Holocene “turn-on” and evolution of the Southern Great Barrier Reef: Revisiting reef cores from the Capricorn Bunker Group

Belinda Dechnik, Jody M. Webster, Peter J. Davies, Juan-Carlos Braga, Paula J. Reimer

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Extensive drilling of the Great Barrier Reef (GBR) in the 70s and 80s illuminated the main factors controlling reef growth during the Holocene. However, questions remain about: (1) the precise nature and timing of reef "turnon" or initiation, (2) whether consistent spatio-temporal patterns occur in the bio-sedimentologic response of the reef to Holocene sea-level rise then stability, and (3) how these factors are expressed in the context of the different evolutionary states (juvenile-mature-senile reefs). Combining 21 new C14-AMS and 146 existing recalibrated radiocarbon and U/Th ages, we investigated the detailed spatial and temporal variations in sedimentary facies and coralgal assemblages in fifteen cores across four reefs (Wreck, Fairfax, One Tree and Fitzroy) from the Southern GBR. Our newly defined facies and assemblages record distinct chronostratigraphic patterns in the cores, displaying both lateral zonation across the different reefs and shallowing upwards sequences, characterised by a transition from deep (Porites/faviids) to shallow (Acropora/Isopora) coral types. The revised reef accretion curves show a significant lag period, ranging from 0.7-2 ka, between flooding of the antecedent Pleistocene substrate and Holocene reef turn-on. This lag period and dominance of more environmentally tolerant early colonizers (e.g., domal Porites and faviids), suggests initial conditions that were unfavourable for coral growth. We contend that higher input of fine siliciclastic material from regional terrigenous sources, exposure to hydrodynamic forces and colonisation in deeper waters are the main factors influencing initially reduced growth and development. All four reefs record a time lag and we argue that the size and shape of the antecedent platform is most important in determining the duration between flooding and recolonisation of the Holocene reef. Finally, our study of Capricorn Bunker Group Holocene reefs suggests that the size and shape of the antecedent substrate has a greater impact on reef evolution and final evolutionary state (mature vs. senile), than substrate depth alone. 

LanguageEnglish
Pages174-190
Number of pages17
JournalMarine Geology
Volume363
Early online date26 Feb 2015
DOIs
Publication statusPublished - 01 May 2015

Keywords

  • Holocene reef
  • Reef growth
  • Coralgal assemblages
  • Radiocarbon dating
  • Sea-level
  • SEA-LEVEL CHANGE
  • CORAL-REEFS
  • WESTERN ATLANTIC
  • GROWTH HISTORY
  • RYUKYU ISLANDS
  • INDIAN-OCEAN
  • PACIFIC
  • SEDIMENTATION
  • MODEL
  • COMMUNITIES

Cite this

Dechnik, Belinda ; Webster, Jody M. ; Davies, Peter J. ; Braga, Juan-Carlos ; Reimer, Paula J. / Holocene “turn-on” and evolution of the Southern Great Barrier Reef: Revisiting reef cores from the Capricorn Bunker Group. In: Marine Geology. 2015 ; Vol. 363. pp. 174-190.
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Holocene “turn-on” and evolution of the Southern Great Barrier Reef: Revisiting reef cores from the Capricorn Bunker Group. / Dechnik, Belinda; Webster, Jody M.; Davies, Peter J.; Braga, Juan-Carlos; Reimer, Paula J.

In: Marine Geology, Vol. 363, 01.05.2015, p. 174-190.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Holocene “turn-on” and evolution of the Southern Great Barrier Reef: Revisiting reef cores from the Capricorn Bunker Group

AU - Dechnik, Belinda

AU - Webster, Jody M.

AU - Davies, Peter J.

AU - Braga, Juan-Carlos

AU - Reimer, Paula J.

