Variations in water discharge at different temporal scales in a mud-prone alluvial succession: The Paleocene-Eocene of the Tremp-Graus Basin, Spain

The late Paleocene to earliest Eocene sedimentary record in the eastern Tremp-Graus Basin (southern Pyrenees, Spain) consists of a mud-prone fluvial succession informally known as ‘Upper Red Garumnian’, which is dominantly composed non-channelized deposits interspersed with channel bodies. records evidence variations water discharge at multiple temporal scales. One-hundred-and-eighty sand-prone and conglomeratic bodies present within otherwise fine-grained have been examined by facies architectural-element analyses. These assigned four distinctive types: (i) simple (ii) compound channelized deposits, (iii) multilateral multistorey elements, (iv) sediment gravity-flow deposits. Simple represent high-energy flows associated respectively single floods or events occurring same belt. Multilateral elements are sedimentation longer-lived belts. An increase occurrence these latter through stratigraphy can be related changes tectonic and/or climatic drivers, heralding change architecture that signifies shift perennial conditions incised-valley backfilling. This itself followed marked architectural style part recording Paleocene-Eocene Thermal Maximum (PETM), when precipitation regime intrabasinal characteristics (e.g., vegetation) this event favoured lateral migration channels, causing development laterally extensive coarse-grained Floodplain sediments comprise heterolithic accumulated vicinities channels where riparian ecosystems were developed, overbank mudstones variable degree pedogenesis, especially wetting drying cycles areas floodplain located distally away from channels. importance water-discharge evolution alluvial systems: it displays arrangements effects highly ephemeral well stratigraphic testifying longer-term hydrological Eocene.