Автор(ы):Herwegh M., Kunze K.
Издание:Journal of Structural Geology, 2002 г., 16 стр.
Язык(и)Английский
The influence of nano-scale second-phase particles on deformation of fine grained calcite mylonites

Grey and white carbonate mylonites were collected along thrust planes of the Helvetic Alps. They are characterised by very small grain sizes and non-random grain shape (SPO) and crystallographic preferred orientation (CPO). Presumably they deformed in the field of grain size sensitive flow by recrystallisation accommodated intracrystalline deformation in combination with granular flow. Both mylonites show a similar mean grain size, but in the grey mylonites the grain size range is larger, the grain shapes are more elongate and the dynamically recrystallised calcite grains are more often twinned. Grey mylonites have an oblique CPO, while the CPO in white mylonites is symmetric with respect to the shear plane. Combustion analysis and ТЕМ investigations revealed that grey mylonites contain a higher amount of highly structured kerogens with particle sizes of a few tens of nanometers, which are finely dispersed at the grain boundaries.

During deformation of the rock, nano-scale particles reduced the migration velocity of grain boundaries by Zener drag resulting in slower recrystallisation rates of the calcite aggregate. In the grey mylonites, more strain increments were accommodated by individual grains before they became refreshed by dynamic recrystallisation than in white mylonites, where grain boundary migration was less hindered and recrystallisation cycles were faster. Consequently, grey mylonites represent 'deformation' microfabrics while white mylonites are characterised by 'recrystallisation' microfabrics. Field geologists must utilise this different deformation behavior when applying the obliquity in CPO and SPO of the respective mylonites as reliable shear sense indicators

ТематикаМинералогия, Структурная геология
МеткиCalcite, Deformation mechanisms, Lattice preferred orientation, Microstructures, Mylonite, Organic content, Recrystallisation, Second phases, Shear sense indicators, Zener drag, Кальцит, Механизм деформации, Микроструктуры, Милониты, Рекристаллизация
Автор(ы):Осипов В.И., Румянцева Н.А., Соколов В.Н.
Редактор(ы):Сергеев Е.М.
Издание:Недра, Москва, 1989 г., 211 стр., УДК: 621.131, ISBN: 5-247-00473-6
Язык(и)Русский
Микроструктуры глинистых пород

Изложены закономерности формирования микроструктуры глинистых пород, процессов структурообразования в глинистых системах, описаны современные методы изучения микроструктуры глинистых осадков. Показано влияние микроструктуры глин на их физические, механические и коллекторские свойства. Рассмотрены тиксотропные й реологические процессы в глинах, природа анизотропии их свойств. Приведены примеры практического использования микроструктурных данных при оценке глинистых пород. Для геологов, изучающих литологию и петрографию осадочных пород, а также специалистов в области коллоидной химии, керамики, физико-химической механики дисперсных систем.

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