Explanation

Igneous rocks containing more than 50% of the first class of carbonate minerals (caldte, dolomite, iron dolomite, siderite, magnesite). According to chemical composition, it can be divided into calcareous carbonate rock, magnesium carbonate rock and iron carbonate rock; According to the main mineral composition, it can be divided into caldte carbonate rock, dolomite carbonate rock and ferruginous carbonate rock. Rock is mostly light gray to gray white; Fine coarse grained structure, sometimes in the form of giant crystal structure; It is usually massive structure, and sometimes primary strip, spherulite and spherulite structures can be seen. Compared with ordinary silicate magmatic rocks? Such rock are rich in Ca () and C () 2, but poor in Si () 2 and AWL; Compared with sedimentary carbonatite, it is rich in Si () 2, Fe, Mg, Al, Ti, P and other oxides. The main minerals are caldte, dolomite and iron dolomite, and occasionally siderite. In addition, it is rich in a variety of (about 180 kinds) secondary minerals and accessory minerals, such as pyroxene, phlogopite, apatite, celestite, cerium rare earth fluorocarbonate minerals, magnetite, niobium tantalum minerals, uranium thorium minerals, fluorite, carborundum, etc. Most of them occur as central intrusive complexes, with occurrences such as rock stocks, circular, conical, and radial rock walls, rock beds, rock flows, and rock covers. The formation and distribution are related to the deep fracture and associated with alkaline rock ultrabasic complex or kimberite. Related minerals include niobium, tantalum, rare earth elements, phosphorus, iron, etc. The most important deposit types are rare earth carbonate rock and pyrochlore carbonate rock. The world-famous Bayan Obo super large rare earth iron phosphate deposit is closely related to carbonate genesis.

Classification