Journal ArticleDOI
Determination of Finite Strain and Initial Shape from Deformed Elliptical Objects
TLDR
In this article, the shape and orientation of deformed pebbles and oolites are studied as ellipses on plane sections, and a shape factor grid enables accurate calculation of the magnitude and orientations of the strain ellipse.Abstract:
To determine finite strain from material such as deformed pebbles and oolites, it is essential to consider the initial shape and orientation of the particles. The ellipsoidal objects are studied as ellipses on plane sections. The distribution of axial ratios and orientations of undeformed particles is used as the basis for a classification of initial distributions. Simple and general equations relating the initial and deformed shape and orientation of the particles are derived by considering the matrix algebra. A shape factor grid enables accurate calculation of the magnitude and orientation of the strain ellipse. A variety of important initial distributions can be determined and used. The sudden onset of continuous cleavage and oriented textures observed in some orogenic areas is partially due to the effect of the initial shape of crystals, grains, and clastic particles.read more
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Calcite twins, their geometry, appearance and significance as stress-strain markers and indicators of tectonic regime: a review
TL;DR: The appearance of calcite twin lamellae changes systematically as a function of deformation temperature as discussed by the authors, and they are found in various tectonic environments and record very small strains in rocks deformed under very little cover.
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Constraints on geological strain rates: arguments from finite strain states of naturally deformed rocks
TL;DR: A summary of known finite strain states is presented in this paper, where the time span available to produce such measureable strains in young orogenic zones seems to be less than 10 m.y.
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Strain and kinematic analysis in general shear zones
Carol Simpson,Declan G. De Paor +1 more
TL;DR: In this article, a unifying theory for the development and distribution of strain markers and kinematic indicators in zones of general shear is presented, and a framework in which data previously considered contradictory may be understood.
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A simple algebraic method for strain estimation from deformed ellipsoidal objects. 1. Basic theory
TL;DR: In this paper, the shape and orientation of the strain ellipsoid were determined by using deformed elliptical objects as strain markers, assuming that the objects are of truly ellipseidal shape with random orientation in the undeformed state, and that they deform homogeneously with their matrix.
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The relationship of strain and preferred orientation of phyllosilicate grains in rocks: a review
TL;DR: In this article, the authors proposed a method to estimate the strain from the preferred orientation of platy phyllosilicate grains, taking strain to be homogeneous from a pragmatic point of view, although numerous theoretical objections to this procedure can be and have been raised.