The Karnataka Late Cretaceous Dykes as products of the Marion Hot Spot at the Madagascar ‐ India Breakup Event: Evidence from<sup>40</sup>Ar‐<sup>39</sup>Ar geochronology and geochemistry

Kumar, Anil; Pande, Kanchan; Venkatesan, T. R.; Rao, Y. J. Bhaskar

doi:10.1029/2001gl013007

Cited by 85 publications

(41 citation statements)

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“…Anil Kumar et al, 2001;Pande et al, 2001). Still earlier, the Rajmahal-Sylhet CFB formed at ~116-120 Ma, about 10 million years after the breakup of eastern Greater India from Australia (e.g., Kent et al, 1997).…”

Section: Structure and Tectonics Of The Indian Shieldmentioning

confidence: 99%

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Sheth¹

2005

Gondwana Research

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Deep mantle plumes supposedly incorporate deeply subducted eclogitized oceanic crust, and continental flood basalts (CFBs) are now thought by some to be derived from such eclogite-bearing peridotite plumes. Eclogite-peridotite mixtures have much lower solidi (and produce much greater melt fractions for a given temperature) than peridotite. Ferich (eclogite-or pyroxenite-bearing) sources have been inferred for many CFBs. However, plumes with considerable amounts of eclogite should have difficulty in upwelling owing to the high density of eclogite. Besides, CFBs are always located along pre-existing lithospheric structures (suture zones, edges of thick cratons) and commonly associated with lithospheric rifting and continental breakup. India's major late Mesozoic CFB, the Deccan Traps, erupted through rift zones and a new continental margin that had developed along ancient suture zones traversing the subcontinent. Many Deccan basalts are too Fe-rich to have been in equilibrium with a peridotite mantle source, and have commonly been considered to be significantly fractionated derivatives of picritic liquids. However, it is possible to view them as relatively less evolved liquids derived from a source with extra fertility (i.e., an Fe-rich source). A new non-plume, plate tectonic model for Icelandic hotspot volcanism involves melting of a shallowly recycled slab of eclogitized Iapetus oceanic crust formerly trapped along the Caledonian suture. The model explains the geochemical-petrological characteristics of Icelandic basalts, and is consistent with passive upper mantle upwelling under Iceland inferred from recent seismic tomography. Based on the petrological and geochemical features of the Deccan flood basalts of the type section, in the Western Ghats, I propose that old, eclogitized oceanic crust trapped in the ancient Indian suture zones could have produced voluminous basaltic melts during the Deccan event.

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Section: Structure and Tectonics Of The Indian Shieldmentioning

confidence: 99%

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Sheth¹

2005

Gondwana Research

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“…More specifically, in the present case, the orogenic corridor is of the Proterozoic period, whereas a number of alkaline complexes (Bose, 1980;Krishnamurthy and Udas, 1981;Sethna, 1989;Srivastava, 1989;Subrahmanyam and Leelanandam, 1989;Rathore and Venkatesan, 1991;Basu et al, 1993;Dessai, 1994;Anil Kumar et al, 2003) having ages between 120-50 Ma, have been reported along various mobile belts affected by the plume activity. The ages of large igneous provinces (Rajmahal, Madagascar-South India and Deccan traps) by Ar-Ar methods (Basu et al, 1993;Baksi, 1994Baksi, , 1995Storey et al, 1995;Radhakrishna et al, 1999;Anil Kumar et al, 2001) also lie between Cretaceous to early Tertiary times. Further, these alkaline complexes are associated with relatively long wavelength gravity highs (Tewari et al, 1991;Raval and Veeraswamy, 1997;Suryaprakasa Rao, 2003) and are strongly suggestive of deep-seated magmatic underplating which is also corroborated by the cospatial high velocity layer inferred by deep seismic studies (Tewari et al, 1991;Singh and Meissner, 1995).…”

Section: Geophysical and Tectonic Evidence Of Channelingmentioning

confidence: 99%

“…1(a)). A number of geophysical anomalies and geotectonic features have been attributed to the interaction of the Indian lithosphere with these plumes since the Cretaceous (Raval, 1989;Kent, 1991;Basu et al, 1993;Singh and Meissner, 1995;Storey et al, 1995;Atchuta Rao et al, 1996;Mall et al, 1999;Mishra et al, 1999;Courtillot et al, 2000;Veeraswamy, 2000, 2003;Anil Kumar et al, 2001;Tewari et al, 2001;Mukhopadhyay, 2002;Roy, 2004;Mahoney et al, 2002). These plumes (P) appear to have affected the MB network of India.…”

Section: Three-phase Breakupmentioning

confidence: 99%

“…It implies that in the breakup along India's western margin too, a mobile belt and plume were involved. The trace and outburst of the Marion plume over Greater India is supported by large-scale magmatism (at ∼90 Ma) over juxtaposed mobile parts of the Madagascan and Indian CL Radhakrishna et al, 1999;Anil Kumar et al, 2001). To further examine the similarity between Indian mobile belts and Madagascar, the geophysical anomalies, juxtaposition and geotectonic data over the Madagascan and Indian mobile belts are compared:…”

Section: Separation From Madagascar (∼90 Ma)mentioning

confidence: 99%

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Chipping of cratons and breakup along mobile belts of a supercontinent

