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Rapid reef island formation and stability over an emerging reef flat; Bewick Cay, northern Great Barrier Reef, Australia

P. S. Kench, S. G. Smithers and R. F. McLean
Rapid reef island formation and stability over an emerging reef flat; Bewick Cay, northern Great Barrier Reef, Australia
Geology (Boulder) (March 2012) 40 (4): 347-350

Abstract

A model that resolves reef island formation in relation to both reef platform substrate development and mid-Holocene sea-level change is presented for Bewick Island, northern Great Barrier Reef, based on morphostratigraphic analysis and radiometrically dated island sediments and reef corals. On Bewick Island, microatolls record reef-flat development at higher sea level (+1.5 m) by 6500 yr B.P. Island building began on a partially emergent reef flat 5000-4000 yr B.P., when sea level was 0.5 m above present. As sea level fell to its present level, the reef platform process window closed and the island core stabilized. Results present the first unequivocal evidence of island building directly over a reef flat comprising microatolls, and the first detailed model of island formation from the Great Barrier Reef. The model demonstrates that the interplay of sea level and reef surface elevation can vary between sites but their convergence is critical for island initiation. Future trajectories of island change will vary, dependent on the unique relative sea level and substrate depth conditions that govern island formation.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 40
Serial Issue: 4
Title: Rapid reef island formation and stability over an emerging reef flat; Bewick Cay, northern Great Barrier Reef, Australia
Affiliation: University of Auckland, School of Environment, Auckland, New Zealand
Pages: 347-350
Published: 20120302
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 23
Accession Number: 2012-035905
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2012096; accessed on March 22, 2012
Illustration Description: illus. incl. sketch maps
Source Medium: WWW
S14°45'00" - S14°40'00", E144°30'00" - E144°49'60"
Secondary Affiliation: James Cook University, AUS, AustraliaUniversity of New South Wales, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201219
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