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Determining deviatoric stress tensors from calcite twins: Applications to monophased synthetic and natural polycrystals
Author(s) -
Laurent Philippe,
Tourneret Christophe,
Laborde Olivier
Publication year - 1990
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/tc009i003p00379
Subject(s) - differential stress , principal stress , geology , nonlinear system , calcite , stress (linguistics) , shear (geology) , cauchy stress tensor , shear stress , critical resolved shear stress , crystal twinning , geometry , deformation (meteorology) , mechanics , mineralogy , mathematical analysis , materials science , mathematics , physics , composite material , shear rate , rheology , philosophy , petrology , oceanography , microstructure , quantum mechanics , linguistics
Theoretically, calcite twins analysis makes possible the full determination of the deviatoric stress tensor responsible for the formation of the twin lamellae, that is, the orientations of the principal stress axes and the three differential stress values (σ i –σ j ) may be calculated, assuming conditions of constant resolved shear stress for twinning. Inverse method using nonlinear regression and robust estimation is proposed. Applications to monophased synthetic polycrystals that are generated numerically by solving the direct problem and to a natural sample from the Quercy (southwest of France) have given good results. Comparison with the first method proposed by Turner (1953), modified by Nissen (1964) for principal stress orientations and by Jamison and Spang (1976) for differential stress values, clearly emphasizes the considerable interest of this new method.