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

This is a Preprint and has not been peer reviewed. This is version 2 of this Preprint.

Downloads

Download Preprint

Authors

Michal Šujan , Régis Braucher, Andrej Chyba, Martin Vlačiky, Kishan Aherwar, Barbara Rózsová, Klement Fordinál, Juraj Maglay, Alexander Nagy, Martina Moravcová, Aster Team

Abstract

This study examines the suitability of the authigenic 10Be/9Be dating method to the dating of the deposits of an incising river, taking as an example the Nová Vieska river terrace, which accumulated during the neotectonic inversion of the Danube Basin (western Slovakia). The succession was formed by a wandering river with minor preservation of proximal floodplain muds. The frequent occurrence of mud intraclasts reflects a significant input of eroded material from underlying, older successions. The ages of 13 authigenic 10Be/9Be dating samples formed three groups: (1) samples from below the base of the river terrace yielded dates of ~4.13–3.70 Ma; (2) muddy intraclasts from the river terrace an age range of ~2.79–1.96 Ma; and (3) in situ muddy layers had ages in the range of ~1.91–1.39 Ma. The large mammal fossil assemblage from channel thalweg deposits yielded a biostratigraphic age of ~3.6–2.2 Ma, matching the age of intraclasts, and thus emphasizing the redeposited origin of those fossils. The relatively wide range of authigenic 10Be/9Be dating ages is interpreted as a result of the redeposition of mud from older strata on three scales: decimeter-scale intraclasts, millimeter-scale rip-up clasts mixed into the newly formed beds, and formation of two authigenic rims with different age and 10Be/9Be record around individual particles. Considering these observations, an age range of in situ layers of ~1.91–1.39 Ma is proposed as the depositional age of the river terrace. The effect of redeposition is thus shown to be potentially limiting to the application of authigenic 10Be/9Be dating to incising rivers, and stands in marked contrast with aggrading river settings, where redeposition of older sediment is limited and the degree of 10Be/9Be variability is low.

DOI

https://doi.org/10.31223/X5Z93B

Subjects

Earth Sciences, Geology, Geomorphology, Sedimentology, Stratigraphy

Keywords

Cosmogenic nuclides, authigenic beryllium, facies analysis, wandering river, redeposition, authigenic beryllium, facies analysis, wandering river, redeposition

Dates

Published: 2022-07-29 19:58

Last Updated: 2022-07-30 02:58

Older Versions
License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

Data Availability (Reason not available):
All data is included in the manuscript

Add a Comment

You must log in to post a comment.


Comments

There are no comments or no comments have been made public for this article.