Rare earth element precipitation induced by non-redox transformation of magnetite to hematite: Microtextural and geochemical evidence from the Kamthai carbonatite complex, western India

Upadhyay, Dewashish; Mondal, Suman; Patel, Ashim Kumar; Mishra, Biswajit; Pruseth, Kamal Lochan; Bhushan, S. K.

doi:10.1016/j.lithos.2021.106381

Cited by 3 publications

(3 citation statements)

References 59 publications

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“…Thus, the sequence of P-bearing minerals at Kamthai is apatite → britholite → daqingshanite. Clasts containing abundant magnetite as suggested by Uphadyay et al (2021) do not appear to be common .…”

Section: Carbothermalite Microbreccia Formationmentioning

confidence: 87%

“…7). Stage 3 represents residual carbothermal fluids undergoing further evolution and becoming enriched in La relative to Ce and other REE together with the mixing of exogenous water enriched in O 18 as shown by Uphadyay et al (2021). These fluids, which can be considered as carbohydrothermal fluids (Mitchell, 2005) invaded, and altered pre-existing breccias, created new breccias and deposited a wide variety of Mn and Fe bearing carbonates together with La -enriched REE fluorocarbonates such as bastnäsite-(La) (Fig.…”

Section: Carbothermalite Microbreccia Formationmentioning

confidence: 99%

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Composition and Paragenesis of Daqingshanite from the Kamthai Carbothermalite, Rajasthan, India.

Mitchell

2024

MinMag

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Daqingshanite in the Kamthai REE deposit (India) occurs as two paragenetic types: primary granular coarse grained crystals coexist ing with primary carbocernaite, barite and bastnäsite; and as aligned micro -ovoid globules within clasts of Sr-bearing calcite. Carbocernaite forming trellis-type lamellae in some of these calcite clasts do not represent exsolution and are considered as rep lacement textures as they formed subsequent to daqingshanite. The origins of the textural relations of the microglobules of daqingshanite to their host Sr-calcite cannot be unambiguously determined, although an exsolution origin is not considered feasible. The textures are similar to those of "chalcopyrite disease" and as such could be interpreted as replacement features formed in a low temperature carbothermal environment which should facilitate replacement. Given that daqingshanite is an early crystallizing phase it is also possible that cotectic crystallization with Sr-calcite occurred, followed by subsolidus re -equilibration with recrystallization along specific crystallo graphic planes in the calcite. The Kamthai REE deposit is best described as a low temperature carbothermalite microbreccia consisting of a wide variety of clasts resulting from the autobrecciation of rocks formed during, and after, the magmatic to carbothermal transition of an undetermined parental calcite carbonatite-forming magma. Many clasts have been replaced by late stage La -enriched carbothermal fluids mixed with exogenous water during the final low temperature stage of evolution of the deposit.

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Section: Carbothermalite Microbreccia Formationmentioning

confidence: 87%

Section: Carbothermalite Microbreccia Formationmentioning

confidence: 99%

Composition and Paragenesis of Daqingshanite from the Kamthai Carbothermalite, Rajasthan, India.

Mitchell

2024

MinMag

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“…Replacement/transformation, both redox (Davis et al, 1968;Powell et al, 1999;Taylor et al, 2001;Morris, 2003) and non-redox (Ohmoto, 2003;Otake et al, 2007;Upadhyay et al, 2021;Yin et al, 2022), of magnetite to hematite is a widely researched topic. Both processes entail the inheritance of orientations by the replaced from the host crystals such that the transformation is characterized by one or more crystallographic relations (Barbosa and Lagoeiro, 2010;Barbosa et al, 2020;Braga de Oliveira et al, 2020;Yin et al, 2022).…”

Section: Topotactic Relationship Between Magnetite and Hematitementioning

confidence: 99%

Deformation mechanisms and characteristics of the meta-BIFs from an early Proterozoic shear system of the Southern Granulite Terrane (SGT), India

Dutta¹,

Misra²,

Karmakar³

2022

Preprint

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We studied three samples of Banded Iron Formation (BIF) rocks from Southern Granulite Terrane (SGT) of India, which was metamorphosed at high-pressure granulite facies and exhumed from 40-50 km depth. We examined the microstructure, texture, and deformation mechanisms of the primary minerals (quartz, magnetite, and hematite). Microstructures, variations in size and shape of quartz grains suggest that the three samples deformed to different intensities and temperatures. The EBSD derived CPOs for quartz and magnetite grains are strong, implying dislocation creep as the dominant mechanism. The presence of distinct subgrains in magnetite, rare in natural samples, attests to the same. Furthermore, twinning on {111}, as evident from the misorientation angle and axis distributions, indicates ductile deformation of magnetite below 400 °C. Subgrain boundary trace analysis in selected magnetite grains reveals that multiple-slip planes {111}, {110}, and {100} were operational. Topotaxial replacement, via redox reaction, of magnetite grains along their octahedral planes by hematite is evident. Well-developed CPOs but low (<1°) GOS values of both magnetite and hematite grains suggest that recovery processes in these were rapid. Post-replacement deformation was weak and did not affect the hematite CPOs that were inherited from the relatively more deformed host magnetite grains.

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Indian ore deposits: current genetic understandings

Mishra,

Upadhyay

2024

Proc.Indian Natl. Sci. Acad.

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Rare earth element precipitation induced by non-redox transformation of magnetite to hematite: Microtextural and geochemical evidence from the Kamthai carbonatite complex, western India

Cited by 3 publications

References 59 publications

Composition and Paragenesis of Daqingshanite from the Kamthai Carbothermalite, Rajasthan, India.

Composition and Paragenesis of Daqingshanite from the Kamthai Carbothermalite, Rajasthan, India.

Deformation mechanisms and characteristics of the meta-BIFs from an early Proterozoic shear system of the Southern Granulite Terrane (SGT), India

Indian ore deposits: current genetic understandings

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