The Caledonides are a major orogenic belt that stretches from the Arctic, through Scandinavia, East Greenland, Britain and Ireland into the Atlantic coast of North America. Following the break-up of Rodinia, the Caledonides formed in the Palaeozoic by the drifting of various continents and their eventual aggregation in the Silurian and Devonian. The orogen subsequently fragmented during the opening of the Atlantic Ocean. This volume brings together 25 papers presenting the results of modern research that investigates the orogenic processes and the provenance of specific components of the belt. The contributions reflect different lines of research, linking traditional field studies with modern analytical techniques. In addition three overview papers summarize the main features of the belts in Scandinavia, Svalbard, East Greenland, Britain and Ireland, highlighting the advances made since the last major synthesis of the Scandinavian Caledonides 30 years ago, and discussing important open questions.

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.

Two of the greatest evolutionary events in the history of life on Earth occurred during Early Paleozoic time. The first was the Cambrian explosion of skeletonized marine animals about 540 million years ago. The second was the "Great Ordovician Biodiversification Event," which is the focus of this book. During the 46-million-year Ordovician Period (489–443 m.y.), a bewildering array of adaptive radiations of "Paleozoic- and Modern-type" biotas appeared in marine habitats, the first animals (arthropods) walked on land, and the first non-vascular bryophyte-like plants (based on their cryptospore record) colonized terrestrial areas with damp environments. This book represents a compilation by a large team of Ordovician specialists from around the world, who have enthusiastically cooperated to produce this first globally orientated, internationally sponsored IGCP (International Geological Correlation Program) project on Ordovician biotas. The major part is an assembly of genus- and species-level diversity data for the many Ordovician fossil groups. The book also presents an evaluation of how each group diversified through Ordovician time, with assessments of patterns of change and rates of origination and extinction. As such, it will become the standard work and data source for biotic studies on the Ordovician Period.

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.

This 1985 book examines the origin of the present diversity of marine invertebrate animals. A brief review of the early stages in the history of life discusses the time-scale of the relevant geological periods alongside corresponding events in the evolutionary sequence. These views of the early history of life are then matched against the fossil record and conjectures drawn from the living fauna, enabling the author to attempt an overview of the early diversification of marine animal life. Transitions to the succeeding assemblages of shellbearing fossils in Palaeozoic rocks are discussed and a number of stratigraphic adjustments are suggested for the period in which evolutionary events had their greatest impact on oceans and marine rock strata. The need for an interdisciplinary approach to early evolution is emphasized.

work on structural and stratigraphic relationships is presented from various parts of the mountain belt. In the first paper of the section, R. O. Greiling (Heidelberg) describes the Middle Allochthon of Vasterbotten, northern Sweden, where tectonic windows through the Upper Allochthon (Seve Nappe) show that the Middle Allochthon has a similar lithostratigraphy to that of the Stalon Nappe Complex of the eastern Caledonian margin but with a more ductile deformation and metamorphosed to a higher grade following thrust emplacement. These relations are explained by suggesting that the window rocks were initially subducted beneath a colliding western plate but were later accreted to the base of the western plate and thrust with it. The thrust geometry of the windows, described as antiformal stacks, agrees with this model. The Middle Allochthon of the Caledonian margin in northern Sweden is described by R. O. Greiling and R. Kumpulainen (Heidelberg and Stockholm) who record two distinct metasedimentary units separated by a thick zone of mylonites interpreted as a lateral thrust ramp. Turbidites in the northern unit were derived from an unidentified igneous source to the east and cannot be correlated with other sequences in the Middle Allochthon. In another paper dealing with the northern Swedish Caledonides, L. Hansen (Uppsala) describes down-to-the-west normal faults cutting the autochthonous Cambrian sediments in the tunnel sections of the Vietas Hydropower Station, but themselves being truncated by the basal decollement of the Lower Allochthon.