Conference papers

New data reveals the complexity of modern Halimeda algal bioherm morphology in the Great Barrier Reef, Australia

Author: McNeil, M., Webster, J., Beaman, R.J., Nothdurft, L.

Year: 2018

Publication: New data reveals the complexity of modern Halimeda algal bioherm morphology in the Great Barrier Reef, Australia, International Sedimentological Congress 2018, 13-17 August 2018. International Association of Sedimentologists (IAS), Quebec, Canada.

Abstract

The modern Halimeda algal bioherms in the northern Great Barrier Reef, Australia, form extensive (>6,000 km2) carbonate sediment deposits on the outer continental shelf, and have been described as modern analogues of the late Palaeozoic phylloid algal mounds.

The widely accepted interpretation of Halimeda bioherm morphology as a series of simple parallel ridges and troughs to hummocky mounds, was derived from limited seismic and singlebeam echosounder profiles, and has permeated the literature since the 1980s.

However, new bathymetry data reveals that Halimeda algal bioherm morphology is far more complex than previously thought, and suggests that previous sedimentological interpretations surrounding their formation need to be reconsidered.

Using the most recently available high-resolution airborne lidar and multibeam bathymetry datasets, we digitally mapped the Halimeda bioherm spatial distribution and geomorphology on the northern Great Barrier Reef.

Truly remarkable is their complex reticulate and annulate ring-shaped morphology revealed in 3D for the first time, and overturning the long-standing morphological interpretation.

These new findings raise questions about whether this complex morphology is unique to the modern Halimeda bioherms, or may also be applicable to interpreting algal bioherm morphology in the geological past.

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