Manganilmenite in the Magnetite Ore Body from Pokphur Area of Nagaland, North East India and the Possibility of Microdiamonds in the Ophiolites of Indo-Myanmar Ranges

Nayak, Bibhuranjan; Meyer, Franz Michael

doi:10.18520/cs/v112/i01/155-160

Cited by 2 publications

(3 citation statements)

References 20 publications

(30 reference statements)

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“…(a) MnO (wt%) versus MgO (wt%) binary plot (b) V 2 O 3 (wt%) versus MnO (wt%) plots for the ilmenites from lamprophyre and mafic dykes (after Kaminsky & Belousova, 2009). Data sources: Nagaland Ophiolites‐Nayak and Meyer (2017), Majhgawan diamondiferous pipe: Mukherjee et al (1997), Southern Indian Kimberlites‐Geological Survey of India, Bulletin No. 6 (Sastry et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…However, from the Indian context, only limited works are there to establish the exact connection in between diamonds/kimberlites with high‐Mn ilmenites. The presence of manganoan ilmenites from the Nagaland area has been linked with occurrences of micro‐diamonds in ophiolitic suites of the Indo‐Myanmar Range (Nayak and Meyer 2017). Mn‐rich ilmenites have been also reported from the mafic dykes of Malanjkhand pluton, Bastar Craton, India (Nehru & Sikka, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…The presence of manganoan ilmenites from the Nagaland area has been linked with occurrences of micro-diamonds in ophiolitic suites of the Indo-Myanmar Range (Nayak and Meyer 2017). Mn-rich ilmenites have been also reported from the mafic dykes of Malanjkhand pluton, Bastar Craton, India (Nehru & Sikka, 2016).…”

Section: Manganoan Ilmenites: Tracers To Diamond Explorationmentioning

confidence: 99%

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Origin and evolution of vanadium‐rich oxide and titanite phases in lamprophyre and mafic dykes from the Nuapada diamondiferous Lamproite field, BastarCraton‐EasternGhats Mobile belt contact, India: Metallogenic and geodynamic implications

2023

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Transitional boundaries of the craton and mobile belt mark diverse and long-term tectono-thermal events like hot and cold lithospheric contact, back-arc-type subduction, and also constitute a favourable locale for metallogeny. The exact nature and origin of such metallogenic enrichment in the lithospheric mantle source beneath contact zones are still uncertain. The contact of Bastar Craton and the Eastern Ghat Mobile Belt (EGMB), India, provides an ideal geological setup to study the metallogenic enrichment processes. In this study, we present a detailed petrographic and mineralogical investigation of various iron oxide phases and titanites in spatially and temporally distinct lamprophyre and mafic dykes from the diamondiferous Nuapada Lamproite Field (NLF) at the contact between Bastar Craton and EGMB. Diverse textural assemblages of oxides, namely, trellis, sandwich-type exsolutions and reaction-replacement, are widespread. Ilmenites, magnetites and titanites from the mafic dykes as well as lamprophyre exhibit an anomalous enrichment of vanadium (V 2 O 3 up to 3.7 wt%), whereas ilmenites are also characterized by their elevated manganese content (MnO up to 3.8 wt%). Mineral chemistry-based plots and thermo-oximetric studies suggest the magmatic origin of iron oxides belonging to the Fe-Ti-V-type ore in which partitioning and sequestration of the elements were controlled by differential crystallization, exsolution and fractionation rather than any imprints of contamination. Multiphase sequestration of vanadium as well as manganese in lamprophyre and mafic dykes, separated in space as well in relative depths of origin, signifies the presence of a fertile mantle. The role of subductionderived metasomatized fluids as a causative factor of vanadium metallogeny in this domain is evaluated. Low-Mg and high-Mn ilmenites of this study are consistent with the reported occurrences of diamonds from the NLF and adjoining areas of the Bastar Craton.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Manganoan Ilmenites: Tracers To Diamond Explorationmentioning

confidence: 99%

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Origin and evolution of vanadium‐rich oxide and titanite phases in lamprophyre and mafic dykes from the Nuapada diamondiferous Lamproite field, BastarCraton‐EasternGhats Mobile belt contact, India: Metallogenic and geodynamic implications

2023

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The Newly Discovered Neoproterozoic Aillikite Occurrence in Vinoren (Southern Norway): Age, Geodynamic Position and Mineralogical Evidence of Diamond-Bearing Mantle Source

Zozulya

Kullerud²,

Ribacki

et al. 2020

Minerals

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During the period 750–600 Ma ago, prior to the final break-up of the supercontinent Rodinia, the crust of both the North American Craton and Baltica was intruded by significant amounts of rift-related magmas originating from the mantle. In the Proterozoic crust of Southern Norway, the 580 Ma old Fen carbonatite-ultramafic complex is a representative of this type of rocks. In this paper, we report the occurrence of an ultramafic lamprophyre dyke which possibly is linked to the Fen complex, although 40Ar/39Ar data from phenocrystic phlogopite from the dyke gave an age of 686 ± 9 Ma. The lamprophyre dyke was recently discovered in one of the Kongsberg silver mines at Vinoren, Norway. Whole rock geochemistry, geochronological and mineralogical data from the ultramafic lamprophyre dyke are presented aiming to elucidate its origin and possible geodynamic setting. From the whole-rock composition of the Vinoren dyke, the rock could be recognized as transitional between carbonatite and kimberlite-II (orangeite). From its diagnostic mineralogy, the rock is classified as aillikite. The compositions and xenocrystic nature of several of the major and accessory minerals from the Vinoren aillikite are characteristic for diamondiferous rocks (kimberlites/lamproites/UML): Phlogopite with kinoshitalite-rich rims, chromite-spinel-ulvöspinel series, Mg- and Mn-rich ilmenites, rutile and lucasite-(Ce). We suggest that the aillikite melt formed during partial melting of a MARID (mica-amphibole-rutile-ilmenite-diopside)-like source under CO2 fluxing. The pre-rifting geodynamic setting of the Vinoren aillikite before the Rodinia supercontinent breakup suggests a relatively thick SCLM (Subcontinental Lithospheric Mantle) during this stage and might indicate a diamond-bearing source for the parental melt. This is in contrast to the about 100 Ma younger Fen complex, which were derived from a thin SCLM.

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Manganilmenite in the Magnetite Ore Body from Pokphur Area of Nagaland, North East India and the Possibility of Microdiamonds in the Ophiolites of Indo-Myanmar Ranges

Cited by 2 publications

References 20 publications

Origin and evolution of vanadium‐rich oxide and titanite phases in lamprophyre and mafic dykes from the Nuapada diamondiferous Lamproite field, BastarCraton‐EasternGhats Mobile belt contact, India: Metallogenic and geodynamic implications

Origin and evolution of vanadium‐rich oxide and titanite phases in lamprophyre and mafic dykes from the Nuapada diamondiferous Lamproite field, BastarCraton‐EasternGhats Mobile belt contact, India: Metallogenic and geodynamic implications

The Newly Discovered Neoproterozoic Aillikite Occurrence in Vinoren (Southern Norway): Age, Geodynamic Position and Mineralogical Evidence of Diamond-Bearing Mantle Source

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