Download or read book Crustal Architecture and Magma Dynamics in a Large Continental Magmatic System written by Dale H. Burns and published by . This book was released on 2014 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ~1 Myr history of the Purico-Chascon volcanic complex (PCVC) records significant changes in the production and storage of magmas in the crust. At ~1 Ma activity at the PCVC initiated with the eruption of a large 80-100 km3 crystal-rich dacite ignimbrite with restricted whole rock 87Sr/86Sr isotope ratios between 0.7085-0.7090. In-situ analyses of plagioclase from the Purico ignimbrite have 87Sr/86Sr=0.7087-0.7090. The dacite magma accumulated and evolved at relatively low temperatures around 800-850 °C in the upper crust at 4-8 km depth. Minor andesite and rhyolite pumice late in the sequence have similar restricted whole rock 87Sr/86Sr=0.7089-0.7091. The radiogenic isotopes of this 0.98 Ma activity are consistent with all these compositions resulting from 50 to 70% crustal assimilation by parental Central Andean "baseline" magmas at depths between 15-30 km. The final eruptions at the PCVC occurred 0.18 Ma producing three small 5 km3 crystal-rich dacite lava domes with whole rock 87Sr/86Sr ratios 0.7075 to 0.7081 containing abundant basaltic-andesite enclaves with whole rock 87Sr/86Sr ratios of 0.7057- 0.7061. Plagioclase and amphibole from samples from the largest of these domes, Cerro Chascon, record two distinct magmatic environments; an upper crustal environment identical to the Purico ignimbrite and a second deeper, ~15-20 km depth, higher temperature (~922-1001 °C) environment consistent with conditions recorded in the basaltic andesite enclaves. Accordingly, plagioclase cores in the host dacite lava and enclaves have enriched in-situ 87Sr/86Sr isotopic compositions of 0.7083 to 0.7095 while plagioclase rims and microphenocrysts in the enclaves have 87Sr/86Sr isotope ratios from 0.7057 to 0.7065 and 0.7062 to 0.7064 respectively. Lavas from Cerro Chascon also contain abundant Fo82 olivine with spinel and basaltic melt inclusions that crystallized in a deep crustal environment (1250 °C) consistent with a lower crustal MASH zone. The high baseline isotopic ratios observed in bulk rock and plagioclase crystals from Cerro Chascon (0.7057-0.7065) are consistent with MASH processes. The evolution of the PCVC is a microcosm of the Andean arc in this region where, from 10 - 1 Ma, dominantly dacitic upper crustal magmatism of the Altiplano-Puna Volcanic Complex ignimbrite flare-up persisted until ~1 Ma, when smaller volume, more heterogeneous and less isotopically enriched basaltic andesite to dacite composite volcanoes signal a return to steady state arc volcanism. I suggest that the PCVC captures the transition of the Andean arc from flare-up to steady state. The temporal trend at the PCVC is consistent with a waning thermal flux. High magmatic fluxes during the flare-up would have resulted in elevated geothermal gradients and efficient crustal processing leading to a dominantly dacitic upper crust (0 to 35 km) that fed the large volume Purico ignimbrite. As magmatic flux and thermal energy wanes, crustal isotherms relax resulting in greater thermal contrast between parental magmas, crust and remnant upper crustal dacite magma. This manifests in more heterogeneity and the survival of less isotopically enriched magmas in the upper crust. These arc scale magma dynamics are recorded even at the intra-crystalline scale. Individual crystals from Cerro Chascon also record vital information on the crystallization and evolution of mantle-derived magmas in continental magmatic arcs. Fo2 olivine, olivine hosted spinel, and basaltic melt inclusions record the crystallization of olivine at1250 °C in conditions consistent with a lower crustal (~70 km depth) MASH zone. Another significant crystallization event appears to have occurred at ~20 km depth, characterized by the crystallization of high An plagioclase (An--24) at ~1100-1050 °C followed by high-Al amphibole (~12-15 wt.% Al2O3) at ~1000-950 °C. The appearance of amphibole on the liquidus appears to have resulted from a nearly 2-fold increase in melt water content following ~45% crystallization of high An plagioclase. Following this extensive crystallization the highly crystalline mafic magma ascended into the upper crust and interacted with the remnant crystal mush from the Purico ignimbrite magma reservoir. Low An plagioclase (An3955), low Al amphibole (~6-9 wt.% Al2O3), sanidine, and biotite retain the chemical composition of the Purico ignimbrite magma, whereas, olivine, high An plagioclase, and high Al amphibole record the mafic recharge magma. The textures and compositions observed in Cerro Chascon are common in both continental and oceanic magmatic arcs worldwide and I propose that multiple crystallization events and upper crustal assimilation are fundamental processes intrinsic to arc magmatism. I have also used in situ 87Sr/86Sr isotope ratios in plagioclase from andesite, dacite, and rhyolite pumice from the ~1 Ma Purico ignimbrite to determine the cause for compositional zoning in the Purico ignimbrite magma reservoir. Andesite pumice contains two texturally, compositionally, and isotopically distinct types of plagioclase, small (500 [micro]m) subhedral to euhedral crystals with high MgO (130-490 ppm) and low 87Sr/86r crystals (0.7076-0.7084) record a hot (900 °C) andesite magma derived from an ~20 km deep magma reservoir. In contrast, the second type of plagioclase in the andesite appear to broken fragments of larger crystals and have significantly lower MgO (90-240 ppm), higher 87Sr/86Sr (0.7096-0.7114), and appears to be derived from the lower temperature (crystallized at ~800-900 °C), upper crustal (10 km) plutonic basement. Dacite pumice also contains two texturally and compositionally distinct types of plagioclase. However, both types have very restricted MgO (b.d.l.-200 ppm) and 87Sr/86Sr (0.7085-0.7095) ratios and appear to have grown at ~850°C. These crystals are also significantly larger (1000 [micro]m) than plagioclase from the andesite pumice and have clear euhedral rims. Rhyolite pumice from the Purico ignimbrite also contains distinct types of plagioclase. Both types of plagioclase are similar in size (

