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

Patel, Suresh C.; Ravi, S.; Anilkumar, Y.; Naik, Ashutosh; Thakur, S. S.; Pati, Jayanta Kumar; Nayak, S.

doi:10.1016/j.jseaes.2008.06.001

Cited by 35 publications

(36 citation statements)

References 37 publications

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“…These P-T conditions are consistent with a mantle geotherm of 45 mW/m 2 , following the model continental geotherms of Pollack and Chapman (1977). This is same as the mantle geotherm beneath the kimberlite fields of the Dharwar Craton reported by Patel et al (2009Patel et al ( ), 2010. Using the geotherm of 45 mW/m 2 , the minimum pressures obtained for the Kalmidadar garnets fall in the range of 16-32 kbar, which correspond to a minimum depth range of 50-100 km.…”

Section: Nature Of Subcontinental Lithospheric Mantlesupporting

confidence: 80%

Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India

Sahu

Gupta²,

Patel³

et al. 2013

Proceedings of 10th International Kimberlite Conference

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This work presents the first mineralogical, geochemical and 40 Ar/ 39 Ar geochronological data on hypabyssal facies lamproites near Kalmidadar and Darlimunda in the Nuapada Lamproite Field of the Bastar Craton. The Kalmidadar lamproite is a diamondiferous intrusion with surface dimension of *320 m 9 160 m, whereas the Darlimunda lamproite is a dyke swarm comprising clusters of several narrow (\5 m wide) and elongated bodies. Indicator mineral suite around the Kalmidadar lamproite is marked by abundance of Cr-spinel, rarity of garnet and absence of Cr-diopside and picroilmenite. Mineralogically, the Kalmidadar lamproite comprises phenocrysts of olivine (pseudomorphed by calcite and talc) and microphenocrysts of phlogopite set in a groundmass of chlorite and calcite. The phlogopite is Ti rich (5.4-7.4 wt % TiO 2 ), and the relationship between its Ti content and octahedral site deficiency indicates two substitution mechanisms, viz. Ti + ' $ 2 Mg and Ti ? 2Al $ Mg ? 2Si. The Darlimunda lamproites have undergone pervasive hydrothermal and/or deuteric alteration, which has resulted in complete chloritisation of phlogopite and extensive silicification of the rocks. Tiny grains of rutile and apatite are commonly scattered in the groundmass of both Kalmidadar and Darlimunda lamproites. The Nuapada lamproites have high contents of compatible elements such as V, Cr and Ni and of incompatible elements such as Ba, Zr, Nb and Hf. They also show high abundance of REE and enrichment in LREE relative to HREE. The incompatible element distribution patterns of the lamproites are marked by Nb, Sr, P, Hf and Zr anomalies relative to REE. The observed petrological and geochemical characteristics of the Nuapada lamproites are consistent with the derivation of the magma from a metasomatised subcontinental lithospheric mantle source. Whole-rock 40 Ar/ 39 Ar isotopic data yields an age of 1055 ± 10 Ma for the Nuapada lamproites.

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Section: Nature Of Subcontinental Lithospheric Mantlesupporting

confidence: 80%

Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India

Sahu

Gupta²,

Patel³

et al. 2013

Proceedings of 10th International Kimberlite Conference

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“…Eclogite xenoliths of pipe KL2 include both bimineralic and kyanite-bearing types (Rao et al, 2001;Anand et al, 2008;Misra et al, 2008). Patel et al (2006Patel et al ( , 2009 observed three types of eclogite xenoliths in this pipe: bimineralic eclogites, enstatite-bearing eclogites, and celsian-bearing kyanite eclogites. Babu et al (2008) also reported coesite/quartz and coesite/quartz-kyanite-bearing varieties.…”

Section: Samples and Petrographymentioning

confidence: 66%

“…However, compared to eclogite xenoliths from South African, Siberian and Canadian cratons, available data and studies on eclogite xenoliths from India are sparse. A few authors, including Patel et al (2006) and Patel et al (2009), have studied eclogite and other mafic xenoliths from the Eastern Dharwar craton, focussing on their major element chemistry and petrology. No detailed studies of the trace element geochemistry and stable isotopes of these eclogites have been published.…”

Section: Introductionmentioning

confidence: 99%

Subduction-related origin of eclogite xenoliths from the Wajrakarur kimberlite field, Eastern Dharwar craton, Southern India: Constraints from petrology and geochemistry

