R7: Petrology, Mineralogy and Economic geology (Joint session with SRG)

[R7P-11] Microstructure and formation process of pseudotachylyte exposed in Aravalli-Delhi orogenic belt, India

*Junya Okazaki¹, Jun-ichi Ando¹, Kaushik Das¹, Naotaka Tomioka², Yu Kodama³ (1. Hiroshima Uni. Sci, 2. JAMSTEC, 3. Marine Works Japan Ltd.)

Keywords:Pseudotachylyte, Fault activity, frictional melting, Plastic deformation

Pseudotachylyte, formed by frictional melting during fault activity, is dark and aphanitic rock and important rock which preserves information of palaeoseismic activity. In Aravalli-Delhi orogenic belt, India, pallalel and cross-cut pseudotachylyte veins to foliation of host rock gneiss occur and show the formation at different depth of crust. Pseudotachylyte consist of crushed clasts and fine matrix and the matrix consist of about 0.5μm mineral grains. Preferential melting occurred in finely crushed clasts and low melting point minerals.