New constraints on the origin of the Australian Great Barrier Reef: results from an international project of deep coring
Alexander, I., Wilson, P.A. and Cooper, M.J. (2001) New constraints on the origin of the Australian Great Barrier Reef: results from an international project of deep coring. Geology, 29, (6), 483-486. (doi:10.1130/0091-7613(2001)029<0483:NCOTOO>2.0.CO;2).
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Two new boreholes provide the first direct evidence of the age of the Australian Great Barrier Reef. An inner shelf sequence (total depth, 86 m; basal age = 210 ± 40 ka) comprises a dominantly siliciclastic unit (thickness 52–86 m), overlain by four carbonate units (total thickness 0–34 m). A shelf-edge and slope sequence (total depth 210 m) reveals three major sections: (1) a lower section of resedimented flows deposited on a lower slope, (2) a mid-section including intervals of corals, rhodoliths, and calcarenites with low- angle graded laminae, and (3) an upper section of four shelf- margin coral-reef units separated by karst surfaces bearing paleosols. Sr isotope and magnetostratigraphic data indicate that the central Great Barrier Reef is relatively young (post Brühnes-Matuyama boundary time), and our best estimate for the onset of reef growth on the outer barrier system is ca. 600 ± 280 ka. This date suggests that reef initiation may have been related to the onset of full eccentricity-dominated glacio-eustatic sea-level oscillation as inferred from large-amplitude “saw-tooth? 100 k.y. ?18O cycles (after marine isotope stage 17), rather than to some regional environmental parameter. A major question raised by our study is whether reef margins globally display a similar growth history. The possibility of a global reef initiation event has important implications for basin to shelf partitioning of CaCO3, atmospheric carbon dioxide levels, and global temperature change during Quaternary time.
|Digital Object Identifier (DOI):||doi:10.1130/0091-7613(2001)029<0483:NCOTOO>2.0.CO;2|
|Keywords:||INTERNATIONAL CONSORTIUM FOR GREAT BARRIER REEF DRILLING, CARBONATE SEDIMENTS, DIAGENESIS, REEFS, SEA LEVEL, GEOLOGY|
|Subjects:||Q Science > QE Geology
G Geography. Anthropology. Recreation > GC Oceanography
|Divisions:||University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
|Date Deposited:||10 Aug 2004|
|Last Modified:||31 Mar 2016 11:10|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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