The crater-facies kimberlite system of Tokapal, Bastar District, Chhattisgarh, India

Mainkar, Datta; Lehmann, Bernd; Haggerty, Stephen E.

doi:10.1016/j.lithos.2004.04.024

Cited by 42 publications

(22 citation statements)

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“…However, spinel is a widespread and abundant phase in this kimberlite and is the only preserved primary mineral of petrogenetic significance. Mainkar et al (2004) suspected presence of very rare phlogopite but it could not be confirmed by detailed electron beam studies of this investigation. The objectives of this study are to (i) characterize the spinel of the Tokapal kimberlite by petrographic and various electron microbeam techniques (BSE imaging and quantitative chemical analyses), (ii) infer the mantle processes in the genesis of the system, and (iii) evaluate the diamond potential of the kimberlite from spinel composition.…”

Section: Introductionmentioning

confidence: 63%

“…No diamond or garnet was found after bulk-processing of three tonnes of sample by the Geological Survey of India and the only indicator mineral that could be recovered was chrome spinel (Geological Survey of India 2010). Likewise, reconnaissance microdiamond testing on two 18 kg samples by the Directorate of Geology and Mining, Chhattisgarh, proved negative (Mainkar et al 2004). The ) T25 T25 T25 T13 T13 T14 T14 T14 T15 T15 T15 Mitchell (1997), combined with chemical data (Mainkar et al 2004).…”

Section: Petrography and Spinel Morphologymentioning

confidence: 98%

“…1). It is one of the world's largest (>550 ha) crater-facies kimberlites (Mainkar et al 2004;Lehmann et al 2006). The Tokapal kimberlite is sandwiched in between the lower Indravati Group of sedimentary rocks of the Cherakur (comprising micaceous purple shale) and Kanger Formations (white and grey limestone) and the upper Jagdalpur Formation (limestone, calcareous shale and sandstone intercalations) of the platformal Indravati Supergroup (Ramakrishnan 1987) (Fig.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…1 Geological setting of the Tokapal kimberlite system (adapted from Mainkar et al 2004). Sample locations of this study are indicated by (+) symbol Diamond-facies chrome spinel from the Tokapal kimberlite plasma mass spectrometry) after lithium metaborate/tetraborate fusion.…”

Section: Sampling and Analytical Techniquesmentioning

confidence: 99%

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Diamond-facies chrome spinel from the Tokapal kimberlite, Indrāvati basin, central India and its petrological significance

et al. 2012

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Widespread and abundant spinel is the only primary mineral of petrogenetic significance preserved in the hydrothermally altered, crater-facies, Neoproterozoic (≥620 Ma) Tokapal kimberlite pipe that intruded the Indrā-vati basin, Bastar craton, Central India. Two distinct spinel populations occur: (i) finer-grained (<50 μm) microcrysts which are zoned from titaniferous magnesiochromitechromite to magnetite; and (ii) larger macrocrysts (>400 μm) with cores having distinctly chromium-rich (Cr 2 O 3 up to 63.67 wt%), and TiO 2 -poor (<0.68 wt%) compositions. Based on their morphology and chemical composition the macrocrysts are inferred to be disaggregated mantle xenocrysts and their compositional range extends well into the diamond stability field. However, the reported absence of diamond and other indicator minerals (such as pyrope garnet, chrome diopside and magnesian ilmenite) in the Tokapal pipe is intriguing since diamondiferous cratonic roots are indeed preserved in the Bastar craton, and also the kimberlite itself was derived from a similar source region(s) as that of the well-known diamondiferous Mesoproterozoic (ca. 1,100 Ma) kimberlites from Wajrakarur, Dharwar craton, southern India. Given the large areal extent (>550 ha) of kimberlite, there is a possibility that it contains diamonds but they were not recovered during the sampling. Alternately, highly oxidising conditions imparted by the metasomatic fluids/melts derived from (i) asthenosphere-lithosphere interaction, or (ii) the kimberlite itself might have played an important role in the destruction of diamond, and other indicator minerals.