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Extensive drilling of the Great Barrier Reef (GBR) in the 70s and 80s illuminated the main factors controlling reef growth during the Holocene. However, questions remain about: (1) the precise nature and timing of reef "turnon" or initiation, (2) whether consistent spatio-temporal patterns occur in the bio-sedimentologic response of the reef to Holocene sea-level rise then stability, and (3) how these factors are expressed in the context of the different evolutionary states (juvenile-mature-senile reefs). Combining 21 new C14-AMS and 146 existing recalibrated radiocarbon and U/Th ages, we investigated the detailed spatial and temporal variations in sedimentary facies and coralgal assemblages in fifteen cores across four reefs (Wreck, Fairfax, One Tree and Fitzroy) from the Southern GBR. Our newly defined facies and assemblages record distinct chronostratigraphic patterns in the cores, displaying both lateral zonation across the different reefs and shallowing upwards sequences, characterised by a transition from deep (Porites/faviids) to shallow (Acropora/Isopora) coral types. The revised reef accretion curves show a significant lag period, ranging from 0.7-2 ka, between flooding of the antecedent Pleistocene substrate and Holocene reef turn-on. This lag period and dominance of more environmentally tolerant early colonizers (e.g., domal Porites and faviids), suggests initial conditions that were unfavourable for coral growth. We contend that higher input of fine siliciclastic material from regional terrigenous sources, exposure to hydrodynamic forces and colonisation in deeper waters are the main factors influencing initially reduced growth and development. All four reefs record a time lag and we argue that the size and shape of the antecedent platform is most important in determining the duration between flooding and recolonisation of the Holocene reef. Finally, our study of Capricorn Bunker Group Holocene reefs suggests that the size and shape of the antecedent substrate has a greater impact on reef evolution and final evolutionary state (mature vs. senile), than substrate depth alone. 

AB - Extensive drilling of the Great Barrier Reef (GBR) in the 70s and 80s illuminated the main factors controlling reef growth during the Holocene. However, questions remain about: (1) the precise nature and timing of reef "turnon" or initiation, (2) whether consistent spatio-temporal patterns occur in the bio-sedimentologic response of the reef to Holocene sea-level rise then stability, and (3) how these factors are expressed in the context of the different evolutionary states (juvenile-mature-senile reefs). Combining 21 new C14-AMS and 146 existing recalibrated radiocarbon and U/Th ages, we investigated the detailed spatial and temporal variations in sedimentary facies and coralgal assemblages in fifteen cores across four reefs (Wreck, Fairfax, One Tree and Fitzroy) from the Southern GBR. Our newly defined facies and assemblages record distinct chronostratigraphic patterns in the cores, displaying both lateral zonation across the different reefs and shallowing upwards sequences, characterised by a transition from deep (Porites/faviids) to shallow (Acropora/Isopora) coral types. The revised reef accretion curves show a significant lag period, ranging from 0.7-2 ka, between flooding of the antecedent Pleistocene substrate and Holocene reef turn-on. This lag period and dominance of more environmentally tolerant early colonizers (e.g., domal Porites and faviids), suggests initial conditions that were unfavourable for coral growth. We contend that higher input of fine siliciclastic material from regional terrigenous sources, exposure to hydrodynamic forces and colonisation in deeper waters are the main factors influencing initially reduced growth and development. All four reefs record a time lag and we argue that the size and shape of the antecedent platform is most important in determining the duration between flooding and recolonisation of the Holocene reef. Finally, our study of Capricorn Bunker Group Holocene reefs suggests that the size and shape of the antecedent substrate has a greater impact on reef evolution and final evolutionary state (mature vs. senile), than substrate depth alone. 

KW - Holocene reef

KW - Reef growth

KW - Coralgal assemblages

KW - Radiocarbon dating

KW - Sea-level

KW - SEA-LEVEL CHANGE

KW - CORAL-REEFS

KW - WESTERN ATLANTIC

KW - GROWTH HISTORY

KW - RYUKYU ISLANDS

KW - INDIAN-OCEAN

KW - PACIFIC

KW - SEDIMENTATION

KW - MODEL

KW - COMMUNITIES

U2 - 10.1016/j.margeo.2015.02.014

DO - 10.1016/j.margeo.2015.02.014

M3 - Article

VL - 363

SP - 174

EP - 190

JO - Marine Geology

T2 - Marine Geology

JF - Marine Geology

SN - 0025-3227

ER -