tailieunhanh - SÁCH TRA CỨU CÁC PHÂN VỊ ĐỊA CHẤT VIỆT NAM

Vỏ Trái đất ở những vùng khác nhau chịu sự chi phối của những quy luật địa chất khác nhau, nên nơi này giàu khoáng sản, thậm chí những khoáng sản mang lại nhiều loại hình khoáng sản có lợi nhuận như kim cương, đá quý, dầu khí, vv., nơi khác lại chẳng có là bao. Cho nên con người sống ở một vùng đất nào đó luôn phải xem xét cặn kẽ mảnh đất bên dưới chân mình. | This is a complicated structure, divided into two halves by the Red River Fault Zone, which has the Precambrian crystalline basement composed of marble, ortho- and para-amphibolite, some pyroxenite, graphite-bearing micaschist, some magmatic intrusions (Phan Ngâm granite, syenite and nepheline-bearing orthogneiss) forming the Huronian materials, even Archean materials in scaly structures, which are exposed in anticlinal block and uplifted dome block (Phan Si Pan, Upper course of Chảy River). Surrounding this basement there are Paleozoic formations (composed mainly of terrigenous sediments, limestone and, locally, interbedded with effusives) forming arc folded structures (Neotriassic arcs in East Bắc Bộ), the most part of them has been attributed to the basement cover, and composed of multigenetic materials, such as: Hercynian ones, including granites, Devonian and Lower Carboniferous sediments unconformably underlying the younger cover and overlying the basement, even simply folded Caledonian materials (lustrous schists of subcontinental to marine facies). Scatteredly distributed in uplifts, there are Anthracolithic granite bodies (Pia Bioc, Pia Ya, possibly even Pia Oắc and Móng Cái). As for the Mesozoic formations within Triassic depressions (eg. Lạng Sơn Strait, Sông Đà Geosyncline), they formed the Indosinian materials, the oldest of which consists of effusives of various composition, from rhyolite, microgranite, a little porphyrite in Nghĩa Lộ area to, mainly, porphyrite in the western slope of the Phan Si Pan Range, lower course of the Đà River and SE Hoà Bình. Between the arcs there are not deep depressions (about 1,000 m) which were filled up with Cenozoic intracontinental sediments.