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Section: Introductionmentioning

confidence: 63%

Section: Petrography and Spinel Morphologymentioning

confidence: 98%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Sampling and Analytical Techniquesmentioning

confidence: 99%

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Diamond-facies chrome spinel from the Tokapal kimberlite, Indrāvati basin, central India and its petrological significance

et al. 2012

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“…Possibility of kimberlite lava formation Kimberlite lava has been reported from Angola (Skinner and Marsh 2004;Eley et al 2008), India (Mainkar et al 2004) and Tanzania (Igwisi Hills: Reid et al 1975;Dawson 1994). Detailed evidence that the Angolan and Indian kimberlites are lavas is lacking.…”

Section: Theoretical Constraintsmentioning

confidence: 99%

A rare occurrence of a crater-filling clastogenic extrusive coherent kimberlite, Victor Northwest (Ontario, Canada)

et al. 2011

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Kimberlite pipes can contain significant proportions of dark and dense kimberlite that have mostly been interpreted as intrusive coherent (hypabyssal) in origin. This study reports a well-documented occurrence of a fresh intra-crater clastogenic extrusive coherent kimberlite that is concluded to have formed as a result of lava fountaining. This paper focuses on a dark, dense, competent, generally crystal-rich, massive kimberlite unit within the Victor Northwest kimberlite pipe (Ontario, Canada). Using a comprehensive volcanological and petrographic analysis of all available drill cores, it is shown that this unit has a fresh well-crystallised coherent groundmass and is extrusive and pyroclastic in origin. The proposed clastogenic coherent extrusive origin is based on deposit morphology, gradational contacts to enveloping pyroclastic units, as well as the presence of remnant pyroclast outlines and angular broken olivines. This paper, and an increasing number of other studies, suggest that fragmental extrusive coherent kimberlite in intra-crater settings may be more common than previously thought. The emplacement history and volcanology of these pipes need to be reconsidered based on the emerging importance of this particular kimberlite facies.

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Tectonic framework of southern Bastar Craton, Central India: a study based on different spatial information data sets

2011

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We present here a regional tectonic fabric analysis of the southern margin of the Bastar Craton, Central India, obtained from different spatial data sets that include Shuttle Radar Topographic Mission (SRTM), Landsat ETM + (Enhanced Thematic Mapper) and IRS (Indian Remote sensing Satellite) P6-LISS3, integrated with available geological information, as well as field and microscopic observations. The southern margin of the Bastar Craton exhibits large-scale structures, such as regional-scale folds, major shear zones and associated tectonic fabric affected by strong brittle-ductile deformation. The deformational features are related to large-scale thrusting, regional compression, and episodic igneous activity during the Precambrian, and display a major tectonic control on magmatism and the evolution of a shear zone system. The NW-SE to E-W and NE-SW trending brittle to ductile shear zones traversing the craton display both dextral as well as sinistral displacements. Well-developed kinematic indicators include, sheared quartz veins, tension gashes, rotated porphyroblasts, S-C fabrics, pinch-andswell structures, sigmoidal foliations and riedel fractures that are well preserved in the basement Sukma-Bengpal supracrustals, as well as in the younger granitoids of the Dongargarh Supergroup. Large-scale well-developed NW-SE trending isoclinal folding in the basement gneisses and major folding in mafic intrusions in the south-western margin and tight, upright doubly-plunging large-scale folds in the eastern margins of the craton represent two major tectonic events. These events can be correlated to large-scale thrusts and suggest an initial N-S compression of the craton followed by E-W thrusting at different intervals during the tectonic evolution of the craton. The occurrence of several NW-SE trending mafic dykes parallel to the shear zones indicate that regional-scale tensile stresses were operating during the Proterozoic, associated with a possible continental rift environment in the centre of the craton. The structural pattern obtained, together with the structures mapped with the coherence of remote sensing images, give significant information and an opportunity to reconstruct the timing, style of deformation and its kinematics in the southern part of the Bastar Craton and provide important constraints on the kinematics of the shear zone system and evolution of the craton.

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The crater-facies kimberlite system of Tokapal, Bastar District, Chhattisgarh, India

Cited by 42 publications

References 2 publications

Diamond-facies chrome spinel from the Tokapal kimberlite, Indrāvati basin, central India and its petrological significance

Diamond-facies chrome spinel from the Tokapal kimberlite, Indrāvati basin, central India and its petrological significance

A rare occurrence of a crater-filling clastogenic extrusive coherent kimberlite, Victor Northwest (Ontario, Canada)

Tectonic framework of southern Bastar Craton, Central India: a study based on different spatial information data sets

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