An overview of the maldivian coral reefs in Felidu and North Malé Atoll (Indian Ocean): Platform drowning by ecological crises

Ciarapica, Gloria; Passeri, Leonsevero

doi:10.1007/bf02539727

Cited by 53 publications

(48 citation statements)

References 24 publications

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“…Discontinuous marginal rims formed by such small atolls surround lagoons with water depths up to 50-60 m. These rims are interrupted by deep passages, allowing strong currents within the atoll lagoons that rework and redeposit sediment and influence the growth of patch reefs (Ciarapica and Passeri, 1993). Modern marginal reefs are composed of robust-branching corals and coralline algae, whereas the lagoonal reefs show domal corals and detrital sand and rubble facies (Gischler et al, 2008).…”

Section: Background Geological Setting Of the Maldivesmentioning

confidence: 99%

“…Modern marginal reefs are composed of robust-branching corals and coralline algae, whereas the lagoonal reefs show domal corals and detrital sand and rubble facies (Gischler et al, 2008). Muddy sediments are present only in the smaller atolls' lagoons protected by a continuous marginal reef rim (Ciarapica and Passeri, 1993;Gischler, 2006).…”

Section: Background Geological Setting Of the Maldivesmentioning

confidence: 99%

“…Currents reach water depths of 200 m and more with only slightly reduced velocities (Tomczak and Godfrey, 2003). Within the modern atolls' passages, currents can exhibit velocities up to 2 m/s at the surface (Preu and Engelbrecht, 1991), accounting for winnowing in the passages and lagoons, where hard bottoms form (Ciarapica and Passeri, 1993;Gischler, 2006). …”

Section: Background Geological Setting Of the Maldivesmentioning

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: Background Geological Setting Of the Maldivesmentioning

confidence: 99%

Section: Background Geological Setting Of the Maldivesmentioning

confidence: 99%

Section: Background Geological Setting Of the Maldivesmentioning

confidence: 99%

See 1 more Smart Citation

Untitled

Betzler¹,

Eberli²,

Giosan³

et al. 2014

International Ocean Discovery Program Scientific Prospectus

View full text Add to dashboard Cite

show abstract

“…Discontinuous marginal rims formed by such small atolls surround lagoons with water depths to 50-60 m. These rims are interrupted by deep passages, allowing strong currents within the atoll lagoons to rework and redeposit sediment and influence the growth of patch reefs (Ciarapica and Passeri, 1993;Betzler et al, 2015). Modern marginal reefs are composed of robust-branching corals and coralline algae, whereas the lagoonal reefs show domal corals and detrital sand and rubble facies (Gischler et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Modern marginal reefs are composed of robust-branching corals and coralline algae, whereas the lagoonal reefs show domal corals and detrital sand and rubble facies (Gischler et al, 2008). Muddy sediments are present only in atoll areas that are protected by large marginal reefs (Ciarapica and Passeri, 1993;Gischler, 2006;Betzler et al, 2015).…”

Section: Introductionmentioning

confidence: 99%