and Oligocene – Miocene (E–W compression). Activity in the Oligocene-Miocene sub-phase gave birth to rift basins in the continental margin of the SCVN. The Late Neotectonic phase began since the RRFZ stopped left-lateral movement and the East Viet Nam (orSouth China) Sea stopped spreading. The Late Neotectonic phase is also divided into two tectonic sub-phases: Late Early Miocene (sub-meridian compression), and Late Miocene – Pliocene (NE–SW compression). The Late Miocene – Pliocene sub-phase is characterized by vertical movements that caused episodic uplifting of the onland terrains, and subsidence of the offshore Phu Khanh basin. Besides, Miocene – Pliocene-Quarternary basaltic eruptions were widespread all over the southern Indosinian terrain and the continental margin.

Neogene‐Recent Reactivation of Pre‐Existing Faults in South‐Central Vietnam, With Implications for the Extrusion of Indochina

“…The EVTZ is a large-scale transform fault inferred to be a regional, extrusion-related fault and is linked to the RRFZ (Fyhn & Phach, 2015;Fyhn et al, 2018;Leloup et al, 2001;H. P. Nguyen et al, 2012;Phach & Anh, 2018;Tapponnier et al, 1986). Several models have proposed that the EVTZ serves as the eastern boundary of the Sundaland block, and the transtensional sinistral slip along the EVTZ has been identified by some authors as the primary driving force for the opening of the EVS/SCS (Hall, 2002;Leloup et al, 1995Leloup et al, , 2001Tapponnier et al, 1986).…”

“…In summary, the basement ages of each lithospheric sector fall within the Permian and Jurassic-Cretaceous Indosinian orogeny. The bounding faults themselves are either ancient suture zones or are long-lived, largescale, lithospheric, extrusion-related faults (Kasatkin et al, 2017;Lepvrier et al, 2004Lepvrier et al, , 2008; V. V. Nguyen & Luong, 2019;Phach & Anh, 2018;T. H. Tran et al, 2014;Van et al, 2001).…”

Characterizing Peridotite Xenoliths From Southern Vietnam: Insight Into the Underlying Lithospheric Mantle

“…Major mapped faults and volcanic centers are modified from published literature (Hoang et al, 1996(Hoang et al, , 2013P. H. Nguyen et al, 2012;Phach & Anh, 2018).…”

“…(b) Map of the study area and sample collection localities. Major mapped faults and volcanic centers are modified from published literature (Hoang et al., 1996, 2013; P. H. Nguyen et al., 2012; Phach & Anh, 2018).…”

Establishing calculation method for chemical composition of primitive magma in the Cenozoic in South Central coast region and the adjacent continental shelf of Vietnam

“…Các nghiên cứu về địa chất, địa mạo và địa vật lý cho thấy hoạt động núi lửa trong giai đoạn Cenozoi muộn diễn ra trên hầu khắp Đông Nam Á bao gồm Lào, Campuchia Tây Nguyên, khu vực Nam Trung Bộ, thềm lục địa và trũng sâu Biển Đông. Dựa trên các tài liệu đã công bố về thạch học, địa hóa, tuổi các đá phun trào và cấu trúc kiến tạo [23,26,27,33,37,38,[48][49][50] tập thể tác giả đã liên kết các vị trí phun trào núi lửa và phân vùng cấu trúc khu vực ven biển và ngoài khơi Nam Trang Bộ. Theo kết quả liên kết, vùng nghiên cứu có thể chia thành hai khu vực hoạt động núi lửa chính: 1) Khu vực 1 nằm về phía bắc vùng nghiên cứu là các diện lộ phân bố đá phun trào tại các tỉnh Quảng Bình, Quảng Ngãi và Tuy Hòa; 2) Khu vực hai bao gồm thềm lục địa đông nam Việt Nam thuộc khu vực tỉnh Bình Thuận (đảo Phú Quý, cụm đảo Tro) và các tỉnh Đồng nai, tỉnh Bà Rịa-Vũng Tàu.…”