Universität zu Köln

Brill, D., May, S. M., Shah-Hosseini, M., Rufer, D., Schmidt, C. and Engel, M. (2017). Luminescence dating of cyclone-induced washover fans at Point Lefroy (NW Australia). Quat. Geochronol., 41. S. 134 - 151. OXFORD: ELSEVIER SCI LTD. ISSN 1878-0350

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Abstract

Reliable age dating of coastal sedimentary landforms is crucial for inferring storm frequencies and magnitudes from geological archives. However, in highly energetic coastal settings, radiocarbon dating is often biased by reworking and/or poorly constrained marine reservoir effects. Due to this, most cyclone driven sediment archives from the semiarid coast of NW Australia - a region frequently affected by tropical cyclones but with a historical record limited to similar to 150 a, and therefore strongly in need of long-term data inferred from geological evidence - are affected by chronological inaccuracies. Optically stimulated luminescence dating (OSL) may overcome these shortcomings by dating the transport of sediment directly. In turn it may be related to other challenges when applied to cyclone deposits from semiarid environments. The cyclone-induced washover fans at Point Lefroy, NW Australia, are composed of a heterogeneous mixture of coral fragments, shell hash and siliciclastic sand. This makes them particularly prone to high dose scatter resulting from a combination of partial bleaching, sediment mixing and dose-rate heterogeneity. The washover fans are further characterised by a discontinuous nature of cyclone deposition, as indicated by erosional features and macroscopic brunification horizons. By using a combination of quartz single grain dating, autoradiography, alpha counting and gamma spectrometry, sediment mixing and dose rate heterogeneity are identified as the main sources of dose scatter. The resulting chronology allows us to discriminate at least four well constrained phases of washover fan activity at similar to 180, similar to 360, similar to 870, and similar to 1300 a ago. Older but less well constrained activity phases occurred similar to 1950, similar to 2300, and similar to 2830 a ago. While these phases of increased cyclone activity correlate with depositional units separated by potential palaeosols, OSL ages, quasi-continuous portable OSL reader measurements and gamma spectrometry measured with increased sampling resolution point to deposition of distinct washover units within a very short period of time. However, unambiguous discrimination between deposition of individual units by single events and deposition by several cyclones within periods of only a few decades is currently not possible .(c) 2017 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Brill, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED May, S. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Shah-Hosseini, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rufer, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmidt, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Engel, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-222891
DOI:	10.1016/j.quageo.2017.03.004
Journal or Publication Title:	Quat. Geochronol.
Volume:	41
Page Range:	S. 134 - 151
Date:	2017
Publisher:	ELSEVIER SCI LTD
Place of Publication:	OXFORD
ISSN:	1878-0350
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language WESTERN-AUSTRALIA; SINGLE-ALIQUOT; DOSE-RATE; FLUVIAL SEDIMENTS; PHRA THONG; DEPOSITS; QUARTZ; CHRONOLOGIES; THAILAND; GRAINS Multiple languages Geography, Physical; Geosciences, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22289