Download or read book Crustal Magmatic System Evolution written by Matteo Masotta and published by John Wiley & Sons. This book was released on 2021-07-07 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive picture of the architecture of crustal magmatic systems The composition of igneous rocks – their minerals, melts, and fluids – reveals the physical and chemical conditions under which magmas form, evolve, interact, and move from the Earth’s mantle through the crust. These magma dynamics affect processes on the surface including crustal growth and eruptive behaviour of volcanoes. Crustal Magmatic System Evolution: Anatomy, Architecture, and Physico-Chemical Processes uses analytical, experimental, and numerical approaches to explore the diversity of crustal processes from magma differentiation and assimilation to eruption at the surface. Volume highlights include: Physical and chemical parameterization of crustal magmatic systems Experimental, theoretical and modelling approaches targeting crustal magmatic processes Timescales of crustal magmatic processes, including storage, recharge, and ascent through volcanic conduits The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about this book in a Q&A with the Editors.

Download or read book Magma Dynamics and Evolution in Continental Arcs written by Stephanie B. Grocke and published by . This book was released on 2014 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Constraining the magma evolution and dynamics that lead to the eruption of large volume continental arc systems is fundamental to our understanding of continental crust formation. An investigation into the magmagenesis that results in the formation of the Central Volcanic Zone (CVZ) in the Andes of South America, situated atop overthickened continental crust (80 km thick), provides insights into large volume silicic magma reservoirs and how they evolve prior to their potentially catastrophic explosive eruption on the Earth's surface. A focused case study of the Cerro Guacha Caldera Complex (CGCC), a nested volcanic system in the Altiplano-Puna Volcanic Complex of SW Bolivia, puts constraints on the progressive stages of development of the magmatic underpinnings of the caldera complex. Whole rock data, in conjunction with matrix glass, mineral compositions and melt inclusions, are used to infer processes that gave rise to the formation of the Guacha II Caldera, the younger of two main collapse features, formed from the supereruption of the Tara Ignimbrite (800 km3 DRE) at 3.49 ± 0.01 Ma. The eruptive history of the Guacha II Caldera from pre-caldera to post-caldera is fully represented, allowing magma dynamics associated with a complete caldera cycle, from pre-climactic (catastrophic caldera-forming) magma accumulation through to post-climactic effusions that are part of the resurgent history of the caldera, to be examined. Analysis of the high-K, calcalkaline suite of andesite to high Si-rhyolite Tara pyroclastic deposits provides insights into the storage conditions and magma dynamics leading up to a supervolcanic eruption. The Tara eruptive products define a liquid line of descent from the basal andesite lava (62 wt % SiO2) to the high-silica rhyolite post-collapse Chajnantor Dome lava (78 wt.% SiO2), with major and trace element trends consistent with fractionation of quartz, plagioclase, orthopyroxene, hornblende, sanidine, biotite, and Fe-Ti oxides. Isotope ratios span a significant range in 87Sr/86Sr (0.709 to 0.713) and a relatively narrow range in 143Nd/144Nd (0.512179 to 0.512297) and [delta]18O[subscript (qtz)] (+8.68 to +8.43[per mil]). These data require AFC processes to explain both the isotope and trace element compositions in the Tara magmas. Geothermobarometry reveals pre-eruptive temperatures (~800 - 950 °C), pressures (~200 MPa), and H2O contents (~5 wt%) that suggest storage of a large-volume rhyodacite magma reservoir between 5 and 9 km depth in the upper crust. Analyses of quartz-hosted melt inclusions from pumices in the climactic plinian and ignimbrite phase of eruption reveal that pre-eruptive H2O contents in the plinian pumice overlap with those in the ignimbrite pumice (2.2 to 6.0 and 2.1 to 5.4 wt.% H2O, respectively). The ignimbrite magma, however, contains higher CO2 (630 versus

