Combining luminescence dating and sedimentary analysis to derive the landscape dynamics of the Velická Valley in the High Tatra Mountains, Slovakia

Luminescence dating is widely used in combination with sedimentological analysis to reconstruct the landscape development of the Quaternary period. Here, quartz and K-feldspar measurements are used to date and evaluate the luminescence characteristics of sediments from seven sites of the lower part of the Velická valley (995-1250 m a.s.l.) in the High Tatra Mountains, Slovakia. The quartz and K-feldspar grains are separated, and multiple quality and control tests are carried out to test the quality of the minerals. The observed characteristics and unreliable results of the quartz are appointed to the weak optical stimulated luminescence signal and the saturation of the signal, this led to using K-feldspar stimulated by infrared stimulated luminescence (IRSL) for further dating of the sampled sediment at the sites. The age of deposition of the sediments is derived from the combined uncorrected and for fading corrected post-IR IRSL at 225°C (pIRIR225), the corrected ages were applied for the samples containing a fading rate exceeding the 3%/decade. From the sampled and dated modern analogues (samples from next to the river; site 6 and 7) could be inferred that the K-feldspar was significantly incompletely bleached. Moreover, for the four oldest samples the pIRIR225 signal showed to be saturated. The results of the dating and the sedimentology are put in the context of landscape dynamics. The deposition of the sediments (except for the modern analogues) dates back to the Middle Pleistocene epoch. Sites 4, 1, 2, and 5 (in order from old to young) are correlated to the Riss I and Riss II glaciation and the Riss II/Würm interglacial. From the evidence that the clasts have been reworked by water, the planar beds, and other evidence the sediments on site 1, 2, 4, and 5 are interpreted to have been transported by different kinds of subaerial flows. Based on the ages and the maximum particle size the ice margin is hypothesized to have been around one kilometer north of the study area during the deposition of the sediment of sites 1 and 2. From this setting and the observations of the sediments, there can be derived that these sediments have been deposited in a proglacial outwash plain. After the deposition of the sediment at site 1 (171±20 ka) the vertical incision of the Velická valley is believed to have taken place, enhanced by an increase of discharged meltwater from the glacier during a glacial to interglacial transition and the sudden sediment release from the outwash plain generating an erosional pulse. Afterwards, when the input of meltwater decreased and a low energy environment took place, the terraces were deposited (142±14 ka) in the Velická valley during the RissII/Würm interglacial.