A new perspective on paleopiezometry: Dynamically recrystallized grain size distributions indicate mechanism changes

作者：Stipp Michael^*; Tullis Jan; Scherwath Martin; Behrmann Jan H

来源：Geology, 2010, 38(8): 759-762.

DOI：10.1130/G31162.1

The dynamically recrystallized grain size is a material parameter associated with dislocation creep of crystalline solids that is especially important as a flow stress indicator via piezometer calibrations. Grain sizes have been measured in many studies of deformed rocks as well as metals and ceramics, but global analyses of the frequency distribution of dynamically recrystallized grain sizes are lacking. Here we present the first systematic investigation of the recrystallized grain size distribution, for quartz. The grain diameters, compiled from 555 samples of 31 studies of quartz mylonites deformed over a wide range of conditions, extend from similar to 3 mu m to 3 mm, with distinct maxima at 10-20 mu m and 70-80 mu m, and minima at 35-40 mu m and similar to 120 mu m. The frequency maxima correlate with distinct microstructures and the minima with the transitions between these microstructures, which we interpret to result from the dominance of the recrystallization mechanisms of bulging, subgrain rotation, and grain boundary migration recrystallization. These results demonstrate the necessity of distinct piezometer calibrations for different recrystallization mechanisms and highlight the importance of the recrystallized grain size for theoretical models of dynamic recrystallization.

• 出版日期2010-8