Effects of spatially variable accommodation rate on channel belt distribution in an alluvial sequence: Authigenic 10Be/9Be-based Bayesian age-depth models applied to the upper Miocene Volkovce Fm. (northern Pannonian Basin System, Slovakia)

Mud redeposition during river incision as a factor affecting authigenic 10Be/9Be dating: Early Pleistocene large mammal fossil‐bearing site Nová Vieska, eastern Danube Basin

“…1D, E). The river terrace deposits have accumulated above the muds and sands of the floodplain‐dominated Volkovce Formation of Late Miocene age (Vlačiky et al , 2008; Šujan and Rybár, 2014; Šujan et al , 2020).…”

“…The regression of Lake Pannon, caused by the progradation of deltaic to shelf slope depositional systems from the northwest to southeast (Magyar et al , 2013), gradually led to the dominance of the alluvial deposition of the Volkovce Formation. The condition of a high accommodation rate to sediment supply ratio during sedimentation led to a high content of muddy floodplain facies, reaching 50–80% (Šujan et al , 2020).…”

“…They differ only in the proportion of floodplain facies and in the prevailing grain size of channel fills. Therefore, a higher number of spatially distributed data is needed to create a statistically robust distinction of the mentioned lithostratigraphic units based solely on the facies analysis (Šujan et al , 2020). Hence, the lithological appearance of all three lithostratigraphic units on a single outcrop can be similar.…”

“…The hypothesis of the redeposition of older sediment as a factor affecting the authigenic 10 Be/ 9 Be dating requires further verification. A validation of the hypothesis by petrographic, mineralogical or geochemical proxies remains problematic, as the floodplain muddy facies of the redeposited Volkovce and Kolárovo formations, as well as the Quaternary sediments, were deposited by comparable processes and with a similar provenance (Šujan et al , 2018b; Šujan et al , 2020). Whether different climatic conditions would allow the tracing of the effect described here in the muddy layers remains an open question.…”

“…It has been shown that sedimentary successions accumulated in endorheic lacustrine basins located in a craton setting with low tectonic activity and stable provenance, such as the Chad Basin in Africa, are highly suited to the employment of the method (Lebatard et al , 2008; Lebatard et al , 2010; Novello et al , 2015). Although located in the more challenging conditions of an Alpine orogenic belt, the Danube Basin has also proven to be suitable for dating using authigenic 10 Be/ 9 Be, especially the alluvial sequences found in the basin, thanks to the high accommodation to sediment supply rate (Šujan et al , 2016; Šujan et al , 2020). On the other hand, the alluvial succession in the Upper Thrace Depression, Bulgaria, displays a high degree of authigenic 10 Be/ 9 Be variability, preventing the effective application of the method (Schaller et al , 2015); a result likely due to the significant tectonic activity of the pull‐apart basins in this extensional province (Burchfiel et al , 2000).…”