SUMMARY

The relationship between tin and tungsten mineralization and granitoid from

the Sa Huỳnh and Ankroet complexes in south Việt Nam

Mai Kim Vinh, Phạm Văn Hường, Trần Ngọc Khai, Trần Duân, Nguyễn Công Cầu

The Sa Huỳnh and Ankroet granitoid complexes in South Vietnam exposed mainly in Quảng Ngãi and Đà Lạt zone, respectively. Sa Huỳnh granitoid complex is made up of medium-course grained biotite granites, two mica granites and fine grained, light-colored granite. The rocks are porphyritic texture. Chemically, the Sa Huỳnh granitoids are peraluminuous and have accessory minerals of topaze, zircon, garnet, sillimanite, cassiterite which characterize for the S-type granites. The rocks are often greisenised in the top of small granitic bodies and in the margin of granitic aplites. The main mineral components of greisened zones are muscovite, potassium feldspar, quartz and casiterit, topaze. The presence of topaze is indicative of the F- rich greisen type. In contrast, the Ankroet granitic complex is charaterised by light color and high differentiation. The rocks are medium-grained granites in composition and have porphyritic texture. Geochemical and rock-forming mineral indicated that they are S-type granites. Granites at the top part of granite bodies are usually greisenised and accessory minerals in greisen zones are of cassiterite, wolframite and tourmaline. The presence of tourmaline in the greisened zones supports for B-rich greisen type. These will help to seek and explore effetively tin and wolfram mineralization.

Người biên tập: TS. Trần Mỹ Dũng; TS. Đỗ Quốc Bình.