Primary and secondary textures of dolomite in Eppawala carbonatites, Sri Lanka: implications for their petrogenetic history

Madugalla, Nadeesha; Pitawala, H.M.T.G.A.; Manthilake, Geeth

doi:10.3190/jgeosci.242

Cited by 7 publications

(9 citation statements)

References 68 publications

(109 reference statements)

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“…Dolomite (~20 vol. %) is the second most common carbonate mineral found in the carbonatites, with five morphological types (Madugalla et al, 2017): (i) coarse-grained dolomite (type-1), (ii) rod-shaped or vermicular dolomite micro-crysts within the type-1 calcite (type-2), (iii) inclusions of dolomite within the type-1 calcite forming plug-or wedge-shaped arrangements (type-3), (iv) dolomite micro-crysts along the grain boundaries of type-1 calcite (type-4) and (v) clusters of dolomite crosscutting the type-1 calcite (type-5). In addition, some of the dolomites are found in association with calcite, forsterite and diopside.…”

Section: Mineralogical and Textural Characteristicsmentioning

confidence: 99%

“…The carbonatite body having emplaced within the crust initially has experienced postmagmatic cooling yielding exsolution of primary magmatic calcite. Subsequently squeezing of the carbonatite body to the upper crust has taken place resulting in recrystallization and rearrangement of carbonate minerals (Madugalla et al, 2017).…”

Section: Mineralogical and Textural Characteristicsmentioning

confidence: 99%

“…Despite a large number of documented studies on carbonate rocks, only a few attempts have been made on textural characteristics of carbonate minerals (Chakhmouradian et al, 2016;Pitawala and Lottermosser, 2012;Zaitsev and Polezhaeva, 1994;Madugalla et al, 2017) However, interpretation of carbonate textures is a useful tool not only to interpret the petrogenesis of carbonate rocks but also to ore-body delineation and understanding industrial minerals potential. Further, the geochemical and stable isotope data of carbonate rocks along with textural characteristics of carbonate minerals provide valuable information on the origin, genesis, temperatures of mineralization, rock-fluid interaction and alteration processes of marbles and crystallization and emplacement history, as well as the post-emplacement history of carbonatites (Hogarth et al, 1985;Barker and Nixon, 1989;Le Bas and Srivastava, 1989;Hornig-Kjarsgaard, 1998;Zaitsev and Chakhmouradian, 2002;Zheng and Hoefs, 1993;Cooper and Reid 1991;Zaitsev and Polezhaeva 1994;Mizuochi, et al, 2010;Mposkos et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Mineralogy, petrography, geochemistry and economic potential of carbonate rocks of Sri Lanka

Pitawala

2019

J. Geol. Soc. Sri Lanka

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Sri Lanka comprises different paragenetic types of carbonate rocks such as Miocene limestone, crystalline limestone (marble), carbonatite and dyke like carbonate bodies. The purpose of this paper is to summarize documented studies on petrogenesis and economic potential of crystalline limestone, carbonatite and dyke-like carbonate bodies. Pure marbles, which are confined to the Highland Complex (HC) of the country are composed mainly of dolomite, while carbonatite occurrences at Eppawala consist mainly of calcite. Monomineralic calcite bodies with trace amounts impurities are found in the Southeastern part of the country. Detailed geochemical, stable isotope and petrological studies on marbles of HC have revealed that they have formed by granulite grade metamorphism of dolostones deposited in an open ocean. Pure marbles basically retain their primary isotopic signatures with only their  18 O values amenable to alteration due to 18 O/ 16 O exchange with percolating waters. Over a limited distance, geochemistry of contact zones of the marbles has been changed significantly due to metamorphic geochemical alterations. Eppawala carbonatites are unique among the other carbonatites in the world in terms of field setting, isotope and elemental geochemistry and textural features of carbonate minerals. Trace and rare earth element composition as well as stable isotope ratios from the Eppawala carbonatites are not comparable with most of carbonatites in the world. But they are within the broader range of carbonatitic rocks and do not show any meta-limestone signatures. Textural features and chemical composition of carbonate minerals suggest that present carbonatite bodies have been dislocated from the emplaced positions in the crust due to deformations experienced by the country rocks. Geochemically and petrographically the dyke-like carbonate bodies differ significantly from both carbonatites and crystalline limestone. Concentrations of Sr and Rare Earth Elements (REEs) of dyke-like bodies lie between those of carbonatites and marbles. However, the concentrations are much lower than those of carbonatites. Carbon and oxygen isotope compositions are similar to those of most meta-sedimentary carbonates suggesting that the carbonate dykes were formed as melts from marbles at crustal levels due to shearing and thrusting of HC and Vijayan Complex (VC) plates. Laboratory experiments carried-out in the recent past were able to synthesize value-added products such as Precipitated Calcium Carbonate (PCC), magnesium hydroxide [Mg(OH) 2 ], magnesium oxide (MgO), their nanoparticles, their polymer-nanocomposites, Amorphous Calcium Carbonate (ACC) and poly(acrylate)(PA-)-encapsulated Mg(OH) 2 ; Hollow Calcium Carbonate (HCC), hydrophobic PCC and hydrophobic Mg(OH) 2 from carbonate rocks of Sri Lanka. Results of those studies suggest that there is a high possibility to synthesize nanoparticles and nanocomposites of PCC, Mg(OH) 2 and MgO using Sri Lankan carbonate rocks with appropriate quality to meet industrial requirements and to fulfi...

