March 15, 2021

Bob Loucks

Robert Loucks

Ocean Anoxic Events


δ13C versus depth curve showing positive δ13C excursions that identify light carbon sequestration events or OAEs. Data is from David Hull.

Robert Loucks, a Senior Research Scientist in the Bureau's Carbonate Reservoir Characterization Research Laboratory (RCRL), is documenting ocean anoxic events (OAEs) in the Lower Cretaceous Aptian through lower Albian stratigraphic section. David Hull, Kelly Hattori, Lucy Ko, Toti Larson, Priyanka Periwal, and Evan Sivil are also on the team studying OAEs.

OAEs are regional to global events that cause abrupt and extreme modification of ocean-water chemistry, during which portions of the ocean become depleted in oxygen over large geographic areas. These changes result in major perturbations in the marine realm that have the potential to significantly affect marine faunal composition and abundance and can drive long-term changes in carbonate platform architecture. During these periods of Earth’s history, excellent source rocks are commonly produced. The Pearsall through lower Glen Rose section in South Texas contains the OAE-1A and OAE-1B, as well as a regional OAE. These events are well documented by δ13C curves. An important aspect of OAEs in the studied interval is they can be correlated worldwide, including the prolific reservoir section of the Middle East.


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