Phase Relations in the Harzburgite–Hydrous Carbonate Melt at 5.5–7.5 GPa and 1200–1350°С
- Authors: Kruk A.N.1, Sokol A.G.1,2, Palyanov Y.N.1,2
-
Affiliations:
- Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences
- Novosibirsk National Research State University
- Issue: Vol 26, No 6 (2018)
- Pages: 575-587
- Section: Article
- URL: https://journals.rcsi.science/0869-5911/article/view/177636
- DOI: https://doi.org/10.1134/S0869591118060036
- ID: 177636
Cite item
Abstract
Phase relations are studied experimentally in the harzburgite–hydrous carbonate melt system, the bulk composition of which represents primary kimberlite. Experiments were carried out at 5.5 and 7.5 GPa, 1200–1350°С, and \({{X}_{{{\text{C}}{{{\text{O}}}_{2}}}}}\) = 0.39–0.57, and lasted 60 hours. It is established that olivine–orthopyroxene–garnet–magnesite–melt assemblage is stable within the entire range of the studied parameters. With increase of temperature and \({{X}_{{{\text{C}}{{{\text{O}}}_{2}}}}}\) in the system, Ca# in the melt and the olivine fraction in the peridotite matrix significantly decrease. The composition of silicate phases in run products is close to those of high-temperature mantle peridotite. Analysis of obtained data suggest that magnesite at the base of subcontinental lithosphere could be derived by metasomatic alteration of peridotite by asthenospheric hydrous carbonate melts. The process is possible in the temperature range typical of heat flux of 40–45 mW/m2, which corresponds to the conditions of formation of the deepest peridotite xenoliths. Crystallization of magnesite during interaction with peridotite matrix can be considered as experimentally substantiated mechanism of CO2 accumulation in subcratonic lithosphere.
Keywords
About the authors
A. N. Kruk
Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences
Author for correspondence.
Email: krukan@igm.nsc.ru
Russian Federation, Novosibirsk, 630090
A. G. Sokol
Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences; Novosibirsk National Research State University
Email: krukan@igm.nsc.ru
Russian Federation, Novosibirsk, 630090; Novosibirsk, 630090
Yu. N. Palyanov
Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences; Novosibirsk National Research State University
Email: krukan@igm.nsc.ru
Russian Federation, Novosibirsk, 630090; Novosibirsk, 630090