From Subduction To Collision

Subduction is a major process that plays a first-order role in the dynamics of the Earth. The sinking of cold lithosphere into the mantle is thought by many authors to be the most important source of energy for plates driving forces. It also deeply modifies the thermal and chemical structure of the mantle, producing arc volcanism and is responsible for the release of most of the seismic energy on Earth. There has been considerable achievements done during the past decades regarding the complex interactions between the various processes acting in subduction zones. This volume contains a collection of contributions that were presented in June 2007 in Montpellier (France) during a conference that gave a state of the art panorama and discussed the perspectives about "Subduction Zone Geodynamics". The papers included in this special volume offer a unique multidisciplinary picture of the recent research on subduction zones geodynamics. They are organized into five main topics: Subduction zone geodynamics, Seismic tomography and anisotropy, Great subduction zone earthquakes, Seismogenic zone characterization, Continental and ridge subduction processes. Each of the 13 papers collected in the present volume is primarily concerned with one of these topics. However, it is important to highlight that papers always treat more than one topic so that all are related lighting on different aspects of the complex and fascinating subduction zones geodynamics.

Arc-continent collision has been one of the important tectonic processes in the formation of mountain belts throughout geological time, and it continues to be so today along tectonically active plate boundaries such as those in the SW Pacific or the Caribbean. Arc-continent collision is thought to have been one of the most important process involved in the growth of the continental crust over geological time, and may also play an important role in its recycling back into the mantle via subduction. Understanding the geological processes that take place during arc-continent collision is therefore of importance for our understanding of how collisional orogens evolve and how the continental crust grows or is destroyed. Furthermore, zones of arc-continent collision are producers of much of the worlds primary economic wealth in the form of minerals, so understanding the processes that take place during these tectonic events is of importance in modeling how this mineral wealth is formed and preserved. This book brings together seventeen papers that are dedicated to the investigation of the tectonic processes that take place during arc-continent collision. It is divided into four sections that deal firstly with the main players involved in any arc-continent collision; the continental margin, the subduction zone, and finally the volcanic arc and its mineral deposits. The second section presents eight examples of arc-continent collisions that range from being currently active through to Palaeoproterozoic in age. The third section contains two papers, one that deals with the obduction of large-slab ophiolites and a second that presents a wide range of physical models of arc-continent collision. The fourth section brings everything that comes before together into a discussion of the processes of arc-continent collision.

Subduction dynamics has been actively studied through seismology, mineral physics, and laboratory and numerical experiments. Understanding the dynamics of the subducting slab is critical to a better understanding of the primary societally relevant natural hazards emerging from our planetary interior, the megathrust earthquakes and consequent tsunamis. Subduction Dynamics is the result of a meeting that was held between August 19 and 22, 2012 on Jeju island, South Korea, where about fifty researchers from East Asia, North America and Europe met. Chapters treat diverse topics ranging from the response of the ionosphere to earthquake and tsunamis, to the origin of mid-continental volcanism thousands kilometers distant from the subduction zone, from the mysterious deep earthquakes triggered in the interior of the descending slabs, to the detailed pattern of accretionary wedges in convergent zones, from the induced mantle flow in the deep mantle, to the nature of the paradigms of earthquake occurrence, showing that all of them ultimately are due to the subduction process. Volume highlights include: Multidisciplinary research involving geology, mineral physics, geophysics and geodynamics Extremely large-scale numerical models with sliate-of-the art high performance computing facilities Overview of exceptional three-dimensional dynamic representation of the evolution of the Earth interiors and of the earthquake and subsequent tsunami dynamics Global risk assessment strategies in predicting natural disasters This volume is a valuable contribution in earth and environmental sciences that will assist with understanding the mechanisms behind plate tectonics and predicting and mitigating future natural hazards like earthquakes, volcanoes and tsunamis.

"The American Cordilleras form a continuous orogen that extends for 12,500 km along the eastern flank of the Pacific Ocean from Arctic to Antarctic latitudes as an integral part of the circum-Pacific orogenic belt. Following two summary chapters on the overall anatomy and evolution of North and South American segments of the orogenic system, this volume includes ten seminal chapters dealing with salient aspects of the key geodynamic processes that have accompanied Cordilleran geotectonic evolution: forearc terrane accretion, arc magmatism, shallow subduction, and backarc intracontinental deformation. The papers in this volume were selected from those presented at the 2006 Backbone of the Americas Meeting, which was sponsored jointly by multiple North and South American geological societies in Mendoza, Argentina."--pub. desc.

Investigating the complex interplay between tectonics and sedimentation is a key endeavor in modern earth science. Many of the world's leading researchers in this field have been brought together in this volume to provide concise overviews of the current state of the subject. The plate tectonic revolution of the 1960's provided the framework for detailed models on the structure of orogens and basins, summarized in a 1995 textbook edited by Busby and Ingersoll. Tectonics of Sedimentary Basins: Recent Advances focuses on key topics or areas where the greatest strides forward have been made, while also providing on-line access to the comprehensive 1995 book. Breakthroughs in new techniques are described in Section 1, including detrital zircon geochronology, cosmogenic nuclide dating, magnetostratigraphy, 3-D seismic, and basin modelling. Section 2 presents the new models for rift, post-rift, transtensional and strike slip basin settings. Section 3 addresses the latest ideas in convergent margin tectonics, including the sedimentary record of subduction intiation and subduction, flat-slab subduction, and arc-continent collision; it then moves inboard to forearc basins and intra-arc basins, and ends with a series of papers formed under compessional strain regimes, as well as post-orogenic intramontane basins. Section 4 examines the origin of plate interior basins, and the sedimentary record of supercontinent formation. This book is required reading for any advanced student or professional interested in sedimentology, plate tectonics, or petroleum geoscience. Additional resources for this book can be found at: www.wiley.com/go/busby/sedimentarybasins.

