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The Bayan Obo iron-rare-earth-niobium deposits, Inner Mongolia, China

January 1, 1990

The plate tectonic setting, regional geology and certain aspects of the economic geology of the iron-rare-earth-niobium ore bodies at Bayan Obo, Inner Mongolia, China, were studied by a team of geologists from the Tianjin Geologic Research Academy and the U.S. Geological Survey between 1987 and 1989. These ore bodies were formed by hydrothermal replacement of Middle Proterozoic dolomite in an intra-continental rift setting. A variety of veins and/or dikes that have a carbonatitelike mineralogy cut the footwall clastic rocks and migmatites. A stockwork of veins occurs at several locations in the footwall. The hanging wall is a shale that has been converted to a K-metasomatite and has microcrystalline potassium feldspar as its principal constituent. This shale served as a sealing caprock that contained the chemical solutions that reacted with the dolomite and created the enormous concentration of mineralized rock in an 18-kilometer-long syncline. The rocks that host these ore bodies and the associated mineralized areas occur today as roof pendants in granitoid rocks of Permian age that were emplaced during a continent-to-continent collision during that period.

Citation Information

Publication Year 1990
Title The Bayan Obo iron-rare-earth-niobium deposits, Inner Mongolia, China
DOI 10.1016/0024-4937(90)90040-8
Authors Lawrence J. Drew, Meng Qingrun, Sun Weijun
Publication Type Article
Publication Subtype Journal Article
Series Title LITHOS
Series Number
Index ID 70015764
Record Source USGS Publications Warehouse
USGS Organization