SUMMARY

Some outlines of the mantle and lithosphere structures in Southeast Asia

Cao Đình Triều, Mai Xuân Bách, Phạm Nam Hưng

In this paper, the authors present some new interpretations on the mantle and lithosphere structures on the basis of the P wave tomography and gravity data. The obtained results have shown that:

1/ Structure of the mantle in SE Asia is characterized rather knotty. Except for vertical layering there still is the horizontal change of the P wave velocity – minimum P wave velocity structures. Perhaps, these structures have brought out from the melting of mantle materials. This phenomenon can be explained by the strong mélange of mantle materials from outside into the SE Asia.

2/ The boundary zone of SE Asia (the collision areas surrounding SE Asia) is characterized by the relative pinching out of the lithosphere (with the depth from 70 to 110 km) and can be divided into the following blocks: 1/ Myanmar (Indo-Burma - 80-100 km); 2/ Nicobar (Andaman Sea - 70-75 km); 3/ Sumatra (75-95 km); 4/ Java (80-95 km); 5/ Timor (95-110 km); 6/ Halmahera (95-105 km); 7/ Sulu Sea (90-110 km); 8/ Sulawesi (70-90 km); 9/ Philippines (85-110 km); 10/ Manila (95-105 km); 11/ Taiwan (80-90 km); 12/ Batan (80-90 km).

3/ The SE Asia intraplate is characterized by very complicated structures of the lithosphere and can be divided into the following blocks: 1/ Sino-Burma (90-100 km); 2/ Shan Thai (95-105 km); 3/ Battani (85-95 km); 4/ Indochina (80-105 km); 5/ Malaysia (85-95 km); 6/ Natuna (100-105 km); 7/ South China - North Việt Nam (85-100 km); 8/ Hoàng Sa (75-85 km); 9/ Centre of Vietnamese East Sea (65-80 km); 10/ Trường Sa (90-110 km); 11/ North Kalimantan (95-100 km); 12/ / Kalimantan (90-95 km); 13/ Barito (85-90 km); 14/ Banda (65-90 km); 15/ Sulu (Sulu Sea and Sulawesi Sea, 60-90 km).

Người biên tập: GS.TS Trần Văn Trị.