The Rise of Oxygen over the Past 205 Million Years and the Evolution of Large Placental Mammals

• DOI: 10.1126/science.1116047
• Publication Date: 2005-09-29T21:52:58Z
• Authors: Paul G. Falkowski; Miriam E. Katz; Allen J. Milligan; Katja Fennel; Benjamin S. Cramer; Marie Pierre Aubry; Robert A. Berner; Michael J. Novacek; Warren M. Zapol
• Keywords: Atmospheric oxygen

On the basis of a carbon isotopic record both marine carbonates and organic matter from Triassic-Jurassic boundary to present, we modeled oxygen concentrations over past 205 million years. Our analysis indicates that atmospheric approximately doubled this period, with relatively rapid increases in early Jurassic Eocene. We suggest overall increase oxygen, mediated by formation passive continental margins along Atlantic Ocean during opening phase current Wilson cycle, was critical factor evolution, radiation, subsequent average size placental mammals.