SUMMARY

Characteristics of manganese ores in Upper Devonian sediments on the territory of Nghệ An, Hà Tĩnh and Quảng Bình Provinces

Dương Văn Huấn

On the territory of the Nghệ An, Hà Tĩnh and Quảng Bình Provinces, manganese mineralization is distributed in a narrow band along the Rào Nậy - Sông Cả Fault, extending from Nam Đàn (Nghệ An) through Đức Thọ, Kỳ Anh (Hà Tĩnh) to Tuyên Hóa (Quảng Bình), with close relation to the Upper Devonian manganese-bearing cherty shale of the Thiên Nhẫn (D₃ tn) and Ngọc Lâm (D₃f nl) Formations.

Manganese ore bodies were formed mainly by the manganese liberation during the weathering and leaching of manganese-bearing cherty shale beds, and lesser, by the ore impregnation and accumulation in fractured and cataclastic zones of cherty shale beds containing interbeds and lenses of manganese ores. The mineral composition of ores consists mainly of pyrolusite and psilomelane. The ores have the average content of main elements as follows (%): Mn = 31.88; Fe = 10.76; SiO₂ = 17.73; và P = 0.02. The potentiality of manganese ores on the territory of Nghệ An, Hà Tĩnh and Quảng Bình Provinces is not large, but it needs to be evaluated and systematically explored, aiming to plan this raw material for factories of metallurgy in the area.

Người biên tập: Trần Đình Sâm