Descent into the Icehouse

“icehouse” (cold) Climates

Earth's climate has changed, within life-sustaining bounds, from warm to cool intervals, on scales from thousands to hundreds of millions of years. In the Phanerozoic Eon there have been three intervals of glaciation (Ordovician, Carboniferous and Cenozoic) lasting tens of millions of years, with ice down to sea level at mid-latitudes (Frakes et al., 1992; Crowell, 1999). These cool " ice-house...

“icehouse” (cold) Climates

“icehouse” (cold) Climates

Icehouse–greenhouse variations in marine denitrification

Long-term secular variation in the isotopic composition of seawater fixed nitrogen (N) is poorly known. Here, we document variation in the N-isotopic composition of marine sediments (δNsed) since 660 Ma (million years ago) in order to understand major changes in the marine N cycle through time and their relationship to first-order climate variation. During the Phanerozoic, greenhouse climate mo...

Stepwise transition from the Eocene greenhouse to the Oligocene icehouse

Department of Earth and Environmental Science, Rensselaer Polytechnic Inst., Troy, New York 12180, USA Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey 08854, USA Institute of Marine and Coastal Science, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA Department of Geology and Geophysics, Texas A&M University, College Station, Texas...