Crustal evolution and sedimentation history of the Bay of Bengal since the Cretaceous

Rao, D. Gopala; Krishna, K. S.; Sar, D.

doi:10.1029/96jb01339

Cited by 136 publications

(90 citation statements)

References 47 publications

(8 reference statements)

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“…It extends ∼5200 km from 30°S, where it intersects Broken Ridge, to ∼17°N, where it is buried beneath the Bengal Fan [Gopala Rao et al, 1997]. Although many explanations have been given for the formation of the NER [Royer et al, 1991, and references therein], it is widely accepted that it formed from hotspot volcanism near the spreading ridge (Wharton Ridge) that separated the Indian and Antarctic plates, leaving a trail of volcanism on the former as it drifted northward during the Late Cretaceous and early Cenozoic [Luyendyk, 1977;Royer et al, 1991].…”

Section: Introductionmentioning

confidence: 99%

Large fault fabric of the Ninetyeast Ridge implies near‐spreading ridge formation

Sager

Paul

Krishna

et al. 2010

Geophysical Research Letters

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[1] Ninetyeast Ridge (NER) is a linear volcanic ridge in the Indian Ocean thought to have formed by hotspot volcanism on the northward-drifting Indian plate. Geological data from the ridge are sparse, so its tectonic evolution is poorly known. We studied satellite-derived gravity data, seismic reflection profiles, and multibeam bathymetry to examine NER structure. Gravity data show that the ridge displays a series of nearly E-W trending lineations with average spacing ∼0.4°(45 km). In seismic and bathymetry data, these lineations correlate with horsts and grabens that probably formed near the time of ridge emplacement. From their extensional nature and trends, we infer that these faulted structures formed near the spreading ridge that separated the Indian and Antarctic plates and their ubiquity implies the hotspot was never far from this spreading ridge.

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Section: Introductionmentioning

confidence: 99%

Large fault fabric of the Ninetyeast Ridge implies near‐spreading ridge formation

Sager

Paul

Krishna

et al. 2010

Geophysical Research Letters

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“…After the continental collision between India and Eurasia, the Ganges and Brahmaputra rivers have discharged a huge volume of sediments from the Himalayan mountain range. Seismic stratigraphic studies of the BOB sediments (Gopala Rao et al 1997;Michael and Krishna, 2011) have recognized the unconformity separating the pre-collision sediments from the postcollision sediments and it has been ascribed an Eocene age, but the age of sediments at the base of the Bengal Fan is still uncertain. The sediment thickness estimated as over 22 km in offshore Bangladesh (Curray, 1991), decreases towards the south with a significant decrease in sediments thickness between 8°and 10°N, with also relative thinning over the 85°E and at University of Southampton on http://gji.oxfordjournals.org/ Downloaded from Ninetyeast ridges.…”

Section: Regional Geologic Setting and Evolutionmentioning

confidence: 99%

“…The geoid grid for the BOB region was extracted from geoid data generated for the northern Indian Ocean by . The regional multi-channel seismic reflection profiles (Curray et al, 1982;Curray, 1991;Gopala Rao et al, 1997;Krishna et al, 2001a;Michael and Krishna, 2011) and sonobuoy refraction data (Naini and Layden, 1977;Curray et al, 1982) within the study region are utilized for gravity-geoid modeling.…”

Section: Datasets Usedmentioning

confidence: 99%

“…Additionally, for the purpose of 2-D flexural analysis over the aseismic ridges, we used several short E-W seismic reflection profiles across the 85°E Ridge (Bastia et al, 2010;Radhakrishna et al, 2012;Krishna et al, 2014;Rao and Radhakrishna, 2014) and across the Ninetyeast Ridge (Curray et al, 1982;Gopala Rao et al, 1997;Subrahmanyam et al, 2008;Maurin and Rangin, 2009 …”

Section: Datasets Usedmentioning

confidence: 99%

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Lithosphere structure and upper mantle characteristics below the Bay of Bengal

et al. 2016

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SUMMARY:The oceanic lithosphere in the Bay of Bengal (BOB) formed 80 -120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85 o E and Ninetyeast) and by the loading of ca.20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths.

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“…comm., 2001). Neither does the conjugate continental margin of East India (e.g., Gopala Rao et al, 1997;Chand et al, 2001), although thick sediments of the Bengal Fan mask the margin's basement structure due south of the Rajmahal Traps (e.g., Kent et al, 1997;Subrahmanyam et al, 1999). Thus, unlike the Iceland hotspot and the associated North Atlantic volcanic province and the Tristan hotspot and the associated Paraná/Etendeka flood basalt province, the peak output of the Kerguelen hotspot cannot be correlated temporally or spatially with a major phase of continental breakup and volcanic margin formation.…”

Section: The Kerguelen Hotspot and Indian Ocean Plate Reconstructionsmentioning

confidence: 99%

Leg 183 Synthesis: Kerguelen Plateau–Broken Ridge—A Large Igneous Province

Frey¹,

Coffin²,

Wallace³

et al. 2003

Proceedings of the Ocean Drilling Program

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The Kerguelen Plateau and Broken Ridge form a large igneous province (LIP) in the southern Indian Ocean. The main objectives of Ocean Drilling Program Leg 183 were to understand the origin and evolution of this LIP and the impact of its formation on the environment. Igneous basement (33 to 233 m of penetration) has been recovered from 11 drill sites on the LIP, and 7 are Leg 183 sites. Studies of the basement and sediment cores lead to the following conclusions. Although an important caveat is that we have access only to uppermost basement of a thick (~20 km) igneous crust, these results are inconsistent with massive volcanism associated with a single plume head and continental breakup. 2. The uppermost igneous basement is dominantly tholeiitic basalt. Based on the physical characteristics of the lava flows, which indicate subaerial eruption, and the occurrence of overlying terrestrially derived sediments containing wood fragments, fern remains, and terrestrial palynoflora, much of the LIP was above sea level when magmatic output was high. 3. The geochemical characteristics of basalt forming the LIP are unlike mid-ocean-ridge basalt (MORB). There are, however,

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Crustal evolution and sedimentation history of the Bay of Bengal since the Cretaceous

Cited by 136 publications

References 47 publications

Large fault fabric of the Ninetyeast Ridge implies near‐spreading ridge formation

Large fault fabric of the Ninetyeast Ridge implies near‐spreading ridge formation

Lithosphere structure and upper mantle characteristics below the Bay of Bengal

Leg 183 Synthesis: Kerguelen Plateau–Broken Ridge—A Large Igneous Province

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