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Full-Text Articles in Geology
Micropaleontology And Isotope Stratigraphy Of The Upper Aptian To Lower Cenomanian (~114-98 Ma) In Odp Site 763, Exmouth Plateau, Nw Australia, Ali Alibrahim
Masters Theses
The biostratigraphy and isotope stratigraphy of the upper Aptian to lower Cenomanian interval including oceanic anoxic events OAE1b, 1c and 1d are investigated in ODP Site 763, drilled on the Exmouth Plateau offshore northwest Australia. Benthic foraminifera suggest that Site 763 was situated in outer neritic to upper bathyal water depths (~150-600 m). OAEs of the Atlantic basin and Tethys are typically associated with organic carbon-rich black shales and δ13C excursions. However, OAEs at this high latitude site correlate with ocean acidification and/or pyrite formation under anoxic conditions rather than black shales. Ocean acidification maybe responsible for sporadic …
Oceanographic Controls On The Expression Of Cretaceous Oceanic Anoxic Events In The Western Interior Sea, Christopher M. Lowery
Oceanographic Controls On The Expression Of Cretaceous Oceanic Anoxic Events In The Western Interior Sea, Christopher M. Lowery
Doctoral Dissertations
The Cretaceous Period (145-66 Ma) was a time of elevated global temperatures superimposed on fluctuating climate regimes and repeated biotic turnover. It recorded several major perturbations of the carbon cycle, characterized by widespread deposition of organic-rich black shale and benthic and photic zone dysoxia to euxinia, termed oceanic anoxic events (OAEs). The Cenomanian-Turonian OAE2 and the enigmatic Coniacian-Santonian OAE3 are well-preserved in the Western Interior Sea (WIS) of North America. The expression of these OAEs in the WIS differs both from each other and from contemporaneous open-ocean sections. Despite decades of research, questions remain about the role of oceanographic parameters …
Paleoceanography And Paleoenvironmental Changes Of The Cenomanian-Turonian Boundary Interval (94-93 Ma): The Record Of Oceanic Anoxic Event 2 In The Central And Eastern Parts Of The Western Interior Sea, Khalifa Elderbak
Doctoral Dissertations
The Cenomanian/Turonian (C/T) boundary marine strata of the Late Cretaceous Western Interior Sea (WIS) exhibit a positive carbon isotopic excursion in the bulk-carbonate and organic carbon. This marks Oceanic Anoxic Event 2 (OAE 2), which spans the uppermost part of the Hartland Shale and one-third of the overlying Bridge Creek Limestone members of the Greenhorn Formation and their equivalents. The interval is characterized by alternating beds of light-colored limestone and dark-colored marlstone and calcareous shale. These lithologic couplets have been related to Milankovitch orbital cyclicity. Foraminiferal assemblages from three selected sites, including the C/T boundary Global Boundary Stratotype Section and …