Product catalogue
A field classification and intensity scale for first-generation cleavages
The chief morphological characteristics and lithological associations of naturally occurring cleavage fabrics are reviewed with the aim of differentiating qualities that represent fabric type from those that represent fabric intensity, and incidental partings from the cleavage fabric itself. This leads to field-based descriptive classifications for types and intensity of rock cleavage which unify diverse previous observations and allow a more formal approach to the description of cleavage. Particular attention is given to first-generation cleavage and incipient cleavage in clastic rocks of low to very low metamorphic grade, although all cleavage types are considered. Two main divisions of cleavage type are recognised: (a) penetrative and (b) non-penetrative, according to the spacing of cleavage domains (where present) with respect to the width of dominant clastic (or detrital) grains. Each division includes three types, each of which is closely related to the lithology and texture of the parent rock (type 1, clay and slaty penetrative types; spaced, crenulation and scaly non-penetrative types). Each of the six cleavage types may display one (or less commonly both) of two kinds of intensity modulation at the mesoscale: shear zones and stripes. Fissility, defined as the small-scale crack-structure which develops along planes of bedding- and cleavage-fabric anisotropy in weathered mudrocks, is proposed as an index property reflecting the relative intensity of cleavage, bedding and intersection fabrics in these lithologies. Fissility-ratios can be quantified in the field by measurements of dimensional ratios of fissility-fragments. The ratios are given named class intervals and are quantitatively discussed with the aid of a logarithmic 3-axis diagram. A reference field-example illustrates a full progression of relative cleavage-fissility intensity from none, through incipient, to strong, in relation to a natural strain gradient. The influences of rock type, initial bedding anisotropy, strain and style of tectonic deformation on fissility-ratios are also discussed. Fissility-ratios provide a rapid means of evaluating the effects of regional variations of total fabric and deformation intensity in a given rock type in low- to very low-grade metamorphic environments; they also represent a new tool that may assist in the study of weak deformations, incipient cleavage, sensitivity of different rock types to cleavage development, deformational or tectonic regimes (as reflected by fissility-fragment shape fields) and fabrics in undeformed mudrocks.
Simple
Identification info
- Date (Publication)
- 1994-01-01T00:00:00
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/81397
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Australian Geological Survey Organisation
Canberra Author Durney, D.W.
1 Author Kisch, H.J.
2
- Name
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AGSO Journal of Australian Geology and Geophysics
- Issue identification
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15:3:257-295
- Point of contact
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Role Organisation / Individual Name Details Custodian Corp
Owner Commonwealth of Australia (Geoscience Australia)
Custodian Commonwealth of Australia (Geoscience Australia)
Voice
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- Geoscientific information
- Maintenance and update frequency
- Unknown
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Product data repository: Various Formats
- Website
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Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
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GA Publication
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Journal
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- Australian and New Zealand Standard Research Classification (ANZSRC)
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Earth Sciences
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- Keywords
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Published_External
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Resource constraints
- Title
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Creative Commons Attribution 4.0 International Licence
- Alternate title
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CC-BY
- Edition
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4.0
- Access constraints
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- License
Resource constraints
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Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
- Language
- English
- Character encoding
- UTF8
Distribution Information
- Distributor contact
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
Voice
- OnLine resource
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Journal article (pdf)
Journal article (pdf)
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pdf
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Resource lineage
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Unknown
- Hierarchy level
- Non geographic dataset
- Other
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GA Publication
- Description
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Source data not available.
Metadata constraints
- Title
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Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
- Metadata identifier
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urn:uuid/fae9173a-7152-71e4-e044-00144fdd4fa6
- Title
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GeoNetwork UUID
- Language
- English
- Character encoding
- UTF8
- Contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice
Type of resource
- Resource scope
- Document
- Name
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AGSO BMR Journal
Alternative metadata reference
- Title
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/81397
- Date info (Revision)
- 2018-04-20T06:07:35
- Date info (Creation)
- 2014-06-03T00:00:00
Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-3
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, September 2018
- Citation identifier
- https://pid.geoscience.gov.au/dataset/ga/122551