Geochemistry of mafic dykes in part of Chotanagpur gneissic complex: Petrogenetic and tectonic implications

Kumar, Akash; Ahmad, Talat

doi:10.2343/geochemj.41.173

Cited by 38 publications

(36 citation statements)

References 23 publications

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“…Trace element data hints to an enriched mantle source as also possible control of crustal contamination. A rift environment for emplacement of the mafic suite has also been envisaged (Kumar and Ahmad, 2007). It is very significant to observe that many of these geochemical characteristics noted above are also observed in the Newer dolerite assemblage within the Singhbhum nucleus.…”

Section: Trace Element Geochemistrymentioning

confidence: 97%

“…Evolution of a calc-alkaline suite comprising pyroxene hornblenditenorite-diorite in Leslieganj-Khamdi area was controlled by fractionation of hydrous mafic magma under a thick crustal zone having characteristic tectono-magmatic setting (Kar and Sarkar, 1989). A recent study (Kumar and Ahmad, 2007) has paid the desired emphasis on trace element chemistry of mafic intrusives from within CGGC. These rocks are significantly enriched in LREE and LILE with corresponding depletion in HFSE.…”

Section: Trace Element Geochemistrymentioning

confidence: 99%

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Precambrian mafic magmatism in the Singhbhum craton, eastern India

Bose

2009

J Geol Soc India

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The Singhbhum craton has a chequred history of mafic magmatism spanning from early Archaean to Proterozoic. However, lack of adequate isotopic age data put constraints on accurately establishing the history of spatial growth of the craton in which mafic magmatism played a very significant role. Mafic magmatism in the craton spreads from ca.3.3 Ga (oldest "enclaves" of orthoamphibolites) to about 0.1 Ga ('Newer dolerite' dyke swarms). Nearly contemporaneous amphibolite and intimately associated tonalitic orthogneiss may represent Archaean bimodal magmatism. The metabasic enclaves are appreciably enriched and do not fulfill the geochemical characteristics of worldwide known early Archaean (>3.0 Ga) mafic magmatism. The enclaves reveal compositional spectrum from siliceous high-magnesian basalt (SHMB) to andesite. However, the occurrence of minor depleted boninitic type within the assemblage has so far been overlooked. High magnesian basalt with boninitic character of Mesoarchaean age is also reported in association with supracrustals from southern fringe of the granitoid cratonic nucleus. The subcontinental lithospheric mantle (SCLM) below the craton is conjectured to have initiated during the early Archaean. Significantly, recurrence of depleted magma types in the craton is observed during the whole span of mafic igneous activity which has been vaguely related to "mantle heterogeneity", although the alternative model of sequential mantle melting is also being explored.The Singhbhum craton includes the Banded Iron Formation (BIF) associated mafic lavas, MORB-like basic and komatiitic ultrabasic bimodal volcanism -documented as Dalma volcanics, Dhanjori lavas, and the Proterozoic Newer dolerite dykes. Three different types of REE fractionation patterns are observed in the BIF-associated mafic lavas. These are the REE unfractionated type is more depleted than N-MORB and some lavas with boninitic type of REE distribution. MORB-like basic and komatiitic ultrabasic (Dalma volcanics) are emplaced within the Proterozoic Singhbhum Basin (PSB). The vista of magmatism in the basin was controlled by a miniature spreading centre represented by the mid-basinal Dalma volcanic ridge. The volcano-sedimentary basinal domain of Dhanjori emerged at the interface of two subprovinces (viz. the mobile volcano-sedimentary belt of PSB and rigid granite platform) under unique stress environment related to extensional tectonic regime. Trace element distribution in Dhanjori lavas is remarkably similar to that in PSB minor intrusions and lavas (except a Ta spike in the latter). The Proterozoic Newer dolerite dykes within Singhbhum nucleus manifest an unusually wide spam of intrusive activity (ca 2100 Ma to 1100 Ma) and unexpectedly uniform mantle melting behaviour.

