1. The transition of very coarse-grained meandering to straight fluvial drainage systems in a tectonized foreland-basement landscape during the Holocene (SE Germany) – A joint geomorphological-geological study.
- Author
-
Dill, H.G., Buzatu, A., Balaban, S.-J., Ufer, K., Techmer, A., Schedlinsky, W., and Füssl, M.
- Subjects
- *
FLUVIAL geomorphology , *STRUCTURAL geology , *HOLOCENE Epoch , *OPTICALLY stimulated luminescence dating , *BRAIDED rivers , *CENOZOIC Era - Abstract
Very coarse-grained meandering to straight fluvial drainage systems evolved during the Holocene (<7950 BP) in a terrain underlain by crystalline basement rocks of Precambrian to Paleozoic age and Mesozoic sedimentary rocks which are separated from each other by an area intersected by fault zones of Cenozoic age. Faulting provoked ridges in the foreland, dykes in the basement and it is accountable for a significant uplift and stream strong gradient. All structural elements show the same NW-SE strike as a consequence of the modern fault tectonic pattern. The Holocene fluvial drainage system under study evolved homoclinal with a presumed paleosurface (relic landscape/peneplain) and represents the upper reaches of the Main River Drainage System in SE Germany. During the Neogene, chemical weathering created a regolith while uplift in the hinterland and subsidence in the foreland provoked tilting of the paleosurface. The coarse-grained meandering drainage system is described by a characteristic trilogy that encompasses (1) intermediate depocenters/sediment traps, (2) subsequent strike streams, and (3) consequent dip streams that upstream grade into straight streams with no braided streams to be. The drainage system developed under temperate humid climates and can be described by five lithofacies types which were investigated with regard to the origin of the individual landform types, their sedimentological, hydrographic, mineralogical and petrographic features. The hydrographic parameters sinuosity, channel density and channel-floodplain ratio are markers for the paleo-gradient and tectonic activity and can also be used as flow rate and fluvial confinement indices. Mass wasting and fluvial processes both shape the morphology of the valleys. Autochthonous and par-autochthonous minerals and organic matters constitute the basis for the physico-chemical facies analysis and for constraining the climatic and early diagenetic regimes. For correlation and chronology of the lithofacies types radiocarbon dating and optically stimulated luminescence proved to be successful. Unlabelled Image • The foreland-basement transition and tectonized boundary zone • The very coarse-grained meandering to straight drainage systems • Five lithofacies types affected by fluvial, mass wasting and aeolian processes • Geomorphology, sedimentology, structural geology, mineralogy, age dating • Gravel analysis – situmetry, granulometry, morphometry and mineralogy [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF