Journal of Tectonics

Journal of Tectonics

Strain-rate estimation using fractal analysis of quartz grain boundary in the gneisses of Chahzar thrust zone

Document Type : Original Article

Authors
Mehdi Abdolzadeh 1
Iraj Rasa 2
ٍSeyed Rahim Hosseini 3
Reaz Derakhshani 4
1 Department of Earth Sciences, Shahid Beheshti University, Tehran, Iran
2 Department of Earth Sciences, Shahid Beheshti University, Tehran
3 Department of Earth Science, Ferdowsi University of Mashhad
4 Department of Earth Sciences, Shahid Bahonar University, Kerman, Iran
10.22077/jt.2025.9926.1209
Abstract
The Golghohar - Rotshun metamorphic complex is located in the southeastern part of the Sanandaj – Sirjan metamorphic zone (SSMZ). During the deformation , dynamic recrystallization commonly occurs , producing interlocking grain boundaries characterized by bulging (range of 250 – 400 °C), subgrain rotation (range of 400 – 500 °C) , and grain boundary migration (range of 500 – 750 °C). To investigate the relationship between quartz dynamic recrystallization microstructures and deformation conditions such as temperature and strain rate, the fractal dimension of grain boundaries was determined using the box - counting method. Based on these data and deformation temperatures obtained from the quartz dynamic recrystallization, the calculated strain rates range between 10 ⁻6.8 and 10 ⁻10.9 s⁻¹, which are higher than typical natural strain rates (〖10〗^(-15)–〖10〗^ (-12) s⁻¹) reported from microstructural and piezometric analyses. The deformation temperatures indicate greenschist - to amphibolite - facies conditions in the studied area.
Keywords
Strain-rate
Fractal analysis
Recrystallization
Temperature
Journal of Tectonics
Volume 7, Issue 28
Winter 2024 Article ID:6