http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/54 Tue, 19 May 2026 13:41:22 GMT 2026-05-19T13:41:22Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/214 Late Eocene metamorphism and ductile deformation age of Con Voi range, the Red River shear zone: evidence from the garnet Sm/Nd dating Nguyen, Van Vuong Con Voi range in Vietnam was a southeastward continuity of the Red River Ailaoshan tertiary shear zone, a boundary between Indochina and south China blocks during the southeastward extrusion of Indochina block. It composed of high grade metamorphic and strongly deformed rocks with various protoliths. The foliation and schistosity folded to produce a large antiform structure during the late phase of ductile deformation and exhumation. Together with the Ailaoshan, Diancangshan, Con Voi range suffered from an intensively sheared and metamorphosed during the collision of Indian with Eurasian plates. The published radiochronological data indicated that the cooling age took place from 28 to 17 m.y. (millions years). Those data did not reflect the timing of peak metamorphic event and associated ductile deformation. New Sm/Nd isochron age on single garnet extracted from biotite-garnet-silimanite bearing gneiss rock within Con Voi range evidenced that the timing of metamorphic culmination and ductile deformation occurred as early as c.a 36 m.y. ago. This implied that the earliest stage of deformation along the Red River-Ailaoshan shear zone could be at least absorbed partially by the opening of Bac Bo basin. Mon, 01 Jan 2007 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/214 2007-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/212 Mechanism of forming the Dien Bien basin Chu, Van Ngoi; Luong, Thi Thu Hoai The Dien Bien basin in the Northwest of Vietnam is the largest one of the pull-apart basins related to the Dien Bien - Lai Chau fault zone. This basin, orientated from the north to the south, is 21km long, 6-8km wide and rhomboidal in shape. The process of forming this basin is related closely to the activities of the Dien Bien - Lai Chau fault zone in Neotectonic time. On analyzing information concerning the kinematics of the Dien Bien - Lai Chau fault zone, the geological structure and the sediments of the basin, we suppose that the Dien Bien basin is a splay pull-apart one related to the movement of the Dien Bien - Lai Chau fault zone in Pliocen- Quaternary time. The determination of the mechanism of forming the Dien Bien basin is important to specify Neotectonic activities of the Dien Bien - Lai Chau fault zone. Mon, 01 Jan 2007 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/212 2007-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/210 Tourism carrying capacity assessment for Phong Nha - Ke Bang and Dong Hoi, Quang Binh Province Tran, Nghi; Nguyen, Thanh Lan; Nguyen, Dinh Thai; Dang, Mai; Dinh, Xuan Thanh Recently, tourism activities in Quang Binh Province have been growing rapidly, especially since the Phong Nha - Ke Bang National Park was certified as the World Natural Heritage in 2004. Among the tourist sites of Quang Binh, Phong Nha and Dong Hoi tourism centers are the two places which attract the largest numbers of visitors. The rapid but unplanned tourism activities have been creating various social and environmental concerns. If appropriate planning measures are not derived from the consideration of the carrying capacities of these sites, tourism centers will be overloaded, tourism quality will be degraded and therefore the benefit obtained from tourism activities will be reduced. This paper presents the tentative establishment of a method to calculate the environmental carrying capacities of three basic components: ecological, economic and social. As the results, the carrying capacities of several tourism activities are quantitatively evaluated for Phong Nha tourism center. The resulting carrying capacities for Phong Nha cave sightseeing, ecotourism forest hiking and cable car ridding are 43893, 1450 and 33000 visits per day respectively. With respect to the Dong Hoi tourism center, the carrying capacities of local beaches are 71000 visits per day. These estimates can be used as the preliminary benchmarks for later tourism planning of the two tourism centers: Phong Nha - Ke Bang and Dong Hoi. Mon, 01 Jan 2007 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/210 2007-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/208 Spatial organization for rational land use and environmental protection in Uong Bi Town by functional sub-areas Truong, Quang Hai Spatial or territorial organization is one of effective tools for sustainable land use. Spatial organization of land use and environmental protection by functional sub-areas is performed on the basis of comprehensive and integrated research on characteristics and differentiation laws of natural components and landscapes, socio-economic factors, the present status and trend of environmental changes as well as the structures and functions of sub-areas. Uong Bi is a national center for tourism, coal mining and thermal power production. The development of economic sectors has led to a series of urgent environmental and social problems, requiring implementation of plans and solutions for ensuring sustainable development. This paper proposes a scientific-based spatial organization of land use and environmental protection by eight functional sub-areas in the Uong Bi Town area. Mon, 01 Jan 2007 00:00:00 GMT http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/208 2007-01-01T00:00:00Z