The western coast of Sylt is a very dynamic sedimentary environment. The interaction of long- to mid-term accretional processes (e.g. spit progradation by swash-bar accretion) and strong erosional events (e.g. storm surges) caused a complex sedimentary architecture of the Holocene barrier spit. A better understanding of coastal sedimentary processes and the related controlling factors (e.g. climate, sediment supply and sea level) is a fundamental issue for developing concepts of enhanced coastal protection. This task requires, in addition to investigations of the sedimentary setting, a reliable estimation of deposition ages of different sedimentary units. The sediment architecture of Listland (North Sylt) was clarified by Lindhorst et al. (2008) using ground-penetrating radar (GPR) and sedimentological investigation. They provide a high-resolution stratigraphic model and show that swash-bars are an important building block of the barrier spit, and that phases of spit progradation were interrupted by strong erosional events several times. Based on these data, samples for optically stimulated luminescence (OSL) dating were taken at selected locations. OSL dating estimates the time elapsed since the sediments last exposure to daylight. Hence, it makes direct deposition ages of the sediment bodies (e.g. swash-bars) and indirect age estimates of the erosional event layers available. First results reveal the excellent suitability of the local sedimentary quartz for dating. First data show that progradation of the Listland spit was completed before 1000 AD.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 2: Coastal Change > WP 2.3: Coastal Systems under Global and Regional Pressures