Lyell Collection
Geological Society, London, Special Publications
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Rider, M. H.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Geological Society, London, Special Publications; 1990; v. 48; p. 27-37;
DOI: 10.1144/GSL.SP.1990.048.01.04
© 1990 Geological Society of London

Sedimentology

Gamma-ray log shape used as a facies indicator: critical analysis of an oversimplified methodology

M. H. Rider

Rider-French consulting, PO Box 1, Rogart, Sutherland, IV28 3XL, UK

Gamma-ray log shapes are often used by geologists to determine sandstone grain size trends and hence depositional facies. However, for the simple methodology of relating shapes to facies to be valid, there must be consistent relationships between gamma-ray log values and clay content and between clay content and grain size. Log to core comparisons and sandstone textural analyses show that these relationships are naturally variable. Consequently, correlation of log shape with grain size trend is tenable only under very limited (and defineable) conditions. A universal application of gamma-ray log shape to grain size trend and depositional facies is wrong.