کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4692268 1636786 2013 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Influence of stress, temperature, and strain on calcite twins constrained by deformation experiments
ترجمه فارسی عنوان
تأثیر تنش، دما و فشار بر روی دوقلوهای کلسیت محدود شده توسط آزمایشات تغییر شکل
کلمات کلیدی
کلسیت، دوقلو، آزمایشات تغییر شکل پالایو پیزومتر، دماسنج پالو
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی


• Carbonate rocks were experimentally deformed in the semibrittle regime.
• Twin density increased roughly proportional to the square of peak stress.
• Dislocation cell structures and densities are important state variables for strength.
• Twin width increased with both temperature and strain.

A series of low-strain triaxial compression and high-strain torsion experiments were performed on marble and limestone samples to examine the influence of stress, temperature, and strain on the evolution of twin density, the percentage of grains with 1, 2, or 3 twin sets, and the twin width—all parameters that have been suggested as either paleopiezometers or paleothermometers. Cylindrical and dog-bone-shaped samples were deformed in the semibrittle regime between 20 °C and 350 °C, under confining pressures of 50–400 MPa, and at strain rates of ~ 10− 4–10− 6 s− 1. The samples sustained shear stresses, τ, up to ~ 280 MPa, failing when deformed to shear strains γ > 1. The mean width of calcite twins increased with both temperature and strain, and thus, measurement of twin width provides only a rough estimation of peak temperature, unless additional constraints on deformation are known. In Carrara marble, the twin density, NL (no of twins/mm), increased as the rock hardened with strain and was approximately related to the peak differential stress, σ   (MPa), by the relation σ=19.5±9.8NL. Dislocation tangles occurred along twin boundaries, resulting in a complicated cell structure, which also evolved with stress. As previously established, the square root of dislocation density, observed after quench, also correlated with peak stress. Apparently, both twin density and dislocation cell structure are important state variables for describing the strength of these rocks.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volume 601, 2 August 2013, Pages 20–36
نویسندگان
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