Signatur:
S 90.0095(180)
In:
Special paper / The Geological Society of America, 180
Materialart:
Schriftenreihen ausleihbar
Seiten:
211 Seiten
,
Illustrationen, graphische Darstellungen
ISBN:
0-8137-2180-6
Serie:
Special paper / The Geological Society of America 180
URL:
http://digitale-objekte.hbz-nrw.de/storage/2008/12/16/file_18/2691471.pdf
Sprache:
Englisch
Anmerkung:
Introduction / Charles E. Chapin and Wolfgang E. Elston
References cited
Ash-flow magmatism / Robert L. Smith
Abstract
Introduction
Volumes of ash-flow sheets
Size of magma chambers
Zoned magma chambers
Crater Lake, Oregon
Bandelier Tuff, New Mexico
SiO₂ and phenocryst variation in ash-flow sheets
Periodicity-volume-composition relationships
Discussion of model
Summary and conclusions
Acknowledgments
References cited
Cooling units and composite sheets in relation to caldera structure / Robert L. Christiansen
Abstract
Introduction
Examples of ash-flow-caldera relations
Mazama eruption and Crater Lake caldera
Bandelier Tuff and Valles-Toledo calderas
Thirsty Canyon Tuff and Black Mountain caldera
Timber Mountain-Oasis Valley caldera complex
Yellowstone Plateau volcanic field
General pattern of ash-flow-caldera relations
Acknowledgments
References cited
The Bishop Tuff: Evidence for the origin of compositional zonation in silicic magma chambers / Wes Hildreth
Abstract
Introduction
Eruptive sequence
Major units
Units of uncertain correlation
Summary of eruptive sequence
Eruptive temperatures
Accuracy and precision of T-fₒ₂ data
Mineralogy
Fe-Ti oxides
Quartz
Sanidine
Plagioclase
Biotite
Pyroxenes
Allanite
Zircon
Apatite
Pyrrhotite
Whole-rock chemistry
Major elements
Trace elements
Compositional gaps
Origin of the compositional zonation
Crystal settling
Assimilation
Basaltic underplating
Liquid immiscibility
Progressive partial melting
Trace elements during partial melting
Convection-driven thermogravitational diffusion
Lines of evidence
Concluding remarks
Acknowledgments
References cited
Rare-earth-element content of some highly differentiated ash-flow tuffs and lavas / Donald C. Noble, Ward L. Rigot, and Harry R. Bowman
Abstract
Introduction
Specimens studied and methods of chemical analysis
Results and discussion
Acknowledgments
References cited
Geochemistry of the Los Chocoyos Ash, Quezaltenango Valley, Guatemala / William I. Rose, Jr., Norman K. Grant, and John Easter
Abstract
Introduction
Field description
Geochemistry
Mineralogy and mineral chemistry
Sr-isotope data
Modeling of crystal fractionation
Time required for crystal fractionation
Conclusions
Acknowledgments
Appendix 1. Analytical methods
References cited
Geochemical correlation of genetically related rhyolitic ash-flow and air-fall ashes, central and western Guatemala and the equatorial Pacific / Gregory A. Hahn, William I. Rose, Jr., and Thomas Meyers
Abstract
Introduction
Previous investigations of chemical fingerprinting
The Los Chocoyos Ash and the stratigraphic sequence of the San Cristobal Group
Characteristics of the ash-flow member
Sample acquisition and preparation
Trace-element analyses
Chemical correlation
Lateral chemical variations
Source of the Los Chocoyos Ash
Age of the Los Chocoyos Ash
Conclusions
Acknowledgments
References cited
Ignimbrites of the Sierra Madre Occidental and their relation to the tectonic history of western Mexico / Fred W. McDowell and Stephen E. Clabaugh
Abstract
Introduction
Volcanic stratigraphy of the Sierra Madre Occidental
Pre-Cretaceous volcanic rocks
Lower volcanic complex
Unconformity between the igneous sequences
Upper volcanic supergroup
Calderas of the upper volcanic supergroup
Structure of the Sierra Madre Occidental
Chemistry
Tectonic relationships
Acknowledgments
References cited
Emplacement of pyroclastic flows: A review / Michael F. Sheridan
Abstract
Introduction
Eruptions
Observed pyroclastic flows
Theoretical eruption models
Mobility
Topographic barriers
Energy line
Deposits
Morphology
Depositional sequence
Textures
Large clasts
Deflation
Compositional variation
Welded peralkaline ignimbrites
Emplacement temperatures
Models
Fluidization
Speculation
Summary
Acknowledgments
References cited
Primary and secondary flow structures in ash-flow tuffs of the Gribbles Run paleovalley, central Colorado / Charles E. Chapin and Gary R. Lowell
Abstract
Introduction
Paleovalleys and the Wall Mountain Tuff
Primary flow structures
Gas cavities (lenticules)
Lineation
Foliation
Primary folds
Rotated lithic fragments
Imbricated crystals
Secondary now structures
Secondary folds and growth faults
Tension cracks
Miscellaneous structures
Steam spiracles
Conclusions
Acknowledgments
References cited
Welded air-fall tuffs / R.S.J. Sparks and J. V. Wright
Abstract
Introduction
Field relationships
Santorini, Greece
The 1875 Askja welded tuffs, Iceland
Other examples
Petrology and chemistry
Grain-size studies
Santorini welded tuffs
Askja welded tuff
Compaction and welding
Strain, bulk density, and porosity measurements
Results for Santorini welded tuffs
Results for Askja welded tuff
Discussion
Acknowledgments
References cited
Globule ignimbrite of Mount Suswa, Kenya / R. L. Hay, W. Hildreth, and R. N. Lambe
Abstract
Introduction
Scope and purpose of study
Geologic setting and previous work
Description and field relationships
Ignimbrite petrography
Vitric materials
Crystals and rock fragments
Devitrification and gas-phase crystallization
Low-temperature alteration
Nature of lower ignimbrite sheet
Nature of the magma
Chemical composition
Temperature and viscosity
Emplacement of ignimbrite and origin of globules
Acknowledgments
References cited
A model of pyroclastic surge / K. H. Wohletz and M. F. Sheridan
Abstract
Introduction
Terminology
Objectives and methods of study
Deposits
Bed forms
Locations
Results
Pyroclastic-surge facies
Discussion and conclusions
Development of bed forms
Reconstruction of the surge cloud
A model of pyroclastic surge: Its fluidization and deflation
Acknowledgments
References cited
Significance of the flattening of pumice fragments in ash-flow tuffs / Donald W. Peterson
Abstract
Introduction
Pumice fragments in the Apache Leap Tuff
Recognition and description of pumice fragments
Flattening of the pumice
Applications of the flattening studies
Recognition of cooling units
Implications of extreme flattening
Determination of stratigraphic level and fault displacement
Commercial application of flattening ratios
Determination of the degree of welding
Pumice flattening as a possible guide to relative temperature of emplacement and rate of accumulation
Conclusions
Acknowledgments
References cited
Ash-flow sheets and calderas: Their genetic relationship to ore deposits in Nevada / Edwin H. McKee
Abstract
Introduction
Metal deposits in volcanic-tectonic systems
Resurgent cauldrons
Geologic setting
Parameters of study
Distribution of mines and ash-flow sheets
Distribution of mines and calderas
Discussion
Acknowledgments
References cited
Standort:
Kompaktmagazin unten
Zweigbibliothek:
GFZ Bibliothek
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