The marine Eocene-Oligocene transition of 34 million years ago was a critical turning point in Earth's climatic history, when the warm, high-diversity "greenhouse" world of the early Eocene ceded to the glacial, "icehouse" conditions of the early Oligocene. This book surveys the advances in stratigraphic and paleontological research and isotopic analysis made since 1989 in regard to marine deposits around the world. In particular, it summarizes the high-resolution details of the so-called doubthouse interval (roughly 45 to 34 million years ago), which is critical to testing climatic and evolutionary hypotheses about the Eocene deterioration. The authors' goals are to discuss the latest information concerning climatic and oceanographic change associated with this transition and to examine geographic and taxonomic patterns in biotic turnover that provide clues about where, when, and how fast these environmental changes happened. They address a range of topics, including the tectonic and paleogeographic setting of the Paleogene; specific issues related to the stratigraphy of shelf deposits; advances in recognizing and correlating boundary sections; trends in the expression of climate change; and patterns of faunal and floral turnover. In the process, they produce a valuable synthesis of patterns of change by latitude and environment.

Marine records show major cooling during the Eocene-Oligocene Climate Transition (EOCT). Most proxy studies in the White River Group suggest drying across the EOCT, and some suggest cooling. The lower resolution continental record has hindered a direct correlation of the marine climate record to Nebraska. I explore various correlation schemes and what they imply for faunal changes. This study compiles and analyzes data from 4,875 specimens in the University of Nebraska State Museum (UNSM) collection to test the hypothesis that climate change across the Eocene-Oligocene (E-O) boundary caused significant abundance changes in mammals. A series of binning schemes was created. One binning scheme followed previously established lithological zones, two schemes were based on average sediment accumulation rates, and three more were created by applying a cubic spline curve to published 206Pb/238U zircon ash dates. For the purpose of correlating the marine and Toadstool sections, I constructed a high-resolution (±0.5 m) carbon isotope stratigraphy across the E-O boundary using fossil enamel from the oreodont Merycoidodon. Results show that turnover in taxonomic abundance occurs throughout the study interval and is not concentrated across the EOCT. The largest pulse of faunal change and largest abundance changes for the most common taxa, Merycoidodon and the horse Mesohippus, slightly predate the EOCT. This raises the possibility that climate change began earlier in the continental interior than indicated by the marine benthic oxygen isotope record. Chord distance analyses reveal that the faunal composition of Orellan zones are more similar to one another than they are to the faunas of Chadron zones. This similarity is likely caused by the extinction, or near extinction, of Chadron taxa like Megacerops around the EOCT. Despite the lack of significant change in evenness, numerous taxa underwent extended changes in relative abundance through time. Archaeotherium, a water-dependent artiodactyl, decreased in relative abundance through time just as Poebrotherium, a water-independent camelid, increased in abundance through time. Changes in the relative abundances of Poebrotherium and Archaeotherium are consistent with a drier environment beginning in EOCT. The level of water-dependence in other taxa is less clear, and their changes in abundance cannot be confidently explained through diet, dentition, body mass, or locomotion.

The transition from the Eocene to the Oligocene epochs was the most significant event in earth history since the extinction of dinosaurs. As the first Antarctic ice sheets appeared, major extinctions and faunal turnovers took place on the land and in the sea, eliminating forms adapted to a tropical world and replacing them with the ancestors of most of our modern animal and plant life. Through a detailed study of climatic conditions and of organisms buried in Eocene-Oligocene sediments, this volume shows that the separation of Antarctica from Australia was a critical factor in changing oceanic circulation and ultimately world climate. In this book forty-eight leading scientists examine the full range of Eocene and Oligocene phenomena. Their articles cover nearly every major group of organisms in the ocean and on land and include evidence from paleontology, stable isotopes, sedimentology, seismology, and computer climatic modeling. The volume concludes with an update of the geochronologic framework of the late Paleogene. Originally published in 1992. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

After a decade of new findings and interpretation based on innovative techniques during the 1980s, archaeologists were pretty sure that 38 million years ago the earth still basked in a subtropical "greenhouse" that had lasted since the age of dinosaurs, but 5 million years later there were glaciers in the Antarctic, signalling the beginning of the "icehouse" state that we know now. Here is a summary of the present understanding of the climatic and biological changes, for nonspecialists who have some familiarity with the terms and concepts of archaeology. Paper edition (08091-3), $24. Annotation copyright by Book News, Inc., Portland, OR

The transition from the Eocene to the Oligocene epoch, occurring approximately 47 to 30 million years ago, was the most dramatic episode of climatic and biotic change since the demise of the dinosaurs. The mild tropical climates of the Paleocene and early Eocene were replaced by modern climatic conditions and extremes, including glacial ice in Antarctica. The first part of this book summarizes the latest information in the dating and correlation of the strata of late middle Eocene through early Oligocene age in North America. The second part reviews almost all the important terrestrial reptiles and mammals found near the Eocene-Oligocene boundary, in the White River Chronofauna--from the turtles, snakes and lizards to the common rodents, carnivores, oreodonts and deer of the Badlands. This is the first comprehensive treatment of these topics in over sixty years, and will be invaluable to vertebrate paleontologists, geologists, mammalogists and evolutionary biologists.

Provides the latest information in dating and correlation of the strata of late middle Eocene through early Oligocene age in North America.

Geologic Time Scale 2020 (2 volume set) contains contributions from 80+ leading scientists who present syntheses in an easy-to-understand format that includes numerous color charts, maps and photographs. In addition to detailed overviews of chronostratigraphy, evolution, geochemistry, sequence stratigraphy and planetary geology, the GTS2020 volumes have separate chapters on each geologic period with compilations of the history of divisions, the current GSSPs (global boundary stratotypes), detailed bio-geochem-sequence correlation charts, and derivation of the age models. The authors are on the forefront of chronostratigraphic research and initiatives surrounding the creation of an international geologic time scale. The included charts display the most up-to-date, international standard as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. As the framework for deciphering the history of our planet Earth, this book is essential for practicing Earth Scientists and academics. - Completely updated geologic time scale - Provides the most detailed integrated geologic time scale available that compiles and synthesize information in one reference - Gives insights on the construction, strengths and limitations of the geological time scale that greatly enhances its function and its utility

Stratigraphy allows us to establish and communicate the timings for the course of Earth history and provides the means to determine the duration and rates of Earth processes. Deciphering Earth’s History: the Practice of Stratigraphy focuses on how to apply the wide spectrum of stratigraphical techniques. It also explains how these techniques can be integrated and details their individual strengths and limitations. Chapters are laid out in a step-by-step style, guiding the reader through a recommended approach and explaining the factors to be considered. The methods are illustrated with flow charts, marginal top tips, checklists, worked examples and over 200 figures. Authors from academia, research centres and industry have contributed to ensure a wide range of perspectives are included. In addition to chapters on each of the stratigraphical techniques there is also material on accounting for stratigraphical incompleteness, constructing geological timescales, handling and archiving stratigraphical data and the application of stratigraphy to space exploration and other disciplines. This book is designed for a wide audience ranging from advanced level undergraduates to professional practitioners wishing to use other stratigraphical techniques or understand the advantages and weaknesses of particular techniques.