Modern sediments and Pleistocene reefs from isolated carbonate platforms (Iles Eparses, SW Indian Ocean): A preliminary study

Jorry, Stéphan; Camoin, Gilbert; Jouet, Gwénaël; Roy, Pascal Le; Vella, Claude; Courgeon, Simon; Prat, Sophie; Fontanier, Christophe; Paumard, Victorien; Boulle, Julien; Caline, Bruno; Borgomano, Jean

doi:10.1016/j.actao.2015.10.014

Cited by 39 publications

(49 citation statements)

References 59 publications

(85 reference statements)

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“…The aragonite muds described here are interpreted as originating from the shallow‐water top of the Juan de Nova platform, where they are precipitated inorganically in supersaturated sea water (Macintyre & Reid, ; Milliman, Freile, Steinen, & Wilber, ), biogenically in the skeletons of organisms where they begin as larger particles and subsequently break down (Conrad Neumann & Land, ), or mechanically/chemically through the feeding and digestive processes of fish (Perry et al., ; Salter et al., ). Core MOZ4‐CS09 lies only 10.5 km from the platform margin, well within the range that fine‐grained sediment could be transported by wind or tide‐generated currents, or by density cascading processes (Jorry et al., ; Wilson & Roberts, ). MAR ar and aragonite percentages in core muds often decrease gradually after the initial rise at the beginning of highstand; this may be due to autocyclic processes (e.g.…”

Section: Discussionmentioning

confidence: 70%

“…The crescent‐shaped morphology of the island and the large sand bank on its northern side (red‐orange in Figure d) are due to the predominance of winds from the south (Figure e; Météo France, ). The top of the overall platform, ranging between +15 and −30 m water depth, is generally flat and circular (Figure d) (Jorry et al., ). Sediment on the platform top is lacking in mud, consisting primarily of carbonate sand <2 mm in diameter, composed mostly of the skeletal fragments of calcareous algae ( Halimeda ), Scleractinian corals, molluscs and foraminifers (Jorry et al., ).…”

Section: Introductionmentioning

confidence: 97%

“…The top of the overall platform, ranging between +15 and −30 m water depth, is generally flat and circular (Figure d) (Jorry et al., ). Sediment on the platform top is lacking in mud, consisting primarily of carbonate sand <2 mm in diameter, composed mostly of the skeletal fragments of calcareous algae ( Halimeda ), Scleractinian corals, molluscs and foraminifers (Jorry et al., ). Clastic or volcanic material has not been observed on the platform top.…”

Section: Introductionmentioning

confidence: 97%

“…Juan de Nova island (40 km 2 ) is the subaerially exposed portion of a small (200 km 2 ), volcano‐cored carbonate platform 135 km off the western coast of Madagascar in the Mozambique Channel (Figure a,b). The subaerial island itself (Figure c) contains evidence of karstification and erosion of lithified carbonate reefs from the previous highstand (Jorry et al., ). The crescent‐shaped morphology of the island and the large sand bank on its northern side (red‐orange in Figure d) are due to the predominance of winds from the south (Figure e; Météo France, ).…”

Section: Introductionmentioning

confidence: 99%

“…Modified from Jorry et al. (), picture from French Southern and Antarctic Lands (TAAF). (d) Detailed bathymetry of platform top (Lidar data from the Litto3D program), flanks and adjacent sea floor (PTOLEMEE cruise; Jorry, ), with superimposed shallow current data (computed from ADCP data, PTOLEMEE cruise; Jorry, ).…”

Section: Introductionmentioning

confidence: 99%

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A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)

