XENOLITHS OF POLYMICTIC BRECCIAS FROM KIMBERLITES OF THE YAKUTIAN DIAMONDIFEROUS PROVINCE
https://doi.org/10.5800/GT-2022-13-4-0660
Abstract
The polymictic breccias, extremely rare mantle conglomerates being the fragments of rocks and large mantle minerals cemented with fine-grained mass have been long provoking interest of petrologists worldwide. This work provides a comparative analysis of two xenoliths of polymictic rocks from kimberlite pipes of different age and productivity occurring in the Siberian craton. The similarity of the chemical composition of some minerals of polymictic breccias from kimberlites within different parts of the Siberian craton assumes possible formation of these minerals caused by the same factors in the prekimberlite period of these parts of the lithospheric mantle. A wide range of compositions and chaotic zoning of minerals, the presence of exsolution textures in orthopyroxene, ilmenite, sulfide, and kelyphite rims on garnet suggest that the fragments of the studied xenoliths are unbalanced. Sample SH18/20 is the first polymictic breccia showing asthenospheric melt-fluids sampling shallow depths of the spinel facies.
Supporting agencies: This research was funded by the Russian Foundation for Basic Research (Grant 20-05-00662), Russian Scientific Foundation (Project 21-17-00082) and was carried out for state assignment of IGM SB RAS.
About the Authors
L. N. Pokhilenko
Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences
Russian Federation
Russian Federation
3 Academician Koptyug Ave, Novosibirsk 630090
N. P. Pokhilenko
Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences; Novosibirsk State University
Russian Federation
Russian Federation
3 Academician Koptyug Ave, Novosibirsk 630090
1 Pirogov St, Novosibirsk 630090
V. P. Afanasiev
Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences
Russian Federation
Russian Federation
3 Academician Koptyug Ave, Novosibirsk 630090
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Review
For citations:
Pokhilenko L.N., Pokhilenko N.P., Afanasiev V.P. XENOLITHS OF POLYMICTIC BRECCIAS FROM KIMBERLITES OF THE YAKUTIAN DIAMONDIFEROUS PROVINCE. Geodynamics & Tectonophysics. 2022;13(4):0660. (In Russ.) https://doi.org/10.5800/GT-2022-13-4-0660
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