Rajmahal Basalts, Eastern India: Mantle Sources and Melt Distribution at a Volcanic Rifted Margin

Kent, Walter; Saunders, Andrew D.; Kempton, Pamela D.; Ghose, Naresh Chandra

doi:10.1029/gm100p0145

Cited by 72 publications

(55 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the AVR were emplaced in an extensional rift tectonic environment and their geochemical characteristics are similar to the magmatic rocks of the Comei–Bunbury LIP of ~132 Ma, we have scrutinized the detailed petrological and geochemical characters in order to verify their genetic relationship with the magmatism of the Comei–Bunbury LIP. Rare earth elemental patterns of the AVR (Figure ) are compared with Cona mafic rocks (after Zhu, Mo, Pan, et al, ), Rajmahal Traps (after Kent et al, ), Sylhet traps (after Ghatak & Basu, ), Bunbury Basalt (after Olierook et al, ), and Kerguelen plateau (after Ingle et al, ; Neal et al, ). But the REE pattern of the AVR is more enriched than Rajmahal and Sylhet trap basalts, which are geochronologically younger and less contaminated than the AVR.…”

Section: Discussionmentioning

confidence: 99%

“…(a) Chondrite‐normalized REE patterns of AVR are comparison with the Cona mafic rocks (after Zhu, Mo, Pan, et al, ), Rajmahal Traps (after Kent, Saunders, Kempton, & Ghose, ), and Sylhet traps (after Ghatak & Basu, ). (b) Comparison with the Bunbury Basalt (after Olierook et al, ) and Kerguelen Plateau (after Ingle, Weis, Scoates, & Frey, ; Neal, Mahoney, & Chazey, ) [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Zircon U–Pb geochronology, Hf isotopic compositions, and petrogenetic study of Abor volcanic rocks of Eastern Himalayan Syntaxis, Northeast India: Implications for eruption during breakup of Eastern Gondwana

et al. 2019

View full text Add to dashboard Cite

This paper reports new zircon U–Pb ages and Hf isotopic compositions of felsic units of the Abor volcanic rocks (AVR) of Eastern Himalayan Syntaxis (EHS), Northeast India, and discusses their relationship to the Kerguelen plume activity. The AVR are bimodal and predominantly constituted by mafic rocks with minor felsic units. Mafic volcanics are identified as basalt and basaltic andesite with light rare earth elements (LREE) enriched and slightly depleted heavy rare earth elements (HREE) pattern without Eu anomalies. Low concentrations of LILE, high contents of Fe2O3, and other incompatible trace elements ratios reflect enriched nature of these mafic volcanics. Felsic volcanic rocks are dacitic to rhyolitic in composition, which have high REE content, high LREE/HREE, and pronounced negative Eu anomalies. Enriched LREE, high Th/Nb, Ce/Nb ratios, and variations in Rb/Zr, K/Rb, La/Sm ratios with negative anomalies of Ba, Nb, Sr, P, Ti in felsic rocks suggest substantial contribution of crustal contamination at the time of eruption. Zircons from felsic units yield an average U–Pb age of ~132 Ma and unradiogenic (ƐHf(t) < 0) Hf isotope values of −7.0 to −13.3 with model ages between 1.5 and 2.1 Ga, suggesting old crustal assimilation in their genesis. The AVR were emplaced in the continental rift tectonic setting, and depth of the magma source is confirmed as near spinel stability zone. The AVR are positively comparable with other flood basalts that were formed due to the Kerguelen plume activity. Therefore, our combined new geochemical and geochronological data show that the AVR were emplaced at early stage (~132 Ma) of eastern Gondwana breakup due to outbreak of the Kerguelen plume. This study thus supports the idea of the Kerguelen plume affecting a large area of Eastern India, Western Australia, and Antarctica during early stage of Gondwana breakup.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Zircon U–Pb geochronology, Hf isotopic compositions, and petrogenetic study of Abor volcanic rocks of Eastern Himalayan Syntaxis, Northeast India: Implications for eruption during breakup of Eastern Gondwana

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Other researchers believed that the Rajmahal Traps originated from the Kerguelen hotspot. Kent et al [51] showed that the Crozet hotspot might not have a relationship with the Rajmahal Traps through analysis of Pb and Sr isotopes. From analysis of the Pb isotope, Mahoney et al [35] considered that there were great differences in the geochemical characters of the Crozet hotspot and the Afanasy Nikitin Plateau and did not support the inference that the Afanasy Nikitin Plateau was created by the Crozet hotspot.…”

Section: Origin Of the Crozet Hotspotmentioning

confidence: 99%

Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma: Implications on the formation of oceanic plateaus and intra-plate seamounts

Zhang

Lin

Gao

2011

Sci. China Earth Sci.

