Eolian deposits such as loess-paleosol sequences are being used intensively for paleoenvironmental research by investigating proxy data variability. In order to accurately interpret this variability through time, reliable age models are necessary. Age models are transferring stratigraphical thickness to geological time, and represent the basis of most studies investigating the timing and/or rate of changes in Earth’s history. As such, age models are based on different methods. However, at the 16m long loess-paleosol sequence at Urluia in Romania correlative and luminescence age models do not agree with each other (Bösken et al., 2018). While the performance of the luminescence data speaks for a reliable chronology, radiometric ages for the oldest samples do not fit the correlative age model. In a depth between 7.7-8.7 m there is a steep increase in equivalent doses by ~260 Gy (ca. 60 ka). In the lower part of the profile, only a minor increase in equivalent doses was observed, which might suggest field saturation of these samples. As there are no sedimentological indicators of erosion in the sequence, the reason for the sudden increase and a corresponding overestimation of ages with regards to the expected stratigraphy remains elusive. Here, we present an observed dependency of testdose size on the saturation characteristics and dose recovery ratios (cf. Colarossi et al., 2018) and discuss whether this might be responsible for the problematic differences between the age models.
Bösken, J., Zeeden, C., Klasen, N., Brill, D., Burow, C., Hambach, U., Veres, D., Obreht, I., Lehmkuhl, F. (2018): Testdose dependence and possible field saturation using pIRIR290 at the Urluia loess-paleosol sequence, Romania. DLED2018-The Swiss Edition, Beatenberg, Switzerland
|Authors||Bösken, Janina and Zeeden, Christian and Klasen, Nicole and Brill, Dominik and Burow, Christoph and Hambach, Ulrich and Veres, Daniel and Obreht, Igor and Lehmkuhl, Frank|
|Title||Testdose dependence and possible field saturation using pIRIR290 at the Urluia loess-paleosol sequence, Romania|
|Organization||DLED2018-The Swiss Edition|