Andean Magmatism And Its Tectonic Setting

"The objective of this volume is to examine the Cenozoic tectonic and magmatic evolution from the arc to the retroarc of a distinctive end-member of the Andean accretionary orogen between 35*S and 39*S. The evolution of the Andes in this region provides an outstanding case study of an orogen where periods of contraction and extension, crustal shortening and normal faulting, and differences in retroarc volcanism reflect a tectonic regime that alternates in space and time. Structural, magmatic, and paleogeographic patterns correlate strongly with the dynamics of the subduction zone. The region includes the Neuquen basin which is one of the most prolific of the Central Andes. The tectonic setting is important in understanding hydrocarbon systems of the sub-Andean basin and the potential for ore deposits in the cordillera. The book is fundamental for researchers working on tectonics and magmatism in Andean type systems as well as those involved in exploration."--Publisher's website.

Andean Tectonics addresses the geologic evolution of the Andes Mountains, the prime global example of subduction-related mountain building. The Andes Mountains form one of the most extensive orogenic belts on Earth, spanning approximately an 8,000-km distance along the western edge of South America, from ~10°N to ~55°S. The tectonic history of the Andes involves a rich record of diverse geological processes, including crustal deformation, magmatism, sedimentary basin evolution, and climatic interactions. This book addresses the range of Andean tectonic processes and their temporal and spatial variations. An improved understanding of these processes is fundamental not only to the Andes but also to other major orogenic systems associated with subduction of the oceanic lithosphere. Andean Tectonics is a critical resource for researchers interested in the causes and consequences of Andean-type orogenesis and the long-term evolution of fold-thrust belts, magmatic arcs, and forearc and foreland basins. Evaluates the history of Andean mountain building over the past 300 million years Integrates recent studies and new perspectives on the complementary records of deformation, magmatism, and sedimentary basin evolution and their interactions in time and space Provides insight into the development of the northern, central, and southern Andes, which have typically been considered in isolation

In this Special Paper, Hildebrand and Whalen present a big-picture, paradigm-busting synthesis that examines the tectonic setting, temporal relations, and geochemistry of many plutons within Cretaceous batholithic terranes of the North American Cordillera. In addition to their compelling tectonic synthesis, they argue that most of the batholiths are not products of arc magmatism as commonly believed, but instead were formed by slab failure during and after collision. They show that slab window and Precambrian TTG suites share many geochemical similarities with Cretaceous slab failure rocks. Geochemical and isotopic data indicate that the slab failure magmas were derived dominantly from the mantle and thus have been one of the largest contributors to growth of continental crust. The authors also note that slab failure plutons emplaced into the epizone are commonly associated with Cu-Au porphyries, as well as Li-Cs-Ta pegmatites.

together with contributions by invited geoscientists The Central Andes, whose orogenic activity is so impressively documented by recent volcanism and and counterparts from other countries, during a workshop held in Berlin, 23-25 May 1990. A great earthquakes, have always attracted the attention of geoscientists. This interest became even more accen number of the papers presented at this workshop are tuated since, a quarter of a century ago, Plate included in this volume. While most of the chapters Tectonics became the basis for the New Global refer regionally to the segment of the southern Andes Tectonics concept, in which this huge mountain range mentioned above, others treat general aspects or deal was the most spectacular example of an active conti with Andean regions farther south, thus showing not only that the structures of this mountain range can be nental margin. Thus, in addition to the continuing research work by South American and foreign geo followed to more distant parts but also that there are scientists dedicated mostly to regional and economic significant structural variations along strike. problems, a great number of special research pro Like other books which originate from workshops grammes were initiated aiming at a better understand and are comprised of contributions from many ing of the processes acting at a convergent plate authors, also this one cannot give a complete and margin. well-balanced view of the scientific subject dealt In 1982, the earth science institutes of the Freie with, in this case the southern Central Andes.

This book provides a comprehensive overview of the geological evolution of the Northern Andes and contiguous shield areas, with a focus upon Colombia. Updated geological interpretations are supported by modern lithogeochemical, seismic, gravity and magnetic data and radiogenic isotope and radiometric age determinations. The composite data permits a detailed interpretation of the tectono-magmatic history of the Northern Andean Block, including the Andes of Colombia, northern Ecuador, western Venezuela and eastern Panamá. Tectonic reconstructions based upon characterization of more than thirty litho-tectonic and morpho-structural units, terrane assemblages and tectonic realms, and their bounding suture and fault systems, highlight the intimate and complementary Mesozoic-Cenozoic history of the Northern Andean Block and the Pacific and Caribbean Plates. The complex nature of Northern Andean assembly contrasts with ‘‘classical’’ Central Andean ‘‘Cordilleran-type’’ orogenic models. Differences render the application of typical Cordilleran-type models inappropriate for the Colombian Andes. The importance of underlying Proterozoic through mid-Mesozoic elements, in the development of Meso-Cenozoic Northern Andean orogeny-phase tectonic configurations is analyzed in the light of spatial-temporal studies and reconstructions related to basin formation, sedimentation, deformation, uplift mechanisms, structural style and magmatic evolution. The pre-Andean architecture of north western South America has played a pre-determinative role in the development of the Northern Andean orogenic system. 16 contributions analyze key stratigraphic, structural, metamorphic, magmatic and tectonic questions, and provide solutions as far as the most recent published field-based studies permit. The volume provides geological interpretations and tectonic models which contrast with repetitive theoretical proposals frequently found in the available literature.

Destructive plate margin magmagenesis is one of the most intensely studied and widely debated topics in the earth sciences at present. Calc-alkaline volcanic and plutonic rocks in orogenic settings exhibit such a diversity of composition and character that the subducted oceanic lithosphere, the overlying 'enriched' lithospheric mantle and the lower continental crust all have been advocated recently as the primary source region for island-arc and continental-margin basaltic to andesitic magmas. The role of the upper continental crust is also a matter of continuing controversy. It is clear that crustal contamination is a common, but not universal, feature of destructive plate margin magmatism. Whether this contamination is introduced at source by subduction-related processes or occurs during magma transit by bulk anatexis and magma mixing, selective contamination or coupled fractional crystallization-assimilation mechanisms is central to most current discussions of andesite petrogenesis. This book presents a series of papers which directly address these and other important geological and geochemical problems within the context of the Mesozoic-Cenozoic calc-alkaline magmatism characteristic of the Andean Cordillera of western South America. Although it is aimed primarily at postgraduate students and researchers familiar with the Andes, it is also a useful general reference for workers in other fields who wish to gain an insight into current thoughts, ideas and speculations on 'andesitic' magmatism at destructive plate margins.