IAG Working Group REEForm – Reef and reef landform responses to environmental and climatic change
Report from Research Expedition, northern Great Barrier Reef, Australia, 26th June to 8th July 2012
Participants:
Chris Perry (University of Exeter, UK), Paul Kench (University of Auckland, NZ), Scott Smithers and James Daniell
(James Cook University, Australia), Bernhard Riegl (Nova Southeastern University, USA)
The second REEForm research expedition took place between 26th June to 8th July 2012 and visited the northern Great
Barrier Reef in Australia. The trip used the James Cook University vessel the RV James Kirby and we are grateful to the
the crew (Gerard and Patrick) for their invaluable assistance and good humour (especially during the very long and rough
steam back south) during the trip. The primary aim of the trip was to revisit some of the low wooded islands examined
during the 1973 Royal Society Great Barrier Reef Expedition and, specifically, to develop an improved understanding of
the chronologies of reef island and reef platform evolution in the area, and the relationships between both these and sealevel. Specific objectives of the trip were as follows:
1. To determine the timing and rates of reef platform development on which the low wooded islands of the
northern GBR have developed.
2. To establish the chronologies of island accumulation in relation to the timing of platform infilling and
development.
To address these objectives, the initial field research programme had intended to visit a number of sites on an across
shelf basis. Unfortunately detrimental weather conditions limited both the focus of sites to those closer to the mainland
and the number of sites that could be examined. The result of this was a more prolonged study of Pipon Reef close to
Princess Charlotte Bay and a brief examination and sampling campaign on Ingham Reef. At Pipon Reef the research
team collected a wide range of data including: the mapping of key reef island landform features, the recovery of both reef
platform top and island cores; data on cross platform bathymetry, and platform top and island sediment samples. At
Ingham Reef time permitted only the mapping of the island and recovery of two main island cores.
Pipon Island: Pipon Island is located close to Cape Melville at 14o 06’50”S, 144o 30’40”E. The reef platform is roughly
oval shaped with the long axis aligned NE-SW. A large rubble ridge complex is located around the NE margin of the
platform behind which there is an area of extensive mangrove development. The main sand island on Pipon Reef is
located towards the west, with smaller sand cays developed along the SW margin. The reef platform interior at Pipon Reef
is essentially full and is at an elevated height relative to Lowest Astronomical Tide (LAT) suggestive of formation during
the mid-Holocene highstand. The contemporary surface of the platform is characterised by sands with isolated coral
rubble, some relict Porites microatolls and by localised areas of seagrass/algal colonisation. The main sand island at
Pipon is ~100 x 50 m in size and orientated NE-SW. Its maximum elevation is ~5 m above the surrounding reef flat and
the island is covered by low scrub. Around the margins of the island are areas of exposed beachrock and/or cay
sandstone, perhaps implying a larger spatial extent of the reefs in the past. We undertook detailed mapping both of the
main sand island on Pipon Reef and of the margin gravel ridges and smaller sand cays. Augered holes and percussion
cores allowed an examination of the internal structure and sedimentology of the main sand island and samples have been
recovered for future AMS radiocarbon dating. Cross platform cores were recovered along a transect running broadly
north-south through the centre of the platform, and along a shorter transect running north-south either side of the island.
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Pipon Reef. The main sand island is to the left margin of
the platform
View NE towards Pipon Island at low tide
Exposed beachrock around the island flanks
View of the vegetated island core
View towards west across the exposed reef platform
Thriving shallow water Acropora colonies on the SW margins
of the platform
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Multiple shingle ridges on the eastern margin of Pipion Reef Cross section through shingle ridges showing the huge
volumes of coral material stored in these features
Ingham Island: Ingham Island is located on the western end of the Ingham-Beanley reef complex (14o 25’ 30”S, 144o 53’
40” E) which is a large sediment infilled reef platform to the south-east of Barrow Point. Ingham Island itself is ~300 x 150
m in size. The island reaches a maximum elevation of ~3 m above the adjacent reef flat and has a low scrub vegetation
cover. The island is surrounded by beach rock. Time constraints did not permit visits to other areas of the reef platform.
Augered holes allowed an examination of the internal structure of the island and samples were recovered for future AMS
radiocarbon dating. One core was recovered from the reef flat some 200 m east of the island.
View of Ingham-Beanley, Ingham Island is top left
View south along island flank
View looking south-east along exposed beachrock and over
the reef platform
Island interior - vegetation colonising surficial sands
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General shots from the trip …..
Chris Perry, July 2012
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