Tổng hợp tài liệu Địa Lý tham khảo cho học sinh, sinh viên.
The Cho Don lead-zinc deposits are situated at the southwest of Cho Don district, about 7 km from the centre. These deposits are sphalerite-galenitepyrite type, occured in middle Paleozoic terrigenous carbonate rocks. They are polymetallic vein type. Ore minerals consist of sphalerite, galenite, pyrite, chalcopyrite, pyrrhotite, arsenopyrite, ...
9 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 581 | Lượt tải: 0
By-products in lead-zinc ores are diversify, depending on ore types: Cho Don type - Cd, In, Ag, As, Cu, Sn, Ga ; Cho Dien type - Cd, In, Ag, Cu, Ga ; Lang Hich type - Cd, Ag ; Na Son type : Cd, Ag, Cu, Ga, REE. Detailed mineralogical investigation reveals that by-product elements are mainly associated with inclusions and isomorphous substitut...
10 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 547 | Lượt tải: 0
Potential field data usually contain noises and in the downward continuation these noises with high frequency are amplified strongly that mask all useful information of the original data. Consequently, the downward continuation maps are difficult to be interpreted. In this paper, we propose using a lineweight function (LWF) to eliminate the no...
6 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 531 | Lượt tải: 0
This paper presents results of fracture investigations in Northwest Vietnam using new inner-layer fracture analysis method and computer processing data. The fractures of sediments of different ages (from Precambrian to Quaternary) are messured and analysed. The studied results are presented by the stereograms for orientating distribution of th...
9 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 537 | Lượt tải: 0
This paper presents some preliminary results of building damage assessment due to earthquakes in Ho Chi Minh City. A methodology for urban seismic risk assessment was applied to six most typical building classes available in the 1 and 3 districts, downtown of the Ho Chi Minh City. GIS technology was used to develop a plausible earthquake scen...
10 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 584 | Lượt tải: 0
This paper presents an estimation of the velocity of the Earth’s crust in Vietnam and the Southeast Asian region, determined from the GPS data in nearly 5 years (4/2005-12/2009) at 3 sites in Vietnam (Hanoi, Hue and Ho Chi Minh city) plus more than 20 ones in Southeast Asia and other regions using GAMIT software. The horizontal velocity vecto...
12 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 638 | Lượt tải: 0
Due to high economical and technical efficiency Geotextile reinforced soil technology is presently a widely applicable solution in construction of weak earth works, slope stability structures and in prevention of earthquake acceleration. However, there were difficulties in applying this technology in Vietnam as lack of a guidance on required p...
10 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 605 | Lượt tải: 0
From 2003 to recent, drought has been occurring widely in Red River Delta. Decreasing of flow of main river system, climate change and the operation unproperly of the upper reservoirs had led to water shortage of the downstream. In addition, increasing of water demand, degradation of water quality, and drought crisis management had made drough...
5 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 753 | Lượt tải: 0
South Central Coastal provinces (including Quang Nam, Da Nang, Quang Ngai, Binh Dinh, Phu Yen, Khanh Hoa, Ninh Thuan and Binh Thuan) have an area of 40,655.7 km2 (equivalent to 12.5 % of total area of whole country). The article referred to the situation and causes for droughts in recent years. Thereby drought preventive measures are proposed...
7 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 564 | Lượt tải: 0
Researching on variation of coastal area in Cuu Long delta was based on chain dataset from 1952 to 2006, including : high resolution satellite photographs, air photographs and topographic maps. The results show that study areas have been changed by natural and human factors. The Ba Lai and Bat Xac areas are 2 within 9 river mouths in research...
8 trang | Chia sẻ: honghp95 | Ngày: 28/11/2020 | Lượt xem: 569 | Lượt tải: 0
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