TY - CONF

T1 - OSL dating of mixed coastal sediment (Sylt, German Bight, North Sea)

A1 - Reimann,Tony

A1 - Lindhorst,Sebastian

A1 - Thomsen,Kristina Jørkov

A1 - Murray,Andrew S.

A1 - Frechen,Manfred

AU - Reimann,Tony

AU - Lindhorst,Sebastian

AU - Thomsen,Kristina Jørkov

AU - Murray,Andrew S.

AU - Frechen,Manfred

PB - Elsevier BV

PY - 2012

Y1 - 2012

N2 - <p>As part of a study on coastal sedimentary processes this paper presents the OSL dating of mixed coastal sediment samples from the southern North Sea island of Sylt (German Bight). During coring of the swash-bar (beach) sediments, five samples were presumably contaminated by younger overwash and aeolian sediments because of the sampling method employed. To obtain reliable burial ages for these swash-bar sediments, single-grain and small aliquot measurements were used together with the Finite Mixture Model (FMM) proposed by Roberts et al. (2000) to identify the grain population containing the largest doses (from the deepest part of the core). Before the FMM was applied to dating, the parameters and performance of the FMM were first investigated by systematically comparing small aliquot (∼20 grains) and single-grain measurements of an undisturbed aeolian and swash-bar sample and a laboratory mixture of both sediments. This test case demonstrates the advantage of selecting the time interval immediately following the initial luminescence signals for background subtraction because unsuitable quartz grains were removed from the dose distribution. It is concluded that the measurement of small aliquots can be regarded as a reliable proxy for single-grain dose distribution if the sediment contains only a small proportion of quartz grains emitting a luminescence signal and that the FMM results are relatively insensitive to changes of the over-dispersion parameter between 5–40% for small aliquots and 10–40% for single-grains.We show that the burial ages of the contaminated swash-bar samples resulting from the maximum age populations from equivalent dose distributions measured using small aliquots are consistent with the stratigraphy and with ages obtained from uncontaminated samples.<br/> © 2012 Elsevier B.V. All rights reserved.</p>

AB - <p>As part of a study on coastal sedimentary processes this paper presents the OSL dating of mixed coastal sediment samples from the southern North Sea island of Sylt (German Bight). During coring of the swash-bar (beach) sediments, five samples were presumably contaminated by younger overwash and aeolian sediments because of the sampling method employed. To obtain reliable burial ages for these swash-bar sediments, single-grain and small aliquot measurements were used together with the Finite Mixture Model (FMM) proposed by Roberts et al. (2000) to identify the grain population containing the largest doses (from the deepest part of the core). Before the FMM was applied to dating, the parameters and performance of the FMM were first investigated by systematically comparing small aliquot (∼20 grains) and single-grain measurements of an undisturbed aeolian and swash-bar sample and a laboratory mixture of both sediments. This test case demonstrates the advantage of selecting the time interval immediately following the initial luminescence signals for background subtraction because unsuitable quartz grains were removed from the dose distribution. It is concluded that the measurement of small aliquots can be regarded as a reliable proxy for single-grain dose distribution if the sediment contains only a small proportion of quartz grains emitting a luminescence signal and that the FMM results are relatively insensitive to changes of the over-dispersion parameter between 5–40% for small aliquots and 10–40% for single-grains.We show that the burial ages of the contaminated swash-bar samples resulting from the maximum age populations from equivalent dose distributions measured using small aliquots are consistent with the stratigraphy and with ages obtained from uncontaminated samples.<br/> © 2012 Elsevier B.V. All rights reserved.</p>

KW - Mixed sediments

KW - Quartz OSL

KW - Single-grain

KW - Finite Mixture Model

KW - North Sea coast

U2 - 10.1016/j.quageo.2012.04.006

DO - 10.1016/j.quageo.2012.04.006

JO - Quaternary Geochronology

JF - Quaternary Geochronology

SN - 1871-1014

VL - 11

SP - 52

EP - 67

ER -