SERPENTINE-CARBONATE ASSOCIATION OF KIMBERLITE MATRIX, YAKUTIA
DOI: 10.24411/0869-5997-2019-10030
Keywords:
matrix, kimberlites, serpentine, carbonates, X-ray amorphous phase, intersertal serpentine, secondary transformations, postmagmatic transformations.Abstract
The ratio of serpentine-carbonate association components in kimberlite matrix of International, Mir, Nyurb ins- kaya, Yubileinaya, Aikhal, Zarnitsa, Udachnaya pipes and Syuldyukarskoye kimberlite body was studied using X-ray examination, thermogravimetric and IR spectrometric methods involving quantitative and semiquantitative mineral content estimation. Thin sections were analyzed, chemical composition was determined using atomic emission (ICP-AS) method. A steady trend to essential prevalence of serpentine over carbonates due to its X-ray amorphous phase was established. Average carbonate content varies from 10 % to 37 %, serpentine (including X-ray amorphous phase) – 21– 80 %, X-ray amorphous serpentine – 16–72 %. It is suggested that X-ray amorphous serpentine presence is caused by poor crystallization of colloid phase formed by amorphous products of olivine decomposition at low pressure. Carbonate content is probably determined by the amount of water and carbon dioxide involved in secondary kimberlite transformations at the final stage as well as their multiple stages.