The Mediterranean and northern Arabian regions provide a unique natural laboratory to constrain geodynamics associated with arc-continent and continent-continent collision and subsequent orogenic collapse by analysing regional and temporal distributions of the various elements in the geological archive. This book combines thirteen new contributions that highlight timing and distribution of the Cretaceous to Recent evolution of the Calabrian, Carpathian, Aegean and Anatolian segments of the Africa-Arabia-Eurasia subduction zone. These are subdivided into five papers documenting the timing and kinematics of Cretaceous arc-continent collision, and Eocene and Miocene continent-continent collision in Anatolia, with westward extrusion of Anatolia as a result. Eight papers provide an overview and new data from stratigraphy, structure, metamorphism and magmatism, covering the geological consequences of the largely Neogene collapse that characterizes the segments of interest, in response to late stage reorganization of the subduction zone, and the roll-back and break-off of (segments of) the subducting slab.

The Tethyan orogenic belt extends from the western Mediterranean to southeast Asia and the exposed rocks and landscapes present today are records of multiple orogenic events. The most recent, the Alpine-Himalayan orogeny, evolved during the Mesozoic-Cenozoic closure of the Neotethys Ocean during the convergence of Gondwana with Laurasia. Over the last few decades, significant advances in geochemical and geochronological methods and their widespread application have created a high-resolution temporal framework that reveals that various proxy records of intercontinental collisions across the Alpine-Himalayan belt differ by tens of millions of years. Consequently, new questions have arisen, including how to unite these seemingly disparate records of subduction and collision into a temporally and spatially credible reconstruction.The work set forth in this dissertation situates the Anatolian segment of the Alpine-Himalayan orogenic belt in the broader discussion on the timescales and drivers of intercontinental collisions and their effect on biogeography. The various suture zones in Anatolia that delineate former branches of the Neotethys Ocean have complex and unresolved geodynamic reconstructions, including single and double subduction systems, pre-collisional subduction of lower plate terranes, forearc and backarc extension, ophiolite obduction, and protracted collisional deformation. Resolving these competing geodynamic scenarios is essential for paleogeographic reconstructions for refining the mechanistic links between subduction, accretion, and collision processes. Furthermore, the role of collisions in the early Cenozoic Anatolian archipelago in facilitating mammalian faunal exchange, including anthropoid primates, between Europe, Asia and Africa relies on accurate paleogeographic and topographic reconstructions. Near-continuous deposition in western Anatolian sedimentary basins preserves an unbroken record of subduction through collision that is unparalleled across the Tethyan realm. This dissertation utilizes this sedimentary record by providing new stratigraphic, sedimentologic, petro- and geochronologic, and sedimentary provenance constraints on the chronology of collision along the İzmir-Ankara-Erzincansuture zone and the Intra-Pontide suture zone in western Anatolia. The sedimentary basin reconstructions presented in this dissertation, synthesized with existing datasets, provide a model for multi-stage continental collision that is applicable across the Tethyan realm. Detrital zircon U-Pb geochronology and sandstone petrography data from the forearc-foreland Central Sakarya Basin in western Anatolia indicate that collision along the İzmir-Ankara-Erzincan suture zone began at 76 Ma, recorded as a major shift in provenance and the onset of exhumation, sediment recycling, and suture zone uplift. Furthermore, new stratigraphy, sedimentology and sedimentary provenance studies from the foreland Sarıcakaya Basin in western Anatolia reveal that significant upper plate deformation was delayed by 20 Myr. By 54 Ma, the Central Sakarya Basin was partitioned by a basement-involved thrust fault, and flexural loading from the thrust created the Sarıcakaya Basin. This 20 Myr protracted collision along the İzmir-Ankara-Erzincan suture zone can be explained by three Tethyan models for multi-stage collision: slab breakoff, relict basin closure, or subduction of thinned passive margin lithosphere. The validity of relict basin closure is evaluated using detrital zircon U-Pb geochronology, detrital rutile U-Pb and trace element geochemistry, and sandstone petrography from sedimentary units across the Intra-Pontide suture. A major shift in provenance in the Paleocene-early Eocene caused by accretionary prism exhumation demonstrates that collisional stress from incipient İzmir-Ankara-Erzincan suturing could have been taken up by the Intra-Pontide suture. Furthermore, the sedimentary evolution of both suture zones reveals that the uplift and exhumation of the accretionary prism is an important signal of collisional geodynamics. Even though continental collisions assembled a larger landmass that favored trans-Tethyan mammalian dispersals, for 30 Myr after initial collision, collisional deformation did not form significant topography; marine barriers and endemism persisted until the late Eocene. Accretionary orogenies, like those in Anatolia, likely have an important control on biogeography. The findings presented in this dissertation bear on fundamental questions regarding the interconnectedness of Earth systems, including the effects of plate tectonics, the causes of topographic change, and the geologic drivers of biodiversity.

This book is devoted to the quantitative physical modeling of subduction and subduction-related processes. It presents a coherent description of the modeling method (including similarity criteria, and a novel applied experimental technique), results from model experiments, theoretical analysis of results on the basis of continuum mechanics, and their geodynamic interpretation. Subduction is modeled in general as well as applied to particular regions using both 2-D and 3-D approaches, with both slab-push and slab-pull driving forces. The modeling covers all stages from subduction initiation to `death', different regimes of subduction producing back arc extension and compression, blocking of subduction and jumps of subduction zone, arc-continent collision and continental subduction. This work is for geologists and geophysicists interested in geodynamics of the convergent plate boundaries and in mechanics of the lithosphere.