Research School of Earth Sciences, The Australian National University Canberra, ACT 0200, Australia.
Sea level control of stacked late Quaternary coastal sequences, central Great Barrier Reef
Article first published online: 14 JUN 2006
Volume 41, Issue 2, pages 329–351, April 1994
How to Cite
GAGAN, M. K., JOHNSON, D. P. and CROWLEY, G. M. (1994), Sea level control of stacked late Quaternary coastal sequences, central Great Barrier Reef. Sedimentology, 41: 329–351. doi: 10.1111/j.1365-3091.1994.tb01409.x
- Issue published online: 14 JUN 2006
- Article first published online: 14 JUN 2006
- Manuscript received 10 February 1993; revision accepted 16 September 1993
Lithofacies analysis, pollen assemblages and radiocarbon age dates of 20 stratigraphic drill holes are used to develop an evolutionary history for late Quaternary sedimentation in two coastal embayments landward of the central Great Barrier Reef. Different physiographic settings of the embayments result in two contrasting styles of sedimentary sequence: (a) an exposed, moderate energy, beach barrier-lagoon system (Wyvuri Embayment) and (b) a protected, low energy, muddy inlet fill sequence (Mutchero Inlet). Despite sharp contrast in sequence style, similar depositional cycles occur in both embayments in response to late Quaternary sea level fluctuations including: (1) a last interglacial highstand (+2 m; c. 125 000 yr bp) beach barrier (Wyvuri); (2) an early to mid-Holocene (8000–6100 yr bp) transgressive beach barrier-lagoon (Wyvuri) and estuarine infill (Mutchero); and (3) mid-Holocene to present highstand beach barrier (Wyvuri) and estuarine (Mutchero) progradation. Preservation of such cycles in the stratigraphic record would produce a series of vertically stacked and offset linear barrier sands surrounded by lagoonal mud and fine grained shoreface sediment juxtaposed to muddy, estuarine infills.
Sea level elevations are well recorded by the upward transition from Rhizophora-dominated intertidal mangrove mud to freshwater swamp (clearly identified by pollen analysis) and by the basal contacts of beach barrier sediments which sharply overlie the upper shoreface. Transgressive sedimentation is interrupted in both embayments by a constructional beach barrier (Wyvuri) and abbreviated progradation (Mutchero) corresponding to a — 5 m pause in relative sea level rise at c. 6800 yr bp. Sea level control of fine scale coastal sedimentation patterns is beginning to be widely recognized and provides an accurate analogue for stacked ancient sequences.