Eclogite xenoliths from Wajrakarur kimberlites, southern India

Patel, Suresh C.; Ravi, S.; Thakur, S. S.; Rao, T. Kameswara; Subbarao, Kakarla

doi:10.1007/s00710-006-0150-8

Cited by 35 publications

(39 citation statements)

References 28 publications

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“…The mineral chemistry of other xenoliths listed in Table 1 such as kyanite-, enstatite-and biminerallic eclogites from KL2, P2 and P10 pipes of WKF can be found in Patel et al (2006). The primary minerals in the mafic xenoliths do not show discernible zoning within individual grains or significant compositional variation among grains in the same xenolith.…”

Section: Mineral Chemistrymentioning

confidence: 91%

“…4). Clinopyroxene compositions for eclogites of KL2, P2 and P10 pipes of WKF are taken from Patel et al (2006) and plotted in this figure for comparison. Clinopyroxene falling in the omphacite field is classified as omphacite, whereas that falling in the Quad field is Ca pyroxene.…”

Section: Clinopyroxenementioning

confidence: 99%

“…The chemistry of all garnets is summarised in the CaO-(FeO + MnO)-MgO ternary plot after Coleman et al (1965) along with the data points for eclogites of KL2, P2 and P10 pipes of WKF from Patel et al (2006) (Fig. 5).…”

Section: Garnetmentioning

confidence: 99%

“…Table 5 Results of geothermobarometry for the mafic xenoliths from the kimberlite pipes of EDC. Mineral analyses used for sample KL2N9a, P10N7b and P10N7c are taken from Patel et al (2006) and those for other samples is from this study T in°C and P in kbar. P (NT) = Cr-in-cpx geobarometer of Nimis and Taylor (2000); P (BK) = Al-in-opx geobarometer of Brey and Kohler (1990).…”

Section: à2mentioning

confidence: 99%

“…The IUGS Subcommission for the nomenclature of metamorphic rocks (SCMR) recently recommended the crystal-chemical classification of clinopyroxene by Morimoto et al (1988) to be used for defining omphacite (Desmons and Smulikowski, 2004 and upgrades). Following this scheme, Patel et al (2006) identified eclogite xenoliths from three kimberlite pipes of the Wajrakarur Kimberlite Field (WKF) in the Eastern Dharwar Craton of southern India (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Patel¹,

Ravi

Anilkumar³

et al. 2009

Journal of Asian Earth Sciences

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Section: Mineral Chemistrymentioning

confidence: 91%

Section: Clinopyroxenementioning

confidence: 99%

Section: Garnetmentioning

confidence: 99%

Section: à2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Patel¹,

Ravi

Anilkumar³

et al. 2009

Journal of Asian Earth Sciences

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Origin and diamond prospectivity of Mesoproterozoic kimberlites from the Narayanpet field, Eastern Dharwar Craton, southern India: insights from groundmass mineralogy, bulk‐chemistry and perovskite oxybarometry

2011

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The Mesoproterozoic Narayanpet Kimberlite Field (NKF) is located~200 km north of the well-known Wajrakarur Kimberlite Field (WKF) in the Eastern Dharwar Craton, southern India. Whereas a majority of the WKF occurrences are diamondiferous and contain mantle xenoliths and xenocrysts, their paucity is a characteristic feature of the NKF. This has been attributed alternately to the derivation of NKF magmas from a shallower depth, or to variability in thickness of the Sub-Continental Lithospheric Mantle (SCLM) beneath the Eastern Dharwar Craton. Recently, exploration by De Beers resulted in the discovery of a number of new kimberlite occurrences from the NKF, with some of their geochemical features and radiogenic isotope systematics subsequently becoming available. In this paper, we present detailed petrography, groundmass mineral composition and new bulk-rock geochemistry data for a number of NKF rocks and attempt to further constrain their origin. We also investigate the influence of redox conditions on diamond prospectivity by estimating oxygen fugacity ( f O 2 ) from Fe-Nb oxybarometry on NKF groundmass perovskites. We identify for the first time in the NKF the presence of volcaniclastic (fragmental textured) facies kimberlite belonging to the diatreme portion of the intrusion. Rarity of olivine macrocrysts and the presence of diopside are hallmarks of the NKF kimberlites, in contrast to archetypal kimberlites of southern Africa. Mineral components of the groundmass display features that are characteristic to both archetypal kimberlites and to orangeites, and it is not straight forward to apply conventional mineral-genetic schemes in the nomenclature of the NKF pipes. Low f O 2 of the NKF magma (ΔNNO (nickel-nickel oxide) = −1.9 to −3.2), indistinguishable from that of diamondiferous kimberlites world-wide, indicates that redox conditions were favourable for diamond prospectivity, and that magmatic emplacement could, instead, have played a major role in their low diamond potential.

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Petrogenesis of lamprophyres synchronous to kimberlites from the Wajrakarur kimberlite field: Implications for contrasting lithospheric mantle sources and geodynamic evolution of the eastern Dharwar Craton of southern India

et al. 2018

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Kimberlite field is an example of widespread Mesoproterozoic intracontinental magmatism. Recent studies have identified deep subcontinental lithospheric mantle as a source region of the kimberlite magmatism while timing, origin, and processes responsible for the generation of coeval lamprophyres remain poorly constrained. Here, we present and discuss new petrological and geochemical data for two lamprophyre dykes from the Wajrakarur kimberlite field and assess their petrogenetic relation to the kimberlite occurrences. Based on mineral compositional and whole‐rock geochemical characters, it is suggested that lamprophyres are formed through low degrees of partial melting of “enriched” lithospheric mantle that was modified and metasomatized by melts derived from recycled crust. This differs from geochemical imprints found in coeval kimberlites, where a crustal source component appears to be absent and is more consistent with rock derivation from “depleted” lithosphere which has experienced interaction with asthenosphere‐derived melts. An apparent lack of garnet in the mantle sources of lamprophyres is suggestive of melting at comparatively shallow depth (~100 km) relative to the kimberlites. Hence, these geochemically contrasting rocks, although have formed at the same time, are derived from vertically heterogeneous lithospheric mantle sources and can be explained through and linked with a thermal anomaly in the underlying convective asthenosphere. We suggest that the deeper mantle source region of the kimberlites was more pristine and devoid of subduction‐related signatures, whereas the shallower mantle source region of the lamprophyres seems to have preserved imprints of plate convergence and subduction associated with the evolution of the Dharwar Craton.

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Eclogite xenoliths from Wajrakarur kimberlites, southern India

Cited by 35 publications

References 28 publications

Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Mafic xenoliths in Proterozoic kimberlites from Eastern Dharwar Craton, India: Mineralogy and P–T regime

Origin and diamond prospectivity of Mesoproterozoic kimberlites from the Narayanpet field, Eastern Dharwar Craton, southern India: insights from groundmass mineralogy, bulk‐chemistry and perovskite oxybarometry

Petrogenesis of lamprophyres synchronous to kimberlites from the Wajrakarur kimberlite field: Implications for contrasting lithospheric mantle sources and geodynamic evolution of the eastern Dharwar Craton of southern India

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