Sea level change over the past 2500 years from northeastern Australia
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Date
2012-08-05
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Geosciences Council
Abstract
This study C-14 dated living and fossil oyster bed deposits (>50 cm thick) to examine when sea level fell to its present position. These thick oyster bed deposits are formed in the inter-tidal zone and are relatively long-lived features with one bed dated in this study growing for ∼1000 years. Consistent growth rates at each sampling location indicated that oyster bed accumulation over time has been continuous, although growth rates varied markedly between locations from 0.30 mm/year to 6.4 mm/year suggesting the influence of localised environmental variability in water circulation, wave exposure and boulder lithology. We will show that a rapid sea-level fall occurred between 800 and 1200 years BP where sea level fell from ∼ + 1 m to present position with rates up to 7 mm/year but no less than 2.5 mm/year. The rapid fall supports the stepped sea-level model. This rapid fall influenced the movements of indigenous people as well as coincided with the development of inshore fringing coral reefs and geomorphological changes along the coastal zone.
Description
Keywords
Carbon 14, Sea level, Australia, Fossils, Oysters, Coastal regions, Lithology, Corals, Geomorphology
Citation
Lewis, S., Wust, R. A. J., Webster, J. M., Collins, J., Wright, S., & Jacobsen, G. (2012). Sea level change over the past 2500 years from northeastern Australia. Paper presented to the 34th International Geological Congress 2012, "Unearthing our Past and Future - Resourcing Tomorrow", Brisbane, Australia, 5-10 August 2012, (pp. 707).