View full text Add to dashboard Cite

This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean. We first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction, and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy. The results reveal that the activities of the Marion hotspot can be divided into three main phases: interaction with the paleo-Rodrigues triple junction (73.6-68.5 Ma), interaction with the SWIR (68.5-42.7 Ma), and intra-plate volcanism (42.7-0 Ma). These three phases correspond to the formation of the eastern, central, and western parts of the Del Cano Rise, respectively. The magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge distance. The periodicity of the Marion hotspot is about 25 Ma, which is much longer than that of the Hawaii and Iceland hotspots (about 15 Ma). Southwest Indian Ocean, hotspot-ridge interaction, magmatic volume flux, oceanic plateaus, seamounts Citation:Zhang T, Lin J, Gao J Y. Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma: Implications on the formation of oceanic plateaus and intra-plate seamounts.Numerous seamounts are generated at plate boundaries by the volcanic and tectonic activities of mid-ocean ridges and transform faults [1]. Correspondingly, hotspots are mainly observed as intra-plate volcanism [2]. With the interaction of mid-ocean ridges and hotspots, the intensity of hotspot activity is amplified, resulting in the formation of broad plateaus [3]. These plateaus and seamounts (or seamount chains) substantially reflect the intensity of magmatism and the tracks of hotspots [2,[4][5][6][7], and record the ages, locations and magmatic volume of seamounts created by hotspots. It would be useful to study the time variation and periodicity of the intensity of hotspot activity and the interaction of hotspots, mid-ocean ridges and transform faults [4,5,8,9]. Radioactive dating of rocks can be adopted to determine directly the ages of seamounts, and the thickness of the oceanic crust (layer 2A to layer 3) can be regarded as a first-order measure of the mantle magmatic volume [10]. However, very few rock samples have been taken and there has been little determination of the crustal thickness from seismic velocity profiles of ocean bottom experiments. In many areas that have been little studied, the mentioned methods cannot be used to calculate hotspot tracks and

show abstract

“…Basalts from the Elan Bank Site 1137, and the Rajmahal type-II basalts, both contaminated with continental crust, are also similar in terms of SrNd-Pb isotope compositions Ingle et al 2002a;Kent et al 1997). Kent et al (1997) Fig. 11 Comparison of the P-T path of metamorphism in the metapelitic clast from Elan Bank conglomerate 36R3, 33-35 cm (see Fig.…”

Section: Discussionmentioning

confidence: 84%

“…For example, in e Nd versus 87 Sr/ 86 Sr and 207 Pb/ 204 Pb versus 206 Pb/ 204 Pb diagrams (Ingle et al 2002b), the gneissic clasts from Elan Bank plot in the field for the high-grade rocks of Chilka area of Eastern Ghats (Rickers et al 2001;Chakrabarti et al 2010), suggesting that the source of the gneissic clasts may have been the highgrade rocks of the Chilka area. Basalts from the Elan Bank Site 1137, and the Rajmahal type-II basalts, both contaminated with continental crust, are also similar in terms of SrNd-Pb isotope compositions Ingle et al 2002a;Kent et al 1997). Kent et al (1997) Fig.…”

Section: Discussionmentioning

confidence: 85%

An intercontinental correlation of the mid-Neoproterozoic Eastern Indian tectonic zone: evidence from the gneissic clasts in Elan Bank conglomerate, Kerguelen Plateau

Chatterjee

Nicolaysen

2011

Contrib Mineral Petrol

View full text Add to dashboard Cite

The Kerguelen Plateau is a submarine, Cretaceous Large Igneous Province in the southern Indian Ocean. Drilling on Elan Bank, a western salient of the Kerguelen Plateau, yielded a *26 m section of fluvial conglomerate intercalated with basalt. Chemical dating of monazite within garnet and matrix monazite in metapelitic clasts from the conglomerate indicates that high-grade metamorphism of the pelitic protolith occurred between 785 ± 12 and 694 ± 18 Ma. A calculated P-T pseudosection indicates that the observed core-to-inner rim compositional zoning in garnet is consistent with P/T decrease from 10.2 kb/760°C to 6.2 kb/560°C. In an Early Cretaceous paleogeographic reconstruction, the Elan Bank drill site is located on a SSW continuation of the Eastern Indian Tectonic Zone (EITZ), a 876-784 Ma, NNE-SSW metamorphic belt with sinistral shear zones in eastern India. The retrograde P-T path of the Elan Bank metapelitic clast overlaps with that of the EITZ metapelite, and the Elan Bank monazite chemical dates and previously determined 824-675 Ma U-Pb isotope monazite dates by the TIMS method are remarkably similar to the monazite chemical dates from the EITZ metapelites and high-grade metamorphic rocks from the eastern margin of the Eastern Ghats Belt. Based on the demonstrable affinity of metamorphic, geochronologic, and spatial data, this study concludes that the EITZ was likely a continuous, *1,800-km-long tectono-metamorphic belt in the Rodinia supercontinent stretching from eastern India through the Eastern Ghats to the basement of Elan Bank and probably to the Rayner Complex of East Antarctica.

show abstract

Rajmahal Basalts, Eastern India: Mantle Sources and Melt Distribution at a Volcanic Rifted Margin

Cited by 72 publications

References 81 publications

Zircon U–Pb geochronology, Hf isotopic compositions, and petrogenetic study of Abor volcanic rocks of Eastern Himalayan Syntaxis, Northeast India: Implications for eruption during breakup of Eastern Gondwana

Zircon U–Pb geochronology, Hf isotopic compositions, and petrogenetic study of Abor volcanic rocks of Eastern Himalayan Syntaxis, Northeast India: Implications for eruption during breakup of Eastern Gondwana

Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma: Implications on the formation of oceanic plateaus and intra-plate seamounts

An intercontinental correlation of the mid-Neoproterozoic Eastern Indian tectonic zone: evidence from the gneissic clasts in Elan Bank conglomerate, Kerguelen Plateau

Contact Info

Product

Resources

About