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Changes in surface layer composition of Koyna-Warna holes rocks under frictionтезисы доклада Тезисы
- Авторы: Ponomarev Alexander, Vettegren Victor, Arora Kusumita, Chadha Rajender, Raza Haris, Mamalimov Rustam, Kulik Vitaly, Scherbakov Igor, Patonin Andrey, Matveev Maxim, Maybuk Yuri
- Сборник: Book of Abstracts of the 36th General Assembly of the European Seismological Commission
- Тезисы
- Год издания: 2018
- Место издания: Mistral Service Anna Lo Presti Via Romagnosi Messina (Italy)
- Первая страница: 340
- Последняя страница: 341
- Аннотация: The texture and clay mineralogy of a slickenside surface and a freshly created fracture in core samples from Phansavale (in ferruginous and silicified metamorphosed gneiss) and Paneri (in basalt showing porphyritic structure with phenocrysts of Plagioclase and Ortho-pyroxenes in fine grained mass with rare zeolites amygdales) deep boreholes at 503 m and 560 m depth from Koyna region is investigated by Infrared (IR), Raman spectroscopy and Photo Luminescence (PL). We report slickenfibres striations and thin films of clay minerals on slickenside surface and 1- 4 mcm thick surface layers of Li-montmorillonite on freshly created fracture in laboratory. The results are compared with the parameters and composition of the surfaces outside the fracture zones. It is shown that shear surface consist of clay minerals with a low coefficient of friction, while the concentration of such minerals on the undisturbed surface is negligible. Presence of clay minerals along existing fracture surfaces indicates creep deformation due to low coefficient of friction. We suggest that new minerals are formed due to mechanical destruction of chemical bonds in the crystal lattice of quartz, feldspars, calcite and dolomite, as a result of which new free radicals and ions are produced along fracture surfaces initiating chemical reactions causing changes in the chemical structure of rocks. We propose creep movements in basalt rocks associated with triggered earthquakes along basement faults in the seismically active Koyna-Warna region in western India. This observation is supported by absence of earthquakes in the top (about 1 km) Deccan Trap rocks during the last five decades. This work was supported by the RFBR grant 16-05-00137 (spectroscopy measurements) and by the Russian-Indian project RSF – DST India: grant of the RSF 16-47-02003, grant of the DST of the Government of India - INT/RUS/RSF/P-13 (preparation of rock samples and conducting experiments).
- Добавил в систему: Пономарев Александр Вениаминович