Download or read book Magmatic Systems written by Michael P. Ryan and published by Academic Press. This book was released on 1994-08-26 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: With its integrated and cohesive coverage of the current research, Magmatic Systems skillfully explores the physical processes, mechanics, and dynamics of volcanism. The text utilizes a synthesized perspective--theoretical, experimental, and observational--to address the powerful regulatory mechanisms controlling the movement of melts and cooling, with emphasis on mantle plumes, mid-ocean ridges, and intraplate magmatism. Further coverage of subduction zone magmatism includes:Fluid mechanics of mixed magma migrationInternal structure of active systemsGrain-scale melt flowRheology of partial meltsNumerical simulation of porous media melt migrationNonlinear (chaotic and fractal) processes in magma transportIn all, Magmatic Systems will prove invaluable reading to those in search of an interdisciplinary perspective on this active topic.Key Features* Fluid mechanics of magma migration from surface region to eruption site* Internal structure of active magmatic systems* Grain-scale melt flow in mantle plumes and beneath mid-ocean ridges* Physics of magmatic systems and magma dynamics

Download or read book Dynamic Magma Evolution written by Francesco Vetere and published by John Wiley & Sons. This book was released on 2021-01-07 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the complex physico-chemical processes involved in active volcanism and dynamic magmatism Understanding the magmatic processes responsible for the chemical and textural signatures of volcanic products and igneous rocks is crucial for monitoring, forecasting, and mitigating the impacts of volcanic activity. Dynamic Magma Evolution is a compilation of recent geochemical, petrological, physical, and thermodynamic studies. It combines field research, experimental results, theoretical approaches, unconventional and novel techniques, and computational modeling to present the latest developments in the field. Volume highlights include: Crystallization and degassing processes in magmatic environments Bubble and mineral nucleation and growth induced by cooling and decompression Kinetic processes during magma ascent to the surface Magma mixing, mingling, and recharge dynamics Geo-speedometer measurement of volcanic events Changes in magma rheology induced by mineral and volatile content The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Download or read book Chemical Physical and Temporal Evolution of Magmatic Systems written by L. Caricchi and published by Geological Society of London. This book was released on 2015-11-06 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of the physical and chemical processes that regulate the evolution of magmatic systems has improved tremendously since the foundations were laid down 100 years ago by Bowen. The concept of crustal magma chambers has progressively evolved from molten-rock vats to thermally, chemically and physically heterogeneous reservoirs that are kept active by the periodic injection of magma. This new model, while more complex, provides a better framework to interpret volcanic activity and decipher the information contained in intrusive and extrusive rocks. Igneous and metamorphic petrology, geochemistry, geochronology, and numerical modelling, all contributed towards this new picture of crustal magmatic systems. This book provides an overview of the wide range of approaches that can nowadays be used to understand the chemical, physical and temporal evolution of magmatic and volcanic systems.

Download or read book Dynamics of Crustal Magma Transfer Storage and Differentiation written by Catherine Annen and published by Geological Society of London. This book was released on 2008 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magmas are subject to a series of processes that lead to their differentiation during transfer through and storage within the Earth's crust. The depths and mechanisms of differentiation, the crustal contribution to magma generation through wall-rock assimilation, the rates and timescales of magma generation, transfer and storage, and how these link to the thermal state of the crust are subject to vivid debate and controversy. This volume presents a collection of research articles that provide a balanced overview of the diverse approaches available to elucidate these topics, and includes both theoretical models and case studies. By integrating petrological, geochemical and geophysical approaches, it provides new insights to the subject of magmatic processes operating within the Earth's crust, and reveals important links between subsurface processes and volcanism.

