Testing for ice sheets during the mid-Cretaceous greenhouse using glassy foraminiferal calcite from the mid-Cenomanian tropics on Demerara Rise

Kazuyoshi Moriya, Paul A. Wilson, Oliver Friedrich, Jochen Erbacher, Hodaka Kawahata

Research output: Contribution to journalArticle

80 Citations (Scopus)

Abstract

The mid-Cretaceous is widely considered the archetypal ice-free greenhouse interval in Earth history, with a thermal maximum around Cenomanian-Turonian boundary time (ca. 90 Ma). However, contemporaneous glaciations have been hypothesized based on sequence stratigraphic evidence for rapid sea-level oscillation and oxygen isotope excursions in records generated from carbonates of questionable preservation and/or of low resolution. We present new oxygen isotope records for the mid-Cenomanian Demerara Rise that are of much higher resolution than previously available, taken from both planktic and benthic foraminifers, and utilizing only extremely well preserved glassy foraminifers. Our records show no evidence of glaciation, calling into question the hypothesized ice sheets and rendering the origin of inferred rapid sea-level oscillations enigmatic. Simple mass-balance calculations demonstrate that this Cretaceous sea-level paradox is unlikely to be explained by hidden ice sheets existing below the limit of δ 18O detection.

Original languageEnglish
Pages (from-to)615-618
Number of pages4
JournalGeology
Volume35
Issue number7
DOIs
Publication statusPublished - 2007 Jul 1
Externally publishedYes

Keywords

  • Cenomanian (Cretaceous)
  • Foraminifera
  • Glaciation
  • Sea level
  • Stable isotopes
  • Tropical environment

ASJC Scopus subject areas

  • Geology

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