Details
| Original language | English |
|---|---|
| Pages (from-to) | 1337–1349 |
| Number of pages | 13 |
| Journal | ACS Earth and Space Chemistry |
| Volume | 7 |
| Issue number | 7 |
| Early online date | 8 Jul 2023 |
| Publication status | Published - 20 Jul 2023 |
Abstract
Various geochemical proxies have been developed to determine if ancient sedimentary strata were deposited in marine or nonmarine environments. A critical parameter for proxy reliability is the residence time of aqueous species in seawater, which is rarely considered for proxies relying on stable isotopes and elemental abundance ratios. Differences in residence time may affect our ability to track geologically short-lived alternations between marine and nonmarine conditions. To test this effect for sulfur and nitrogen isotopes and sulfur/carbon ratios, we investigated a stratigraphic section in the Miocene Oberpullendorf Basin in Austria. Here, previous work revealed typical seawater-like rare earth element and yttrium (REY) systematics transitioning to nonmarine-like systematics. This shift was interpreted as a brief transition from an open marine depositional setting to a restricted embayment with a reduced level of exchange with the open ocean and possibly freshwater influence. Our isotopic results show no discernible response in carbonate-associated sulfate sulfur isotopes and carbon/sulfur abundance ratios during the interval of marine restriction inferred from the REY data, but nitrogen isotopes show a decrease by several permil. This observation is consistent with the much longer residence time of sulfate in seawater compared with REY and nitrate. Hence, this case study illustrates that the residence time is a key factor for the utility of seawater proxies. In some cases, it may make geochemical parameters more sensitive to marine water influx than paleontological observations, as in the Oberpullendorf Basin. Particular care is warranted in deep time, when marine residence times likely differ markedly from the modern.
Keywords
- Miocene, nitrogen isotopes, nonmarine environments, Paratethys, residence time, stromatolites, sulfur isotopes
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
- Earth and Planetary Sciences(all)
- Space and Planetary Science
- Earth and Planetary Sciences(all)
- Atmospheric Science
Sustainable Development Goals
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In: ACS Earth and Space Chemistry, Vol. 7, No. 7, 20.07.2023, p. 1337–1349.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Exploring the Effects of Residence Time on the Utility of Stable Isotopes and S/C Ratios as Proxies for Ocean Connectivity
AU - Stüeken, Eva E.
AU - Viehmann, Sebastian
AU - Hohl, Simon V.
N1 - EES acknowledges funding from a NERC Frontiers grant (NE/V010824/1). SV acknowledges the support of Erich Draganits, Robert Kujawa, Patrick Meister, and Tobias Prost during stromatolite sampling at the Rabenkopf section. We thank the editor and four reviewers for constructive feedback that improved the manuscript. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.
PY - 2023/7/20
Y1 - 2023/7/20
N2 - Various geochemical proxies have been developed to determine if ancient sedimentary strata were deposited in marine or nonmarine environments. A critical parameter for proxy reliability is the residence time of aqueous species in seawater, which is rarely considered for proxies relying on stable isotopes and elemental abundance ratios. Differences in residence time may affect our ability to track geologically short-lived alternations between marine and nonmarine conditions. To test this effect for sulfur and nitrogen isotopes and sulfur/carbon ratios, we investigated a stratigraphic section in the Miocene Oberpullendorf Basin in Austria. Here, previous work revealed typical seawater-like rare earth element and yttrium (REY) systematics transitioning to nonmarine-like systematics. This shift was interpreted as a brief transition from an open marine depositional setting to a restricted embayment with a reduced level of exchange with the open ocean and possibly freshwater influence. Our isotopic results show no discernible response in carbonate-associated sulfate sulfur isotopes and carbon/sulfur abundance ratios during the interval of marine restriction inferred from the REY data, but nitrogen isotopes show a decrease by several permil. This observation is consistent with the much longer residence time of sulfate in seawater compared with REY and nitrate. Hence, this case study illustrates that the residence time is a key factor for the utility of seawater proxies. In some cases, it may make geochemical parameters more sensitive to marine water influx than paleontological observations, as in the Oberpullendorf Basin. Particular care is warranted in deep time, when marine residence times likely differ markedly from the modern.
AB - Various geochemical proxies have been developed to determine if ancient sedimentary strata were deposited in marine or nonmarine environments. A critical parameter for proxy reliability is the residence time of aqueous species in seawater, which is rarely considered for proxies relying on stable isotopes and elemental abundance ratios. Differences in residence time may affect our ability to track geologically short-lived alternations between marine and nonmarine conditions. To test this effect for sulfur and nitrogen isotopes and sulfur/carbon ratios, we investigated a stratigraphic section in the Miocene Oberpullendorf Basin in Austria. Here, previous work revealed typical seawater-like rare earth element and yttrium (REY) systematics transitioning to nonmarine-like systematics. This shift was interpreted as a brief transition from an open marine depositional setting to a restricted embayment with a reduced level of exchange with the open ocean and possibly freshwater influence. Our isotopic results show no discernible response in carbonate-associated sulfate sulfur isotopes and carbon/sulfur abundance ratios during the interval of marine restriction inferred from the REY data, but nitrogen isotopes show a decrease by several permil. This observation is consistent with the much longer residence time of sulfate in seawater compared with REY and nitrate. Hence, this case study illustrates that the residence time is a key factor for the utility of seawater proxies. In some cases, it may make geochemical parameters more sensitive to marine water influx than paleontological observations, as in the Oberpullendorf Basin. Particular care is warranted in deep time, when marine residence times likely differ markedly from the modern.
KW - Miocene
KW - nitrogen isotopes
KW - nonmarine environments
KW - Paratethys
KW - residence time
KW - stromatolites
KW - sulfur isotopes
UR - http://www.scopus.com/inward/record.url?scp=85165868651&partnerID=8YFLogxK
U2 - 10.1021/acsearthspacechem.3c00018
DO - 10.1021/acsearthspacechem.3c00018
M3 - Article
VL - 7
SP - 1337
EP - 1349
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 7
ER -