Advanced

Bulk sediment 14C dating in an estuarine environment: : How accurate can it be?

Lougheed, Bryan C. LU ; Obrochta, Stephen P.; Lenz, Conny LU ; Mellström, Anette LU ; Metcalfe, Brett; Muscheler, Raimund LU ; Reinholdsson, Maja LU ; Snowball, Ian LU and Zillén, Lovisa LU (2017) In Paleoceanography 32(2). p.123-131
Abstract
Abstract Due to a lack of marine macrofossils in many sediment cores from the estuarine Baltic Sea, researchers are often forced to carry out 14C determinations on bulk sediment samples. However, ambiguity surrounding the carbon source pathways that contribute to bulk sediment formation introduces a large uncertainty into 14C geochronologies based on such samples, and such uncertainty may not have been fully considered in previous Baltic Sea studies. We quantify this uncertainty by analyzing bulk sediment 14C determinations carried out on densely spaced intervals in independently dated late-Holocene sediment sequences from two central Baltic Sea cores. Our results show a difference of ~600?14C?yr in median bulk sediment reservoir age, or... (More)
Abstract Due to a lack of marine macrofossils in many sediment cores from the estuarine Baltic Sea, researchers are often forced to carry out 14C determinations on bulk sediment samples. However, ambiguity surrounding the carbon source pathways that contribute to bulk sediment formation introduces a large uncertainty into 14C geochronologies based on such samples, and such uncertainty may not have been fully considered in previous Baltic Sea studies. We quantify this uncertainty by analyzing bulk sediment 14C determinations carried out on densely spaced intervals in independently dated late-Holocene sediment sequences from two central Baltic Sea cores. Our results show a difference of ~600?14C?yr in median bulk sediment reservoir age, or R(t)bulk, between the two core locations (~1200?14C?yr for one core, ~620?14C?yr for the other), indicating large spatial variation. Furthermore, we also find large downcore (i.e., temporal) R(t)bulk variation of at least ~200?14C?yr for both cores. We also find a difference of 585?14C?yr between two samples taken from the same core depth. We propose that studies using bulk sediment 14C dating in large brackish water bodies should take such spatiotemporal variation in R(t)bulk into account when assessing uncertainties, thus leading to a larger, but more accurate, calibrated age range. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
radiocarbon, bulk sediment, reservoir age, Baltic Sea, estuary, 14C
in
Paleoceanography
volume
32
issue
2
pages
9 pages
publisher
John Wiley & Sons, Ltd
external identifiers
  • scopus:85011634467
ISSN
0883-8305
DOI
10.1002/2016PA002960
language
English
LU publication?
yes
id
ffba440a-6045-463b-b6fd-bd99cb7a21f5
date added to LUP
2019-05-20 13:17:57
date last changed
2019-06-11 04:05:09
@article{ffba440a-6045-463b-b6fd-bd99cb7a21f5,
  abstract     = {Abstract Due to a lack of marine macrofossils in many sediment cores from the estuarine Baltic Sea, researchers are often forced to carry out 14C determinations on bulk sediment samples. However, ambiguity surrounding the carbon source pathways that contribute to bulk sediment formation introduces a large uncertainty into 14C geochronologies based on such samples, and such uncertainty may not have been fully considered in previous Baltic Sea studies. We quantify this uncertainty by analyzing bulk sediment 14C determinations carried out on densely spaced intervals in independently dated late-Holocene sediment sequences from two central Baltic Sea cores. Our results show a difference of ~600?14C?yr in median bulk sediment reservoir age, or R(t)bulk, between the two core locations (~1200?14C?yr for one core, ~620?14C?yr for the other), indicating large spatial variation. Furthermore, we also find large downcore (i.e., temporal) R(t)bulk variation of at least ~200?14C?yr for both cores. We also find a difference of 585?14C?yr between two samples taken from the same core depth. We propose that studies using bulk sediment 14C dating in large brackish water bodies should take such spatiotemporal variation in R(t)bulk into account when assessing uncertainties, thus leading to a larger, but more accurate, calibrated age range.},
  author       = {Lougheed, Bryan C. and Obrochta, Stephen P. and Lenz, Conny and Mellström, Anette and Metcalfe, Brett and Muscheler, Raimund and Reinholdsson, Maja and Snowball, Ian and Zillén, Lovisa},
  issn         = {0883-8305},
  keyword      = {radiocarbon,bulk sediment,reservoir age,Baltic Sea,estuary,14C},
  language     = {eng},
  month        = {02},
  number       = {2},
  pages        = {123--131},
  publisher    = {John Wiley & Sons, Ltd},
  series       = {Paleoceanography},
  title        = {Bulk sediment 14C dating in an estuarine environment: : How accurate can it be?},
  url          = {http://dx.doi.org/10.1002/2016PA002960},
  volume       = {32},
  year         = {2017},
}