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Section: Trace Element Geochemistrymentioning

confidence: 97%

Section: Trace Element Geochemistrymentioning

confidence: 99%

Precambrian mafic magmatism in the Singhbhum craton, eastern India

Bose

2009

J Geol Soc India

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“…The CGC is considered to be a cratonized mobile belt of Archean age (cf. Naqvi and Rogers, 1987;Kumar and Ahmad, 2007;Sharma, 2009;Srivastava et al, , 2012. The cratonic nature of the CGC is supported by a number of ENE-to E-trending intracontinental rift/shear zones responsible for distinct magmatism in the region (Ghose and Chatterjee, 2008).…”

Section: Geological Backgroundmentioning

confidence: 99%

Nature of Cretaceous dolerite dikes with two distinct trends in the Damodar Valley, eastern India: Constraints on their linkage to mantle plumes and large igneous provinces from 40Ar/39Ar geochronology and geochemistry

et al. 2019

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Two distinct sets of Cretaceous dolerite dikes intrude the Chhotanagpur gneissic complex of eastern India, mostly within the Damodar Valley Gondwanan sedimentary basins. One dike set trends NNE to ENE, whereas the other set, which includes the prominent Salma dike, trends NW to NNW. One dike from each set in the Raniganj Basin was dated using the 40Ar/39Ar method in order to resolve a controversy concerning the emplacement age of the Salma dike. The NE-trending dike yielded a plateau age of 70.5 ± 0.9 Ma, whereas the NNW-trending Salma dike is much older, with a plateau age of 116.0 ± 1.4 Ma. These results demonstrate that the Salma dike was emplaced at ca. 116 Ma and not at ca. 65 Ma, as suggested in an earlier study. Geochemical characteristics of the two dikes are also distinct and indicate that they belong to previously identified high-Ti and low-Ti dolerite groups, respectively. The observed geochemical characteristics of both dike sets are comparable with the geochemistry of basalts of the Kerguelen Plateau, Bunbury Island, and Rajmahal Group I and suggest a connection to mantle plumes. The new age data presented herein indicate that these two magmatic episodes in the eastern Indian Shield were related to the ca. 120–100 Ma Kerguelen mantle plume and its associated Greater Kerguelen large igneous province and the ca. 70–65 Ma Réunion plume and its associated Deccan large igneous province, respectively.

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“…It is also evident from the positive correlation (Fig. 7d) observed in these rocks between Zr/Y and Zr (cf., Floyd, 1993;Ahmad et al, 1999;Kumar and Ahmad, 2007). From the foregoing discussion it is envisaged that, the fractional crystallization as observed is considered to have occurred in the resultant hybrid magma, after the initial fractionation of the mafic melts during the partial melting of mantle source with an eclogite or garnet amphibolite residue.…”

Section: Magma-mixing and Fractional Crystallization Of Resultant Magmamentioning

confidence: 99%

Mantle-derived arc related mafic enclaves and host orthogneiss from the Shyok Suture Zone of NE Ladakh, India: An evidence of magma-mixing

Rao

Daga

Rai³

2013

Geochem. J.

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The Shyok valley in the northern Ladakh is a linear NW-SE trending suture zone (Shyok Suture Zone) and separates two distinct terranes, the southern continental margin of Eurasian Plate to north, and Ladakh magmatic arc to south. The crustal growth in the Shyok Suture Zone (SSZ) can be explained by two stage melting process involving the generation of orthogneiss (OG) with mafic enclaves (ME) (pre-collision), and temporal evolution towards increasingly more evolved felsic magmas during reworking processes (post-collision). In this paper, the geochemistry of various ME and host OG that fall within the Shyok-Darbuk corridor of the suture zone are discussed.The field, petrographic and geochemical data suggest that the ME and host OG are genetically related. The ME has formed by low degree of partial melting of a garnet-bearing source or from the partial melting of a basaltic source with a clinopyroxene-garnet eclogite as residue. The LILE and LREE enrichment of ME have been influenced by mantle-magma interaction during the passage of the hydrous primary arc-magma through the overlying lithosphere. The likely interpretation for the genetic linkage of ME and host OG is explained through the mixing of coeval mafic (enclave) and felsic melts, resulting in hybrid magma. Besides, several geochemical lines of evidence suggest that fractional crystallization of the resultant hybrid magma had played a complementary role in the evolution of these rocks.

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Geochemistry of mafic dykes in part of Chotanagpur gneissic complex: Petrogenetic and tectonic implications

Cited by 38 publications

References 23 publications

Precambrian mafic magmatism in the Singhbhum craton, eastern India

Precambrian mafic magmatism in the Singhbhum craton, eastern India

Nature of Cretaceous dolerite dikes with two distinct trends in the Damodar Valley, eastern India: Constraints on their linkage to mantle plumes and large igneous provinces from 40Ar/39Ar geochronology and geochemistry

Mantle-derived arc related mafic enclaves and host orthogneiss from the Shyok Suture Zone of NE Ladakh, India: An evidence of magma-mixing

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