Redox conditions and ecological resilience during Oceanic Anoxic Event 2 in the Western Interior Seaway
Redox conditions and ecological resilience during Oceanic Anoxic Event 2 in the Western Interior Seaway
Oceanic Anoxic Events (OAEs) are important geological events that may be analogues to future climate-driven deoxygenation of our oceans. Much of the global ocean experienced anoxic conditions during the Cenomanian–Turonian OAE (OAE2; ∼94 Ma), whereas the Western Interior Seaway (WIS) experienced oxygenation at this time. Here, organic geochemical and palynological data generated from Cenomanian–Turonian age sediments from five sites in the WIS are used to investigate changing redox and ecological conditions across differing palaeoenvironments and palaeolatitudes. Heterogeneity across the sites is apparent, but important relationships and trends among oceanographic variables are recognised: 1) Increasing total organic carbon (TOC) and CaCO
3 percentages indicate the onset of a sea-level maximum towards the end of OAE2; 2) C
28 sterane is shown to be a useful marker for prasinophyte abundance, and concurrent increases in this marker and overall sterane abundance indicate prasinophyte-driven increase in algal productivity in a stratified water column; and 3) sterane ratios can be a more reliable geochemical proxy than redox proxies for assessing the Benthic Oxic Zone. Our redox data do not always follow established trends for the WIS overall, particularly for proximal settings. We therefore surmise that local effects, such as nutrient-driven expansion of the oxygen minimum zone and/or sedimentation-driven anoxia just below the sediment-water interface, have overprinted regional trends.
Cretaceous, Organic geochemistry, Prasinophytes, Steranes
111496
Robinson, L.j.
67deebbb-0394-4d4a-9aba-4f2b0f0982c3
George, K.s.
9ef2fd09-84bc-4f74-8d03-81f4c8f0b822
Fox, C.p.
fc503642-a38b-4b7c-ab80-126d2c522f74
Marshall, J.e.a.
cba178e3-91aa-49a2-b2ce-4b8d9d870b06
Harding, I.c.
f9c29efb-cce9-428a-9284-4d6b795f0fd1
Bown, P.r.
773e1a6d-1c12-4e57-af3b-ec981390a64a
Lively, J.r.
2a41186c-66a8-4e5e-9f17-783491921ba3
Marroquín, S.
90a3f6dc-aef8-4f3c-85e1-016d5a1fffc2
Leckie, R.m.
8bf3b242-7a16-42f2-a926-3713d1978b82
Dameron, S.
0fdd6ff4-4b40-44a4-ac1f-6c2a84c5d9fa
Gröcke, D.r.
d33af9f3-012b-4f01-9c8e-190cc474a341
Papadomanolaki, N.m.
f93eba62-0fd9-4712-acf4-87487e8638fa
Van Helmond, N.a.g.m.
86263d1a-4e9d-4984-b94a-53bf4aec4eb6
Whiteside, J.h.
7d7d9398-2320-4ed1-b39e-5e5bf0174215
15 May 2023
Robinson, L.j.
67deebbb-0394-4d4a-9aba-4f2b0f0982c3
George, K.s.
9ef2fd09-84bc-4f74-8d03-81f4c8f0b822
Fox, C.p.
fc503642-a38b-4b7c-ab80-126d2c522f74
Marshall, J.e.a.
cba178e3-91aa-49a2-b2ce-4b8d9d870b06
Harding, I.c.
f9c29efb-cce9-428a-9284-4d6b795f0fd1
Bown, P.r.
773e1a6d-1c12-4e57-af3b-ec981390a64a
Lively, J.r.
2a41186c-66a8-4e5e-9f17-783491921ba3
Marroquín, S.
90a3f6dc-aef8-4f3c-85e1-016d5a1fffc2
Leckie, R.m.
8bf3b242-7a16-42f2-a926-3713d1978b82
Dameron, S.
0fdd6ff4-4b40-44a4-ac1f-6c2a84c5d9fa
Gröcke, D.r.
d33af9f3-012b-4f01-9c8e-190cc474a341
Papadomanolaki, N.m.
f93eba62-0fd9-4712-acf4-87487e8638fa
Van Helmond, N.a.g.m.
86263d1a-4e9d-4984-b94a-53bf4aec4eb6
Whiteside, J.h.
7d7d9398-2320-4ed1-b39e-5e5bf0174215
Robinson, L.j., George, K.s., Fox, C.p., Marshall, J.e.a., Harding, I.c., Bown, P.r., Lively, J.r., Marroquín, S., Leckie, R.m., Dameron, S., Gröcke, D.r., Papadomanolaki, N.m., Van Helmond, N.a.g.m. and Whiteside, J.h.
