Transformations of some kimberlite minerals under the influence of traps

The mineralogical composition of zones where kimberlite rocks had been affected by trap intrusions were comprehensively studied. Previous studies demonstrated that primary kimberlite minerals (diamond and its paragenetic associated minerals) can be significantly transformed in such cases. The rock-forming minerals (serpentines and carbonates), secondary formations, and layered silicates (phlogopite and its alteration products, chlorite and vermiculite) are also transformed. At the initial stage of the metamorphism, the transformation of the phlogopite and chlorite are predominantly expressed in decreasing the degree of their structural ordering. Then, with approaching the intrusion, the phlogopite ordering degree is expressed lesser, increasing with only the beginning of its chloritization. All the above described transformations are related to only intrusions of differentiated traps, while “dry” rocks have a little effect on the kimberlites transformation.