Lithosphere structure and upper mantle characteristics below the Bay of Bengal

Rao, G. Srinivasa; Radhakrishna, M.; Sreejith, K. M.; Krishna, K. S.; Bull, Jonathan M.

doi:10.1093/gji/ggw162

Cited by 24 publications

(3 citation statements)

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“…modelling, Rao et al (2016) inferred that the 85°E Ridge was emplaced in off-ridge environment. Recently, based on the detailed analysis of high resolution and deep-penetration multi-channel seismic reflection sections, Ismaiel et al (2017) delineated the internal structure of the 85°E Ridge and inferred this feature to represent a volcanic construct built by both subaqueous and multiphase submarine volcanisms.…”

Section: The Satellite-derived Free-air Gravity Anomaly Map Of the mentioning

confidence: 99%

Structure and tectonics of the continental margins of India and the adjacent deep ocean basins: current status of knowledge and some unresolved problems

Yatheesh

2020

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March 2020 586 The Indian Ocean and the bordering continental margins are characterized by a number of tectonic features consisting of deep ocean basins, aseismic ridges/ submarine plateaus and seamounts. Marine geophysical studies carried out over these regions for the past four decades have led to an increased understanding of the formation and evolution of these features. The present paper synthesizes an up-to-date compilation of the results of the salient inferences of those studies to describe the structure and tectonic evolution of these features as well as the Indian Ocean in general. A review of the existing knowledge on the structure and tectonics of the continental margins of India and the adjacent ocean basins reveal the existence of several unresolved problems, primarily due to the inherent tectonic complexities or the paucity of adequate data. Some of the major problems that need to be addressed/examined are: the existence and extent of the Prathap and Kori-Comorin ridges; the locations of the continent-ocean boundaries around the continental margins of India; the timing of formation of the deep offshore regions adjacent to the Indian continental margins; the deeper crustal structure and trend of the 85°E Ridge; the crustal configuration as well as the extent of the postulated micro-continental slivers; and the cause of intense seismicity over the Chagos Bank segment of the Laccadive-Chagos Ridge. In addition to addressing these questions, the present paper suggests ways to go forward by acquiring high-resolution and deep penetration multichannel seismic reflection data, seismic refraction data using Ocean Bottom Seismometers (OBS) and closely spaced sea-surface and deep-tow magnetic profiles along with high-resolution seafloor mapping.

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Section: The Satellite-derived Free-air Gravity Anomaly Map Of the mentioning

confidence: 99%

Structure and tectonics of the continental margins of India and the adjacent deep ocean basins: current status of knowledge and some unresolved problems

Yatheesh

2020

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“…В Центрально-Бенгальском седиментационном бассейне фундамент опущен на глубину 12 км, а мощность осадочных отложений достигает 8.5 км [Rao, Krishna, 1997]. На широте о. Шри-Ланка наблюдается подъем фундамента и соответственно уменьшение мощности осадочного чехла, что, собственно, подтверждается картой глубин фундамента Бенгальского залива [Rao et al, 2016] (рис. 2).…”

Section: природа земной коры южной части бенгальского залива и прилег...unclassified

“…С другой стороны, в работе [Rao et al, 2016], опубликованной на 6 лет позже 3D-гравиметрического моделирования, на двумерном профиле была получена очень близкая к результатам моделирования по данным донных станций [Altenbernd et al, 2020] модель строения земной коры. По крайней мере, глубина границы Мохо всего на 1 км меньше, что вполне допустимо, так как гипотетический 2D-гравиметрический профиль находится в 100 км севернее и параллелен сейсмическому.…”

Section: обсуждение полученных результатовunclassified

Исторические Сейсмические Катастрофы На Ферганском Участке Великого Шелкового Пути

