“The past may not repeat itself, but it does rhyme.”
As Earth scientists learn more about the way in which our planet functions, we find that the decoded patterns of Earth history illustrate Mark Twains proverb. The patterns of Earth history may not be exactly the same time after time, but these patterns are very similar in many respects. Our understanding of these trends and their variation through time comes directly from the rock record. This laboratory manual, written for introductory Historical Geology courses at the university-level, covers the basic principles used by geologists and other Earth scientists to interpret the stratigraphic record. Unlike other Historical Geology manuals, this book provides a wider coverage of more topics, techniques, and applications. Exercises are presented that incorporate information from several different geological disciplines because no single area of geology can explain what we can document in Earths past. It is necessary to use several different and complementary approaches to understand our planets past. Four and a half BILLION years of history are not easy to explain using one or even two isolated approaches. Many exercises are based upon real data, allowing the student to follow the lines of reasoning and logic used to decipher Earths saga. Where possible, analogies also are used to help the student appreciate the parallels between how Earth operates today and how it operated in the deep past.
Deciphering Earth History consists of exercises that are both traditional and contemporary in approach. Traditional exercises provide the foundations of our reading of Earth history, while contemporary approaches include small projects designed to demonstrate the trends on Earth over long intervals of time. As we face uncertainties about future global climate change and the response of ecosystems to this change, the recent and deep past provide models of ancient (and not so ancient) responses to similar trends. These data are found both in the biological (monerans, protists, fungi, plants, and animals) and abiological systems (for example, sedimentology and geochemistry, stratigraphy and radioisotopes, tectonics and geophysics). In the development of these exercises and overall goals of the manual, we have not relied upon any one approach to introduce the concepts. Rather, we have drawn from all available examples to demonstrate that Earth and its components are a unified whole.