Tectonic stability since the last interglacial offsets the Glorieuses Islands from the nearby Comoros archipelago - Archive ouverte HAL Access content directly
Journal Articles Coral Reefs Year : 2013

Tectonic stability since the last interglacial offsets the Glorieuses Islands from the nearby Comoros archipelago

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Abstract

The four fossil terraces of the Glorieuses Islands are described, and new dates are provided to resolve their stratigraphy, depositional setting, and tectonic behavior. Most outcrops consist of a single sedimentary unit that represents the remains of an extensive reef flat dominated by Isopora palifera corals. At Lys Island, this unit is locally overlain by dipping layered beds composed of Halimeda segments, tentatively interpreted as storm overwash. Reliable U/Th dates obtained from corals sampled from the fossil outcrops mostly fall between 127 and 123 kyr, suggesting that these reefs formed exclusively during the first MIS-5e sea-level highstand, when sea level reached +3 m. The mean elevation of these terraces being +4.5 m, an uplift of 0.012 ± 0.002 mm year−1 is inferred. This relative tectonic stability contrasts with the subsidence reported from Mayotte Island, suggesting a different geologic setting for the nearby Comoros and Glorieuses archipelagoes.

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hal-00909859 , version 1 (27-11-2013)

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Mireille M. M. Guillaume, J.-L. Reyss, P. A. Pirazzoli, J. Henrich Bruggemann. Tectonic stability since the last interglacial offsets the Glorieuses Islands from the nearby Comoros archipelago. Coral Reefs, 2013, 32 (3), pp.719--726. ⟨10.1007/s00338-012-1006-9⟩. ⟨hal-00909859⟩
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