Geochemistry of the mafic dykes in the Prakasam Alkaline Province of Eastern Ghats Belt, India: Implications for the genesis of continental rift-zone magmatism

Kumar, K. Vijaya; Rathna, K.

doi:10.1016/j.lithos.2007.12.012

Cited by 34 publications

(13 citation statements)

References 103 publications

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“…Geochemical studies on the lamprophyres from the Prakasam province infer their derivation from deeper portions of the mantle (close to spinel -garnet stability field) and their observed geochemical variation can be accounted by the vein-plus-wall rock model (e.g. Madhavan et al 1992Madhavan et al , 1998Ratnakar et al 2008;Vijaya Kumar and Rathna, 2008). Predominance of mica, clinopyroxene and apatite in the glimmeritic enclave is strikingly similar to those of veined phases envisaged by this model.…”

Section: Discussionmentioning

confidence: 99%

Glimmeritic enclave in a lamprophyre from the Settupalle alkaline pluton, Eastern Ghats mobile belt

Rao

2010

J Geol Soc India

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A rare occurrence of glimmeritic (mica-rich) enclave -composed of abundant modal biotite, subordinate proportions of clinopyroxene and apatite, minor amounts of feldspar, carbonate and sphene -is reported from the lamprophyre of Settupalle alkaline pluton, Eastern Ghats mobile belt (EGMB), India. The enclave displays very coarse grained equigranular texture (mica laths up to 5 mm and clinopyroxene grains up to 4 mm). In comparison, the host lamprophyre exhibits a marked porphyritic-panidiomorphic texture comprising phenocrysts of clinopyroxene; other phases such as biotite and potash-and plagioclase-feldspar are restricted to the groundmass. A tight closeness in mineral chemistry of the glimmerite and lamprophyre imply a possible genetic relationship between their parent magmas. Glimmeritic enclave is construed to be an autolith of the proto-lamprophyre magma, which failed to reach the surface, and lined the wall-rock along the conduit of the lamprophyric intrusion. Glimmerite enclave provides a direct evidence for the multi-stage modification of the lithospheric mantle due to the infiltration of the potassium-rich hydrous melts such as lamprophyres. Mineralogy of the glimmeritic enclave is also similar to that of a vein component of the hydrous, mafic and potassic-ultrapotassic veined lithosphere in the EGMB.

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Section: Discussionmentioning

confidence: 99%

Glimmeritic enclave in a lamprophyre from the Settupalle alkaline pluton, Eastern Ghats mobile belt

Rao

2010

J Geol Soc India

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“…Mesoproterozoic rift-zone igneous activity in the southern segment of the EGGB is represented by the intrusion of ARCs as well as three geochemically distinct mafic dikes (alkali basaltic, lamprophyric, gabbroic) and their plutonic differentiates. The alkali basaltic magmas formed by low degrees of melting of the lithosphere-asthenosphere boundary layer, whereas both the gabbroic and lamprophyric dikes were derived from lithospheric sources and their geochemical variation can be explained by a 'vein-plus-wall-rock melting model' (Vijaya Kumar and Rathna 2008). The vein/wall-rock ratio is low for the sources of gabbroic dikes, whereas it is high for the lamprophyric dikes.…”

Section: Evidence For Supercontinent Columbia Fragmentation: Mesoprotmentioning

confidence: 98%

“…Palaeoproterozoic subduction-related crustal growth, represented by the Kandra Ophiolite Complex, the Kondapalli Layered Complex, and mafic and felsic granulites in the Kondapalli-Ongole Domain, was followed by a major tectonothermal event, resulting in widespread granulite facies metamorphism of the protoliths at around 1.6 Ga, possibly due to terminal continent-continent collision. A second stage of continental rifting at 1.35 Ga produced a variety of felsic alkaline rocks, mafic alkaline, and tholeiitic dikes and their plutonic differentiates ( Figure 1C; Upadhyay et al 2006;Vijaya Kumar et al 2007;Vijaya Kumar and Rathna 2008). In the southern segment of the EGGB, the rift-zone magmatism is located between the Vinjamuru and Ongole domains ( Figure 1C).…”

Section: Eastern Ghats Granulite Beltmentioning

confidence: 99%

“…Evidence for the fragmentation of Columbia is illustrated by Mesoproterozoic continental rifting and formation of rift-related alkaline igneous rocks + carbonatites (ARCs; Leelanandam 1989;Ratnakar and Leelanandam 1989;Upadhyay et al 2006;Vijaya Kumar et al 2007;Upadhyay 2008); the occurrence of variegated mafic dikes is also characteristic of continental rift-zone magmatism (Vijaya Kumar and Rathna 2008). Mesoproterozoic rift-zone igneous activity in the southern segment of the EGGB is represented by the intrusion of ARCs as well as three geochemically distinct mafic dikes (alkali basaltic, lamprophyric, gabbroic) and their plutonic differentiates.…”