Dongre¹,

Jacob

Stern

2015

Geochimica et Cosmochimica Acta

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“…The fresh hard kimberlite is exposed only in the south eastern part of the intrusion and is characterized by the presence of olivine, small angular carbonate clasts, and numerous locally-derived crustal xenoliths of granite gneiss, dolerite, amphibolites, and gabbro (Ravi et al 2009;Fareeduddin and Mitchell 2012). Xenoliths and xenocrysts present are: enstatite-garnet pyroxenite; chromian-spinel-garnet pyroxenite; chrome-diopside; ilmenite; spinel; red and orange garnet (Rao et al 2001;Fareeduddin and Mitchell 2012;Patel et al 2013). Olivine, phlogopite, perovskite, serpentine, spinel, carbonate, and apatite are the only minerals reported from P-12 by Chalapathi .…”

Section: Geology Of Pipe P-12mentioning

confidence: 99%

Mineralogy of the P-12 K-Ti-richterite diopside olivine lamproite from Wajrakarur, Andhra Pradesh, India: implications for subduction-related magmatism in eastern India

Kaur

Mitchell

2015

Miner Petrol

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The P-12 Bpara-kimberlite^from Wajrakarur consists of forsteritic olivine, Al-Na-poor diopside, Fe-Tirich, Al-poor phlogopite, K-Ti-richterite, spinel, perovskite, cymrite, apatite, barite, Ba-Sr-bearing calcite, gittinsite, witherite, strontianite, and hydrogrossular (hydrogarnet). The rock also contains small clasts consisting dominantly of calcite, with lesser Ba-Srbearing calcite, cymrite, barite, strontianite, witherite, apatite, and hydrogrossular. Two generations of forsteritic olivine (Fo 80-93 ) crystals are present: common phenocrystalto-microphenocrystal; and rare anhedral macrocrystic olivines. Phlogopite occurs as microphenocrysts and as groundmass poikilitic plates with inclusions of spinel, perovskite, apatite, and chlorite pseudomorphs (after pyroxene). Phlogopites also occur as reaction rims around olivine crystals. The phlogopites have extremely low Al 2 O 3 (2.2-3.8 wt.%) , moderate-to-high FeO (6.9-16 wt.%), TiO 2 (1.9-4.6 wt.%), and Na 2 O (0.4-2.7 wt.%) contents and are enriched in fluorine (up to 6.0 wt.%) and considered to be tetraferriphlogopite. The pyroxenes occur in five parageneses as: (1) phenocrysts and microphenocrysts; (2) small slender crystals(<30 μm) forming part of the groundmass; (3) the cores of richterite crystals; (4) reaction products replacing earlier-formed olivine; (5) acicular crystals mantling carbonate clasts. These pyroxenes do not differ significantly in composition and are all diopsides with minor variation in their TiO 2 , Al 2 O 3 , Na 2 O contents. Titanian-potassium richterite commonly occurs as: (1) groundmass poikilitic plates;(2) small prismatic crystals (<30 μm); (3) reaction rims on olivine and pyroxene crystals. Groundmass poikilitic richterites commonly enclose pyroxene and apatite. Perovskites have a bimodal size distribution. Small (<20 μm) euhedral perovskites are scattered throughout the groundmass, whereas larger (100-300 μm) subhedral-to-euhedral perovskites are patchily-zoned and commonly broken. Micro-clasts consisting of accumulations of perovskite with phlogopite and apatite are also present. Spinels occur as large atoll crystals and small (<20 μm), euhedral-to-subhedral crystals, scattered throughout the groundmass. Some small spinel crystals are also present in the rims of olivine and pyroxene crystals. Atoll spinels are up to 100 μm in size, commonly with single and double cores. Atoll spinels are typically associated with perovskites. The euhedral-tosubhedral small spinels are ulvospinels. The atoll spinels have cores of titanian aluminous magnesiochromite with rims of magnesian titaniferous magnetite. The spinels have compositions which evolve along the lamproite-spinel compositional trend. Zoned calcite crystals occur as residual phases. Late stage residual calcite and carbonate clasts host prismatic cymrite crystals which are interpreted as pseudomorphs after potassium feldspar and/or barite. Subhedral-to-euhedral gittinsite and its Sr-analog are reported for the first time from the groundmass carbonatechlorite mesostasis of a lamproit...

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

Cited by 35 publications

References 37 publications

Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India

Petrology of Lamproites from the Nuapada Lamproite Field, Bastar Craton, India

Subduction-related origin of eclogite xenoliths from the Wajrakarur kimberlite field, Eastern Dharwar craton, Southern India: Constraints from petrology and geochemistry

Mineralogy of the P-12 K-Ti-richterite diopside olivine lamproite from Wajrakarur, Andhra Pradesh, India: implications for subduction-related magmatism in eastern India

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