Study of glacial deposits of the Ice Brook Formation (of Proterozoic age) in the Mackenzie Mountains (Northwest Territories and Yukon) which may offer evidence of two Late Proterozoic glaciations rather than the single (Rapitan) event previously suggested.
In recent years, interest in Neoproterozoic glaciations has grown as their pivotal role in Earth system evolution has become increasingly clear. One of the main goals of the IGCP Project number 512 was to produce a synthesis of newly available information on Neoproterozoic successions worldwide. This Memoir consists of a series of overview chapters followed by site-specific chapters. The overviews cover key topics including the history of research on Neoproterozoic glaciations, identification of glacial deposits, chemostratigraphic techniques and datasets, palaeomagnetism, biostratigraphy, geochronology and climate modelling. The site specific chapters include reviews of the history of research on these rocks and up-to-date syntheses of the structural framework, tectonic setting, palaeomagnetic & geochronological constraints, physical, biological, and chemical stratigraphy, and descriptions of the glaciogenic and associated strata, including economic deposits.
This volume presents a sample of views and visions among some of the growing numbers of Neoproterozoic workers. It includes a set of multidisciplinary reviews on the Neoproterozoic fossil record, evolutionary developmental biology of animals, and molecular clock estimates of phylogenetic divergences. These topics are of continuing interest to geoscientists and bioscientists who are intrigued by the deep history of the Earth and its inhabitants.
Ancient ice ages are revealed by distinctive stratal facies that tell us much about the times of coolness and how the climate system works. Several strong ice ages were recorded in the late Paleozic time and during transitions from the Devonian in to the Carboniferous and from the Ordovician in to the Silurian. In Precambrian time, several are documented for both the late and early Proterozoic age. This title explores findings on the pre-Mesozoic ice ages, examining climate in relation to tectonobiogeochemical activities rooted in the changing earth-air-ocean system.
The early chapters of the volume present data and interpretations of the geophysics of the craton and summarise, with sequential maps, the tectonic evolution of the craton. The main body of the text and accompanying plates and figures present the stratigraphy, structural history, and economic geology of specific sedimentary basins and regions. The volume concludes with a summary chapter in which the currently popular theories of cratonal tectonics are discussed and the unresolved questions are identified.
Past Glacial Environments, Second Edition, presents a revised and updated version of the very successful first edition of Menzies' book, covering a breadth of topics with a focus on the recognition and analysis of former glacial environments, including the pre-Quaternary glaciations. The book is made up of chapters written by various geological experts from across the world, with the editor's expertise and experience bringing the chapters together. This new and updated volume includes at least 45% new material, along with five new chapters that include a section on techniques and methods. Additionally, this new edition is presented in full color and features a large collection of photographs, line diagrams, and tables with examples of glacial environments and landscapes that are drawn from a worldwide perspective. Informative knowledge boxes and case studies are included, helping users better understand critical issues and ideas. - Provides the most complete reference concerning the study of glacial processes and their geological, sedimentological, and geomorphological products - Comprised of chapters written by various geological experts from across the world - Includes specific case studies to alert readers to important ideas and issues - Uses text boxes throughout to explain key concepts from glacial literature - Presents full color photographs, line diagrams, and tables throughout
"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"--