Seismic evidence of continental margin influence on the NinetyEast Ridge in the Bay of Bengal

• Published in: Geophysical Research Letters
• Main Authors: Moeremans, Raphaele E., Singh, Satish C.
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: NinetyEast Ridge; Bay of Bengal; continental margin; Andaman subduction; Cretaceous sediments; seismic reflection; [SDU]Sciences of the Universe [physics]; Indian; Ner; Antarc*; Antarctica
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-03581071; https://hal-insu.archives-ouvertes.fr/insu-03581071/document; https://hal-insu.archives-ouvertes.fr/insu-03581071/file/Geophysical%20Research%20Letters%20-%202014%20-%20Moeremans%20-%20Seismic%20evidence%20of%20continental%20margin%20influence%20on%20the%20NinetyEast%20Ridge.pdf; https://doi.org/10.1002/2014GL061598

International audience The NinetyEast Ridge (NER), one of the most enigmatic features in the Indian Ocean, is covered by thick Bengal Fan sediment north of 9°N. We present seismic reflection data on the eastern flank of the NER, at 10°N, that show the presence of 4-5 km thick sediments beneath the Bengal Fan sediments. These sediments can be imaged up to 60 km beneath the Andaman fore-arc accretionary wedge, suggesting that the décollement lies above these sediments. The presence of thick sediments above the northernmost segment of the NER suggests that this segment was close to a continental margin during its emplacement. We propose that these sediments were deposited soon after the breakup of India and Antarctica, between 130 and 100 Ma, and might act as source rocks for oil and gas generation beneath recent Bengal Fan sediments. Furthermore, subducting thick sediments can significantly change the seismogenic behavior of the Andaman subduction zone.