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Extrapolation in geologic fabrics

Gerhard Oertel
Extrapolation in geologic fabrics
Geological Society of America Bulletin (1962) 73 (3): 325-342

Index Terms/Descriptors

Fabrics are 3-dimensional and geometrically complex. They can be resolved into fabric elements, the simplest constituents of compound fabrics. The fabric elements can range from geometrically simple structures with families of planes or lines to complex structures with families of more or less regularly curved, congruent or incongruent surfaces or lines. The fabric elements are understood more easily if one projects derived families of parallel lines (axes) with well-defined geometric relations to the fabric itself into them. As fabric elements become more complex, these axes can degenerate into discrete lines or curves with a definite position. The purely geometrical character of Sander's fold axis beta is confirmed, and the stacking axis alpha is defined. These axes may coexist in certain fabric elements and together define a family of parallel planes, the axial plane. Individual members of the penetrative family of axial planes are singled out as axial surfaces, such as the axial hinge surface. Other discrete axial surfaces result from coexistence of discrete axial lines or curves with a penetrative axis. One can extrapolate along axes, axial planes, and axial surfaces. They are, therefore, important for the geologist whose knowledge by observation is always restricted to the small accessible part of his object. Examples demonstrate application of geometry to specific geological problems, ranging from current bedding to refolded folds and the position of oil traps.

ISSN: 0016-7606
EISSN: 1943-2674
Serial Title: Geological Society of America Bulletin
Serial Volume: 73
Serial Issue: 3
Title: Extrapolation in geologic fabrics
Author(s): Oertel, Gerhard
Pages: 325-342
Published: 1962
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
Accession Number: 1962-011445
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Update Code: 1962
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