Shape fabrics of particles in low concentration suspensions: 2D analogue experiments and application to tiling in magma

Research areas:
Year:
1996
Authors:
Journal:
JOURNAL OF STRUCTURAL GEOLOGY
Volume:
18
Number:
7
Pages:
941-950
Month:
July
ISSN:
0191-8141
BibTex:
Abstract:
Jeffery's equations ascribe a theoretical cyclic nature to the shape
fabric of non-interacting rigid particles immersed in a viscous fluid
undergoing simple shear flow. This theoretical behaviour is confirmed at
`low' shear strains (gamma 6) by two-dimensional experiments in a
torsion apparatus, inducing shape fabric development of particles evenly
distributed on the surface of a silicon fluid and at low particle
concentrations (13-14\% in area). For larger shear strains owever (6 1 (second experiment: 178 particles with two size
classes), then become stable at 17\% (first experiment) and at more than
50\% (second experiment) of the population of particles. Due to the
contribution of the tiled particles, the shape fabric becomes
asymmetrical in its orientation distribution, with a maximum lying above
the shear plane. The latter result provides a new shear sense indicator,
in addition to the statistical determination of the tiled features. The
study also suggests that crystalline fabrics in magmas could be acquired
at high melt fractions, i.e. early in the crystallization history of the
magma. Copyright (C) 1996 Elsevier Science Ltd.