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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
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.

10
Name

Record

Issue identification

2007/002

Point of contact
Role Organisation / Individual Name Details
Custodian

EGD

Owner

Commonwealth of Australia (Geoscience Australia)

Custodian

Commonwealth of Australia (Geoscience Australia)

Voice
Topic category
  • Geoscientific information

Extent

N
S
E
W


Maintenance and update frequency
Unknown

Resource format

Title

Product data repository: Various Formats

Website

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

Keywords
  • GA Publication

  • Record

Theme
  • continental shelf

Theme
  • seabed

Theme
  • environmental

Theme
  • sedimentology

Theme
  • marine

Keywords
  • AU-NT

  • AU-QLD

Australian and New Zealand Standard Research Classification (ANZSRC)
  • Earth Sciences

Keywords
  • Published_External

Resource constraints

Title

Creative Commons Attribution 4.0 International Licence

Alternate title

CC-BY

Edition

4.0

Website

http://creativecommons.org/licenses/

Access constraints
License
Use constraints
License

Resource constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified
Language
English
Character encoding
UTF8

Distribution Information

Distributor contact
Role Organisation / Individual Name Details
Distributor

Commonwealth of Australia (Geoscience Australia)

Voice
OnLine resource

Download the record (pdf)

Download the record (pdf)

Distribution format
  • pdf

OnLine resource

File download

Appendices

Resource lineage

Statement

Unknown

Hierarchy level
Non geographic dataset
Other

GA Publication

Description

Source data not available.

Metadata constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified

Metadata

Metadata identifier
urn:uuid/a05f7892-cf8e-7506-e044-00144fdd4fa6

Title

GeoNetwork UUID

Language
English
Character encoding
UTF8
Contact
Role Organisation / Individual Name Details
Point of contact

Commonwealth of Australia (Geoscience Australia)

Voice

Type of resource

Resource scope
Document
Name

GA Record

Alternative metadata reference

Title

Geoscience Australia - short identifier for metadata record with

uuid

Citation identifier
eCatId/65073

Metadata linkage

https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/a05f7892-cf8e-7506-e044-00144fdd4fa6

Date info (Revision)
2018-04-22T08:51:51
Date info (Creation)
2007-01-12T00:00:00

Metadata standard

Title

AU/NZS ISO 19115-1:2014

Metadata standard

Title

ISO 19115-1:2014

Metadata standard

Title

ISO 19115-3

Title

Geoscience Australia Community Metadata Profile of ISO 19115-1:2014

Edition

Version 2.0, September 2018

Citation identifier
https://pid.geoscience.gov.au/dataset/ga/122551

 
 

Spatial extent

N
S
E
W


Keywords

continental shelf environmental marine seabed sedimentology

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