Title

Terrigenous Sediment-Dominated Reef Platform Infilling: An Unexpected Precursor to Reef Island Formation and a Test of the Reef Platform Size–Island Age Model in the Pacific

Document Type

Article

Publication Date

9-2017

Publication Title

Coral Reefs

Keywords

Coral reefs, Reef islands, Reef platform, Great Barrier Reef, Terrigenous sedimentation

ISSN

0722-4028

Volume

36

First Page

1013

Last Page

1021

Abstract

Low-lying coral reef islands are considered highly vulnerable to climate change, necessitating an improved understanding of when and why they form, and how the timing of formation varies within and among regions. Several testable models have been proposed that explain inter-regional variability as a function of sea-level history and, more recently, a reef platform size model has been proposed from the Maldives (central Indian Ocean) to explain intra-regional (intra-atoll) variability. Here we present chronostratigraphic data from Pipon Island, northern Great Barrier Reef (GBR), enabling us to test the applicability of existing regional island evolution models, and the platform size control hypothesis in a Pacific context. We show that reef platform infilling occurred rapidly (~4–5 mm yr−1) under a “bucket-fill” type scenario. Unusually, this infilling was dominated by terrigenous sedimentation, with platform filling and subsequent reef flat formation complete by ~5000 calibrated years BP (cal BP). Reef flat exposure as sea levels slowly fell post highstand facilitated a shift towards intertidal and subaerial-dominated sedimentation. Our data suggest, however, a lag of ~1500 yr before island initiation (at ~3200 cal BP), i.e. later than that reported from smaller and more evolutionarily mature reef platforms in the region. Our data thus support: (1) the hypothesis that platform size acts to influence the timing of platform filling and subsequent island development at intra-regional scales; and (2) the hypothesis that the low wooded islands of the northern GBR conform to a model of island formation above an elevated reef flat under falling sea levels.

Comments

©Springer-Verlag Berlin Heidelberg 2017

Additional Comments

UK Natural Environment Research Council Radiation Facility allocation #: 1654.0912

ORCID ID

0000-0002-6003-9324

ResearcherID

F-8807-2011

DOI

10.1007/s00338-017-1592-7

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