Abstract


CORAL SUCCESSIONS IN THE GREAT BARRIER REEF DURING GLACIAL-INTERGLACIAL CYCLES

Tropical coral reef ecosystems have been affected by drastic sea level and environmental changes during Quaternary glacial-interglacial cycles. However, their responses to these perturbations prior to the Holocene are still poorly understood. Recent offshore drilling of the submerged fossil reefs along the shelf edge of the Great Barrier Reef of Australia (GBR) revealed multiple reef sequences formed during the last glacial period and subsequent deglaciation (IODP Expedition 325). A total of 34 boreholes drilled along four transects at three localities (Hydrographers Passage, Noggin Pass, and Ribbon Reef) were used to resolve for the first time the geometry and composition of the GBR during glacial-deglacial conditions when the continental shelf was exposed and reef growth was restricted to the shelf edge. Here we analyse the evolution of reef coral composition in the GBR during glacial-interglacial cycles by comparing the IODP Exp. 325 data set with coral data from two deep boreholes drilled in 1995 in Ribbon Reef 5 (RR5) and Boulder Reef (BR) in the northern GBR (International Consortium for GBR drilling). The RR5 and BR boreholes record a succession of highstand reef sequences formed during late deglacial-interglacial conditions when the shelf was innundated. Our statistical analysis points to a marked difference in coral composition between glacial-early deglacial fringing reefs and late deglacial-interglacial barrier reefs, and highlights the relationships between reef architecture, shelf morphology and coral composition.

Authors

Humblet, M., Nagoya University, Japan, humblet.marc@f.mbox.nagoya-u.ac.jp

Webster, J. M., The University of Sydney, Australia, jody.webster@sydney.edu.au

Details

Oral presentation

Session #:34
Date: 06/23/2016
Time: 14:15
Location: 311

Presentation is given by student: No