The Terrane Puzzle

"Displaced or tectonostratigraphic terranes comprise a huge portion of real estate in the North American Cordillera. Terranes are discrete, fault-bound blocks of regional extent, with rocks and fossils that differ to a great extent from those of adjacent blocks. The allochthonous nature of most terranes, relative to adjacent craton, is well established. When mapped, they resemble a collage of mixed rock types, tectonic styles, metamorphism, and volcanic origins--each part resembling the pieces of a puzzle. Terrane studies remain integral to understanding the geological evolution of western North America. Since the initiation of the concept summarized in 1979 by the late David L. Jones, the significance of fossils and stratigraphy has been key to solving the puzzle. Chapters of this book written by experts in their field, provide a sense of the diversity of approaches in paleontology and stratigraphy. Contributions span geologic time from the Precambrian (Vendian) to Cretaceous and address over 20 Cordilleran terranes."--Publisher's website.

This book introduces the reader to the principles of terrrane analysis, and describes how accretion tectonics relates to classic plate tectonics theory and what this represents in terms of mountain building and continental growth processes. A forensic-like investigation of continental geology is detailed, integrating many different sub-disciplines of the Earth Sciences. The concepts outlined have a practical bent and help to explain the nature and occurrences of petroleum and metallic mineral deposits.

Year by year the Earth sciences grow more diverse, with an inevitable increase in the degree to which rampant specialization isolates the practitioners of an ever larger number of sub fields. An increasing emphasis on sophisticated mathematics, physics and chemistry as well as the use of advanced technology have. set up barriers often impenetrable to the uninitiated. Ironically, the potential value of many specialities for other, often non-contiguous once has also increased. What is at the present time quiet, unseen work in a remote corner of our discipline, may tomorrow enhance, even revitalize some entirely different area. The rising flood of research reports has drastically cut the time we have available for free reading. The enormous proliferation of journals expressly aimed at small, select audiences has raised the threshold of access to a large part of the literature so much that many of us are unable to cross it. This, most would agree, is not only unfortunate but downright dangerous, limiting by sheer bulk of paper or difficulty of comprehension, the flow of information across the Earth sciences because, after all it is just one earth that we all study, and cross fertilization is the key to progress. If one knows where to obtain much needed data or inspiration, no effort is too great. It is when we remain unaware of its existence (perhaps even in the office next door) that stagnation soon sets in.

Compiled for the 2011 joint meeting of the GSA Rocky Mountain and Cordilleran Sections, this field guide provides an introduction to some of the remarkable geology of the Rocky Mountain and Cordillera regions.

Accretionary orogens form at convergent plate boundaries and include the supra-subduction zone forearc, magmatic arc and backarc components. They can be broken into retreating and advancing types, based on their kinematic framework and resulting geological character.Accretionary systems have been active throughout Earth history, extending back until at least 3.2 Ga, and provide an important constraint on the initiation of horizontal motion of lithospheric plates on Earth. Accretionary orogens have been responsible for major growth of the continental lithosphere, through the addition of juvenile magmatic products, but are also major sites of consumption and reworking of continental crust through time.The aim of this volume is to provide a better understanding of accretionary processes and their role in the formation and evolution of the continental crust. Fourteen papers deal with general aspects of accretion and metamorphism and discuss examples of accretionary orogens and crustal growth through Earth history, from the Archaean to the Cenozoic.

"This Memoir focuses on 7 'turning points' that had specific and lasting impacts on Laurentian evolution: The Neoarchean, characterized by cratonization; the Paleoproterozoic and the initial assembly of Laurentia; the Mesoproterozoic southern margin of Laurentia; the Midcontinent rift and the Grenville orogeny; (5) the Neoproterozoic breakup of Rodinia; the mid-Paleozoic phases of the Appalachian-Caledonian orogen; and the Jurassic-Paleogene assembly of the North American Cordillerar"--