Ca. 750–1100 Ma magmatic events and Grenville-age deformation in Sri Lanka: relevance for Rodinia supercontinent formation and dispersal, and Gondwana amalgamation

Kröner, Alfred; Kehelpannala, K.V. Wilbert; Hegner, E.

doi:10.1016/s1367-9120(03)00060-9

Cited by 91 publications

(52 citation statements)

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“…The Kadugannawa Complex consisting of hornblende gneiss, biotite-hornblende gneiss and migmatites occurs within elongate synformal basins around Kandy in central Sri Lanka (Cooray, 1994). Although a number of petrological studies have been carried out later on this terrain (e.g., Kehelpannala, 1997;Mathavan et al, 1999;Mathavan and Fernando, 2001;Kröner et al, 2003;Kröner et al, 2013;Dharmapriya et al, 2014;Santosh et al, 2014;He et al, 2016a), lithological nomenclature and petrology of the terrain introduced by Cooray (1994) is widely recognized.…”

Section: Introductionmentioning

confidence: 99%

“…Baur et al (1991) and Hölzl et al (1994) recognized zircon upper intercept ages around 1.9-1.8 Ga for orthogneisses, and interpreted them as the crystallization ages of the protoliths. However, Kröner et al (1987Kröner et al ( , 2003 found lead loss in zircon and identified zircon growth events at 1.1-0.75 Ga. Sajeev et al (2003Sajeev et al ( , 2007 also proposed 1.4 Ga and 530 Ma thermal events in the Highland Complex, although Sajeev et al (2007) pointed out that the 1.1 Ga and 1.4 Ga ages require reexamination. Sajeev et al (2010) has given evidences of age clusters at about 1.7 Ga, episodes of zircon growth at 1.04-0.83 Ga and two generations of overgrowths in zircon at 569 ± 5 and 551 ± 7 Ma in quartz-saturated granulites.…”

Section: Introductionmentioning

confidence: 99%

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Internal texture and U–Th–total Pb isochron ages of monazite in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

Wanniarachchi

Akasaka

2016

Journal of Mineralogical and Petrological Sciences

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The Chemical U-Th-total Pb isochron method (CHIME) dating was performed for internal domains and zones within monazites in garnet-biotite gneiss and garnet-biotite-cordierite gneiss from the Precambrian Southwestern Highland Complex (SWHC), Sri Lanka, to evaluate evolution of the metamorphic rocks which have been subjected to multiple thermal events during the Gondwana amalgamation. Monazites are abundant in garnetbiotite gneisses. The monazites have core-rim zoned, inherited core-bearing, complexly zoned, and oscillatory zoned type internal textures. The core domains of the core-rim zoned, inherited core-bearing, and complexly zoned type monazites show ages of 533-503, 1788-512, and 1686-678 Ma, respectively, and the rim domains show younger ages of 500-434 Ma. Even though its repeated zonings, oscillatory zoned type monazites show the only young age of 470 ± 45 Ma. The determined isochron ages are grouped into four clusters: group I of 1766 ± 140 and 1788 ± 30 Ma (at present 1686 ± 186 Ma age may be grouped into group I); group II of 679 ± 99 Ma; group III of ages in a range between 533 ± 22 and 481 ± 42 Ma; and group IV of ages in a range between 472 ± 17 and 433 ± 14 Ma. The ages of the group I may imply magma emplacement ages. The ages of the group II correspond to the stage of the most prominent thermal event recorded in the region. The groups III and IV can be identified as post-peak thermal events. The age data given for the monazites in the SWHC are consistent with the published data for the Central Highland Complex, and indicate that the SWHC has been subjected to the same thermal events as the Central Highland Complex.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Internal texture and U–Th–total Pb isochron ages of monazite in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

Wanniarachchi

Akasaka

2016

Journal of Mineralogical and Petrological Sciences

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“…The Eppawala carbonatite bodies are exposed in the WC close to their tectonic boundary with the HC. The HC is composed of meta-sedimentary rocks such as pelitic to semi-pelitic gneiss, quartzite, marble and calc-silicate (Cooray 1984(Cooray , 1994 as well as late-to post-tectonic granitoids and mafic magmatic rocks (Kröner et al 2003) that yield Nd-model ages from 2.0 to 3.4 Ga (Milisenda et al 1988(Milisenda et al , 1994 lithologies in the HC has occurred between 550 and 600 Ma (Milisenda et al 1994).…”