(2023)
Redox conditions and ecological resilience during Oceanic Anoxic Event 2 in the Western Interior Seaway.
Palaeogeography, Palaeoclimatology, Palaeoecology, 618, , [111496].
(doi:10.1016/j.palaeo.2023.111496).
Abstract
Oceanic Anoxic Events (OAEs) are important geological events that may be analogues to future climate-driven deoxygenation of our oceans. Much of the global ocean experienced anoxic conditions during the Cenomanian–Turonian OAE (OAE2; ∼94 Ma), whereas the Western Interior Seaway (WIS) experienced oxygenation at this time. Here, organic geochemical and palynological data generated from Cenomanian–Turonian age sediments from five sites in the WIS are used to investigate changing redox and ecological conditions across differing palaeoenvironments and palaeolatitudes. Heterogeneity across the sites is apparent, but important relationships and trends among oceanographic variables are recognised: 1) Increasing total organic carbon (TOC) and CaCO
3 percentages indicate the onset of a sea-level maximum towards the end of OAE2; 2) C
28 sterane is shown to be a useful marker for prasinophyte abundance, and concurrent increases in this marker and overall sterane abundance indicate prasinophyte-driven increase in algal productivity in a stratified water column; and 3) sterane ratios can be a more reliable geochemical proxy than redox proxies for assessing the Benthic Oxic Zone. Our redox data do not always follow established trends for the WIS overall, particularly for proximal settings. We therefore surmise that local effects, such as nutrient-driven expansion of the oxygen minimum zone and/or sedimentation-driven anoxia just below the sediment-water interface, have overprinted regional trends.
Text
Robinson et al OAE2 WIS Final
- Accepted Manuscript
More information
Accepted/In Press date: 5 March 2023
Published date: 15 May 2023
Additional Information:
Funding Information: LJR acknowledges support from the Natural Environmental Research Council UK (NE/L002531/1), AAPG Foundation Grant-in-Aid (Marta S. Weeks Named Grant) and Geological Society of London Research Grant (William George Fearnsides fund). Samples were generously donated by Mark Leckie (Lohali Point and Billings Landfill), Guy Plint (Pratts Landing) and the USGS Core Research Centre (Rebecca Bounds). Samples from Lohali Point originate from Navajo and Hopi ancestral lands. We thank the Bureau of Land Management for access to Gunnison Gorge NCA, with work conducted under BLM permit to JRL. Marjean Cone assisted in sample acquisition from Gunnison Gorge, and David Noe provided important guidance on the stratigraphy of the area. We thank Richard Twitchett (Natural History Museum) for insightful conversations. CPF acknowledges CIRA grant CIRA-2019-066.
Funding Information:
LJR acknowledges support from the Natural Environmental Research Council UK ( NE/L002531/1 ), AAPG Foundation Grant-in-Aid (Marta S. Weeks Named Grant) and Geological Society of London Research Grant (William George Fearnsides fund). Samples were generously donated by Mark Leckie (Lohali Point and Billings Landfill), Guy Plint (Pratts Landing) and the USGS Core Research Centre (Rebecca Bounds). Samples from Lohali Point originate from Navajo and Hopi ancestral lands. We thank the Bureau of Land Management for access to Gunnison Gorge NCA, with work conducted under BLM permit to JRL. Marjean Cone assisted in sample acquisition from Gunnison Gorge, and David Noe provided important guidance on the stratigraphy of the area. We thank Richard Twitchett (Natural History Museum) for insightful conversations. CPF acknowledges CIRA grant CIRA-2019-066.
Publisher Copyright:
© 2023
Keywords:
Cretaceous, Organic geochemistry, Prasinophytes, Steranes
Identifiers
Local EPrints ID: 477562
URI: http://eprints.soton.ac.uk/id/eprint/477562
ISSN: 0031-0182
PURE UUID: 2bf5c432-93e0-4c9c-a2e8-6cf7b258d5e9
Catalogue record
Date deposited: 08 Jun 2023 16:44
Last modified: 17 Mar 2024 02:34
Export record
Altmetrics
Contributors
Author:
L.j. Robinson
Author:
K.s. George
Author:
C.p. Fox
Author:
I.c. Harding
Author:
P.r. Bown
Author:
J.r. Lively
Author:
S. Marroquín
Author:
R.m. Leckie
Author:
S. Dameron
Author:
D.r. Gröcke
Author:
N.m. Papadomanolaki
Author:
N.a.g.m. Van Helmond
Author:
J.h. Whiteside
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics
