Details
| Original language | English |
|---|---|
| Pages (from-to) | 249-260 |
| Number of pages | 12 |
| Journal | Palaeogeography, Palaeoclimatology, Palaeoecology |
| Volume | 489 |
| Early online date | 18 Oct 2017 |
| Publication status | Published - 1 Jan 2018 |
Abstract
The Black Sea repeatedly experienced major hydrographic changes during glacial-interglacial transitions, with alternating limnic and brackish stages. While the redox conditions during the present Holocene brackish period (since ~ 9,000 yr BP) have been intensively studied, the redox evolution during the last interglacial, the Eemian (~ 128,000-120,000 yr BP), remains largely unexplored. With its at least 3 °C warmer climate and an up to 10 m higher global sea level, the Eemian could open a window into the future development of the Black Sea. This study provides a detailed comparison of the Black Sea redox evolution during Eemian and Holocene sapropel formation. We show that the redox conditions and associated geochemical processes in the Black Sea water column can strongly deviate from the Holocene when sea level and climate conditions are different. Mo/Al and Re/Mo as well as Mo and Fe isotope proxies record a comparatively uniform rise of the Eemian redoxcline culminating in pronounced euxinia. This scenario strongly contrasts with weaker euxinic conditions during the Holocene Unit II sapropel (~ 8,000-2,500 yr BP). Higher Mo/TOC ratios during the Eemian and Mo inventory considerations suggest a higher Eemian Mo availability, possibly due to an improved connection to the Mediterranean Sea. We conclude that higher temperatures, productivity, sea level-associated salinity changes, and corresponding higher sulphide levels were ultimately responsible for enhanced trace metal enrichment during the Eemian Black Sea sapropel stage.
Keywords
- Euxinia, Interglacials, Restricted basin, Trace metals, δFe, δMo
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Oceanography
- Agricultural and Biological Sciences(all)
- Ecology, Evolution, Behavior and Systematics
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
- Earth and Planetary Sciences(all)
- Palaeontology
Sustainable Development Goals
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In: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 489, 01.01.2018, p. 249-260.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Redox evolution during Eemian and Holocene sapropel formation in the Black Sea
AU - Wegwerth, Antje
AU - Eckert, Sebastian
AU - Dellwig, Olaf
AU - Schnetger, Bernhard
AU - Severmann, Silke
AU - Weyer, Stefan
AU - Brüske, Annika
AU - Kaiser, Jérôme
AU - Köster, Jürgen
AU - Arz, Helge W.
AU - Brumsack, Hans Jürgen
N1 - © 2017 Elsevier B.V. All rights reserved.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - The Black Sea repeatedly experienced major hydrographic changes during glacial-interglacial transitions, with alternating limnic and brackish stages. While the redox conditions during the present Holocene brackish period (since ~ 9,000 yr BP) have been intensively studied, the redox evolution during the last interglacial, the Eemian (~ 128,000-120,000 yr BP), remains largely unexplored. With its at least 3 °C warmer climate and an up to 10 m higher global sea level, the Eemian could open a window into the future development of the Black Sea. This study provides a detailed comparison of the Black Sea redox evolution during Eemian and Holocene sapropel formation. We show that the redox conditions and associated geochemical processes in the Black Sea water column can strongly deviate from the Holocene when sea level and climate conditions are different. Mo/Al and Re/Mo as well as Mo and Fe isotope proxies record a comparatively uniform rise of the Eemian redoxcline culminating in pronounced euxinia. This scenario strongly contrasts with weaker euxinic conditions during the Holocene Unit II sapropel (~ 8,000-2,500 yr BP). Higher Mo/TOC ratios during the Eemian and Mo inventory considerations suggest a higher Eemian Mo availability, possibly due to an improved connection to the Mediterranean Sea. We conclude that higher temperatures, productivity, sea level-associated salinity changes, and corresponding higher sulphide levels were ultimately responsible for enhanced trace metal enrichment during the Eemian Black Sea sapropel stage.
AB - The Black Sea repeatedly experienced major hydrographic changes during glacial-interglacial transitions, with alternating limnic and brackish stages. While the redox conditions during the present Holocene brackish period (since ~ 9,000 yr BP) have been intensively studied, the redox evolution during the last interglacial, the Eemian (~ 128,000-120,000 yr BP), remains largely unexplored. With its at least 3 °C warmer climate and an up to 10 m higher global sea level, the Eemian could open a window into the future development of the Black Sea. This study provides a detailed comparison of the Black Sea redox evolution during Eemian and Holocene sapropel formation. We show that the redox conditions and associated geochemical processes in the Black Sea water column can strongly deviate from the Holocene when sea level and climate conditions are different. Mo/Al and Re/Mo as well as Mo and Fe isotope proxies record a comparatively uniform rise of the Eemian redoxcline culminating in pronounced euxinia. This scenario strongly contrasts with weaker euxinic conditions during the Holocene Unit II sapropel (~ 8,000-2,500 yr BP). Higher Mo/TOC ratios during the Eemian and Mo inventory considerations suggest a higher Eemian Mo availability, possibly due to an improved connection to the Mediterranean Sea. We conclude that higher temperatures, productivity, sea level-associated salinity changes, and corresponding higher sulphide levels were ultimately responsible for enhanced trace metal enrichment during the Eemian Black Sea sapropel stage.
KW - Euxinia
KW - Interglacials
KW - Restricted basin
KW - Trace metals
KW - δFe
KW - δMo
UR - http://www.scopus.com/inward/record.url?scp=85033597648&partnerID=8YFLogxK
U2 - 10.1016/j.palaeo.2017.10.014
DO - 10.1016/j.palaeo.2017.10.014
M3 - Article
AN - SCOPUS:85033597648
VL - 489
SP - 249
EP - 260
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
SN - 0031-0182
ER -