Constraints on geological strain rates: Arguments from finite strain states of naturally deformed rocks

Publisher Website
Google Scholar
Abstract
A summary of known finite strain states is presented; longitudinal strains (1 +e) as measured in many rocks often range from 1 to 40 and 1 to 0.025. The time span available to produce such measurable strains in young orogenic zones seems to be less than 10 m.y., possibly less than 1 m.y., which constrains conventional strain rates into the range of 10−13s−1to 10−15s−1. For both pure and simple shear (the most efficient way and a much less efficient way to accumulate incremental strains, respectively) the ellipticity of the finite strain ellipse increases in a nonlinear manner. Finite strain variations in adjacent layers, which give rise to features such as cleavage refraction, arise with only slight differences in the strain rates within these layers.