Foraminiferal Response to Ecological Perturbations Along the Eastern Margin of the Canadian Western Interior Seaway, Cenomanian-Turonian Interval

Microvertebrate faunal assemblages of the Favel Formation (late Cenomanian-middle Turonian) of Manitoba, Canada

“…S3 ). The presence of H. globulosa further supports the stratigraphic position of the ‘Near Keld base, Vermilion R.’ horizon as within the Keld Member, though does not distinguish whether the horizon is of late Cenomanian or early Turonian age because of its chronostratigraphic range ( McNeil & Caldwell, 1981 ; Dionne, Schröder-Adams & Cumbaa, 2016 ). Although examination was brief, the presence of H. globulosa and apparent absence of Clavihedbergella simplex and Whiteinella aprica indicates the ‘Near Keld base, Vermilion R.’ horizon is of late Cenomanian age ( Dionne, Schröder-Adams & Cumbaa, 2016 ).…”

“…Globally recognized events representing significant climate changes recorded in the Favel Formation include the Cenomanian-Turonian oceanic anoxic event (OAE-2), the associated Cretaceous Thermal Maximum, and peak transgression of the Greenhorn WIS marine cycle ( Kyser et al, 1993 ; Schröder-Adams, 2014 ; Dionne, Schröder-Adams & Cumbaa, 2016 ; Scotese et al, 2021 ). These events have been recognized in the form of δ 18 O trends analyzed from phosphate of fish remains, δ 18 O and δ 13 C trends from calcareous planktonic foraminifers and coccoliths, aragonite of ammonites, aragonite and calcite prisms of inoceramid clams, δ 13 C, organic carbon, and hydrogen index trends from mudstones, as well as relative abundances of foraminifera ( Kyser et al, 1993 ; Schröder-Adams, 2014 ; Dionne, Schröder-Adams & Cumbaa, 2016 ; Scotese et al, 2021 ). In the Riding Mountain area of MB, the stratigraphic position of the pronounced positive organic δ 13 C excursion associated with the OAE2 event is approximately 8 to 9 m above the Ashville-Favel interformational contact and near the base of the Laurier Limestone beds of the Keld Member ( Kyser et al, 1993 ).…”

“…Paleontology of the Favel Formation has been previously investigated and described in terms of macrovertebrates ( Bardack, 1968 ), macroinvertebrates ( Wickenden, 1945 ), foraminifera ( McNeil & Caldwell, 1981 ; Schröder-Adams et al, 2001 ; Dionne, Schröder-Adams & Cumbaa, 2016 ), and nannofossils ( Schröder-Adams et al, 2001 ); however, microvertebrate fossil occurrences have not yet been described in detail. Although several geologists provided early reports of vertebrate fossils from the Manitoba escarpment, Bardack (1968) was the first to provide descriptions, including descriptions of the first known vertebrate fossils collected in present-day MB, two chondrichthyan symphyseal teeth (CMN 5071) collected by J.W.…”

Redox conditions and ecological resilience during Oceanic Anoxic Event 2 in the Western Interior Seaway

“…This, coupled with the stratified and anoxic conditions indicated by geochemical redox proxies, culminated in low abundances of agglutinated benthic foraminifera and an absence of bioturbation (Schröder-Adams et al, 1996;Simons et al, 2003). As sea-level rose through the late Cenomanian to early Turonian, planktic foraminifera and nannofossils appeared at some southern Canadian sites, signalling the influence of more normal saline marine Tethyan waters (McNeil and Caldwell, 1981;Caldwell et al, 1993;Schröder-Adams et al, 1996;Dionne et al, 2016). However, abundance and diversity was low, interpreted to be due to stable stratification (perhaps enhanced by a freshwater lid), anoxic conditions and inhospitable conditions for benthic or planktic fauna to thrive (Schröder- Adams et al, 2001;Schröder-Adams, 2014;Dionne et al, 2016).…”

Biotic and Paleoceanographic Changes Across the Late Cretaceous Oceanic Anoxic Event 2 in the Southern High Latitudes (IODP Sites U1513 and U1516, SE Indian Ocean)

“…Planktonic foraminifera across the Cenomanian‐Turonian boundary interval studied in several low to mid latitude regions of the Tethyan Realm (e.g., England: Falzoni & Petrizzo, 2020; Keller et al., 2001; Paul et al., 1999; Austria: Gebhardt et al., 2010; Wagreich et al., 2008; Italy: Coccioni & Luciani, 2004, 2005; Luciani & Cobianchi, 1999; Scopelliti et al., 2004, 2008; SE France: Falzoni & Petrizzo, 2022; Falzoni, Petrizzo, Jenkyns, et al., 2016; Grosheny et al., 2006; Takashima et al., 2009; Spain: Lamolda et al., 1997; Tunisia and Algeria: Benadla et al., 2018; Caron et al., 2006; Grosheny et al., 2013; Nederbragt & Fiorentino, 1999; Reolid et al., 2015; Zaghbib‐Turki & Soua, 2013; Iran: Kalanat et al., 2016; Kalanat & Vaziri‐Moghaddam, 2019; Morocco: Aquit et al., 2013; Falzoni et al., 2018; Keller et al., 2008), of the central Atlantic Ocean (Nigeria: Gebhardt, 1997; Morocco: Jati et al., 2010; Mexico: Ifrim et al., 2011), of the Indian Ocean (Tibet: Bomou et al., 2013), of the Pacific Ocean (Japan: Hasegawa, 1999), and of the Western Interior Seaway (e.g., USA: Caron et al., 2006; Desmares et al., 2007; Elderbak & Leckie, 2016; Elderbak et al., 2014; Keller & Pardo, 2004; Canada: Dionne et al., 2016; Bryant et al., 2021) underwent a significant change.…”