Metasomatism in mantle xenoliths from the Letlhakane kimberlites: estimation of element fluxes

Water plays a key role in evolution and dynamic of the Earth. It can change physical and chemical properties of mantle minerals, or the part of the mantle, for instance, the effect on mineral deformation and its impact on mantle rheology (Miller et al., 1987). Mantle xenoliths from kimberlites are one of direct source of information on the petrology and geochemistry of the deep mantle rocks.Sytykanskaya pipe located in the central part of Yakutian diamondiferous province is characterized by a large amount of deep-seated xenoliths which contain relics of fresh minerals, e.g. clinopyroxenes, garnets, olivines, phlogopites, amphiboles, chromites, ilmenites and some other rare phases (Ashchepkov et al., 2015). Moreover it is known that there are several processes which can affect the mantle xenoliths, including metasomatism. Five peridotite xenoliths have been studied in order to indentify water enrichment. Using calibration coefficients (Bell et al., 2003) we calculated water content in the olivines. Water contents in olivine range from 12 to 92 ppm. In previous research (Kolesnichenko et al., 2017) we have studied peridotites from Udachnaya kimberlite pipe and found similar water content in olivines (2-95 ppm). So, the variably low water contents suggest a heterogeneous distribution of water beneath the mantle, which can be connected with metasomatism of essentially dry diamondiferous cratonic roots by hydrous and carbonatitic agents, and its related hydration and carbonation of peridotite accompanied by oxidation and dissolution of diamonds.This work was supported by the Russian Science Foundation under Grant No 16-17-10067.Miller, G. H., Rossman, G. R., & Harlow, G. E. (1987). The natural occurrence of hydroxide in olivine. Physics and chemistry of minerals, 14(5), 461-472.Ashchepkov, I. V., Logvinova, A. M., Reimers, L. F., Ntaflos, T., Spetsius, Z. V., Vladykin, N. V., & Palesskiy, V. S. (2015). The Sytykanskaya kimberlite pipe: Evidence from deep-seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit, Yakutia, Russia. Geoscience Frontiers, 6(5), 687-714.Bell, D. R., Rossman, G. R., Maldener, J., Endisch, D., & Rauch, F. (2003). Hydroxide in olivine: A quantitative determination of the absolute amount and calibration of the IR spectrum. Journal of Geophysical Research: Solid Earth, 108(B2).Kolesnichenko, M. V., Zedgenizov, D. A., Litasov, K. D., Safonova, I. Y., & Ragozin, A. L. (2017). Heterogeneous distribution of water in the mantle beneath the central Siberian Craton: Implications from the Udachnaya Kimberlite Pipe. Gondwana Research, 47, 249-266.

Peridotite

Xenolith

Metasomatism

Amphibole

Phlogopite

10.5194/egusphere-egu2020-21023

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Citations (0)

Multistage Mantle Metasomatism during the Generation of Kimberlite Melts: Evidence from Mantle Xenoliths and Megacrysts of the Grib Kimberlite, Arkhangelsk, Russia

Petrology (2021)

А. В. Каргин

Peridotite

Metasomatism

Xenolith

Phlogopite

Ultramafic rock

Primitive mantle

10.1134/s0869591121030024

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Citations (10)

Petrology and oxygen-isotope geochemistry of the Yamba Lake kimberlite rocks, N.W.T.

Canadian Journal of Earth Sciences (2000)

Pauline Orr Robert W. Luth

The Torrie, Sputnik, and Eddie kimberlite rocks, located near Yamba Lake, central Slave province, N.W.T., are volcaniclastic, macrocrystic, heterolithic, olivine-rich tuff, and olivine-rich tuff breccia. Torrie and Sputnik kimberlite rocks contain pyroxene and garnet xenocrysts and megacrysts with major-element compositions consistent with derivation mostly from disaggregated garnet lherzolite, with subordinate contributions from eclogite, spinel lherzolite, garnet harzburgite, and websterite. The presence of primary groundmass phlogopite and compositionally evolved spinel, and the absence of mantle xenocrysts, xenoliths, and megacrystic ilmenite distinguish the Eddie kimberlite pipe from the other two kimberlite pipes. Large variations in δ 18 O of garnet and clinopyroxene in xenocrysts and xenoliths (+3.98 to +6.36), nonequilibrium intermineral isotopic fractionation, and major-element heterogeneity are interpreted as resulting from infiltration of fluids or melts produced by dehydration or melting of subducted oceanic crust into overlying peridotite. Although the timing is unconstrained for the xenocysts, the xenolith must have experienced this metasomatic interaction shortly before entrainment in the kimberlite. Variable δ 18 O values for magnesian ilmenite are also interpreted to result indirectly from such metasomatic activity in the mantle as well. The Torrie and Sputnik kimberlite rocks have low concentrations of diamond indicator minerals consistent with their low-diamond grades. These kimberlite rocks did not sample a significant amount of garnet harzburgite, the rock type commonly associated with high-diamond grades in other kimberlite rocks. Furthermore, metasomatism just prior to kimberlite eruption may have caused the resorption of any diamond present.

