Computer based experimental studies of the Fry method of strain analysis on 2- and 3- dimensional grain populations

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6318203

Longiaru, S; Bhattacharyya, T

Inherent in Fry's (1979) all-object separation method of strain analysis are the subtle conditions that 1) the grains or phenocrysts being counted are of equal diameter and 2) that the true centers of such grains lie within the plane of measurement. When such conditions are met, the technique yields accurate, easily interpreted voids within all-object separation (AOS) plots for both deformed and non-deformed populations. Natural grain or phenocryst populations generally do not conform to these limitation and practical application of the technique from either a cut rock surface or thin section often yields diffuse patterns that are not easily interpreted. The authors examine the effect of grain size variation and grain/matrix ratio on AOS diagrams developed from computer generated spherical grain populations constructed in both two and three dimensions. They employ a random number generator and simple fitting algorithm to develop grain populations with known statistical parameters. Such control allows for the modeling of many types of natural grain size populations such as fluvial sandstones, porphyritic ash flow tuffs, augen gneisses, etc. They show that significant grain size variation in a two dimensional population contributes substantial noise in to the AOS diagram and that an additional level of noise is encountered when dealing with slices through populations modeled in three dimensions. Some of this noise can be eliminated by rigorous sampling of only subsets of the total grain population.

• Research Organization: Univ. of California, Santa Cruz (USA)
• OSTI ID: 6318203
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GNEISSES
ROCK MECHANICS
STRESS ANALYSIS
COMPUTERIZED SIMULATION
MATHEMATICAL MODELS
SANDSTONES
TUFF
ALGORITHMS
GRAIN SIZE
PETROGRAPHY
PETROLOGY
STRAINS
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
CRYSTAL STRUCTURE
GEOLOGY
MATHEMATICAL LOGIC
MECHANICS
METAMORPHIC ROCKS
MICROSTRUCTURE
ROCKS
SEDIMENTARY ROCKS
SIMULATION
SIZE
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)