Coral Reefs

, Volume 35, Issue 2, pp 625–639

Holocene sea level instability in the southern Great Barrier Reef, Australia: high-precision U–Th dating of fossil microatolls

  • Nicole D. Leonard
  • J-x Zhao
  • K. J. Welsh
  • Y-x Feng
  • S. G. Smithers
  • J. M. Pandolfi
  • T. R. Clark
Report

DOI: 10.1007/s00338-015-1384-x

Cite this article as:
Leonard, N.D., Zhao, J., Welsh, K.J. et al. Coral Reefs (2016) 35: 625. doi:10.1007/s00338-015-1384-x

Abstract

Three emergent subfossil reef flats from the inshore Keppel Islands, Great Barrier Reef (GBR), Australia, were used to reconstruct relative sea level (RSL). Forty-two high-precision uranium–thorium (U–Th) dates obtained from coral microatolls and coral colonies (2σ age errors from ±8 to 37 yr) in conjunction with elevation surveys provide evidence in support of a nonlinear RSL regression throughout the Holocene. RSL was as least 0.75 m above present from ~6500 to 5500 yr before present (yr BP; where “present” is 1950). Following this highstand, two sites indicated a coeval lowering of RSL of at least 0.4 m from 5500 to 5300 yr BP which was maintained for ~200 yr. After the lowstand, RSL returned to higher levels before a 2000-yr hiatus in reef flat corals after 4600 yr BP at all three sites. A second possible RSL lowering event of ~0.3 m from ~2800 to 1600 yr BP was detected before RSL stabilised ~0.2 m above present levels by 900 yr BP. While the mechanism of the RSL instability is still uncertain, the alignment with previously reported RSL oscillations, rapid global climate changes and mid-Holocene reef “turn-off” on the GBR are discussed.

Keywords

Sea level Holocene Great Barrier Reef Microatoll Uranium–thorium Reef hiatus 

Supplementary material

338_2015_1384_MOESM1_ESM.docx (6.8 mb)
Supplementary material 1 (DOCX 7003 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.School of Earth SciencesThe University of QueenslandSt LuciaAustralia
  2. 2.Radiogenic Isotope FacilityThe University of QueenslandSt LuciaAustralia
  3. 3.School of Earth and Environmental SciencesJames Cook UniversityTownsvilleAustralia
  4. 4.Australian Research Council Centre of Excellence for Coral Reef Studies, Centre for Marine Science, School of Biological SciencesThe University of QueenslandSt LuciaAustralia