Download or read book Himalaya Dynamics of a Giant Tectonic Units and Structure of the Himalaya written by Rodolphe Cattin and published by John Wiley & Sons. This book was released on 2023-08-29 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Volcanic Processes written by Sarah A. Fagents and published by Cambridge University Press. This book was released on 2021-02-11 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the physical behavior of volcanoes is key to mitigating the hazards active volcanoes pose to the ever-increasing populations living nearby. The processes involved in volcanic eruptions are driven by a series of interlinked physical phenomena, and to fully understand these, volcanologists must employ various physics subdisciplines. This book provides the first advanced-level, one-stop resource examining the physics of volcanic behavior and reviewing the state-of-the-art in modeling volcanic processes. Each chapter begins by explaining simple modeling formulations and progresses to present cutting-edge research illustrated by case studies. Individual chapters cover subsurface magmatic processes through to eruption in various environments and conclude with the application of modeling to understanding the other volcanic planets of our Solar System. Providing an accessible and practical text for graduate students of physical volcanology, this book is also an important resource for researchers and professionals in the fields of volcanology, geophysics, geochemistry, petrology and natural hazards.

Download or read book Magma Supply and Storage in Volcanic Systems written by Tanya Marie Blacic and published by . This book was released on 2005 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure and Emplacement of High level Magmatic Systems written by Kenneth Thomson and published by Geological Society of London. This book was released on 2008 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are continual rounds of annual conferences, special sessions and other symposia that provide ample opportunity for researchers to convene and discuss igneous processes. However, the origin of laccoliths and sills continue to inspire and confound geologists. In one sense, this is surprising. After all, don't we know all we need to know about these rocks by now? As testified by the diverse range of topics covered in this volume, the answer is clearly 'no'. This book contains contributions on physical geology, igneous petrology, volcanology, structural geology, crustal mechanics and geophysics that cover the entire gambit of geological processes associated with the shallow emplacement of magma. High-level intrusions in sedimentary basins can also act as hydrocarbon reservoirs and as sources for thermal maturation. In drawing together a diversity of perspectives on the emplacement of sills, laccoliths and dykes we hope to advance further our understanding of their behaviour.

Download or read book Physical Geology of Shallow Magmatic Systems written by Christoph Breitkreuz and published by Springer. This book was released on 2018-03-23 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a high-level summary of shallow magmatic systems (dykes, sills and laccoliths) to support geoscience master and PhD students, scientists and practicing professionals. The product of the LASI (Laccoliths and Sills conference) workshop, it comprises thematic sections written by one or more experts on the respective field. It features reviews concerning the physical properties of magma, geotectonic settings, and the structure of subvolcanic systems, as well as case studies on the best-known systems. The book provides readers a broad and comprehensive understanding of the subvolcanic perspective on pluton growth, which is relevant for mineralogical processes as well as the genesis of mineral deposits.

Download or read book Volcanic Unrest written by Joachim Gottsmann and published by Springer. This book was released on 2018-12-18 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book summarizes the findings of the VUELCO project, a multi-disciplinary and cross-boundary research funded by the European Commission's 7th framework program. It comprises four broad topics: 1. The global significance of volcanic unrest 2. Geophysical and geochemical fingerprints of unrest and precursory activity 3. Magma dynamics leading to unrest phenomena 4. Bridging the gap between science and decision-making Volcanic unrest is a complex multi-hazard phenomenon. The fact that unrest may, or may not lead to an imminent eruption contributes significant uncertainty to short-term volcanic hazard and risk assessment. Although it is reasonable to assume that all eruptions are associated with precursory activity of some sort, the understanding of the causative links between subsurface processes, resulting unrest signals and imminent eruption is incomplete. When a volcano evolves from dormancy into a phase of unrest, important scientific, political and social questions need to be addressed. This book is aimed at graduate students, researchers of volcanic phenomena, professionals in volcanic hazard and risk assessment, observatory personnel, as well as emergency managers who wish to learn about the complex nature of volcanic unrest and how to utilize new findings to deal with unrest phenomena at scientific and emergency managing levels. This book is open access under a CC BY license.

