Age, Nd–Hf isotopes, and geochemistry of the Vijayan Complex of eastern and southern Sri Lanka: A Grenville-age magmatic arc of unknown derivation

Kröner, Alfred; Rojas‐Agramonte, Yamirka; Kehelpannala, K.V. Wilbert; Zack, Thomas; Hegner, E.; Geng, Haifeng; Wong, J.; Barth, Matthias

doi:10.1016/j.precamres.2012.11.001

Cited by 85 publications

(36 citation statements)

References 85 publications

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“…The ca. 1100–700 Ma magmatic and deformation events in blocks originally located in the western greater India, including Sri Lanka [e.g., Kröner et al ., , ], Madagascar [e.g., Handke et al ., ], Seychelles [e.g., Torsvik et al ., ], and the Delhi Fold Belt [e.g., Dharma Rao et al ., ], were also considered by many as formed by subduction‐accretion along the western margin of Rodinia. Other possible records of the circum‐Rodinia subduction‐accretion system include the ca.…”

Section: Discussionmentioning

confidence: 99%

Mid-Neoproterozoic (ca. 830-800 Ma) metamorphicP-Tpaths link Tarim to the circum-Rodinia subduction-accretion system

Zhu

Wilde

2016

Tectonics

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Long‐lived exterior accretionary orogeny shapes tectonothermal evolution of the peripheral building blocks of supercontinents and leads to considerable crustal growth. However, such accretionary orogeny has only been locally recognized for the Rodinia supercontinent. Here a suite of newly discovered mid‐Neoproterozoic high‐grade metamorphic rocks in the northern Tarim Craton, NW China, are used to test the exterior accretion hypothesis for Rodinia. These rocks occur as dark‐colored mafic and calc‐silicate boudins in impure marbles and mica schists. Geochemical data suggest a protolith of arc‐related basalts metasomatized by Ca‐rich fluids. Mineral assemblages, phase diagram modeling, and mineral compositions for a garnet pyroxenite and a garnet clinopyroxene gneiss reveal upper amphibolite to high‐pressure granulite facies peak metamorphism (660–700°C, 11–12 kbar) following a counterclockwise P‐T path, which is characterized by prograde burial and heating, followed by near‐isothermal burial and retrograde exhumation and cooling. This P‐T path is interpreted to have recorded crustal thickening of an earlier magmatic arc transformed to a fore arc by subduction erosion and subsequent burial along bent isotherms near the subduction channel. All studied samples record ca. 830–800 Ma metamorphic zircon U‐Pb ages, which probably date the early exhumation and cooling according to Ti‐in‐zircon temperatures, zircon rare earth element patterns, and Hf isotopes. This is the first mid‐Neoproterozoic P‐T‐t path in Tarim, and it provides metamorphic evidence for a mid‐Neoproterozoic advancing‐type accretionary orogeny, which is coeval with the initial breakup events of Rodinia and thus links Tarim to the circum‐Rodinia accretion system, supporting the peripheral subduction model.

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Section: Discussionmentioning

confidence: 99%

Mid-Neoproterozoic (ca. 830-800 Ma) metamorphicP-Tpaths link Tarim to the circum-Rodinia subduction-accretion system

Zhu

Wilde

2016

Tectonics

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“…The second group is less luminescent with only vague zonation and has round terminations (e.g., spots (04)-(07); Fig. 6a), probably grown from magmas but affected by superimposed recrystallization (Kröner et al, 2013). All 36 analyses from thirty zircon grains are characterized by high Th/U values ( Table 3).…”

Section: Garnet-biotite-plagioclase Gneiss (Zk26-1 Wj Unit)mentioning

confidence: 99%

Archean crustal evolution in the southeastern North China Craton: New data from the Huoqiu Complex

Wang¹,

Zheng²,

Pan³

et al. 2014

Precambrian Research

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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%

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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Age, Nd–Hf isotopes, and geochemistry of the Vijayan Complex of eastern and southern Sri Lanka: A Grenville-age magmatic arc of unknown derivation

Cited by 85 publications

References 85 publications

Mid-Neoproterozoic (ca. 830-800 Ma) metamorphicP-Tpaths link Tarim to the circum-Rodinia subduction-accretion system

Mid-Neoproterozoic (ca. 830-800 Ma) metamorphicP-Tpaths link Tarim to the circum-Rodinia subduction-accretion system

Archean crustal evolution in the southeastern North China Craton: New data from the Huoqiu Complex

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

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