Sedimentation Tectonics And Eustasy

Over the last ten years, seismic and sequence stratigraphic studies have emphasized the role of worldwide fluctuations in sea level in controlling patterns of sedimentation. Widely recognized cycles of coastal onlap are thought to have been caused by such global changes. This postgraduate and reference text contains contributions from an international team of specialists. The book is based upon an IAS meeting which focused attention on the situation at active plate margins, covering three major themes: the underlying mechanics and rates of relative sea-level change at active plate margins; the interaction of eustatic and tectonic processes at modern margins; recognition of the products in the sedimentary record and possible criteria for distinguishing global eustatic from local tectonic effects. This book is intended for those studying and working in sedimentology, basin analysis, exploration geophysics and petroleum geology.

Sequence stratigraphy has advanced considerably since the early applications of the concepts on seismic data. It attempts to discern the migration of facies re sulting from changes in a combination of factors such as, sea level, tectonics, climate and sediment flux, and integrates it with a meaningful chronostratigraphy. The stratigraphic record is envisioned as a framework of repetitive packages of genetically-related strata, formed in response to the shifting base level, in which the locus of deposition of various sediment types may be anticipated. This attribute is rapidly promoting sequence stratigraphy as an indispensable tool for prediction of facies in exploration and production geology. In hydrocarbon exploration the application of sequence stratigraphy has ranged from anticipating reservoir- and source-rock distribution to predicting carbonate diagenesis, porosity and permeability. The capability to anticipate vertical and lateral distribution of facies and reservoir sands in the basinal, shoreface, incised valley-fill and regressive settings alone has been a great asset for exploration. In frontier areas, where data are often limited to seismic lines, sequence-stratigraphic methodology has helped determine the timing and of types of unconformities and anticipate transgressive- and regressive-prone intervals. In production it is aiding in field development by providing improved source and seal predictions for secondary oil recovery. A recognition of stratigraphic causes of poor recovery through improved understanding of internal stratal architecture can lead to new well recompletions and enhanced exploitation in existing fields. The sequence-stratigraphic discipline is in a state of rapid expansion.

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.

Stratigraphers and sedimentologists who are presently describing and interpreting the infill of sedimentary basins are generally agreed that it is difficult to disentangle the signatures of tectonic processes from those of climate and eustatic sea level change in the resultant rock succession. Until better criteria are developed to distinguish between the roles played by the major variables, it is still most useful to document and interpret basin-fill architectures where we know, from independent evidence, that one of the main controls is likely to have been a major contributor. This book contains a collection of papers describing situations where the tectonic setting is fairly well established, and it can be assumed that at least the tectonic factor has contributed to the resultant signatures.

This book is intended as a practical handbook for those engaged in the task of analyzing the paleogeographic evolution of ancient sedimentary basins. The science of stratigraphy and sedimentology is central to such endeavors, but although several excellent textbooks on sedimentology have appeared in recent years little has been written about modern stratigraphic methods. Sedimentology textbooks tend to take a theoretical approach, building from physical and chemical theory and studies of mod ern environments. It is commonly difficult to apply this information to practical problems in ancient rocks, and very little guidance is given on methods of observation, mapping and interpretation. In this book theory is downplayed and the emphasis is on what a geologist can actually see in outcrops, well records, and cores, and what can be ob tained using geophysical techniques. A new approach is taken to stratigraphy, which attempts to explain the genesis of lithostratigraphic units and to de-emphasize the importance of formal description and nam ing. There are also sections explaining principles of facies analysis, basin mapping methods, depositional systems, and the study of basin thermal history, so important to the genesis of fuels and minerals. Lastly, an at tempt is made to tie everything together by considering basins in the con text of plate tectonics and eustatic sea level changes.

Sedimentary basins with a marine connection show significant stratigraphic variations that result from eustatic sea-level fluctuation. Other key factors controlling stratigraphy include the availability of sediment and the role of tectonically induced subsidence and uplift. Tectonic activity is important as a causal mechanism for the production of certain regional and local-scale sequence boundaries, generating accommodation space, altering base levels and controlling source areas. These papers address the relative roles of tectonics, eustasy and sediment supply in generating stratigraphy.