Download or read book Volcanism in Antarctica 200 Million Years of Subduction Rifting and Continental Break up written by J.L. Smellie and published by Geological Society of London. This book was released on 2021-06-09 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: This memoir is the first to review all of Antarctica’s volcanism between 200 million years ago and the Present. The region is still volcanically active. The volume is an amalgamation of in-depth syntheses, which are presented within distinctly different tectonic settings. Each is described in terms of (1) the volcanology and eruptive palaeoenvironments; (2) petrology and origin of magma; and (3) active volcanism, including tephrochronology. Important volcanic episodes include: astonishingly voluminous mafic and felsic volcanic deposits associated with the Jurassic break-up of Gondwana; the construction and progressive demise of a major Jurassic to Present continental arc, including back-arc alkaline basalts and volcanism in a young ensialic marginal basin; Miocene to Pleistocene mafic volcanism associated with post-subduction slab-window formation; numerous Neogene alkaline volcanoes, including the massive Erebus volcano and its persistent phonolitic lava lake, that are widely distributed within and adjacent to one of the world’s major zones of lithospheric extension (the West Antarctic Rift System); and very young ultrapotassic volcanism erupted subglacially and forming a world-wide type example (Gaussberg).

Download or read book Crustal Deformation During Arc Flare Up Magmatism Field and Microstructural Analysis of a Mid Crustal Melt Enhanced Shear Zone written by John Bennett Gilbert and published by . This book was released on 2017 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study combines structural field data with microstructural observations in an analysis of a mid-crustal shear zone related to the emplacement of the Misty pluton during a high-flux magmatic event in Northern Fiordland, New Zealand. These high-flux magmatic events transport massive amounts of heat and material as they develop along accretionary continental margins, and represent a primary source of continental crust. Fiordland, New Zealand possesses, perhaps, the most extensive middle and lower crustal exposure of these systems on earth. Therefore, this study area provides a significant opportunity to understand processes of continental crust formation in the mid-crust and how these events relate to the broader construction of continents. Herein, I document the four-stage geologic history of the Cozette Burn field area. Pre-existing structures along the Gondwana accretionary margin hosted a regional flare-up magmatic event that produced the Misty pluton and several other large plutons of the West Fiordland Orthogneiss (WFO). This study primarily focuses on the mid-crustal emplacement of the Misty pluton during oblique convergence along the accretionary margin, forming the upper-amphibolite facies Misty Shear Zone (MSZ). The exposures of the MSZ within the Cozette Burn preserve rare structural relationships between host rock and the intrusive Misty pluton. Together, these structures developed during end-stage contractional tectonics that constructed a long-lived (~270+ Ma) composite batholith. Heterogeneous ductile shearing defines the MSZ, with microstructural evidence indicating an interplay of high-temperature crystal plastic deformation along with partial melting of host rock and melt channeling. This resulted in focused, melt-assisted shearing under regional transpressive deformation. These accommodative processes provided an efficient mechanism for moving heat, fluids and magma sourced from the lower crust/mantle boundary into the mid-crust during 15-25 km of crustal thickening related to arc flare-up magmatism. This flare up magmatism and MSZ formation occurred during the final stages of crustal thickening along Gondwana continental margin. High-strain, mylonitic- ultramylonitic shear zones developed in a later phase of deformation, cutting MSZ fabrics near contacts between the Misty pluton and host rock. These more localized shear zones can be attributed to either accommodation of localized melt-pressure buildup or the shift to extensional tectonics. Brittle faulting cut these structures with oblique-thrust in the Tertiary. These mid-crustal structures carry economic relevance: thickened-crust events along accretionary continental margins produce deep-crustal sourced, metal-bearing magmas that are transferred into mid-crust prior to their hydrothermal emplacement as ore deposits in the upper crust. The lasting influence of these processes warrants consideration when assessing continental crust architecture at all scales.

Download or read book Volumes Timescales and Frequency of Magmatic Processes in the Earth s Lithosphere Part I and II written by Mattia Pistone and published by Frontiers Media SA. This book was released on 2020-06-25 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Timescales of Magmatic Processes written by Anthony Dosseto and published by John Wiley & Sons. This book was released on 2011-06-24 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantifying the timescales of current geological processes is critical for constraining the physical mechanisms operating on the Earth today. Since the Earth’s origin 4.55 billion years ago magmatic processes have continued to shape the Earth, producing the major reservoirs that exist today (core, mantle, crust, oceans and atmosphere) and promoting their continued evolution. But key questions remain. When did the core form and how quickly? How are magmas produced in the mantle, and how rapidly do they travel towards the surface? How long do magmas reside in the crust, differentiating and interacting with the host rocks to yield the diverse set of igneous rocks we see today? How fast are volcanic gases such as carbon dioxide released into the atmosphere? This book addresses these and other questions by reviewing the latest advances in a wide range of Earth Science disciplines: from the measurement of short-lived radionuclides to the study of element diffusion in crystals and numerical modelling of magma behaviour. It will be invaluable reading for advanced undergraduate and graduate students, as well as igneous petrologists, mineralogists and geochemists involved in the study of igneous rocks and processes.