Links between deformation, chemical enrichments and Li-isotope compositions in the lithospheric mantle of the central Siberian craton

Ionov, Dmitri A.; Doucet, Luc S.; Strandmann, Philip A.E. Pogge von; Golovin, Alexander V.; Korsakov, Andrey V.

doi:10.1016/j.chemgeo.2017.10.038

Cited by 32 publications

(27 citation statements)

References 106 publications

(195 reference statements)

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“…The cores of olivine crystals examined in the CMI show Mg# varying from 95.6 to 98.9. Such MgO-rich (55-56 wt%) olivine has been identified previously neither among olivines from Udachnaya mantle xenoliths [85][86][87][88][89] nor among xenocrystic/phenocrystic olivine [90,91] from kimberlites of the Udachnaya-East pipe (Figure 8). Among olivine xenocrysts/phenocrysts from global kimberlites samples with Fo > 95 are exceptionally rare [92].…”

Section: Compositional Evolution Of Stage 2-related Mineralsmentioning

confidence: 62%

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

et al. 2020

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More than forty mineral species of epigenetic origin have been identified in an orthopyroxenite from the Udachnaya-East kimberlite pipe, Daldyn kimberlite field, Siberian platform. Epigenetic phases occur as: (1) Mineral inclusions in the rock-forming enstatite, (2) daughter minerals within large (up to 2 mm) crystallized melt inclusions (CMI) in the rock-forming enstatite, and (3) individual grains and intergrowths in the intergranular space of the xenolith. The studied minerals include silicates (olivine, clinopyroxene, phlogopite, tetraferriphlogopite, amphibole-supergroup minerals, serpentine-group minerals, talc), oxides (several generations of ilmenite and spinel, rutile, perovskite, rare titanates of the crichtonite, magnetoplumbite and hollandite groups), carbonates (calcite, dolomite), sulfides (pentlandite, djerfisherite, pyrrhotite), sulfate (barite), phosphates (apatite and phosphate with a suggested crystal-chemical formula Na2BaMg[PO4]2), oxyhydroxide (goethite), and hydroxyhalides (kuliginite, iowaite). The examined epigenetic minerals are interpreted to have crystallized at different time spans after the formation of the host rock. The genesis of minerals is ascribed to a series of processes metasomatically superimposed onto the orthopyroxenite, i.e., deep-seated mantle metasomatism, infiltration of a kimberlite-related melt and late post-emplacement hydrothermal alterations. The reaction of orthopyroxene with the kimberlite-related melt has led to orthopyroxene dissolution and formation of the CMI, the latter being surrounded by complex reaction zones and containing zoned olivine grains with extremely high-Mg# (up to 99) cores. This report highlights the utility of minerals present in minor volume proportions in deciphering the evolution and modification of mantle fragments sampled by kimberlitic and other deep-sourced magmas. The obtained results further imply that the whole-rock geochemical analyses of mantle-derived samples should be treated with care due to possible drastic contaminations from “hiding” minor phases of epigenetic origin.

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Section: Compositional Evolution Of Stage 2-related Mineralsmentioning

confidence: 62%

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

et al. 2020

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“…2). These features indicate derivation of olivine cores from the disaggregation of typical mantle peridotites, as well as other mantle lithologies that are more enriched in Fe, i.e., megacrysts and some sheared peridotites (10,(19)(20)(21)(22)(23)(24)(25), which derive from complex processes of hybridization between earlier kimberlite (or related) melts and peridotite wall rocks [e.g., (26)(27)(28)]. Some cores could also derive from the crystallization of failed (29,30) or from disaggregation of "replacive" dunites where interaction with earlier kimberlite melts promoted olivine formation at the expense of other silicate phases (31).…”

Section: Olivine Composition In Kimberlitesmentioning

confidence: 99%

Kimberlite genesis from a common carbonate-rich primary melt modified by lithospheric mantle assimilation

et al. 2020

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Quantifying the compositional evolution of mantle-derived melts from source to surface is fundamental for constraining the nature of primary melts and deep Earth composition. Despite abundant evidence for interaction between carbonate-rich melts, including diamondiferous kimberlites, and mantle wall rocks en route to surface, the effects of this interaction on melt compositions are poorly constrained. Here, we demonstrate a robust linear correlation between the Mg/Si ratios of kimberlites and their entrained mantle components and between Mg/Fe ratios of mantle-derived olivine cores and magmatic olivine rims in kimberlites worldwide. Combined with numerical modeling, these findings indicate that kimberlite melts with highly variable composition were broadly similar before lithosphere assimilation. This implies that kimberlites worldwide originated by partial melting of compositionally similar convective mantle sources under comparable physical conditions. We conclude that mantle assimilation markedly alters the major element composition of carbonate-rich melts and is a major process in the evolution of mantle-derived magmas.

