Quaternary Geology and Paleoenvironments

Abstract

The Quaternary is defined by its unusual climate, which was originally characterized as advances and retreats of continental ice sheets in the Northern Hemisphere. The earliest such glaciation, at about 2.6 Ma, is now recognized as one step in a worldwide cooling trend that began some 38 million years ago when the world ocean first felt the effect of the great Antarctic ice sheet. With the loss of ocean warmth, the cycles in the Earth’s orbit that affect the solar radiation reaching the surface have had a steadily increasing influence on world climate, and glacial-interglacial swings have grown progressively stronger. The earliest Homo appears in the fossil record at the same time that the more extreme Quaternary climate changes began to increase grasslands in Equatorial Africa, giving wider opportunity for bipedal, stone-wielding scavengers.