Submerged Coral Reefs and Benthic Habitats of the Southern Gulf of Carpentaria: Post-Survey Report - GA Survey 276, RV Southern Surveyor
In 2003, Geoscience Australia discovered three large patch reefs in the southern Gulf of Carpentaria (GA Survey 238; SS-03/2004; Harris et al., 2004). The submerged platform reefs (R1, R2 and R3) are located east of Mornington Island and appear to have been formed when sea level was ~30 m below its present position, however as the ship did not come prepared with a drill-core sampler, the sub-surface composition of the reefs was not determined. The submerged platforms support live hard corals in many locations and their discovery raised the question of the possibility of widespread reef occurrence in that region. Survey 276 was designed to deliver some answers to these questions.
The current survey used rotary drilling of reefs R1, R2 and R3 which recovered coral material from 8 sites and confirmed the coral reef composition of these features. Multibeam sonar bathymetry and rotary drill cores were collected over two sections (R4 and R5) of a large (>100 km long) submerged platform that extends westwards from Mornington Island. The platform exhibits a Karst erosion surface, exhibiting drainage and depressions with raised rims, overprinting relict reef-growth geomorphic features. Reef growth features include raised rims, spur and groove reef front and elevated back-reef mounds. Other platform reefs were mapped in the south-western Gulf (R6 and R7) and in the Arafura Sea (R8). Rotary drilling has confirmed the coral reef composition of these features.
Preliminary assessments of the recovered drill cores indicate that reef growth has persisted in the region for several glacial cycles, extending over at least the past 120,000 years. Dating of Holocene corals by the U/Th method demonstrates that a phase of rapid (1-2 m per kyr) reef growth occurred at most sites between 9 and 7 kyr before present, with zero or much reduced growth rates occurring after 7 kyr ago. Although coral growth occurs in many areas, the production of carbonate has not been sufficient to build the reef-tops upwards to the present sea level. The observations of live corals, but low carbonate production rates, are consistent with a 'catch-up' reef growth pattern, in which the upper surfaces of the reefs are submerged 20 to 30 m below present sea level, with isolated local reef-tops having reached to within 18 m of the sea surface. An analysis of the hypsometry of the reef surfaces indicates that platform surfaces at all sites (R1 to R8) are confined to two narrow depth intervals, centred at 26.8 ± 1 m and 30.7 ± 0.3 m. The good correspondence of hypsometric peaks indicates regionally significant phases of carbonate deposition during a prolonged, Pleistocene sea level still stand.
This voyage has proved that the southern Gulf of Carpentaria contains a previously unknown major coral reef province in Australia. The reefs support locally diverse and luxuriant coral growth. From a management perspective, the slow rates of coral growth point to the need for protection of these reef systems because of their limited capacity to recover from natural or human-induced disturbances.
Simple
Identification info
- Date (Publication)
- 2007-01-01T00:00:00
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/65073
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Geoscience Australia
Canberra Author Harris, P.T.
1 Author Heap, A.D.
2 Author Marshall, J.
3 Author Hemer, M.
4 Author Daniell, J.
5 Author Hancock, A.
6 Author Buchanan, C.
7 Author Sbaffi, L.
8 Author Brewer, D.
9 Author Heales, D.
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- Name
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Record
- Issue identification
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2007/002
- Point of contact
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Role Organisation / Individual Name Details Custodian EGD
Owner Commonwealth of Australia (Geoscience Australia)
Custodian Commonwealth of Australia (Geoscience Australia)
Voice
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- Geoscientific information
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))
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Product data repository: Various Formats
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Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
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GA Publication
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Record
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continental shelf
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seabed
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environmental
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sedimentology
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marine
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AU-NT
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AU-QLD
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- Australian and New Zealand Standard Research Classification (ANZSRC)
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Earth Sciences
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Published_External
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Creative Commons Attribution 4.0 International Licence
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CC-BY
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4.0
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Australian Government Security ClassificationSystem
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- 2018-11-01T00:00:00
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- English
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
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Download the record (pdf)
Download the record (pdf)
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pdf
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- OnLine resource
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File download
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Unknown
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- Non geographic dataset
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GA Publication
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Source data not available.
Metadata constraints
- Title
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Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
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urn:uuid/a05f7892-cf8e-7506-e044-00144fdd4fa6
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GeoNetwork UUID
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- English
- Character encoding
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- Contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice
Type of resource
- Resource scope
- Document
- Name
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GA Record
Alternative metadata reference
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/65073
- Date info (Revision)
- 2018-04-22T08:51:51
- Date info (Creation)
- 2007-01-12T00:00:00
Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-3
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, September 2018
- Citation identifier
- https://pid.geoscience.gov.au/dataset/ga/122551