Extremereignisse (Wirbelstürme, Tsunami) und Meeresspiegelschwankungen in Westaustralien - Geobioarchive als Schlüssel zur Erforschung der holozänen Küstenentwicklung
Final Report Abstract
The project focused on the coastal evolution and sea-level changes between Broome and the NW Cape, NW Australia, as well as the identification of suitable sedimentary archives to reconstruct occurrence patterns of tropical cyclones during the mid- to late Holocene. The field survey covered the sites of Admiral Bay, the Ashburton River delta near Onslow, the NW Cape, Eighty Mile Beach, and Cape Keraudren. At Admiral Bay, multi-proxy data from the sediment cores show rapid sea-level rise until c. 6000 cal BP when the estuary including the mangrove populations reached much further landward. During and after the Holocene sea-level highstand, the long sequence of beach ridges started to form, driven by slow relative sea-level fall and longshore drift. Our results further suggest that the coarse layers of shell debris found in the ridge stratigraphy may be interpreted as candidate event layers, resulting from storm surge and foredune overwash processes. At Onslow, deposits of tropical cyclones were differentiated from a candidate deposit of the 1883 Krakatoa tsunami based on lower heavy mineral content, different bleaching pattern and higher microfaunal abundance. Precise optically stimulated luminescence (OSL) dating of the historical sediment archive was possible due to high environmental dose rates and high luminescence sensitivity of the quartz grains. At the NW Cape, a mudflat depression covers the mid-Holocene transgression. The uppermost thick and massive sand unit of shelf origin is most likely related to the 1994 Java tsunami, which is known to have flooded the site and laid deposits from sand to boulders. Different pulses of the tsunami wave train are reflected by internal stratification of the unit. Below, thin sand sheets of littoral and shelf material may correlate to TC impacts. The results suggest that, depending on the local sedimentary environment, tsunami and storm events create different depositional patterns at one site. This confirms similar findings from studies worldwide. The remaining sites were, thus far, only surveyed in the field.
Publications
- 11–13 Oct 2012: 38th Annual Meeting of the German Working Group on Geomorphology, Freising: Washover deposits and landforms along the coast of Western Australia – preliminary findings and their potential for palaeotempestological research
S.M. May, H. Brückner, M. Engel, A. Pint, A. Scheffers, D. Kelletat, P. Squire
- 17 Jan 2012: Colloquium “Quaternary Research, Geoarchaeology, and Geochronology” of the Institute of Geography, Universität zu Köln: The potential of different overwash deposits for palaeotempestological research - preliminary findings from Western Australia
S.M. May, H. Brückner, A. Scheffers, D. Kelletat, P. Squire, M. Engel, A. Pint
- 26–30 Aug 2012: 32nd International Geographical Congress, Cologne: The potential of different overwash deposits for palaeotempestological research – preliminary findings from Western Australia
S.M. May, H. Brückner, M. Engel, D. Kelletat, A. Scheffers, P. Squire, A. Pint
- 07–12 Apr 2013: European Geoscience Union (EGU) General Assembly, Vienna: Geomorphological and sedimentological characteristics of cyclone-generated landforms and washover deposits along the coasts of NW Australia
S.M. May, M. Engel, H. Brückner, A. Pint, D. Kelletat, A. Scheffers, P. Squire
- 18–20 Apr 2013: 30th Annual Meeting of the German Working Group on Geography of Oceans and Coasts, Cologne: Geomorphological and sedimentological characteristics of cyclone-generated landforms and washover deposits along the coasts of NW Australia
S.M. May, M. Engel, D. Brill, H. Brückner, D. Kelletat, A. Pint, A. Scheffers, P. Squire
- 2013. Coastal hazards from tropical cyclones and extratropical winter storms based on Holocene storm chronologies. In: Finkl, C. (ed.), Coastal Hazards. Springer, Coastal Research Library 6, 557–585
May, S.M., Engel, M., Brill, D., Squire, P., Scheffers, A., Kelletat, D.
(See online at https://doi.org/10.1007/978-94-007-5234-4_20) - 27–31 Aug 2013: 8th IAG International Conference on Geomorphology, Paris: Geomorphology, sedimentology and geochronology of cyclone-generated landforms and washover deposits along the coasts of NW Australia
S.M. May, M. Engel, H. Brückner, A. Pint, D. Kelletat, A. Scheffers, P. Squire