Section: Geological Settingmentioning

confidence: 99%

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

Madugalla¹,

Pitawala²,

Manthilake³

2017

J. Geosci.

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Textural studies of carbonate minerals over the past three decades revealed that their textures are useful tool for understanding of petrogenesis of carbonatites. Petrographic, cathodoluminescence (CL) and electron-microprobe studies on textures of calcite and dolomite were performed for interpretation of evolution of Eppawala carbonatites in Sri Lanka. The studied carbonatites are dominated by calcite with subordinate dolomite. Calcites occur in two different morphological forms, reflecting two generations: as grains with dolomite inclusions (type-1) and dolomite-free (type-2) ones. Dolomites were subdivided into five distinct morphological types: randomly distributed, coarse-grained dolomite (type-1), rod--shaped or vermicular dolomite microcrysts within the type-1 calcite (type-2), inclusions of dolomite within the type 1 calcite forming plug-or wedge-shaped arrangements (type-3), dolomite microcrysts along the grain boundaries of the type 1 calcite (type-4) and clusters of dolomite crosscutting the type 1 calcite (type-5).The geochemical results indicate that these five morphological types accounts for three different generations of dolomites. Type-1 dolomite and type-1 calcite are interpreted as primary magmatic. Type-2 and type-3 represent exsolved dolomite formed by exsolution from type-1 calcite. Type-4 and type-5 dolomites are recrystallized and reorganized dolomites of exsolved type-2 and type-3 dolomites. Type-2 calcite reflects later recrystallization event. The composition of type-1 calcite indicates minimum temperatures of exsolution of c. 650 °C. The exsolution and recrystallization kinetics reflected the equilibration of carbonatite magma at two crustal depths during the petrogenesis of Eppawala carbonatite. The re-localization may have been related to the deformations experienced by the country rocks. : carbonatites, calcite, dolomite, exsolution, recrystallization Received: 15 March 2016; accepted: 24 August 2017; handling editor: V. Rapprich (Cooper and Reid 1991) have been well studied. Such studies revealed that textures of carbonate minerals are important tools to interpret the specific conditions of super cooling, cooling rates and super-saturation prevailing in the corresponding magmatic body. Additionally, the intergrowth textures of calcite and dolomite, where dolomite forms vermicules, plates, rods, segmented rods, blebs and xenomorphic grains have been reported from certain carbonatites (Van der Veen 1965;Zaitsev and Polezhaeva 1994). These textures yielded the composition of the primary carbonate phases, information on crystal-melt segregation and crystallization temperature as well as depth and timing of sub-solidus processes that have modified them (Van der Veen 1965;Cooper and Reid 1991;Wall et al. 1993;Zaitsev and Polezhaeva 1994). In the past several decades, intergrowth formation mechanisms have been subject to discussion. Exsolution (Goldsmith 1983;Puhan 1984) or metasomatism with recrystallization (Zaitsev and Polezhaeva 1994) could lead to the formation of such textures....

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“…The Kadugannawa Complex consisting of hornblende gneiss, biotitehornblende gneiss, and migmatites occurs within elongate synformal basins around Kandy in central Sri Lanka (Cooray, 1994). The terrain subdivision introduced by Cooray (1994) have been widely followed in a number of petrological studies (e.g., Kehelpannala, 1997;Mathavan et al, 1999;Mathavan and Fernando, 2001;Kröner et al, 2003;Kröner et al, 2013;Dharmapriya et al, 2014;Santosh et al, 2014;He et al, 2016aHe et al, , 2016b.…”

Section: Introductionmentioning

confidence: 99%

“…Baur et al (1991) and Hölzl et al (1994) obtained zircon upper intercept ages around 1900-1800 Ma for orthogneisses, which were interpreted as crystallization ages of the protoliths. On the other hand, Kröner et al (1987Kröner et al ( , 2003 identified lead loss and zircon growth events at 1100-750 Ma. Sajeev et al (2003Sajeev et al ( , 2007 also proposed 1400 and 530 Ma thermal events in the CHC, although Sajeev et al (2007) pointed out that the 1100 and 1400 Ma ages require reexamination.…”

Section: Introductionmentioning

confidence: 99%

Internal textures and U–Pb geochronology of zircons in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

Wanniarachchi

Akasaka

Hayasaka

et al. 2016

Journal of Mineralogical and Petrological Sciences

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Internal textures and U-Pb ages of zircons in garnet-biotite gneiss of the Southwestern Highland Complex (SWHC), Sri Lanka, were studied to clarify the repeated thermal events in the study area. The zircons from garnet-biotite gneiss consist of the detrital cores and overgrowths with two to five growth stages. The detrital zircon cores are rounded or euhedral to subhedral in shape, and show transgressive internal textures or oscillatory zoning.The rounded or subhedral to euhedral detrital core morphology suggests several major Archaean to Proterozoic sources of detritus zircons in the SWHC. Ages of the detrital cores are in a range of 3.3-1.7 Ga, and can be categorized into five ranges of 3380-3220, 2730-2660, 2550-2490, 2220-2170, and 1900-1700 Ma, implying the source rock ages. The detrital cores in the 3380-2170 Ma have Th/U-ratios of more than 0.3, suggesting igneous origin. The detrital cores in the range 1900-1700 Ma have Th/U of >0.3 or 0.3-0.1, suggesting an igneous or metamorphic origin. Some overgrowths with the ages in the ranges of 1900-1700 and 630-500 Ma have Th/U-ratios less than 0.1 implying that zircon growth corresponds to the thermal events. Zircons lacking detrital cores and having growth zones with characteristic metamorphic internal textures gave ages in a range of 630-500 Ma, implying the generation at the final granulite grade metamorphic event.

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Ca. 750–1100 Ma magmatic events and Grenville-age deformation in Sri Lanka: relevance for Rodinia supercontinent formation and dispersal, and Gondwana amalgamation

Cited by 91 publications

References 70 publications

Internal texture and U–Th–total Pb isochron ages of monazite in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

Internal texture and U–Th–total Pb isochron ages of monazite in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

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

Internal textures and U–Pb geochronology of zircons in metamorphic rocks from the Southwestern Highland Complex, Sri Lanka

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