Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
doi:10.5194/cp-2016-111
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
25 Nov 2016
Review status
This discussion paper is under review for the journal Climate of the Past (CP).
Cenomanian to Coniacian Water-mass Evolution in the Cretaceous Western Interior Seaway of North America and Equatorial Atlantic
James S. Eldrett1, Paul Dodsworth2, Steven C. Bergman3, and Milly Wright4 1Shell International Exploration & Production B.V, Kesslerpark 1, 2288 GS Rijswijk, Netherlands
2StrataSolve Ltd, 42 Gaskell Street, Stockton Heath, Warrington, WA4 2UN, UK
3Shell International Exploration and Production Inc, 3333 Highway 6 South, Houston, TX, 77082, USA
4Chemostrat Inc., 3760 Westchase Drive, Houston, Texas, TX 77042, USA
Abstract. The Late Cretaceous Epoch was characterized major global perturbations in the carbon cycle, the most prominent occurring near the Cenomanian-Turonian (CT) transition marked by Oceanic Anoxic Event/OAE-2 at 94.9–93.7 Ma. The Cretaceous Western Interior Seaway (KWIS) was one of several epicontinental seas in which a complex water-mass evolution was recorded in widespread sedimentary successions. This contribution integrates new data on the main components of organic matter, geochemistry, and stable isotopes along a North-South transect from the KWIS to the equatorial western Atlantic and Southern Ocean. In particular, cored sedimentary rocks from the Eagle Ford Group of West Texas (~ 90–98 Ma) demonstrate subtle temporal and spatial variations in paleoenvironmental conditions and provide an important geographic constraint for interpreting water-mass evolution. High latitude (boreal-austral), equatorial tethyan and locally sourced Western Interior Seaway water-masses are distinguished by distinct palynological assemblages and geochemical signatures. The northward migration of a tethyan water-mass into the KWIS occurred during the early-middle Cenomanian (98–95 Ma) followed by a major re-organization during the latest Cenomanian-Turonian (95–94 Ma) as a full connection with a northerly- boreal water-mass was established during peak transgression. This oceanographic change promoted de-stratification of the water column and improved oxygenation throughout the KWIS and as far south as the Demerara Rise off Suriname. In addition the recorded decline in redox-sensitive trace metals during the onset of OAE-2 likely reflects a genuine oxygenation event related to open water-mass exchange and may have been complicated by variable contribution of organic matter from different sources (e.g. refractory/terrigenous material), requiring further investigation.

Citation: Eldrett, J. S., Dodsworth, P., Bergman, S. C., and Wright, M.: Cenomanian to Coniacian Water-mass Evolution in the Cretaceous Western Interior Seaway of North America and Equatorial Atlantic, Clim. Past Discuss., doi:10.5194/cp-2016-111, in review, 2016.
James S. Eldrett et al.
James S. Eldrett et al.
James S. Eldrett et al.

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This contribution integrates new data on the main components of organic matter, geochemistry, and stable isotopes for the Cenomanian to Coniacian stages of the Late Cretaceous, along a North-South transect from the Cretaceous Western Interior Seaway to the equatorial western Atlantic and Southern Ocean. Distinct palynological assemblages and geochemical signatures allow insights into paleoenvironmental conditions and water-mass evolution during this Greenhouse climate period.
This contribution integrates new data on the main components of organic matter, geochemistry,...
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