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dc.contributor.authorPlavsa, D
dc.contributor.authorCollins, Alan
dc.contributor.authorFoden, John
dc.contributor.authorKropinski, L
dc.contributor.authorSantosh, M
dc.contributor.authorChetty, T.
dc.contributor.authorClark, Chris
dc.date.accessioned2017-01-30T10:54:11Z
dc.date.available2017-01-30T10:54:11Z
dc.date.created2013-03-06T20:00:38Z
dc.date.issued2012
dc.identifier.citationPlavsa, Diana and Collins, Alan and Foden, John and Kropinski, Louise and Santosh, M. and Chetty, T. and Clark, Chris. 2012. Delineating crustal domains in Peninsular India: Age and chemistry of orthopyroxene-bearing felsic gneisses in the Madurai Block. Precambrian Research 198-199: pp. 77-93.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/6615
dc.identifier.doi10.1016/j.precamres.2011.12.013
dc.description.abstract

The Madurai Block of southern India is rich in granitic orthogneiss, much of which is orthopyroxene-bearing (charnockite). This study has identified that orthogneiss from the northwest of the Madurai Block (broadly defined as north and west of the Karur–Kambam–Painavu–Trichur lineament) has a very different origin from that in the south-eastern Madurai Block. To the north and north-west of the Madurai Block, charnockites record Neoarchaean (~2.7–2.5 Ga) crystallization ages with metamorphic overprinting at ~535 Ma. Their Archaean Nd depleted mantle model ages (2.51–3.01 Ga), high ɛNd(T) values (between −3.28 and +4.55) and low to moderate initial 87Sr/86Sr ratios (0.7017–0.7106) indicate a primarily mantle-derived origin with variable involvement of Archaean crustal material. The south-east Madurai Block samples have much younger crystallization ages of 1007 ± 23 Ma and 784 ± 18 Ma and a range of Nd depleted mantle model ages between 1.38 and 1.69 Ga, suggesting a significantly different isotopic evolution of this terrane. The isotopic signature of these charnockites (ɛNd(T) = +2.58 to −3.28, initial 87Sr/86Sr = 0.7054–0.7084) suggests the involvement of a mantle source with variable input from the contemporary crust. All samples show subsequent zircon growth, or isotopic disturbance, due to Ediacaran–Cambrian metamorphism (~535 Ma).The sharply contrasting primary igneous U–Pb ages of orthogneisses identify two distinct terranes; an Archaean basement terrane to the north and west and a Proterozoic terrane dominated by metasedimentary rocks to the south and east of the Madurai Block. The isotopic boundary between the two is here defined as a broad zone south of the Karur–Kambam–Painavu–Trichur (KKPT) lineament and appears as a southerly dipping series of seismic reflectors. A correlation is made with central Madagascar where Proterozoic metsedimentary rocks are thrust over Neoarchaean orthogneisses of the Antananarivo Block.

dc.publisherElsevier BV
dc.titleDelineating crustal domains in Peninsular India: Age and chemistry of orthopyroxene-bearing felsic gneisses in the Madurai Block
dc.typeJournal Article
dcterms.source.volume198-199
dcterms.source.startPage77
dcterms.source.endPage93
dcterms.source.issn0301-9268
dcterms.source.titlePrecambrian Research
curtin.department
curtin.accessStatusFulltext not available


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