Laurent, Ph, Kern, H. and Lacombe, O. (2000) Determination of deviatoric stress tensors based on inversion of calcite twin data from experimentally deformed monophase samples. Part II. Axial and triaxial stress experiments. Tectonophysics, 327 (1-2). pp. 131-148. DOI 10.1016/s0040-1951(00)00165-7.

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Abstract

Three samples of a bioclastic bajocian limestone from Burgundy (France) were experimentally deformed under axial and triaxial conditions at 200 and 300°C. In each sample, a series of three mutually orthogonal thin sections were studied using a U stage. The intracrystalline deformation of the calcite grains involved mainly twinning on the e planes. Precise measurement of the e twin lamellae combined with the Etchecopar inverse method (1984) allowed the calculation of the four parameters of the reduced stress tensor responsible for the twinning. As the principal differential stress values of the experimental deviatoric stress tensors were known, the critical resolved shear stress (CRSS) values [tau]s for twinning on the e planes were then determined in each case: at 200°C and 4.8% strain, [tau]s is close to 15 MPa; at 300°C and at 8.7 and 9.4% strain, the calculated [tau]s values are close to 10.1 and 13.4 MPa, respectively. When compared with the data published by Turner et al. (1954), Turner and Heard (1965) and Lacombe and Laurent (1996), our results confirm that the CRSS values are more or less dependent on both the temperature and the bulk amount of strain. Consequences for the estimation of the actual principal differential stress values ([sigma]1-[sigma]3) are described, particularly for very weakly deformed cover rocks in the forelands of mountain chains.

Document Type:	Article
Keywords:	triaxial tests calcite twins shear stress
Research affiliation:	Kiel University
Date Deposited:	02 Feb 2012 09:13
Last Modified:	09 Oct 2012 03:57
URI:	https://oceanrep.geomar.de/id/eprint/16346

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