Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 319 (5860), 189-92

Isotopic Evidence for Glaciation During the Cretaceous Supergreenhouse

Affiliations

Isotopic Evidence for Glaciation During the Cretaceous Supergreenhouse

André Bornemann et al. Science.

Abstract

The Turonian (93.5 to 89.3 million years ago) was one of the warmest periods of the Phanerozoic eon, with tropical sea surface temperatures over 35 degrees C. High-amplitude sea-level changes and positive delta18O excursions in marine limestones suggest that glaciation events may have punctuated this episode of extreme warmth. New delta18O data from the tropical Atlantic show synchronous shifts approximately 91.2 million years ago for both the surface and deep ocean that are consistent with an approximately 200,000-year period of glaciation, with ice sheets of about half the size of the modern Antarctic ice cap. Even the prevailing supergreenhouse climate was not a barrier to the formation of large ice sheets, calling into question the common assumption that the poles were always ice-free during past periods of intense global warming.

Comment in

Similar articles

See all similar articles

Cited by 7 PubMed Central articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback