Geochronology of the khondalite belt of Trivandrum Block, Southern India: Electron probe ages and implications for Gondwana tectonics

Santosh, M.; Morimoto, T.; Tsutsumi, Yukiyasu

doi:10.1016/j.gr.2005.11.003

Cited by 109 publications

(55 citation statements)

References 36 publications

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“…4a, 4b, 4d and 4f). Unlike in previous studies on monazites from southern India (e.g., Santosh et al, , 2006aSantosh et al, , 2006b, no detrital core was detected in Thoppur samples. From the contrast BEI, some dark anhedral core portions can be detected (Figs.…”

Section: Resultscontrasting

confidence: 96%

“…Southern India records a wide span of geological history with a protracted crustal evolution ranging from Early Archaean to Late Neoproterozoic (Harris et al, 1994;Bartlett et al, 1998;Santosh et al, , 2006aSantosh et al, , 2006b. The polymetamorphic crustal blocks in this region occupied a central position in the Gondwana supercontinent assembly (Collins and Pisarevsky, 2005).…”

Section: Geological Background and Samplingmentioning

confidence: 99%

“…Since the pioneering work of Adachi (1991, 1992), the chemical dating technique has been widely applied to understand the timing of tectonothermal events in orogenic belts worldwide. In addition to the timing of major thermal events, information on the nature and age of source as well as depositional age of the protolith have been also tapped from zircon and monazite through the application of microprobe geochronology techniques (Santosh et al, , 2006a(Santosh et al, , 2006bBrown and Appel, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Electron microprobe dating of monazites from an ultrahigh-temperature granulite in Southern India: Implications for the timing of Gondwana assembly

Santosh

Yokoyama

Tsutsumi

et al. 2008

Journal of Mineralogical and Petrological Sciences

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We report here monazite geochronology on a newly discovered high pressure (HP) and ultrahigh -temperature (UHT) granulite locality at Thoppur within the Palghat -Cauvery Shear Zone system in southern India. In situ dating of monazites associated with the UHT minerals using electron probe technique yielded PbO vs. ThO 2 * apparent isochron age of 544 ± 5 Ma. This is the first study from southern India where older monazite cores or complex age patterns are virtually absent, and all the monazite population in the studied samples crystallized/recrystallized during a single thermal maximum which we correlate with the timing of extreme crustal metamorphism during the final assembly of the Gondwana supercontinent.

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Section: Resultscontrasting

confidence: 96%

Section: Geological Background and Samplingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electron microprobe dating of monazites from an ultrahigh-temperature granulite in Southern India: Implications for the timing of Gondwana assembly

Santosh

Yokoyama

Tsutsumi

et al. 2008

Journal of Mineralogical and Petrological Sciences

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“…Detail of the analytical method is described in Supplementary Documentation, which essentially follow that described in Hokada et al (2004). Internal monazite standards with their ages ranging from 3460 to 1 Ma have been routinely monitored to check the reliability of the obtained ages (Santosh et al, 2006). Ma.…”

Section: Electron Microprobe Monazite Chronologymentioning

confidence: 99%

Peak and post–peak development of UHT metamorphism at Mather Peninsula, Rauer Islands: Zircon and monazite U–Th–Pb and REE chemistry constraints

Hokada

Harley

Dunkley

et al. 2016

Journal of Mineralogical and Petrological Sciences

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Zircon and monazite in ultrahigh temperature (UHT) metamorphic rocks from the Rauer Islands of Prydz Bay in East Antarctica were investigated in terms of U-Th-Pb and rare earth elements (REE) chemistry along with textural context. All five analyzed samples, three from the Mather Paragneiss UHT unit and two from the host orthogneiss unit yield 522-517 Ma concordant zircon ages, with older protolith/inherited zircon ages of 3268 and 2800-2400 Ma along with highly discordant Mesoproterozoic to Neoproterozoic ages. Our data confirm the Archaean protolith age for the host orthogneiss surrounding the UHT Mather Paragneiss. The Archaean and Mesoproterzoic components of the Rauer Islands were not amalgamated in the Rauer Tectonic Event at 1030-990 Ma, and deposition of the Mather Paragneiss was considered at some time after the Rauer Tectonic Event. In contrast to the well-defined 520 Ma ages obtained from the zircons in the UHT rocks, monazite grains measured by electron microprobe show a distinct internal zonation, from 580-560 Ma dark-backscattered electron image (BSE) cores enriched in middle rare earth elements (MREE) and heavy rare earth elements (HREE) to 550-520 Ma mid-BSE mantles and 510-500 Ma bright-BSE rims. From the chemical and textural evidence we infer that the MREE-HREE-rich 580-560 Ma monazite cores may have formed through the decomposition of garnet during decompression just after the UHT event, whereas the MREE-HREE-depleted 550-500 Ma monazite grains/rims formed or recrystallized in reactions associated with subsequent extensive hydration during the upper-amphibolite to granulite-facies main Prydz Tectonic Event, which also caused marked recrystallization of zircon. The above data strongly support the interpretation that the UHT metamorphism occurred prior to 590-580 Ma.

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“…The southern Indian granulite terrane (SGT) is a classic example for a collage of lower crustal fragments that underwent high -grade metamorphism during the Late Neoproterozoic to Early Cambrian time, coincident with the final stage of the amalgamation of the Gondwana supercontinent (~ 0.55 Ga, e.g., Santosh et al, 2006;Collins et al, 2007a;Tsunogae and Santosh, 2007). Traditionally, the SGT is lithologically and structurally subdivided into several crustal blocks (Fig.…”

Section: Introductionmentioning

confidence: 99%

Metamorphic P-T path of the eastern Trivandrum Granulite Block, southern India: implications for regional correlation of lower crustal fragments

Tadokoro

Tsunogae

Santosh

2008

Journal of Mineralogical and Petrological Sciences

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We report here the metamorphic P -T path for granulite -facies metapelites from the eastern part of the Trivandrum Granulite Block (TGB), southern India, and compare with the paths from the western part of the block as well as from other granulite blocks and shear zones in this region for understanding of exhumation history of the southern granulite terrane. The peak temperature condition of the eastern part (900 -1000 °C) is almost consistent with that from the western part, suggesting regional ultrahigh -temperature (UHT) metamorphism throughout the TGB. However, there is a slight difference in peak pressure conditions between the eastern part (12 kbar) and the western part (10 kbar) estimated from different Zn content within spinel in equilibrium with quartz. Such P ~ 12 kbar high -pressure event is consistent with that obtained from granulite -facies rocks further north in the Palghat -Cauvery Shear Zone system (PCSZ) and Madurai Granulite Block (MGB). The results therefore suggest that the TGB, MGB, and PCSZ underwent similar prograde high -pressure metamorphism followed by peak UHT event along a clockwise P -T trajectory, related to the collisional orogeny during the assembly of the Gondwana Supercontinent.

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Geochronology of the khondalite belt of Trivandrum Block, Southern India: Electron probe ages and implications for Gondwana tectonics

Cited by 109 publications

References 36 publications

Electron microprobe dating of monazites from an ultrahigh-temperature granulite in Southern India: Implications for the timing of Gondwana assembly

Electron microprobe dating of monazites from an ultrahigh-temperature granulite in Southern India: Implications for the timing of Gondwana assembly

Peak and post–peak development of UHT metamorphism at Mather Peninsula, Rauer Islands: Zircon and monazite U–Th–Pb and REE chemistry constraints

Metamorphic P-T path of the eastern Trivandrum Granulite Block, southern India: implications for regional correlation of lower crustal fragments

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