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Section: Mineralogical and Textural Characteristicsmentioning

confidence: 99%

Section: Mineralogical and Textural Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mineralogy, petrography, geochemistry and economic potential of carbonate rocks of Sri Lanka

Pitawala

2019

J. Geol. Soc. Sri Lanka

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“…Also indicated on Figure 5 is the location of the Eppawala carbonatite (EC), the main carbonatite unit in Sri Lanka, which crops out within the WC (Manthilake et al 2008;Madugalla et al 2017). The EC consists of apatite-rich carbonate rocks that occur as massive, discontinuous N-S-trending oval bodies and intrude the Precambrian, high-grade metamorphic terrane (WC)…”

Section: Sri Lankamentioning

confidence: 99%

Boron isotope compositions establish the origin of marble from metamorphic complexes: Québec, New York, and Sri Lanka

Kuebler

Simonetti

et al. 2022

American Mineralogist

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The origin of an array of marble samples found in both the Grenville Province and southwestern Sri Lanka remains uncertain, whether magmatic, sedimentary, or mixed, due to their proximity to both carbonatite bodies and carbonate-rich metasedimentary rocks. This study reports boron and trace element abundances, in addition to carbon, oxygen, boron, and strontium isotopic compositions in order to determine the petrogenesis of these carbonate-rich samples.Boron abundances for all of the samples are relatively high and variable (1.48 -71.1 ppm) compared to those for carbonatites worldwide (≤ 1 ppm), and mostly overlap those documented for sedimentary sources (up to 54 ppm). The rare earth element (REE) abundances (0.5 -1068 ppm) for the marbles studied are similar to those for local sedimentary units, and thus contain, in general, lower REE contents than both the average worldwide calcio-carbonatite and respective neighboring carbonatite bodies. The δ 13 C V-PDB and δ 18 O V-SMOW compositions for all of the This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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“…Presence of Mg rich foresterite exhibiting spectacular resorbed texture in the carbonatite of Sung Valley Complex has indicated early crystallization of olivine and subsequent crystal-melt interaction between the early formed silicate and carbonate melt. Madugalla et al [42] provided the detail variations in textures of dolomite and calcite followed by compositional differences in Eppawala carbonatites, Sri Lanka and thier petrogenetic link. They explain two morphological forms for calcite i.e., calcite-I and II, while dolomites were subdivided into five distinct morphological types i.e., dolomite-I, II, III, IV and V. There geochemical variations indicate that type-I dolomite and type-I calcite are primary magmatic in origin.…”

Section: Mineralogy and Mineral Chemistrymentioning

confidence: 99%

An Overview of the Carbonatites from the Indian Subcontinent

Randive

Meshram

2020

Open Geosciences

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AbstractCarbonatites are carbonate-rich rocks of igneous origin. They form the magmas of their own that are generated in the deep mantle by low degrees of partial melting of carbonated peridotite or eclogite source rocks. They are known to occur since the Archaean times till recent, the activity showing gradual increase from older to younger times. They are commonly associated with alkaline rocks and be genetically related with them. They often induce metasomatic alteration in the country rocks forming an aureole of fenitization around them. They are host for economically important mineral deposits including rare metals and REE. They are commonly associated with the continental rifts, but are also common in the orogenic belts; but not known to occur in the intra-plate regions. The carbonatites are known to occur all over the globe, majority of the occurrences located in Africa, Fenno-Scandinavia, Karelian-Kola, Mongolia, China, Australia, South America and India. In the Indian Subcontinent carbonatites occur in India, Pakistan, Afghanistan and Sri Lanka; but so far not known to occur in Nepal, Bhutan, Bangladesh and Myanmar. This paper takes an overview of the carbonatite occurrences in the Indian Subcontinent in the light of recent data. The localities being discussed in detail cover a considerable time range (>2400 Ma to <0.6 Ma) from India (Hogenakal, Newania, Sevathur, Sung Valley, Sarnu-Dandali and Mundwara, and Amba Dongar), Pakistan (Permian Koga and Tertiary Pehsawar Plain Alkaline Complex which includes Loe Shilman, Sillai Patti, Jambil and Jawar), Afghanistan (Khanneshin) and Sri Lanka (Eppawala). This review provide the comprehensive information about geochemical characteristics and evolution of carbonatites in Indian Subcontinent with respect to space and time.

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Primary and secondary textures of dolomite in Eppawala carbonatites, Sri Lanka: implications for their petrogenetic history

Cited by 7 publications

References 68 publications

Mineralogy, petrography, geochemistry and economic potential of carbonate rocks of Sri Lanka

Mineralogy, petrography, geochemistry and economic potential of carbonate rocks of Sri Lanka

Boron isotope compositions establish the origin of marble from metamorphic complexes: Québec, New York, and Sri Lanka

An Overview of the Carbonatites from the Indian Subcontinent

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