Jürgen Wunderlich

Environmental change and fluvial activity during the Younger Dryas in central Germany

Abstract Late Pleistocene climatically induced environmental changes are reconstructed by applying a multidisciplinary approach on floodplain sediments of small- to medium-sized catchments in central Germany. Radiocarbon dating, pollen analysis and the presence of an accurately dated tephra layer allow the establishment of a reliable chronology. The beginning of the Younger Dryas is marked by a change in fluvial activity that lasts for several hundred years. During this period gravels and sands were deposited by a braided river system. Fluvial systems at this time were predominantly controlled by the climatic conditions of the surrounding uplands, where the climatic deterioration led to a lowering of the forest limit and enhanced periglacial slope processes. An open pine forest prevailed in the basin areas and no evidence of slope wash and solifluction was found. The second part of the Younger Dryas is characterised by a meandering fluvial system and the deposition of overbank fines. The rapid transition from Younger Dryas to Preboreal coincides with an increase in organic deposition.

Barrier rollover and spit accretion due to the combined action of storm surge induced washover events and progradation: Insights from ground-penetrating radar surveys and sedimentological data

ABSTRACT Tillmann, T. and Wunderlich, J., 2013. Barrier rollover and spit accretion due to the combined action of storm surge induced washover events and progradation: Insights from ground-penetrating radar surveys and sedimentological data. Barrier islands and spits are geological young, highly dynamic and represent a complex coastal system that includes a number of different but closely related sedimentary depositional environments. In this study ground-penetrating radar data of different antenna frequencies and sedimentological data were combined to reveal the sedimentary structure and architecture of the southern barrier island spit of Sylt and to set up a barrier island stratigraphy. Based on these data, two sedimentological models have been generated for Southern Sylt which describes the inter-action between extreme events, coastal processes and sedimentary development and contains the major episodes of barrier island evolution. The first model is concerned with the spit add-on zone where the barrier spit is attached to the central island moraine core and shows a landward migration through barrier rollover affected by an interplay of barrier retreat and washover flooding associated with accumulation of sediment in a backbarrier environment as a result of several storm surges. The spit add-on zone reveals a transgressive coarsening upward sequence starting with sandy mud flat deposits at the bottom which turn into coarser sandy tidal flat deposits toward the top. Sandy tidal flat deposits are overlain by washover sheet and washover fan deposits. The second model demonstrates a barrier spit accretion through southerly directed progradation. Eroded sediment was transported along the west coast of Sylt by longshore drift and was added to the southern spit-end. Progradation and barrier spit accretion were interrupted by severe storm surges. Storm surge generated erosion unconformities in a foreshore to shoreface environment redraw old spit-end positions that represent stages of barrier spit progradation.

Dewey’s concept of experience for inquiry-based landscape drawing during field studies

Abstract The epistemological and educational philosophy of John Dewey is used as a theoretical basis to analyze processes of knowledge construction during geographical field studies. The experience of landscape drawing as a method of inquiry and a starting point for research-based learning is empirically evaluated. The basic drawing skills are acquired through an online drawing course. The main aim is to foster the self-organized acquisition of relevant skills to explore, describe and reflect on subjective mental and linguistic concepts in relation to scientific landscape models. The results, based on an evaluation of the students’ drawings, their responses to questionnaires and a review of students’ “reflective notes”, indicate that the approach motivated students to learn about the processes which formed the landscape and that the students perceived the method of inquiry after Dewey as a way to overcome cognitive dissonance.