This volume contains a representative cross-section of current research on extension-related arc volcanism in the broadest sense, and is intended to stimulate further discussion and research into the complex tectonics and petrology of covergent plate margins. Papers include: Subduction systems and magmatism; Geochemistry of Lau Basin volcanic rocks: influence of ridge segmentation and arc proximity; Gamilaroi Terrane: A Devonian rifted intra-oceanic island-arc assemblage, NSW, Australia; Neogene volcanoes of Chios, Greece: the relative importance of subduction and back-arc extension; and others.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 88. This volume focuses on the volcanic, fluid, sedimentary, and tectonic processes occurring in the trencharc-backarc systems of the western Pacific—a natural regional focus for studies of these themes. The results of ocean drilling and associated site surveys in the western Pacific have brought fundamental changes to our understanding of volcanism, crustal deformation, fluid circulation, and sedimentation in active margins and marginal basins. Our goal here is to synthesize the results of ocean drilling in a multi-disciplinary manner, including a comparison of the findings from drilling legs having similar themes, and to emphasize the significance of these results to the broader geoscience community.

This volume aims at providing answers to some puzzling questions concerning the formation and the behavior of collapse calderas by exploring our current understanding of these complex geological processes. Addressed are problems such as:- How do collapse calderas form? - What are the conditions to create fractures and slip along them to initiate caldera collapse and when are these conditions fulfilled? - How do these conditions relate to explosive volcanism?- Most products of large caldera-forming eruptions show evidence for pre-eruptive reheating. Is this a pre-requisite to produce large volume eruptions and large calderas?- What are the time-scales behind caldera processes? - How long does it take magma to reach conditions ripe enough to generate a caldera-forming eruption?- What is the mechanical behavior of magma chamber walls during caldera collapse? Elastic, viscoelastic, or rigid? - Do calderas form by underpressure following a certain level of magma withdrawal from a reservoir, or by magma chamber loading due to deep doming (underplating), or both?- How to interpret unrest signals in active caldera systems?- How can we use information from caldera monitoring to forecast volcanic phenomena?In the form of 14 contributions from various disciplines this book samples the state-of-the-art of caldera studies and identifies still unresolved key issues that need dedicated cross-boundary and multidisciplinary efforts in the years to come. - International contributions from leading experts - Updates and informs on all the latest developments - Highlights hot topic areas and identifies and analyzes unresolved key issues

Recent developments have shown that many full and partial ophiolites are preserved in Precambrian cratons. This book provides a comprehensive description and discussion of the field aspects, geochemistry, geochronology and structure of the best of these ophiolites. It also presents syntheses of the characteristics of ophiolites of different ages, and an analysis of what the characteristics of these ophiolites mean for the thermal and chemical evolution of the earth. This title emphasizes new studies of Precambrian Geology that have documented ophiolites, ophiolitic fragments, and ophiolitic melanges in many Precambrian terranes. Each chapter focuses on individual Precambrian ophiolites or regions with numerous Precambrian ophiolites, and covers field aspects, petrology, geochemistry, geochronology, and other descriptive aspects of these ophiolites, it also delves into more theoretical and speculative aspects about the interpretation of the significance of these ancient ophiolites.

This book presents the most relevant basaltic plateau exposures in the provinces of Neuquén (northern Patagonia) and Santa Cruz (southern Patagonia), and analyzes their geomorphological and morphometric characteristics. The existence of wetland ecosystems near the volcanic plateaus is quantified, thus providing indexes that describe the quantitative relationships between these landscape features. These indexes also make it possible to estimate the development of these wetlands in non-surveyed areas, opening the door for studying remote, isolated areas by means of remote sensing images. In turn, the book proposes a numerical classification system for this type of landscape that summarizes the main geomorphological and hydrological characteristics.teristics.

Kent C. Condie

This book is written by 16 experienced geologists with first hand knowledge of the geology of Iraq and deals with all aspects of the country's geology. The aims of the book are to present a synthesis of the geological history of Iraq and a description of its economic geology, and to provide a key reference for both students and professional geologists. It updates the text books of Buday (1980) and Buday and Jassim (1987). The book includes previously unpublished information collected during the regional geological surveys of Iraq carried out from 1970 to 1990. Each chapter has been extensively edited to create a concise text. The stratigraphy of Iraq is placed within a consistent tectonostratigraphic framework.

The 32 papers in this volume examine the mode and nature of igneous, metamorphic, tectonic, sedimentological, and biological processes associated with the evolution of oceanic crust in different tectonic settings in Earth history as revealed in various ophiolites and ophiolite belts around the world, and the geodynamic significance of these ophiolites in the evolution of different orogenic systems. Divided into six thematic sections, the book presents a wealth of new data and syntheses from mainly Phanerozoic ophiolites around the world.