Current and sea-level signals in periplatform ooze (Neogene, Maldives, Indian Ocean)

Betzler, Christian; Lüdmann, Thomas; Hübscher, Christian; Fürstenau, Jörn

doi:10.1016/j.sedgeo.2013.03.011

Cited by 62 publications

(77 citation statements)

References 39 publications

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“…For the last 2 My, coarser deposits formed at times (~1.5-0.34 Ma) of an intensified monsoon regime (Betzler et al, 2013b), as presented in Zhisheng et al (2011). During the early mid-Pleistocene transition, the first large Pleistocene sea level fall triggered deposition of a grain-flow interval in the Inner Sea; subsequently, a strong bottom current led to winnowing of fines at the seafloor.…”

Section: Relationship With Previous Drillingmentioning

confidence: 73%

“…With weakening of the monsoon system around marine isotope stage (MIS) 10, Site 716 grain-size variations become positively correlated with oxygen isotope data and aragonite contents, resembling the sawtooth pattern of Late Pleistocene glacial-interglacial cycles. This reflects highstand shedding from the shallow banks (Paul et al, 2012;Betzler et al, 2013b).…”

Section: Relationship With Previous Drillingmentioning

confidence: 97%

“…The 264 m thick periplatform ooze bears a mixed record of sea level and bottom-current velocity changes (Lüdmann et al, 2013;Betzler et al, 2013b); grain-size variations for the last 7 My correlate with DS boundaries. Further, the amount of the fine fraction varies, providing insights into past bottom-current speed fluctuations.…”

Section: Relationship With Previous Drillingmentioning

confidence: 99%

“…Previously, the Maldives platform evolution was ubiquitously related to sea level changes Droxler, 2004a, 2004b). This model has recently been challenged based on new seismic and hydroacoustic data sets ( Figure F4) that show that the carbonate edifice contains major sediment drift bodies, indicating that currents (i.e., environmental changes) were a major driver of its evolution (Betzler et al, 2009(Betzler et al, , 2013a(Betzler et al, , 2013bLüdmann et al, 2013).…”

Section: To Decipher the Record Of Neogene Environmental Changes In Tmentioning

confidence: 99%

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Betzler¹,

Eberli²,

Giosan³

et al. 2014

International Ocean Discovery Program Scientific Prospectus

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International Ocean Discovery Program (IODP) Expedition 359 is designed to address sea level, currents, and monsoon evolution in the Indian Ocean. Seven proposed drill sites are located in the Maldives and one site is located in the Kerala-Konkan Basin on the western Indian continental margin. The Maldives carbonate edifice bears a unique and mostly unread Indian Ocean archive of the evolving Cenozoic icehouse world. It has great potential to serve as a key area for better understanding the effects of this global evolution in the Indo-Pacific realm. Based mainly on seismic stratigraphic data, a model for the evolution of this carbonate bank has been developed, showing how changing sea level and ocean current patterns shaped the bank geometries. A dramatic shift in development of the carbonate edifice from a sea level-controlled to a predominantly current-controlled system is thought to be directly linked to the evolving Indian monsoon. Fluctuations in relative sea level control the stacking pattern of depositional sequences during the lower to middle Miocene. This phase was followed by a two-fold configuration of bank development: bank growth continued in some parts of the edifice, whereas in other places, banks drowned. Drowning steps seem to coincide with onset and intensification of the monsoon-related current system and the deposition of giant sediment drifts. The shapes of drowned banks attest to the occurrence of these strong currents. The drift sediments, characterized by off-lapping geometries, formed large-scale prograding complexes, filling the Maldives Inner Sea basin. Because the strong current swept most of the sediment around the atolls away, relict banks did not prograde, and steady subsidence was balanced by aggradation of the atolls, which are still active today.One important outcome of Expedition 359 is ground-truthing the hypothesis that the dramatic, pronounced change in the style of the sedimentary carbonate sequence stacking was caused by a combination of relative sea level fluctuations and ocean current system changes. Answering this question will directly improve our knowledge on processes shaping carbonate platforms and their stratigraphic records. Our findings would be clearly applicable to other Tertiary carbonate platforms in the Indo-Pacific region and to numerous others throughout the geological record. In addition, the targeted successions will allow calibration of the Neogene oceanic 13 C record with data from a carbonate platform to platform-margin series. This is becoming important, as such records are the only type that exist in deep time. Drilling will provide the cores required for reconstructing changing current systems through time that are directly related to the evolution of the Indian monsoon. As such, the drift deposits will provide a continuous record of Indian monsoon development in the region of the MalExpedition 359 Scientific Prospectus 4 dives. These data will be valuable for a comparison with proposed Site KK-03B in the Kerala-Konkan Basin (see Geological...

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Section: Relationship With Previous Drillingmentioning

confidence: 73%

Section: Relationship With Previous Drillingmentioning

confidence: 97%

Section: Relationship With Previous Drillingmentioning

confidence: 99%

Section: To Decipher the Record Of Neogene Environmental Changes In Tmentioning

confidence: 99%

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Betzler¹,

Eberli²,

Giosan³

et al. 2014

International Ocean Discovery Program Scientific Prospectus

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“…On the Inner Sea side, terraced atoll slopes have the same dip angles but reach water depths of only 150 m, where the gradient rapidly declines (Fürstenau et al, 2010). The Inner Sea is characterized by periplatform ooze deposition that locally accumulates into sediment drift bodies (Droxler et al, 1990;Malone et al, 1990;Betzler et al, 2009Betzler et al, , 2013aBetzler et al, , 2013bPaul et al, 2012;Lüdmann et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Volume 359: Maldives Monsoon and Sea Level

Betzler¹,

Eberli²,

Zarikian³

2017

Proceedings of the International Ocean Discovery Program

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Lowstand wedges in carbonate platform slopes (Quaternary, Maldives, Indian Ocean)

Betzler

Hübscher

Lindhorst

et al. 2016

The Depositional Record

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Seismic, hydroacoustic and sedimentological data were used to analyse the response of atoll-slope sedimentation in the Maldives to the late Quaternary sea-level change. The slope deposits, as imaged in multichannel seismic profiles, are arranged into stacked aggrading to backstepping basinward thinning wedges. In a piston core recovered at the lower slope of one of the atolls, the sediment texture ranges from packstone to rudstone. Major components are blackened bioclasts, the large benthic foraminifers Operculina and Amphistegina, together with Halimeda debris and red algae. Radiocarbon dating at a core depth of 66 cm indicates that the wedge sedimentation stopped or was largely reduced after 16 ka BP. Therefore, the atoll-slope deposits largely consist of sediment formed in situ and deposited during the last glacial lowstand in sealevel. This is in apparent contradiction to the concept of highstand shedding of tropical carbonate platforms, which requires slope sedimentation during sealevel highstands, when the platform is flooded. Rather than intrinsic factors, such as sediment bypass along the steep slope, the extrinsic process of current winnowing of the slope appears to be a major controlling factor in the production of this feature. This process may be relevant for other case studies of carbonate platforms, as currents may be accelerated around such edifices, leading to slope winnowing and sediment deposition in more current-protected zones. The study results also have consequences for the interpretation of outcrop and seismic subsurface data of carbonate platform slope series, because such slope sediment wedges are not necessarily formed during sea-level highstands, but can consist of lowstand wedges only.

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Current and sea-level signals in periplatform ooze (Neogene, Maldives, Indian Ocean)

Cited by 62 publications

References 39 publications

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Volume 359: Maldives Monsoon and Sea Level

Lowstand wedges in carbonate platform slopes (Quaternary, Maldives, Indian Ocean)

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