Author

Donna M. Fuss

Publication Date

1986

Document Type

Dissertation/Thesis

First Advisor

Walker, James Allen, 1952-

Degree Name

M.S. (Master of Science)

Department

Department of Geology

LCSH

Ignimbrite--Chile||Sedimentation and deposition--Chile

Abstract

The sedimentological characteristics of the San Andres ignimbrite relate information of the preemptive, eruptive and depositional conditions during a large explosive volcanic eruption. Grain size analysis was accomplished by sieving the coarser fractions and pipetting the finer fractions. Separation of the pumice, crystal and lithic components coarser than 1 phi (1/2 mm) were done to examine the grading of the components . Beta quartz and biotite zonation within the ignimbrite supports the existence of a zoned magma chamber. The San Andres ignimbrite was deposited as a pyroclastic flow from a large-volume, high eruption column. The flow was highly fluidized, based on the presence of coarse-tail grading, reverse grading of pumice, normal grading of lithics and lithic-rich breccia lenses. The flow moved by laminar flow based on the preservation of the mineralogic zonations; however, turbulence did occur locally. The formation of some of the lithic breccia concentrations was due to the occurrence of hydraulic jumps.

Comments

Bibliography: pages [89]-94.

Extent

ix, 100 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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