"OAE 3" – regional Atlantic organic carbon burial during the Coniacian–Santonian

Abstract

Abstract. The Coniacian-Santonian time interval is the inferred time of oceanic anoxic event 3 (OAE 3), the last of the Cretaceous OAEs. A detailed look on the temporal and spatial distribution of organic-rich deposits attributed to OAE 3 suggests that black shale occurrences are restricted to the equatorial to mid-latitudinal Atlantic and adjacent basins, shelves and epicontinental seas like parts of the Caribbean, the Maracaibo Basin and the Western Interior Basin, and are largely absent in the Tethys, the North Atlantic, the southern South Atlantic, and the Pacific. Here, oxic bottom waters prevailed as indicated by the widespread occurrence of red deep-marine CORBs (Cretaceous Oceanic Red Beds). Widespread CORB sedimentation started during the Turonian after Oceanic Anoxic Event 2 (OAE 2) except in the Atlantic realm where organic-rich strata continue up to the Santonian. The temporal distribution of black shales attributed to OAE 3 indicates that organic-rich strata do not define a single and distinct short-time event, but are distributed over a longer time span and occur in different basins during different times. This suggests intermittent and regional anoxic conditions from the Coniacian to the Santonian. A comparison of time-correlated high-resolution δ 13 C curves for this interval indicates several minor positive excursions of up to 0.5 ‰, probably as a result of massive organic carbon burial cycles in the Atlantic. Regional wind-induced upwelling and restricted deep basins may have contributed to the development of anoxia during a time interval of widespread oxic conditions, thus highlighting the regional character of inferred OAE 3 as regional Atlantic event(s).

Cenomanian to Santonian radiolarian biostratigraphy, carbon isotope stratigraphy and paleoenvironments of the Sverdrup Basin, Ellef Ringnes Island, Nunavut, Canada

“…The interval from 360 to 400 m is tentatively interpreted as OAE 3, a less defined OAE with several minor positive δ 13 C excursions spanning the Coniacian to Santonian interval (e.g. Wagreich, 2012). This interval corresponds to a finely laminated black shale interval, but characterized by significantly lower TOC values (up to 3.5%) of terrestrialderived organic matter compared to the OAE 2 interval.…”

“…This event is mainly recognized in the Atlantic and bordering seaways such as the Western Interior Sea (e.g. Wagreich, 2012). The upper Coniacian is marked by renewed increase of nassellarian species and the occurrence of the Dictyomitra multicostata partial range zone (Figs.…”

The Late Hauterivian Faraoni ‘Oceanic Anoxic Event’: an update

“…The designation of OAE 1b has been applied either to all or only to part of this interval; -a middle Albian event (~107 Ma), called OAE 1c or Jassines event [Gale et al, 2011], is associated with the Amadeus level in Italy [Coccioni and Galeotti, 1993] or Toolebuc Formation in Australia [Leckie et al, 2002]; -a Latest Albian event (~101 Ma), called OAE 1d, which coincides with the Breistroffer level in SE France [Bréhéret, 1997] or Pialli level in central Italy [Coccioni, 2001]; -a possible Santonian-Coniacian event (~90-83 Ma), also known as OAE 3, is represented mainly in the Atlantic ocean [Jenkyns, 1980;Wagner, 2002;Hofman et al, 2003;Rey et al, 2004;März et al, 2009;Wagreich, 2012], although occurrences beyond this region (Canada, Tibet, …) are also known.…”

Cenomanian–Campanian (Late Cretaceous) planktonic assemblages of the Crimea–Caucasus area: Palaeoceanography, palaeoclimate and sea level changes

“…This morphotype may be related to the presence ofOAE-3 (Loclaire et al, 2011;Wagreich, 2012) near the Santonian-Campanian boundary or, more probably, with global climatic change during the Campanian-…”