The influence of sea level and cyclones on Holocene reef flat development: Middle Island, central Great Barrier Reef

Ryan, E.J., Smithers, S.G., Lewis, S.E., Clark, T.R., and Zhao, J.X. (2016) The influence of sea level and cyclones on Holocene reef flat development: Middle Island, central Great Barrier Reef. Coral Reefs, 35 (3). pp. 805-818.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1007/s00338-016-145...
1


Abstract

The geomorphology and chronostratigraphy of the reef flat (including microatoll ages and elevations) were investigated to better understand the long-term development of the reef at Middle Island, inshore central Great Barrier Reef. Eleven cores across the fringing reef captured reef initiation, framework accretion and matrix sediments, allowing a comprehensive appreciation of reef development. Precise uranium–thorium ages obtained from coral skeletons revealed that the reef initiated ~7873 ± 17 years before present (yBP), and most of the reef was emplaced in the following 1000 yr. Average rates of vertical reef accretion ranged between 3.5 and 7.6 mm yr⁻¹. Reef framework was dominated by branching corals (Acropora and Montipora). An age hiatus of ~5000 yr between 6439 ± 19 and 1617 ± 10 yBP was observed in the core data and attributed to stripping of the reef structure by intense cyclones during the mid- to late-Holocene. Large shingle ridges deposited onshore and basset edges preserved on the reef flat document the influence of cyclones at Middle Island and represent potential sinks for much of the stripped material. Stripping of the upper reef structure around the outer margin of the reef flat by cyclones created accommodation space for a thin (<1.2 m) veneer of reef growth after 1617 ± 10 yBP that grew over the eroded mid-Holocene reef structure. Although limited fetch and open-water exposure might suggest the reef flat at Middle Island is quite protected, our results show that high-energy waves presumably generated by cyclones have significantly influenced both Holocene reef growth and contemporary reef flat geomorphology.

Item ID: 46108
Item Type: Article (Refereed Research - C1)
Keywords: Holocene, reef cores, cyclones, U-Th dating, reef accretion, inshore Great Barrier Reef
ISSN: 1432-0975
Funders: National Environmental Research Program (NERP), Great Barrier Reef Marine Park Authority (GBRMPA)
Projects and Grants: NERP Project 1.3
Date Deposited: 12 Oct 2016 07:31
FoR Codes: 04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040601 Geomorphology and Regolith and Landscape Evolution @ 40%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040606 Quaternary Environments @ 30%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 30%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 50%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 50%
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page