Table of Contents - SPE285: Tonsteins: Altered Volcanic Ash Layers in Coal-Bearing Sequences
Abstract
Nomenclature and Classification
Geographical Occurrence of Tonsteins
Volcanic Characteristics of Tonsteins
Methods of Study
Mineralogy
Primary Minerals
Quartz
Feldspars
Biotite
Apatite
Ilmenite and Magnetite
Zircon
Rutile and Sphene (Titanite)
Other Primary Components
Glass
Secondary Minerals
Kaolinite
Smectite
Illite
Phosphates
Pyrite
Diatoms
Weathering Products
Gross Texture of Tonsteins
Vermicules, Plates, and Microspherules
Accretionary Lapilli
Graupen
Breccia
Flint Clay
Clay-Free Partings
Glass Shards and Lapilli
Rooting and Burrowing
Stumps, Twigs, and Other Plant Materials
Reworking
Alteration of Volcanic Ash to Tonstein
Time of Alteration
Influence of Bed Thickness
Ash Composition
Alteration Sequence
Environmental Effects of Thick Ash Falls
Plants, Hydrology, and Coal Chemistry
Secondary Minerals
Stratigraphic Uses of Tonsteins
Radiometric Dating of Primary Minerals
Calibration of Fossil Zones
Isochron Horizons
Correlation of Individual Units
Lithologic Succession
Field Appearance (e.g., Thickness, Color, and Texture)
Bulk Clay Mineralogy
Bulk and Trace-Element Chemistry
Relative Abundance of Nonclay Minerals
Elemental Composition of Mineral Species
Morphology of Mineral Species
Recording Eruptive Histories
Intercontinental Correlations
Summary and Conclusions
Acknowledgments
References Cited