A Geologic Time Scale 2004

INTRODUCTION

Over the past century, paleoclimatological research has led to wide acceptance that quasi-periodic oscillations in the Sun—Earth position have induced significant variations in the Earth's past climate. These orbitally forced variations influenced climate-sensitive sedimentation, and thereby came to be fossilized in the Earth's cyclic stratigraphic record. The detection of orbital variations in Earth's cycle stratigraphy was progressively facilitated by advancements in celestial mechanics, which have provided more accurate models of the Earth's orbital—rotational behavior through geological time, and by improvements in data collection and analysis.

A principal outcome of the research has been the recognition that cycle stratigraphy, when shown to carry the signal specific to Earth's orbital behavior, serves as a powerful geochronometer. High-quality data collected over the past decade, in particular, have proven to have faithfully recorded all of the orbital cycles predicted by modern celestial mechanics over 0–23 Ma.