Xenolith

Metasomatism

Phlogopite

Peridotite

10.1139/e00-021

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Citations (6)

Evidence for subduction-related signatures in the southern African lithosphere from the N-O isotopic composition of metasomatic mantle minerals

Geochimica et Cosmochimica Acta (2019)

Angus Fitzpayne Andrea Giuliani Chris Harris Émilie Thomassot Cheng Chen

Metasomatism

Phlogopite

Xenolith

Amphibole

Primitive mantle

Peridotite

10.1016/j.gca.2019.02.037

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Citations (27)

Peridotite and pyroxenite xenoliths from the Muskox kimberlite, northern Slave craton, Canada

Canadian Journal of Earth Sciences (2015)

David E. Newton Maya Kopylova Jennifer Burgess Pamela Strand

We present petrography, mineralogy, and thermobarometry for 53 mantle-derived xenoliths from the Muskox kimberlite pipe in the northern Slave craton. The xenolith suite includes 23% coarse peridotite, 9% porphyroclastic peridotite, 60% websterite, and 8% orthopyroxenite. Samples primarily comprise forsteritic olivine (Fo 89–94), enstatite (En 89–94), Cr-diopside, Cr-pyrope garnet, and chromite spinel. Coarse peridotites, porphyroclastic peridotites, and pyroxenites equilibrated at 650–1220 °C and 23–63 kbar (1 kbar = 100 MPa), 1200–1350 °C and 57–70 kbar, and 1030–1230 °C and 50–63 kbar, respectively. The Muskox xenoliths differ from xenoliths in the neighboring and contemporaneous Jericho kimberlite by their higher levels of depletion, the presence of a shallow zone of metasomatism in the spinel peridotite field, a higher proportion of pyroxenites at the base of the mantle column, higher Cr 2 O 3 in all pyroxenite minerals, and weaker deformation in the Muskox mantle. We interpret these contrasts as representing small-scale heterogeneities in the bulk composition of the mantle, as well as the local effects of interaction between metasomatizing fluid and mantle wall rocks. We suggest that asthenosphere-derived pre-kimberlitic melts and fluids percolated less effectively through the less permeable Muskox mantle, resulting in lower degrees of hydrous weakening, strain, and fertilization of the peridotitic mantle. Fluids tended to concentrate and pool in the deep mantle, causing partial melting and formation of abundant pyroxenites.

Peridotite

Xenolith

Metasomatism

Enstatite

Asthenosphere

Amphibole

Pyrope

10.1139/cjes-2015-0083

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Citations (10)

Composition of garnet and clinopyroxene in peridotite xenoliths from the Grib kimberlite pipe, Arkhangelsk diamond province, Russia: Evidence for mantle metasomatism associated with kimberlite melts

Lithos (2016)

А. В. Каргин Л. В. Сазонова А. А. Носова V.V. Tretyachenko

Peridotite

Metasomatism

Xenolith

Phlogopite

Primitive mantle

10.1016/j.lithos.2016.07.015

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Citations (42)

Ultramafic xenoliths from the 1.15 Ga Certac kimberlite, eastern Superior Craton

The Canadian Mineralogist (2020)

Adrian Van Rythoven Daniel J. Schulze Donald W. Davis

ABSTRACT Xenoliths and xenocrysts of mantle material from kimberlite dikes located underground at the Certac Au mine, Québec, in the eastern Superior Craton, were studied in terms of the major element composition of their constituent minerals. The kimberlite was dated at 1151 ± 46 Ma by the U-Pb perovskite method. This suite thus provides a rare glimpse into the Mesoproterozoic mantle of the Superior Craton. Two parageneses of mantle material unrelated to the kimberlite magmatism occur: (1) an olivine + ilmenite ± magnetite association characterized by relatively Fe-rich olivine (Mg# = 0.68–0.84) and ilmenite enriched in Mg and Cr (4–13 wt.% MgO, Cr2O3 up to 3 wt.%), and (2) spinel peridotite characterized by Mg-rich olivine (Mg# = 0.91–0.94). The Fe-rich association is interpreted as a magmatic cumulate likely unrelated to the kimberlite. No mantle-derived garnet occurs in the xenoliths or as xenocrysts. The presence of Cr-rich spinel (Cr# = 0.84–0.98) in high temperature (860–953 °C) chromite peridotite indicates bulk compositions too depleted in Al for garnet to be stable, although geothermometry suggests they equilibrated at depths corresponding to garnet stability (90–131 km, depending on the geothermal gradient). Alternatively, the presence of phlogopite in two of the three high temperature (i.e., deepest) chromite peridotites suggests the absence of garnet and presence of low-Al chromite may have been caused by metasomatism from a K-rich fluid that replaced garnet with phlogopite + clinopyroxene ± chromite. Less depletion at shallower depths is indicated by a chromite (Cr# = 0.60) dunite that equilibrated at 831 °C and a low temperature (752 °C) Mg-Al-spinel lherzolite.

Phlogopite

Chromite

Peridotite

Xenolith

Ilmenite

Metasomatism

Ultramafic rock

10.3749/canmin.1900064

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Citations (1)

The Cenozoic lithospheric mantle beneath the interior of South China Block: Constraints from mantle xenoliths in Guangxi Province

Lithos (2014)