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Jorry

Riveiros

et al. 2019

The Depositional Record

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A 27 m core collected on the sea floor near Juan de Nova island at 1,909 m depth in the SW Indian Ocean preserves a high‐resolution record of carbonate sediment export to the deep sea over the past 1 Myr. Core chronology was established using calcareous nannofossil biostratigraphy and benthic foraminiferal δ18O. Throughout the core, preserved highstand intervals (MIS 1, 5, 7, 9, 11, 13, 15, 23 and 25) are marked by an increase in the aragonite content within the sediment. Aragonite is likely sourced from the nearby Juan de Nova carbonate platform ca 10 km to the south, and is interpreted as resulting from flooding of the platform top. Platform inundation allows carbonate muds to be winnowed from their original shallow‐water environment of deposition, suspended in the water column, and redeposited onto the proximal slopes and within the basin. Sharp increases in aragonite content at the beginning of each highstand interval can be used to estimate the approximate sea‐level range when platform flooding occurred; results show that the depth of the platform top has likely changed little over the past 1 Myr due to balanced aggradation and subsidence. Previously hypothesized large‐scale aragonite dissolution cycles are evidenced by a disproportionally low aragonite increase during MIS 11. This study provides a new, exceptionally long record of highstand shedding, expanding the known occurrences of the process to the southern Indian Ocean and supporting its importance as a globally significant depositional mechanism that impacts deep‐sea stratigraphic records.

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Section: Discussionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)

Counts

Jorry

Riveiros

et al. 2019

The Depositional Record

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Changes in mesophotic carbonate‐platform export across the end of the last glacial cycle (Saya de Malha Bank, western Indian Ocean)

Bialik,

Betzler,

Braga

et al. 2024

The Depositional Record

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The export of neritic material from the top of carbonate platforms is a key process in the construction of their slopes. However, our knowledge of the supply pattern of materials from platforms is dominantly based on platforms lying in the euphotic zone during the present sea‐level highstand. This is a somewhat biased perspective as through geological time not all platforms were euphotic. The Saya de Malha Bank in the Mascarene Plateau is an example of a modern mesophotic carbonate platform, and as such, its flooding and export patterns differ from those of euphotic ones. Using cores collected on the western slope of the Saya de Malha Bank, the export patterns of the platform since the last glacial maximum were explored. Material on the platform edge is winnowed and transported to the slope by multiple possible processes. The material on the platform is a combination of high and low magnesium calcite as well as high and low strontium aragonite, integrating pelagic and neritic sources. The ratio of these constituents varies over time with changes in the platform production capability as it was flooded and drowned during the Holocene transgression. The material from the platform is transported in both confined flows, mainly during lowstands, and unconfined flows, mainly during late transgression and early highstand. In the present state of the highstand, supply may have diminished, leading to erosion of the canyon shoulders.

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Functional convergence in macroalgal assemblages of isolated coral reefs in the Mozambique Channel

et al. 2019

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The understanding of macroalgae functions and processes requires a good understanding of the spatial distribution of the functional diversity of macroalgae. In coral reef environments, this information remains fragmentary. Here, based on 314 species sorted according to a set of 10 functional traits, the functional niches of macroalgae at three remote coral reefs of the Îles Éparses in the Indian Ocean (Europa, Glorioso, and Juan de Nova) are described. For the comparison of intra-and inter-reef functional structures, we characterized both taxonomic and functional beta diversities, and their turnover and nestedness-resultant components. Within the three reefs, we observed strong taxonomic and functional dissimilarities across sampling sites, mainly determined by turnover. Null models highlighted several processes, which structured macroalgal assemblages across sites: a combined effect of environmental variables (geomorphology and wave exposure), limiting similarity and stochastic effects. At the inter-reef scale, the three reefs only shared a small number of species, but the functional beta diversity between Glorioso and Juan de Nova was weak. This suggested that although assemblages were different, fairly similar environmental conditions may have homogenized macroalgae functions through both ecological and evolutionary scale processes. Our results support the idea that macroalgal assemblages can provide similar functional trait portfolios, despite distinct species composition. We stress the need to focus on macroalgae life-history traits for a better understanding of the processes structuring their communities.

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Modern sediments and Pleistocene reefs from isolated carbonate platforms (Iles Eparses, SW Indian Ocean): A preliminary study

Abstract: Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

Cited by 39 publications

References 59 publications

A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)

A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean)

Changes in mesophotic carbonate‐platform export across the end of the last glacial cycle (Saya de Malha Bank, western Indian Ocean)

Functional convergence in macroalgal assemblages of isolated coral reefs in the Mozambique Channel

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