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“…[20,70,72,73] Detailed studies of the chemical and mineralogical compositions of these unaltered kimberlites can be found elsewhere. [13][14][15]17,18,[72][73][74][75][76][77][78] These kimberlites also contain various types of unserpentinised mantle xenoliths [66][67][68][79][80][81] The studied sheared peridotite xenoliths are defined by the presence of large porphyroclasts (1-10 mm) of olivine, garnet, and pyroxene, which are set in a matrix consisting of very fine-grained neoblasts (0.1-0.5 mm) of mostly olivine and lesser pyroxene (Figures 1b and 2). According to textural classifications, [82,83] the studied samples have porphyroclastic, mosaic-porphyroclastic, and fluidal-mosaic-porphyroclastic textures (Figures 1b and 2 and Table 1).…”

Section: Geological Setting and Sample Descriptionmentioning

confidence: 99%

“…Additional information on similar xenoliths from the Udachnaya-East pipe can be found elsewhere. [66][67][68]88,89]…”

Section: Geological Setting and Sample Descriptionmentioning

confidence: 99%

“…Carbonate-rich mantle melts entrapped as inclusions in olivine from sheared peridotite xenoliths from the Udachnaya-East kimberlite pipe (Siberian craton) were reported by Golovin et al [41] It is widely believed that sheared peridotites are among the deepest derived mantle rocks and are located near the asthenosphere-lithosphere boundary. [64][65][66][67][68] The crystallised melt inclusions in olivine are composed of abundant Na-K-Ca-, Na-Ca-, Na-Mg-, Ca-Mg-, and Ca-carbonates. [41] These inclusions are considered to be relics of near-primary or primitive kimberlitic melts that later formed the Udachnaya pipes.…”

Section: Introductionmentioning

confidence: 99%

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Can primitive kimberlite melts be alkali‐carbonate liquids: Composition of the melt snapshots preserved in deepest mantle xenoliths

Golovin

Sharygin

Korsakov

et al. 2019

J Raman Spectroscopy

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The study of kimberlite rocks is important as they provide critical information regarding the composition and dynamics of the continental mantle and are the principal source of diamonds. Despite many decades of research, the original compositions of kimberlite melts, which are thought to be derived from depths > 150 km, remain highly debatable due to processes that can significantly modify their composition during ascent and emplacement. Snapshots of the kimberlite‐related melts were entrapped as secondary melt inclusions hosted in olivine from sheared peridotite xenoliths from the Udachnaya‐East pipe (Siberian craton). These xenoliths originated from 180‐ to 220‐km depth and are among the deepest derived samples of mantle rocks exposed at the surface. The crystallised melt inclusions contain diverse daughter mineral assemblages (>30 mineral species), which are dominated by alkali‐rich carbonates, sulfates, and chlorides. The presence of aragonite as a daughter mineral suggests a high‐pressure origin for these inclusions. Raman‐mapping studies of unexposed inclusions show that they are dominated by carbonates (>65 vol.%), whereas silicates are subordinate (<13 vol.%). This indicates that the parental melt for the inclusions was carbonatitic. The key chemical features of this melt are very high contents of alkalis, carbon dioxide, chlorine, and sulfur and extremely low silica and water. Alkali‐carbonate melts entrapped in xenolith minerals likely represent snapshots of the primitive kimberlite melt. This composition is in contrast with the generally accepted notion that kimberlites originated as ultramafic silicate water‐rich melts. Experimental studies revealed that alkali‐carbonate melts are a very suitable diamond‐forming media. Therefore, our findings support the idea that some diamonds and kimberlite magmatism may be genetically related.

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Links between deformation, chemical enrichments and Li-isotope compositions in the lithospheric mantle of the central Siberian craton

Cited by 32 publications

References 106 publications

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

Kimberlite genesis from a common carbonate-rich primary melt modified by lithospheric mantle assimilation

Can primitive kimberlite melts be alkali‐carbonate liquids: Composition of the melt snapshots preserved in deepest mantle xenoliths

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