Section: Evidence For Supercontinent Columbia Fragmentation: Mesoprotmentioning

confidence: 99%

“…Lithospheric mantle beneath the Ongole Domain was enriched by subduction-related events between 1.85 and 1.7 Ga, which was the timing of formation of the regional Andean-type continental margin (Leelanandam and Vijaya Kumar 2007). Subsequent to subduction-related enrichment, the lithosphere mantle underwent partial melting around 1.35 Ga during continental rifting, forming the gabbroic dikes possessing subduction signatures (Vijaya Kumar and Rathna 2008).…”

Section: Evidence For Supercontinent Columbia Fragmentation: Mesoprotmentioning

confidence: 99%

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Formation and fragmentation of the Palaeoproterozoic supercontinent Columbia: evidence from the Eastern Ghats Granulite Belt, southeast India

Kumar

Leelanandam

Ernst

2011

International Geology Review

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Recognition of Palaeoproterozoic subduction-induced continental collision andMesoproterozoic rifting within the Great Proterozoic Fold Belt (GIPFOB) of India supports the existence of Columbia. The Eastern Ghats Granulite Belt (EGGB) is an important component of the GIPFOB and a key player in models of the configuration of the supercontinent. The southern segment of the EGGB records widespread 1.85-1.7 Ga subduction-related arc magmatism and 1.5-1.35 Ga rift-zone igneous activity. The Kondapalli Layered Complex and associated felsic and mafic granulites show unambiguous subduction-related bulk-rock geochemistries and appear to represent deeply eroded remnants of a Palaeoproterozoic continental-margin magmatic arc. The Kandra Ophiolite Complex (KOC), containing a well-developed sheeted-dike complex and plagiogranite, characterizes new oceanic crust formed in a suprasubduction-zone environment. Internal structures, lithological associations, and bulk-rock compositions indicate that the KOC represents a Rocas Verdes-type continental backarc basin. Mesoproterozoic extension, initiated between 1.5 and 1.35 Ga, involved the intrusion of alkaline complexes + variegated mafic dikes and the development of large sedimentary basins. This rifting produced an outboard transitional-to-true oceanic crust paralleling the Palaeoproterozoic arc axis. Voluminous Palaeoproterozoic subduction-related and Mesoproterozoic rift-related magmatism within the EGGB provide strong evidence for global events that correlate with the assembly and break-up of Columbia.

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Petrogenesis of lamprophyres synchronous to kimberlites from the Wajrakarur kimberlite field: Implications for contrasting lithospheric mantle sources and geodynamic evolution of the eastern Dharwar Craton of southern India

et al. 2018

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Kimberlite field is an example of widespread Mesoproterozoic intracontinental magmatism. Recent studies have identified deep subcontinental lithospheric mantle as a source region of the kimberlite magmatism while timing, origin, and processes responsible for the generation of coeval lamprophyres remain poorly constrained. Here, we present and discuss new petrological and geochemical data for two lamprophyre dykes from the Wajrakarur kimberlite field and assess their petrogenetic relation to the kimberlite occurrences. Based on mineral compositional and whole‐rock geochemical characters, it is suggested that lamprophyres are formed through low degrees of partial melting of “enriched” lithospheric mantle that was modified and metasomatized by melts derived from recycled crust. This differs from geochemical imprints found in coeval kimberlites, where a crustal source component appears to be absent and is more consistent with rock derivation from “depleted” lithosphere which has experienced interaction with asthenosphere‐derived melts. An apparent lack of garnet in the mantle sources of lamprophyres is suggestive of melting at comparatively shallow depth (~100 km) relative to the kimberlites. Hence, these geochemically contrasting rocks, although have formed at the same time, are derived from vertically heterogeneous lithospheric mantle sources and can be explained through and linked with a thermal anomaly in the underlying convective asthenosphere. We suggest that the deeper mantle source region of the kimberlites was more pristine and devoid of subduction‐related signatures, whereas the shallower mantle source region of the lamprophyres seems to have preserved imprints of plate convergence and subduction associated with the evolution of the Dharwar Craton.

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Geochemistry of the mafic dykes in the Prakasam Alkaline Province of Eastern Ghats Belt, India: Implications for the genesis of continental rift-zone magmatism

Cited by 34 publications

References 103 publications

Glimmeritic enclave in a lamprophyre from the Settupalle alkaline pluton, Eastern Ghats mobile belt

Glimmeritic enclave in a lamprophyre from the Settupalle alkaline pluton, Eastern Ghats mobile belt

Formation and fragmentation of the Palaeoproterozoic supercontinent Columbia: evidence from the Eastern Ghats Granulite Belt, southeast India

Petrogenesis of lamprophyres synchronous to kimberlites from the Wajrakarur kimberlite field: Implications for contrasting lithospheric mantle sources and geodynamic evolution of the eastern Dharwar Craton of southern India

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