Deep-sea paleotemperature record of extreme warmth during the Cretaceous

Abstract

Oxygen isotope analyses of well-preserved foraminifera from Blake Nose (30°N paleolatitude, North Atlantic) and globally distributed deep-sea sites provide a long-term paleotemperature record for the late Albian-Maastrichtian interval that is difficult to reconcile with the existence of significant Cretaceous ice sheets. Given reasonable assumptions about the isotopic composition of Cretaceous seawater, our results suggest that middle bathyal water temperatures at Blake Nose increased from ~12 °C in the late Albian through middle Cenomanian to a maximum of 20 °C during the latest Cenomanian and earliest Turonian. Bottom waters were again ~12 °C during the middle Campanian and cooled to a minimum of 9 "C during the Maastrichtian. Correlative middle bathyal foraminifera from other ocean basins yield paleotemperature estimates that are very similar to those from Blake Nose. Comparison of global bottom-water temperatures and latitudinal thermal gradients suggests that global climate changed from a warm greenhouse state during the late Albian through late Cenomanian to a hot greenhouse phase during the latest Cenomanian through early Campanian, then to cool greenhouse conditions during the mid-Campanian through Maastrichtian.

Widespread Development of Silcrete in the Cretaceous and Evolution of the Poaceae Family of Grass Plants

“…3). The formation of Cretaceous silcretes at such high palaeolatitudes suggests an upward warming trend, consistent with palaeotemperature estimates for the early Cretaceous (e.g., Huber et al, 1995Huber et al, , 2002Friedrich et al, 2012). Apart from their widespread occurrence, which is anomalous, Cretaceous silcretes are no different from those formed during other geologic ages in terms of morphology and chemical composition.…”

100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants

“…This warm peak may have also been the trigger for the expansion of the angiosperms in the Antarctic, represented by a marked increased abundance of angiosperm pollen in Turonian sediments (Keating et al, 1992). On a global scale this corresponds to the Cretaceous thermal maximum, from about 100-80 Ma, reported from many sites (e.g., Clark and Jenkyns, 1999;Huber et al, 2002), and possibly attributed to rising atmospheric CO 2 levels due to a tectonically driven oceanographic event in the opening of the equatorial Atlantic gateway (Poulsen et al, 2003).…”

Correlated terrestrial and marine evidence for global climate changes before mass extinction at the Cretaceous–Paleogene boundary

“…of the Cretaceous, and the coolest deep and surface water temperatures of this interval are recorded in Site 690 sediments from Ϸ66.6 Ma (Fig. 1b) (48). Bottom and surface waters warmed near 66.2 Ma and again at Ϸ66.0 Ma.…”