Bay of Bengal (Indian Ocean)

The Bay of Bengal has been one of the first areas to be surveyed by MTU in greater detail with acoustic and seismic methods, starting in 1993 with the participation in the BGR Sonne Cruise SO93. This cruise was mostly focusing on sediment sampling and collection of complimentary digital Parasound sediment echosounder data. Main objectives were the overall sediment budget and the tracing of the later Quaternary and Holocene sediment delivery along the active channel.

In 1997, two R/V Sonne Cruises SO125 and SO126., jointly proposed by MTU and BGR, were including multichannel seismic work in the deeper Bangal Fan as well as on the Bangladesh Shelf. 

Data from SO125 were used subsequently to develop in 1998 a drilling pre-proposal to IODP, submitted by C. France-Lanord (CRPG), Volkhard Spiess and Joe Curry (SIO). After several revisions and collection of more site survey data to increase the spatial coverage of our data set on R/V  Sonne Cruises SO188-1/2 in 2006, ulitimately in 2015 the drilling campaign IODP Expedition 354 was performed at 8°N latitude along a 300 km long transect of 7 sites.

R/V  Sonne Cruises SO188-1/2, proposed and carried out in cooperation with BGR, University of Kiel, CRPG and WHO in 2006 was also collecting multichannel seismic data across the whole fan, on the Bangladesh slope and shelf comvined with extended sediment sampling.


Background

The Bengal Fan covers the entire floor of the Bay of Bengal, from the continental margins of India and Bangladesh to the sediment-filled Sunda Trench off Myanmar and the Andaman Islands and along the west side of the Ninetyeast Ridge. It spills out south of the Bay of Bengal at its distal end to ~7°S. Another lobe of the fan, the Nicobar Fan, lies east of the Ninetyeast Ridge, but it apparently was cut off from its primary source of turbidites, the head of the Bay of Bengal, during the Pleistocene by convergence between the northern end of the Ninetyeast Ridge and the Sunda Trench. The northeastern edges of the fans are subducted, and some of the Tertiary turbidites cropping out in the Indo-Burman Ranges of Myanmar, the Andaman and Nicobar Islands, and the outer arc ridge off Sumatra are interpreted as old Bengal and Nico- bar Fan sediments.

The initiation of deposition and progradation of the Bengal Fan followed the collision of India with Asia and the formation of a large proto-Bay of Bengal. Continued convergence of the Indian and Australian plates with the Southeast Asian plate reduced the size of the bay and focused the source of turbidites into the present Bengal Ba-in, Bangladesh shelf, and the Swatch-of-No-Ground (SoNG) shelf canyon. Fans grow by progradation, and the first sediments are deposited at the mouth of a canyon and at the base of the slope, typically the continental slope. With time, fans prograde farther from the original base of the slope. 

Source-to-Sink Pathways and Sediment Delivery

Sediment delivery into the Bengal Fan originates from the SoNG (Kottke et al., 2003; Michels et al., 1998; Palamenghi, 2011), which represents the only feature of this kind today. Sediments from the Ganges, Brahmaputra, and Meghna Rivers are transported to the mouth and then westward by currents parallel to the delta front (Kudrass et al., 1998). Approximately one-third of the Himalayan material is stored in the floodplain, and a significant portion is constructing a prograding shelf sequence (Goodbred et al., 1999). The remaining portion, approximately one-third, enters the SoNG, for example, by coast-parallel currents, partially initiated by storm events (Kudrass et al., 1998), to be finally delivered to the Bengal Fan. 

Turbidity Currents and Channel-Levee Systems

Mechanisms of this transport, which must be associated with the initiation of turbidity currents, are largely unknown. However, sediment physical data for 47 cores along the 3000 km long transport path from the delta platform to the lower fan distinguish different turbiditic environments (Weber et al., 2003). One of the main characteristics of the Bengal Fan is the presence of channel-levee systems of remarkable size (e.g., Hübscher et al. 1989; compilation by Curray et al., 2003). They are believed to form from mostly unchannelized turbidity currents. If they are able to erode the seafloor to the degree that an incision forms, subsequent turbidity currents are confined. As a consequence, erosion is enhanced, the cross section of the turbidity current is further constrained, and turbulent energy can be maintained over very long distances. If sufficient fine-grained material is incorporated in the suspension cloud, spillover deposits can form a wedge-shaped geometry because the sedimentation decreases with lateral distance from the channel axis (levee), constructing a channel-levee system. 

For the Bengal Fan, these turbidity current characteristics were described in detail along the active channel by Hübscher et al. (1997), Weber et al. (1997, 2003), and Schwenk et al. (2003, 2009). Work by Hübscher et al. (1997) and Schwenk and Spiess (2009) confirms an overall similarity of channel-levee complexes and their geometries, scales, and distribution downfan between 8°N and 16°N. Weber et al. (1997) show that these levees can build up over short time spans of several thousand years. Schwenk et al. (2003) further demonstrate that the evolution of these deep-sea channels led to a pronounced, meandering formation of cut-off loops and their sub- sequent fill. In this sense, the latitudinal drilling transect will well recover the characteristics of Bengal Fan architecture, whereas the sediment delivery system through channels will likely reveal a pronounced spatial and temporal variability over relatively short time periods.



Expeditions

  • 1993 - R/V Sonne Cruise SO093 Legs 1-3 - Bengal Fan & Bengal Shelf
  • 1997 - R/V Sonne Cruise SO125 - Bengal Fan
  • 1997 - R/V Sonne Cruise SO126 - Bengal Shelf
  • 2006 - R/V Sonne Cruise SO188-1 - Bengal Fan
  • 2006 - R/V Sonne Cruise SO188-2 - Bengal Shelf
  • 2015 - R/V Sonne Cruise IODP Exp 354 - Bengal Fan
  • 2024 - R/V Sonne Cruise SO304 - Bengal Shelf
  • 20xx - R/V Sonne Cruise SO281 (cancelled for 2021) - Bengal Fan & Bengal Shelf
  • 20xx - R/V Sonne Cruise SOxxx (WinTip; to be scheduled)


River Expedition


Publications Bengal Fan and Shelf

Reilly Brendan T., Bergmann F., Weber ME., Stoner JS, Selkin P., Meynadier L., Schwenk T., Spiess V., France-Lanord C. (2020) Middle to late Pleistocene evolution of the Bengal Fan: Integrating core and seismic observations for chronostratigraphic modeling of the IODP Expedition 354 8 north transect. Geochemistry, Geophysics, Geosystems 21, https://doi.org/10.1029/2019GC008878.

Bergmann, Fenna, Schwenk T., Spiess V., France-Lanord C. (2019) Middle to late Pleistocene architecture and stratigraphy of the lower Bengal Fan — integrating multichannel seismic data and IODP Expedition 354 results. Geochemistry, Geophysics, Geosystems 21, https://doi.org/10.1029/2019GC008702.

Bergmann, Fenna (2018) The Bengal Fan on different temporal and spatial scales. Integrating seismoacoustic and IODP Expedition 354 data to examine internal and external controls on depositional processes. Dissertation, xx. pp.. https://media.suub.uni-bremen.de/bitstream/elib/1540/1/00106937-1.pdf

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Expedition 354 Summary. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.101.2016.

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1449. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.103.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1450. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.104.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1451. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.105.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1452. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.106.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1453. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.107.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1454. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.108.2016 

France-Lanord, Christian, Spiess V., Klaus A., Schwenk T., and the Expedition 354 Scientists (2016) Site 1455. Proceedings of the International Ocean Discovery Program Volume 354, https://doi.org/10.14379/iodp.proc.354.103.2016.

France-Lanord C., Spiess V., Schwenk T., Klaus A., Adhikari RR., Adhikari SK., Bahk JJ., Baxter AT., Cruz JW., Das SK., Dekens P., Duleba W., Fox LR., Galy A., Galy V., Ge J., Gleason JD., Gyawali BR., Huyghe P., Jia G., Lantzsch H., Manoj MC., Martin YM., Meynadier L., Najman YMR., Nakajima A., Ponton C., Reilly BT., Rogers KG., Savian JF., Selkin PA., Weber ME., Williams T., Yoshida K. (2015) Neogene and late Paleogene record of Himalayan orogeny and climate: A transect across the Middle Bengal Fan. Integrated Ocean Drilling Program: Preliminary Reports. (354), 1-46. https://doi.org/10.14379/iodp.pr.354.2015 (PDF)

Palamenghi, Luisa (2012) Tectonic and sea level control on the transport and depositional processes in a siliciclastic sedimentary basin. Insights from the Ganges-Brahmaputra Delta, Bengal Basin, Bangladesh. Dissertation, xx pp.. https://media.suub.uni-bremen.de/bitstream/elib/409/1/00102878-1.pdf.