2022

ГПБ

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Аннотация. По материалам глубинного сейсмического зондирования, полученным в 2003 г. с борта НИС «Мезень» в Бенгальском заливе, построены два скоростных разреза, характеризующие строение земной коры в его южной части. Результаты сейсмических исследований показали, что в Бенгальском секторе Восточно-Индийского хребта (ВИХ) развита кора субконтинентального типа, мощность которой достигает 19.5 км. У западного подножья ВИХ скоростной разрез представлен редуцированной переходной корой мощностью 13 км. На основе оцифрованной базы данных мощности осадочного чехла в Индийском океане (NDGS), которая находится в свободном доступе в сети Интернет, построена карта глубин акустического фундамента, позволившая установить морфологические особенности его строения. Проведен сейсмостратиграфический анализ строения осадочного чехла, развитого на горстовых блоках, сгруппированных у подножья западного склона ВИХ; на гребне ВИХ; в прилегающей части Центральной котловины. Было установлено, что в позднем мелу-палеогене Бенгальский сектор ВИХ и горстовые блоки представляли единую платформенную структуру. В новейшую фазу тектонической активизации (поздний миоцен-плиоцен) платформа была разбита на горстовые блоки, которые испытали дифференцированное погружение. Установлено, что горстовые блоки играют основную роль в строении хребта 85°. Хребет 85° структурно не связан с плато Афанасия Никитина и по своей природе не является «трассерным хребтом».Ключевые слова: акустический фундамент, базальный осадочно-вулканогенный комплекс, континентальная кора, горстовые блоки, дифференцированные движения, новейшая фаза тектонической активизации.

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S‐velocity characterization of the crust and upper mantle structure beneath the Bay of Bengal

Corchete

2018

Geological Journal

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A 3D S‐velocity model has been determined from fundamental‐mode Rayleigh‐wave analysis in a wide period band (from 5 s to 175 s), to attain the characterization of the geologic structures existing in the Bay of Bengal, from 0 to 300 km depth. This model is presented by means of S‐velocity maps. In these maps, the S‐velocity in the depth range from 0 to 10 km is principally affected by the distribution of the sediment deposits. The S‐velocity generally increases with depth, showing the lowest values for shallow depths in which are present unconsolidated sediments. The S‐velocity mapping also allows the clear differentiation between the 85E Ridge and the 90E Ridge. The lower S‐velocity determined for the 85E Ridge compared with its adjacent region suggests that this ridge is less dense than its adjacent region. The existence of compensation beneath both ridges also is definitively confirmed in the Moho map performed in this study. The lower S‐velocities determined for the regions of the Andaman Sea and the northernmost part of the Bay of Bengal, in the depth range from 15 to 40 km, are associated to the existence of a thick crust beneath this regions. The results obtained in the present study confirm that the crust beneath the Bay of Bengal is in general thin crust. Although the controversy about the nature of the crust beneath the Bay of Bengal (is it oceanic or continental?) still persist, the results of the present study show that both hypotheses (oceanic crust and continental crust) are reasonable. The 3D S‐velocity model shows that the huge sediment load located at the northernmost part of the Bay of Bengal has originated at the thickening of the crust and the lithosphere, whereas the asthenosphere is almost unaffected by this load. This model also shows that the subduction of the Indian Plate below the Burma Plate, at the east of the Sunda Trench, also has produced a thickening of the crust and the lithosphere, but the asthenosphere is almost not affected by this effect. Finally, the dependency of the S‐velocity with the age of the lithosphere and the asthenosphere is shown very clearly for the lithosphere whereas it is only slight visible for the asthenosphere.

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Lithosphere structure and upper mantle characteristics below the Bay of Bengal

Cited by 24 publications

References 80 publications

Structure and tectonics of the continental margins of India and the adjacent deep ocean basins: current status of knowledge and some unresolved problems

Structure and tectonics of the continental margins of India and the adjacent deep ocean basins: current status of knowledge and some unresolved problems

Исторические Сейсмические Катастрофы На Ферганском Участке Великого Шелкового Пути

S‐velocity characterization of the crust and upper mantle structure beneath the Bay of Bengal

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