Veeraswamy

Raval

2014

Earth Planet Sp

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Probably one of the most significant heterogeneities of a continental lithosphere is the noticeable difference in the thickness and properties of its cratonic and mobile parts. The trans-continental mobile belts (Paleoorogens/paleo-sutures) represent a relatively thinner, warm, wet and weak lithosphere, which makes it more vulnerable to episodic mantle (or plume) upwellings and compressional forces. Here evidence is presented from the Indian continental lithosphere to show that these properties of mobile belts (MB) facilitate channeling of thermomagmatic fluxes (TMF) in both lateral as well as vertical directions. This, to a major extent, can account for the observed concentration (or focusing) of geophysical anomalies, tectonomagmatic features and strain along these MBs. In addition, a closer examination of the three continental breakups of Greater India since the Cretaceous reveals that the combination of a sufficiently weakened MB and mantle plume could become 'fatal' for the supercontinental stability. On the other hand, the thick (>200 km) or deep-rooted continental lithosphere beneath cratons is characterized by a relatively cold and dry lithosphere, which resists remobilization. From this relative impenetrability, TMFs are channeled mostly through the MBs following the long-term stability of the cratonic lithosphere. This difference in cratonic and MB regimes results in strongly heterogeneous thermal blanketing. However, in certain situations, the edge of a cratonic region may also get chipped-off following a number of thermotectonic rejuvenations of adjoining MBs-as exemplified by the breakup of the Antongil and Masora cratonic blocks (now lying on the Madagascar) from the Western Dharwar craton (India) during the IndiaMadagascar separation. From the study of supercontinental dispersals, it seems that the processes of breakup along pre-existing mobile belts may be globally applicable. This is, at times, also accompanied by chipping of cratons.

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“…The latter dykes have a restricted occurrence in southern Kerala, along the southernmost tip of India, and may be related to rifting preceding the separation of Australia, Antarctica and India [18]. The K^Ar ages of V85 Ma for both a major leucogabbro dyke from central Kerala [19] and for a major felsite dyke from north Kerala [18] and 40 Ar^3 9 Ar ages of V88^90 Ma for the ENEŴ SW striking dykes in Karnataka [20] have been reported.…”

Section: Introductionmentioning

confidence: 99%

40Ar–39Ar age of the St. Mary’s Islands volcanics, southern India: record of India–Madagascar break-up on the Indian subcontinent

Pande

Sheth

Bhutani

2001

Earth and Planetary Science Letters

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The felsic volcanics (rhyolites and rhyodacites) of the St. Mary's Islands (SMI), southern India (V13³N), were originally interpreted as a distant outlier of the V65 Ma Deccan volcanic province of west^central India, comprising dominantly flood basalts. Later the SMI volcanics were dated at V93 Ma by the K^Ar technique. However, this K^Ar age' was dubious, being merely an average of five out of six widely varying dates and arbitrary data selectivity being involved in this averaging. Our first 40 Ar^3 9 Ar dating of the SMI volcanics yields excellent plateau and isochron ages, and their weighted mean isochron age is 85.6 þ 0.9 Ma (2c). Interestingly, the southern Indian Precambrian terrain is intruded by numerous mafic^doleritic dyke swarms ranging in age from Proterozoic to the latest Cretaceous (69^65 Ma, Deccan-related), and indeed, two regional dykes (a leucograbbro and a felsite) from the Kerala region of southwestern India remain previously dated at V85 Ma, but again with the K^Ar technique. However, this age for the SMI volcanics also corresponds excellently with 40 Ar^3 9 Ar ages of V89^85 Ma (weighted mean isochron age 87.6 þ 1.2 Ma, 2c: equivalent to 88.1 þ 1.2 Ma corresponding to MMhb-1 age of 523.1 þ 2.6 Ma) for the Madagascar flood basalt province. Together, therefore, the Madagascar flood basalt province, the SMI volcanics, and possibly the Kerala dykes could represent volcanic activity associated with the break-up of Greater India (India plus Seychelles) and Madagascar, thought to have occurred in the Upper Cretaceous at V88 Ma. ß

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The Karnataka Late Cretaceous Dykes as products of the Marion Hot Spot at the Madagascar ‐ India Breakup Event: Evidence from⁴⁰Ar‐³⁹Ar geochronology and geochemistry

Cited by 85 publications

References 12 publications

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Chipping of cratons and breakup along mobile belts of a supercontinent

40Ar–39Ar age of the St. Mary’s Islands volcanics, southern India: record of India–Madagascar break-up on the Indian subcontinent

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The Karnataka Late Cretaceous Dykes as products of the Marion Hot Spot at the Madagascar ‐ India Breakup Event: Evidence from40Ar‐39Ar geochronology and geochemistry

Cited by 85 publications

References 12 publications

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Were the Deccan Flood Basalts Derived in Part from Ancient Oceanic Crust Within the Indian Continental Lithosphere?

Chipping of cratons and breakup along mobile belts of a supercontinent

40Ar–39Ar age of the St. Mary’s Islands volcanics, southern India: record of India–Madagascar break-up on the Indian subcontinent

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The Karnataka Late Cretaceous Dykes as products of the Marion Hot Spot at the Madagascar ‐ India Breakup Event: Evidence from⁴⁰Ar‐³⁹Ar geochronology and geochemistry