Blake Nose stable isotopic evidence against the mid-Cenomanian glaciation hypothesis

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doi: 10.1130/G25580A.1
Author(s): Ando, Atsushi; Huber, Brian T.; MacLeod, Kenneth G.; Ohta, Tomoko; Khim, Boo-Keun
Author Affiliation(s): Primary:
Smithsonian National Museum of Natural History, Department of Paleobiology, Washington, DC, United States
Other:
University of Missouri, United States
Kyoto University, Japan
Pusan National University, South Korea
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 37(5), p.451-454. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2009111. 32 refs.; illus., incl. chart, strat. col.
Summary: Detailed multitaxon stable isotope (δ18O and δ13C) data from Blake Nose (western North Atlantic) argue against a mid-Cenomanian glaciation event during the mid-Cretaceous greenhouse. Results generated are precisely correlated to sea-level changes inferred from European sequence stratigraphy using the twin δ13C excursions mid-Cenomanian event (MCE) Ia and MCE Ib. Microfossils analyzed (surface-dwelling to deep-dwelling planktonic foraminifera, benthic foraminifera, coccoliths) show remarkably consistent intertaxon δ18O and δ13C offsets; comparative scanning electron microscope and Sr/Ca analyses allow some δ18O data to be eliminated because of selective diagenesis. Across MCE Ia, the proposed interval of major glacioeustatic regression, the planktonic δ18O values are constant for each taxon. The absence of a mean seawater δ18O shift contradicts predictions for the mid-Cenomanian glaciation episode. The benthic δ18O records show significant fluctuations during MCE I, implying short-term variability in North Atlantic intermediate-water and deep-water circulation patterns and/or sources at that time.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Alkaline earth metals; Ancient ice ages; Atlantic Ocean; Benthic taxa; Biochemistry; Blake Nose; Blake Plateau; C-13/C-12; Calcium; Carbon; Cenomanian; Coccolithophoraceae; Cretaceous; Experimental studies; Foraminifera; Geochemistry; Glaciation; Invertebrata; Isotope ratios; Isotopes; Leg 171B; Marine sediments; Mesozoic; Metals; Microfossils; Middle Cenomanian; North Atlantic; O-18/O-16; ODP Site 1050; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleoclimatology; Planktonic taxa; Plantae; Protista; SEM data; Sediments; Sr/Ca; Stable isotopes; Strontium; Upper Cretaceous
Coordinates: N300600 N300600 W0761406 W0761406
Record ID: 2009050011
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