The Heller fan (“Heller Sande”) is located on the eastern slope of the Elbe Valley north of Dresden and belongs to a series of coalescing alluvial fans that cover the eastern slope of the Elbe Valley. The fans run parallel to the Lusatian Thrust, which forms part of the Elbe Fault Zone. The origin and age of these alluvial fan deposits have been controversial for many years.
They overly Cretaceous shallow-marine sandstones and/or Middle Pleistocene Saalian glaciolacustrine deposits, which were deposited into the large ice-dammed Elbe Lake. To get insight into the timing of alluvial-fan deposition luminescence dating was applied to 18 samples collected from the Heller fan. Fan onset and aggradation occurred in response to climate change at the end of MIS 3. The major period of fan aggradation was between 33-18 ka. Involutions, isolated syngenetic ice-wedge casts and frost fissures indicate that temperatures were sufficiently cold to permit the development of ice wedges and point to periods with intense seasonal frost or permafrost conditions under persisting sediment aggradation. Rapid fan aggradation was followed by fan inactivity, abandonment and incision during the Lateglacial.
Post-Middle Pleistocene fault activity is indicated by the formation of disaggregation bands that cross-cut Middle Pleistocene Saalian glaciolacustrine deposits and show the same orientation as the Lusatian Thrust (Winsemann et al., 2022).
Winsemann, J., Hartmann, T., Lang. J., Fälber, R., Lauer, T. (2022): Depositional architecture and aggradation rates of sandrich, supercritical alluvial fans: control by autogenic processes or high-frequency climatic osciallations? Sedimentary Geology 440, 106238. https://doi.org/10.1016/j.sedgeo.2022.106238.