Schwenk, Tilmann, Spiess V. (2009) Architecture and Stratigraphy of the Bengal Fan as Response to Tectonic and Climate Revealed From High-Resolution Seismic Data, SEPM Special Publication, 92, External Controls on Deep-Water Depositional Systems, 107-131, (PDF).

Hübscher, Christian, Spiess V. (2005) Forced regression system tracts on the Bengal Shelf. Mar. Geol., 219, 207-218, https://doi.org/10.1016/j.margeo.2005.06.037.

Schwenk, Tilmann, Spiess V., Breitzke M., Hübscher C. (2005) The architecture and evolution of the Middle Bengal Fan in vicinity of the active channel-levee system imaged by high-resolution seismic data, Marine and Petroleum Geology, 22, 637-656, https://doi.org/10.1016/j.marpetgeo.2005.01.007.

Schwenk, Tilmann (2004) The Bengal fan: architecture, morphology and depositional processes at different scales revealed from high-resolution seismic and hydroacoustic data. Dissertation, 139 pp... https://media.suub.uni-bremen.de/bitstream/elib/1973/1/E-Diss803_TSchwenk.pdf

Kottke, Bernd, Schwenk T., Breitzke M., Wiedicke M., Kudrass HR., Spiess V. (2003) Acoustic Facies and Depositional Processes in the Upper Submarine Canyon Swatch of No Ground (Bay of Bengal). Deep-Sea Research II, 50, 979-1001, https://doi.org/10.1016/S0967-0645(02)00616-1.

Schwenk, Tilmann, Spiess V., Hübscher C., Breitzke M. (2003) Frequent channel avulsions within the active channel-levee system at the middle Bengal Fan – an exeptional channel-levee development derived from Parasound and Hydrosweep data, Deep Sea Research II, 50, 1023-1045, https://doi.org/10.1016/S0967-0645(02)00618-5.

Michels Klaus H., Suckow A., Breitzke M., Kudrass HR., Kottke B. (2003) Sediment transport in the shelf canyon ‘‘Swatch of No Ground’’ (Bay of Bengal), Deep-Sea Research II 50 (2003) 1003–1022, https://doi.org/10.1016/S0967-0645(02)00617-3.

Gutowski, Martin, Breitzke M., Spiess V. (2002) Fast static correction methods for high-frequency multichannel marine seismic reflection data: A high-resolution seismic study of channel-levee systems on the Bengal Fan. Mar. Geophys. Res., 23, 57.75, https://doi.org/10.1023/A:1021240415963.

Hübscher, Christian, Breitzke M., Michels K., Kudrass HR., Spiess V., Wiedicke M. (1998) Late Quaternary seismic stratigraphy of the eastern Bengal Shelf. Mar. Geophys. Res., 20, 57-81, https://doi.org/10.1023/A:1004375908399.

Hübscher, Christian, Spiess V., Breitzke M., Weber ME. (1997) The youngest channel-levee system of the Bengal Fan: results from digital sediment echosounder data. Mar. Geol., 141, 121-145, https://doi.org/10.1016/S0025-3227(97)00066-2.

Weber Michael E, Wiedicke MH., Kudrass HR., Hübscher C., Erlenkeuser H. (1997) Active growth of the Bengal Fan during sea-level rise and highstand. Geology, 25, 315-318, https://doi.org/10.1130/0091-7613(1997)025<0315:AGOTBF>2.3.CO;2.



Master Theses

Adeboye, Adeniyi (2019) Understanding the architectural style of the channel levee systems in Bengal Fan using high resolution multichannel seismic data

Junge, Verena (2018) Seismic stratigraphy of the upper Bengal Fan - Integration of Seismic Data & IODP Drilling Results from Expedition 353 Site U1444

Ezeadebor, Chike (2017) Reconstruction of subsidence rates from the seismic sequence stratigraphy of the Bengal Shelf

Schaper, Timo (2011) Mapping of surface channel-levee systems and their succession with hydroacoustic methods to decipher the sediment distribution in time and space on the Bengal Fan

Kuehl, Bastian (2010) Identification of systems tracts on the Bengal Shelf by means of different high-resolution seismic data sets

Gutowski, Martin (2001) Optimierte Bearbeitung hochfrequenter Watergun Daten aus dem Bengal Fächer (FS Sonne Expedition 125)

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