Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland
Radiocarbon dating marine sediments is complicated by the strongly heterogeneous age of ocean waters. Tephrochronology provides a well-established method to constrain the age of local radiocarbon reservoirs and more accurately calibrate dates. Numerous ultra-distal cryptotephra deposits (non-visible...
Published in: | Geochronology |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2023
|
Subjects: | |
Online Access: | https://pure.au.dk/portal/en/publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 https://doi.org/10.5194/gchron-5-229-2023 http://www.scopus.com/inward/record.url?scp=85159486843&partnerID=8YFLogxK |
id |
ftuniaarhuspubl:oai:pure.atira.dk:publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 |
---|---|
record_format |
openpolar |
spelling |
ftuniaarhuspubl:oai:pure.atira.dk:publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 2024-01-07T09:44:55+01:00 Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland Monteath, Alistair J. Bolton, Matthew S.M. Harvey, Jordan Seidenkrantz, Marit-Solveig Pearce, Christof Jensen, Britta 2023-05 https://pure.au.dk/portal/en/publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 https://doi.org/10.5194/gchron-5-229-2023 http://www.scopus.com/inward/record.url?scp=85159486843&partnerID=8YFLogxK eng eng https://pure.au.dk/portal/en/publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 info:eu-repo/semantics/openAccess Monteath , A J , Bolton , M S M , Harvey , J , Seidenkrantz , M-S , Pearce , C & Jensen , B 2023 , ' Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland ' , Geochronology , vol. 5 , no. 1 , pp. 229-240 . https://doi.org/10.5194/gchron-5-229-2023 article 2023 ftuniaarhuspubl https://doi.org/10.5194/gchron-5-229-2023 2023-12-13T23:59:49Z Radiocarbon dating marine sediments is complicated by the strongly heterogeneous age of ocean waters. Tephrochronology provides a well-established method to constrain the age of local radiocarbon reservoirs and more accurately calibrate dates. Numerous ultra-distal cryptotephra deposits (non-visible volcanic ash more than 3000km from source) have been identified in peatlands and lake sediments across north-eastern North America and correlated with volcanic arcs in the Pacific north-west. Previously, however, these isochrons have not been identified in sediments from the north-west Atlantic Ocean. In this study, we report the presence of two ultra-distal cryptotephra deposits; Mazama Ash and White River Ash eastern lobe (WRAe), in Placentia Bay, North Atlantic Ocean. We use these well-dated isochrons to constrain the local marine radiocarbon reservoir offset (δR) and develop a robust Bayesian age-depth model with a δR that varies through time. Our results indicate that the marine radiocarbon offset in Placentia Bay was -126±151 years (relative to the Marine20 calibration curve) at the time of Mazama Ash deposition (7572 ± 18 yr BP) and -396 ± 144 years at the time of WRAe deposition (1098-1097 yr BP). Changes in δR appear to coincide with inferred shifts in relative influences of the inner Labrador Current and the Slopewater Current in the bay. An important conclusion is that single-offset models of δR are easiest to apply and often hard to disprove. However, such models may oversimplify reservoir effects in a core, even over relatively short timescales. Acknowledging potentially varying offsets is critical when ocean circulation and ventilation characteristics have differed over time. The addition of tephra isochrons permits the calculation of semi-independent reservoir corrections and verification of the single δR model. Article in Journal/Newspaper Newfoundland North Atlantic North West Atlantic Aarhus University: Research Newfoundland Pacific Geochronology 5 1 229 240 |
institution |
Open Polar |
collection |
Aarhus University: Research |
op_collection_id |
ftuniaarhuspubl |
language |
English |
description |
Radiocarbon dating marine sediments is complicated by the strongly heterogeneous age of ocean waters. Tephrochronology provides a well-established method to constrain the age of local radiocarbon reservoirs and more accurately calibrate dates. Numerous ultra-distal cryptotephra deposits (non-visible volcanic ash more than 3000km from source) have been identified in peatlands and lake sediments across north-eastern North America and correlated with volcanic arcs in the Pacific north-west. Previously, however, these isochrons have not been identified in sediments from the north-west Atlantic Ocean. In this study, we report the presence of two ultra-distal cryptotephra deposits; Mazama Ash and White River Ash eastern lobe (WRAe), in Placentia Bay, North Atlantic Ocean. We use these well-dated isochrons to constrain the local marine radiocarbon reservoir offset (δR) and develop a robust Bayesian age-depth model with a δR that varies through time. Our results indicate that the marine radiocarbon offset in Placentia Bay was -126±151 years (relative to the Marine20 calibration curve) at the time of Mazama Ash deposition (7572 ± 18 yr BP) and -396 ± 144 years at the time of WRAe deposition (1098-1097 yr BP). Changes in δR appear to coincide with inferred shifts in relative influences of the inner Labrador Current and the Slopewater Current in the bay. An important conclusion is that single-offset models of δR are easiest to apply and often hard to disprove. However, such models may oversimplify reservoir effects in a core, even over relatively short timescales. Acknowledging potentially varying offsets is critical when ocean circulation and ventilation characteristics have differed over time. The addition of tephra isochrons permits the calculation of semi-independent reservoir corrections and verification of the single δR model. |
format |
Article in Journal/Newspaper |
author |
Monteath, Alistair J. Bolton, Matthew S.M. Harvey, Jordan Seidenkrantz, Marit-Solveig Pearce, Christof Jensen, Britta |
spellingShingle |
Monteath, Alistair J. Bolton, Matthew S.M. Harvey, Jordan Seidenkrantz, Marit-Solveig Pearce, Christof Jensen, Britta Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
author_facet |
Monteath, Alistair J. Bolton, Matthew S.M. Harvey, Jordan Seidenkrantz, Marit-Solveig Pearce, Christof Jensen, Britta |
author_sort |
Monteath, Alistair J. |
title |
Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
title_short |
Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
title_full |
Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
title_fullStr |
Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
title_full_unstemmed |
Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland |
title_sort |
ultra-distal tephra deposits and bayesian modelling constrain a variable marine radiocarbon offset in placentia bay, newfoundland |
publishDate |
2023 |
url |
https://pure.au.dk/portal/en/publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 https://doi.org/10.5194/gchron-5-229-2023 http://www.scopus.com/inward/record.url?scp=85159486843&partnerID=8YFLogxK |
geographic |
Newfoundland Pacific |
geographic_facet |
Newfoundland Pacific |
genre |
Newfoundland North Atlantic North West Atlantic |
genre_facet |
Newfoundland North Atlantic North West Atlantic |
op_source |
Monteath , A J , Bolton , M S M , Harvey , J , Seidenkrantz , M-S , Pearce , C & Jensen , B 2023 , ' Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland ' , Geochronology , vol. 5 , no. 1 , pp. 229-240 . https://doi.org/10.5194/gchron-5-229-2023 |
op_relation |
https://pure.au.dk/portal/en/publications/c1ee1c81-d180-4b0d-a4e8-c9408baf2d05 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/gchron-5-229-2023 |
container_title |
Geochronology |
container_volume |
5 |
container_issue |
1 |
container_start_page |
229 |
op_container_end_page |
240 |
_version_ |
1787426348936986624 |