Geochemical Features of Bellara Trap Volcanic Rocks of Chitradurga Greenstone Belt, Western Dharwar Craton, India: Insights into MORB-BABB Association from a Neoarchean Back-Arc Basin

Manikyamba, C.; Ganguly, Sohini; Pahari, Arijit

doi:10.1007/s12583-021-1472-5

Cited by 7 publications

(2 citation statements)

References 129 publications

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“…(a) Al 2 O 3 versus TiO 2 plot where the Sandur and Chitradurga clays indicate their predominantly felsic provenance (after Ekosse, 2001); (b) Zr/Sc versus Th/Sc plot displaying a varied source for the studied clays and (c) Th versus La plot after McLennan (1989) indicating the origin of studied clays from a mixed tonalite–trondhjemite–granodiorite (TTG), felsic and mafic source. Fields of TTG of Dharwar Craton are after Jayananda et al (2015), Chitradurga andesite (CA), basalt (CB) and granite (CG) are from Manikyamba et al (2021, 2022) and Ram Mohan et al (2022); Sandur volcanics are from Harshitha Reddy et al (2023), Manikyamba et al (2008) and Manikyamba and Naqvi (1997), respectively. SB, Sandur basalts; SK, Sandur komatiites; SR, Sandur rhyolites.…”

Section: Discussionmentioning

confidence: 99%

Manganiferous clays of Dharwar Craton, southern peninsular India: Insights on Archean weathering and ore formation processes

Harshitha,

Manikyamba,

Sridhar

et al. 2023

Geological Journal

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Vast clay deposits of Chitradurga and Sandur greenstone belts of the Dharwar Craton, southern peninsular India, hosting pockets of high‐grade manganese (Mn) ore, provide remarkable clues related to the ore‐forming processes and palaeo‐environmental conditions. In this study these Fe–Mn‐rich clays were investigated through mineralogical and geochemical characteristics to comprehend their palaeo‐weathering and genetic constraints and their role in the supergene accumulation of Mn ore. Their mineralogy is characterized by predominant kaolinite, muscovite, birnessite, haematite, goethite, halloysite along with quartz and traces of ilmenite. Chemical indices of alteration and weathering indicate intense weathering conditions under high palaeo‐precipitation rates in a humid, tropical climate under shallow burial conditions and K‐metasomatism. The presence of authigenic kaolinite and absence of illite reflect on diagenesis up to mesodiagenetic stage. Positive to negative Ce anomalies (Ce/Ce* = 0.67–5.93) of these clays suggest varying oxic‐anoxic conditions during their genesis, whereas conspicuous negative Eu anomalies (Eu/Eu* = 0.61–0.99) are attributed to precursor sediment signatures and hydrothermal imprints of the Mn ore. These kaolinite‐rich clays are suggested to have been formed by in situ chemical alteration, whereas kaolinitization of the Fe–Mn‐rich arenaceous and argillaceous sediments was derived from predominant tonalite and felsic provenance in a shallow marine passive margin setting. Based on the morphologies of birnessite, haematite and goethite in the investigated clays, we propose that these clays have played a key role in the oxidation and deposition of Mn (II) from the migrating aqueous solutions and acted as organo‐polymerization templates for the proliferation of ancient microbial life on the planet Earth.

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Section: Discussionmentioning

confidence: 99%

Manganiferous clays of Dharwar Craton, southern peninsular India: Insights on Archean weathering and ore formation processes

Harshitha,

Manikyamba,

Sridhar

et al. 2023

Geological Journal

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“…Continuous eruption led to the formation of bulbous structures (Fig. 2B, C), generating interconnected pillow basalt units, whose occurrence within a back-arc basin (Bhowmick and Mondal, 2021;Manikyamba et al, 2021) is indicative of uninterrupted lava flow. A cross-section of an individual pillow shows distinct colour contrast separating the chilled margin, the glassy zone and the relatively crystalline inner zone.…”

Section: Regional Geology and Pillow Basaltmentioning

confidence: 99%

Understanding the spatio-temporal evolution of fractures in pillow basalt

Mondal,

Biswas

et al. 2023

GeA

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We investigated the origin and spatio-temporal evolution of cooling fractures in pillow basalt which undergo thermal contraction after their eruption in an aqueous environment. Through a computer-based simulation using Fourier transformation, the thermo elastic stress displacement profiles within individual pillow units are determined. The scaled model (pillow diameter - 1 meter) generated radial, linear fractures perpendicular to pillow margin and irregular discrete flaws in the pillow interior like the ones observed in natural examples. Radial linear fractures of 3–5 centimetre in length have been measured in pillows of average one-metre diameter from the Maradihalli region, in the Chitradurga Schist Belt, India. An estimated time of 94–118 minutes was required to get radial fractures of similar length in the simulation. Our model efficiently replicated the generation and distribution of thermal fractures and allowed an estimation of cooling time for the peripheral glassy zone but has limitations in deciphering the formation of fracture networks in progressively crystalline inner zone of pillows.

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Geochemistry of basalts in unravelling the mantle processes and crustal evolution: Insights from the greenstone belts of western Dharwar Craton

Manikyamba

Pahari

Santosh

et al. 2022

Geosystems and Geoenvironment

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Geochemical Features of Bellara Trap Volcanic Rocks of Chitradurga Greenstone Belt, Western Dharwar Craton, India: Insights into MORB-BABB Association from a Neoarchean Back-Arc Basin

Cited by 7 publications

References 129 publications

Manganiferous clays of Dharwar Craton, southern peninsular India: Insights on Archean weathering and ore formation processes

Manganiferous clays of Dharwar Craton, southern peninsular India: Insights on Archean weathering and ore formation processes

Understanding the spatio-temporal evolution of fractures in pillow basalt

Geochemistry of basalts in unravelling the mantle processes and crustal evolution: Insights from the greenstone belts of western Dharwar Craton

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