| Autor: |
Sarkar, Ayan Kumar, Manna, Anirban, Chatterjee, Sadhana M., Roy, Alip |
| Předmět: |
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| Zdroj: |
Geosciences Journal; Dec2023, Vol. 27 Issue 6, p735-752, 18p |
| Abstrakt: |
Previous work reveals a syn-tectonic granite named Phulad granite, which is emplaced (∼820 Ma) in the western part of the South Delhi Fold Belt (SDFB) along and across the Phulad Shear Zone (PSZ). There is a lack of information about the detailed microstructural study, differential stress and strain rate variation from this granite body. These pieces of information are crucial in developing deformational history associated with the shear zone deformation. The granite preserves a variety of dynamic recrystallization from grain boundary bulging (BLG) to sub-grain rotation (SGR) to grain boundary migration (GBM). There is a variation in the fractal dimension (D) in the granite, such as higher D at the shear zone, and with increasing distance from the shear zone, D values are low. Strain rates (10−7.52 s−1–10−7.99 s−1) are much higher than the geological strain rates in the natural systems. The strain rates indicate that the method to calculate strain rate using the D value (1.007 ± 0.017 to 1.031 ± 0.022) is to some extent erroneous or fails to give geologically reasonable value for high-temperature syn-tectonic granite such as Phulad granite. Based on the quartz piezometer, our findings reveal variation in flow stress with distance from the shear zone, which depends on the grain size. Volume gain and mass balance calculations indicate that fluid incorporation at the shear zone reduces deformation temperature, which also validates the findings from the microstructural study. These microstructures and grain size calculations are discussed to interpret the deformation mechanism, various stress-strain pattern and evolution of the Phulad granite throughout the area. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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