Tracing marine cryptotephras in the North Atlantic during the Last Glacial Period: Identification, characterisation and depositional controls

This is a Preprint and has not been peer reviewed.

Downloads

Download Preprint

Supplementary Files
Authors

Peter Abbott , Adam Griggs, Anna Bourne, Siwan Davies

Abstract

Tephrochronology is increasingly being utilised as a key tool for improving chronological models and correlating disparate palaeoclimatic sequences. For many sedimentary environments, however, there is an increased recognition that a range of processes may impart a delay in deposition and/or rework tephra. These processes can affect the integrity of tephra deposits as time-synchronous markers, therefore, it is crucial to assess their isochronous nature, especially when cryptotephras are investigated in a dynamic marine environment. A methodology for the identification and characterisation of marine cryptotephras alongside a protocol for assessing their integrity is outlined. This was applied to a wide network of North Atlantic marine sequences covering the last glacial period. A diverse range of cryptotephra deposits were identified and based on similarities in physical characteristics, indicative of common modes of tephra delivery and post-depositional reworking, a deposit type classification scheme was defined. The presence and dominance of different deposit types within each core allowed an assessment of spatial and temporal controls on tephra deposition and preservation. Overall, isochronous horizons can be identified across a large portion of the North Atlantic due to preferential atmospheric dispersal patterns. However, the variable influence of ice-rafting processes and an interplay between the high eruptive frequency of Iceland and relatively lower sedimentation rates can also create complex tephrostratigraphies in this sector. We show that sites within a wide sector to the south and east of Iceland have the greatest potential to be repositories for isochronous horizons that can underpin or facilitate the synchronisation of palaeoclimatic records.

DOI

https://doi.org/10.31223/osf.io/p7n5k

Subjects

Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics

Keywords

Dates

Published: 2018-12-12 16:33

Older Versions
License

CC BY Attribution 4.0 International

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.