We substantially revised the first and second editions of this book while retaining our original objectives: to help you better understand (1) the processes that erode, transport, and deposit sediments (sedimentology); (2) the characteristics and origins of sedimentary rocks (sedimentary petrology); and (3) the complex distribution of the sedimentary rock record in space and time (stratigraphy). The first two areas are the subjects of Chapters 1 through 14. The field of stratigraphy is covered in Chapters 15 through 19.

Some 75% of the rocks at the Earth’s surface are sedimentary in origin, and these include the familiar sandstones, limestones and shales, and the less common but equally well-known salt deposits, ironstones, coal and chert. Sedimentary rocks of the geological record were deposited in the whole range of natural environments that exist today. The study of these modern environments and their sediments and processes contributes much to the understanding of their ancient equivalents. There are some sedimentary rock types; however, for which there are no known modern analogues, or their inferred depositional environments are only poorly represented at the present time.

formations or indeed on any other process in which time played an integral and fundamental role. The advent of radionuclide dating, with the attendant absolute measure of age, changed the views of geology and processes that can occur in ways that have been of major significance. In addition, the radionuclides allow a direct comparison of absolute age to the prior proxies. Accordingly, not only had one available a true age dating but also a proxy scale that could be tie <...>

Sedimentary rock-hosted disseminated gold ores lithologically and chemically similar to those of Carlin-type deposits of the western United States are present in the Yauricocha district, central Peru. The Purisima Concepcion deposit is located in the core of a steeply plunging anticline several hundred meters beyond large pipe-shaped Cu-Zn-Pb-Ag-Au replacement orebodies in limestone bordering a late Miocene granodiorite stock. The central part of the stock is potassium-silicate altered and contains high-salinity fluid inclusions.