Atlas of Deformational and Metamorphic Rock Fabrics

herausgegeben von: Graham J. Borradaile, M. Brian Bayly, Chris McA. Powell

Verlag: Springer Berlin Heidelberg

Enthalten in: Professional Book Archive

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In May 1976 Lucian B. Platt organized a highly successful Penrose Confer ence on The Formation of Rock Cleavage at Bryn Mawr College in Penn sylvania, U. S. A. The meeting drew together about 70 specialists from both sides of the Atlantic and from Australasia, who contributed discussions on various aspects of rock cleavage and its formation. Even early in the meet ing it became clear to the participants that they lacked a common terminol ogy, that often the same technical word implied different things to different people and that observables and descriptors were loosely defined. In an at tempt to improve communication the present editors contacted about 190 workers after the conference with a view to compiling a set of photographs with captions to illustrate exactly what workers were talking about. As a re sult the compilation was published as a limited edition by an inexpensive offset process at the University of Tasmania. The success of that provisional edition of the Atlas of Rock Cleavage and the responses of the readers prompted us to make a more extensive collection of material, contact a wider range of workers and, with the support of Dr. Konrad Springer, to publish the present higher-quality reproduction of the contributors' plates.

Inhaltsverzeichnis

Frontmatter

Chapter I. Introduction

Abstract

Our knowledge of metamorphic and deformational rock fabrics has been acquired largely by studying the products of deformation in ancient fold belts. As such, our understanding of how rock fabrics form has been built up from inferences about, rather than direct observations of, processes that might have operated, and many of those inferences have proved incorrect. Extension of the deep-sea drilling project to actively deforming Continental margins is a step towards providing information about rock fabrics that are currently forming, as is the attempt to measure stress, strain and nature of pore fluid in modern fold belts, but these approaches are very much in their infancy. Similarly, direct observations of fabric changes have begun using analogue materials. The problem arising from such an inferential study is that we have no prior knowledge of the natural categories or divisions that exist. The major categories of rock fabric have, by necessity, been established arbitrarily in the hope that they provide a useful subdivision. As novel observations or techniques open new vistas, earlier ideas have had to be modified or discarded.

Graham J. Borradaile, M. Brian Bayly, Chris McA. Powell

Chapter II. Processes Contributing to Development of Cleavage

Abstract

An analysis of possible processes is offered that attempts two properties, (a) it is exhaustive (b) the processes üsted are nonoverlapping. The intention is not to change present usage, but to emphasize successful terms or practices (that quickly and accurately transfer an idea from writer to reader) and to guard against trouble-some terms or practices (that seem likely to cloud the quick, accurate transfer of ideas). At the outset it is important to separate geo-metrical processes from material processes. For example, geometrical processes include change of shape and change of size. By contrast, material processes include diffusion of atoms through a crystal lattice and transport of atoms as solutes by a moving solvent. The plan will be to list geometrical processes first and material processes later.

Graham J. Borradaile, M. Brian Bayly, Chris McA. Powell

Chapter III. Possible Links Between Observables and Processes

Abstract

This chapter is different in a fundamental way from the two preceding chapters on observables and processes; essentially, it cannot be written. We do not at present know how to infer a group of processes from a group of observables. The purpose of this Atlas is to improve the groundwork from which people attack this task. If the Atlas is effective, it will help in the current trend toward exchange of opinions about how different cleavages form, and perhaps at some future time, the combined knowledge and insight of many people will result in a robust system of patterns of inference; but at present we do not have such a system — it is the absence of such a system that provoked the creation of the Atlas in the first place. (By robust system of patterns of inference we mean something like the Facies Classification of metamorphic rocks. For all its defects, this constituted a framework within which people could compare notes, distinguish the commonplace from the exceptional, and assemble a pattern of dominant tendencies.

Graham J. Borradaile, M. Brian Bayly, Chris McA. Powell

Chapter IV. The Plates

Abstract

In the Introduction we discussed sehemes for classifying tectonic and metamorphic fabrics using features observable at a variety of scales. We have emphasized that descriptors used to describe such observables carry no genetic implications. Furthermore the descriptors should not overlap in meaning with other descriptors. In understanding the geometric similarities or relationships between different types of cleavage and schistosity it was necessary to resort to three-dimensional diagrams (Fig. 1.5, p4). However, the relationships are often gradational in more than three directions and in an ideal universe we would like several more dimensions in which to depict the possible transitions from one type of cleavage to another.

G. J. Borradaile, M. M. Kehlenbeck, M. Friedman, N. G. Higgs, R. F. C. Morritt, C. McA. Powell, R. H. Vernon, A. J. Watkinson, B. M. Bayly, N. S. Mancktelow, W. Davies, B. Z. Lincoln, W. D. Means, K. R. McClay, D. S. Russell-Head, C. J. L. Wilson, M. M. Kehlenbeck, V. A. Williams, O. A. Pfiffner, M. R. Steuer, J. W. Cosgrove, H. J. Bradbury, A. L. Harris, D. R. Gray, R. J. Holcombe, D. Martin, D. Puppolo, K. Weber, R. J. Knipe, S. H. White, J. W. Granath, D. A. C. Gardner, L. Solé-Sugrañes, J. C. Maxwell, J. H. Spang, A. E. Oldershaw, E. D. Ghent, M. Z. Stout, W. Alvarez, T. Engelder, S. A. Sansone, P. L. Hancock, K. A. W. Crook, J. G. Dennis, T. O. Wright, G. Gill, L. B. Platt, Y. Mimran, R. B. De Boer, P. J. C. Nagtegaal, E. K. Wright, D. Cook, C. A. Boulter, D. W. Durney, D. B. Seymour, A. Beach, R. Ahmad, N. B. Lebedeva, P. R. Williams, P. F. Williams, R. P. Nickelsen, W. J. Gregg, S. F. Cox, M. A. Etheridge, H. R. Burger, D. G. Bishop, M. C. Kennedy, F. W. Breaks, W. D. Bond, S. Finley, J.-L. Bouchez, H. R. Wenk, J. Ainsworth, K. R. Cclay, F. Boudier, A. Nicolas, C. J. Talbot, G. Twombly, N. C. Wardlaw, P. J. Hudleston, S. A. Kissin, H. C. Heard, P. J. Conaghan, A. J. Maltman, T. H. Bell, M. J. Rubenach, R. H. Moench, D. E. B. Bates, K. H. Poulsen, P. A. Jackson, K. C. Hughes, R. A. Glen, B. C. Burchfiel, D. Roberts, R. I. Simon

Backmatter

Titel: Atlas of Deformational and Metamorphic Rock Fabrics
herausgegeben von: Graham J. Borradaile
M. Brian Bayly
Chris McA. Powell
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-642-68432-6
Print ISBN: 978-3-642-68434-0
DOI: https://doi.org/10.1007/978-3-642-68432-6

Springer Professional

Über dieses Buch

Inhaltsverzeichnis

Frontmatter

Chapter I. Introduction

Chapter II. Processes Contributing to Development of Cleavage

Chapter III. Possible Links Between Observables and Processes

Chapter IV. The Plates

Backmatter