Authigenic and allogenic organic remains as an indicator of geomorphological process activity within the floodplain environment: two case studies from Racibórz Basin, southern Poland

Abstract

Abstract. Distinction between organic components accumulated in situ and those deposited by sedimentation is essential for the assessment of the intensity and extent of impact of geomorphological processes. Authigenic components include moss remains, fragments of the root systems of herbaceous plants and trees, the epidermis of rhizomes, and leaf sheaths, as well as a fungal mycelium. Among the allogenic components are aboveground parts of plants, including leaves of vascular plants, wood, epidermis and periderm, sporomorphs, sporangia, fruits and seeds, as well as zooclasts and protist remains. Microscopic grid analysis allows the share of individual morphological forms of organic matter to be determined in order to reconstruct the deposition conditions on the floodplain. This method makes it possible to detect episodes of activity of fluvial, aeolian and slope processes even when not accompanied by sedimentation of mineralogenic components.

Mineral matter composition of drained floodplain soils in north-eastern Poland

“…Soils rich in organic matter frequently occur in river valleys. In some river valley sections, in small depressions located on the floodplains, simultaneous accumulation of well-decomposed organic matter (of autogenous origin as well as transported by river waters) and fine-grained mineral particles takes place (Kalisz and £achacz 2008;Devesa-Rey and Barral 2012;Gonzáles et al 2014;Wójcicki 2015;Graf-Rosenfellner et al 2016). Organic deposits accumulating in these places resemble well-decomposed low-moor peat (fen peat) and are termed "muds" (Okruszko 1969).…”