Universität zu Köln

Brill, Dominik, May, Simon Matthias ORCID: 0000-0001-6762-7500, Mhammdi, Nadia ORCID: 0000-0002-8722-9507, King, Georgina, Lehmann, Benjamin ORCID: 0000-0003-0077-6792, Burow, Christoph, Wolf, Dennis, Zander, Anja and Brueckner, Helmut (2021). Evaluating optically stimulated luminescence rock surface exposure dating as a novel approach for reconstructing coastal boulder movement on decadal to centennial timescales. Earth Surf. Dyn., 9 (2). S. 205 - 235. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 2196-632X

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Abstract

Wave-transported boulders represent important records of storm and tsunami impact over geological timescales. Their use for hazard assessment requires chronological information on their displacement that in many cases cannot be achieved by established dating approaches. To fill this gap, this study investigated, for the first time, the potential of optically stimulated luminescence rock surface exposure dating (OSL-RSED) for estimating cliff-detachment ages of wave-transported coastal boulders. The approach was tested on calcarenite clasts at the Rabat coast, Morocco. Calibration of the OSL-RSED model was based on samples with rock surfaces exposed to sunlight for similar to 2 years, and OSL exposure ages were evaluated against age control deduced from satellite images. Our results show that the dating precision is limited for all targeted boulders due to the local source rock lithology which has low amounts of quartz and feldspar. The dating accuracy may be affected by erosion rates on boulder surfaces of 0.02-0.18 mm yr(-1). Nevertheless, we propose a robust relative chronology for boulders that are not affected by significant post-depositional erosion and that share surface angles of inclination with the calibration samples. The relative chronology indicates that (i) most boulders were detached from the cliff by storm waves; (ii) these storms lifted boulders with masses of up to - similar to 24 t; and (iii) the role of storms in the formation of boulder deposits along the Rabat coast is more significant than previously assumed. Although OSL-RSED cannot provide reliable absolute exposure ages for the coastal boulders in this study, the approach has large potential for boulder deposits composed of rocks with larger amounts of quartz or feldspar and less susceptibility to erosion.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Brill, Dominik UNSPECIFIED UNSPECIFIED UNSPECIFIED May, Simon Matthias UNSPECIFIED orcid.org/0000-0001-6762-7500 UNSPECIFIED Mhammdi, Nadia UNSPECIFIED orcid.org/0000-0002-8722-9507 UNSPECIFIED King, Georgina UNSPECIFIED UNSPECIFIED UNSPECIFIED Lehmann, Benjamin UNSPECIFIED orcid.org/0000-0003-0077-6792 UNSPECIFIED Burow, Christoph UNSPECIFIED UNSPECIFIED UNSPECIFIED Wolf, Dennis UNSPECIFIED UNSPECIFIED UNSPECIFIED Zander, Anja UNSPECIFIED UNSPECIFIED UNSPECIFIED Brueckner, Helmut UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-582873
DOI:	10.5194/esurf-9-205-2021
Journal or Publication Title:	Earth Surf. Dyn.
Volume:	9
Number:	2
Page Range:	S. 205 - 235
Date:	2021
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	2196-632X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LISBON EARTHQUAKE; SINGLE ALIQUOT; EROSION RATES; TSUNAMI; DEPOSITS; RABAT; TRANSPORT; AGE; SEDIMENTATION; PLEISTOCENE Multiple languages Geography, Physical; Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58287