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

Type Article
Acceptance Date 2019 IN PRESS
Language English
Author(s) Counts John1, 2, Jorry StephanORCID2, Vazquez Riveiros NataliaORCID2, Jouet Gwenael2, Giraudeau Jacques3, Cheron Sandrine2, Boissier AudreyORCID2, Miramontes Elda4
Affiliation(s) 1 : Irish Centre for Research in Applied Geosciences (iCRAG); O'Brien Centre for Science, University College Dublin; Belfield Dublin 4 Ireland
2 : IFREMER; Unité Géosciences Marines - Pointe du Diable; 29280 Plouzané France
3 : UMR CNRS 5805 EPOC; Université de Bordeaux; Allée Geoffroy Saint-Hilaire; CS 50023 33615 Pessac Cedex France
4 : CNRS, UMR6538, Laboratoire Géosciences Océan; Institute Universitaire Européen de la Mer - Université de Bretagne Occidentale (IUEM-UBO); 29280 Plouzané France
Source The Depositional Record (20554877) (Wiley) In Press
DOI 10.1002/dep2.57
Abstract

A 27 m core collected on the seafloor near Juan de Nova island at 1909 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 ~10 km to the south, and is interpreted to result 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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Counts John, Jorry Stephan, Vazquez Riveiros Natalia, Jouet Gwenael, Giraudeau Jacques, Cheron Sandrine, Boissier Audrey, Miramontes Elda A Late Quaternary record of highstand shedding from an isolated carbonate platform (Juan de Nova, southern Indian Ocean). The Depositional Record IN PRESS. Publisher's official version : https://doi.org/10.1002/dep2.57 , Open Access version : https://archimer.ifremer.fr/doc/00474/58553/