Cenozoic Paleoclimate Record of Oregon

A view of Columbia River basalts capped by the Rattlesnake tuff in central Oregon taken from Bone Creek.

Long-term Paleoclimatic Trends


This figure is from Sheldon et al. (2002, J. Geol. 110:687) and shows the long-term paleoprecipitation and paleotemperature trends from a series of paleosols in the Clarno and John Day Formations of Central Oregon. The proxies used to determine paleoprecipitation and paleotemperature are based on transfer functions relating different measurements of chemical weathering in modern soils to mean annual temperature and mean annual precipitation. These records show that while climate was changing across the Eocene-Oligocene boundary, the change was gradual and prolonged rather than sudden and sharply defined.