Paleostress and Fluid Pressure Analysis of Vein Opening Using 3D Mohr Circle from the Quartz Vein Orientation Data of the South Delhi Terrane, Ambaji Area, NW India

Genesis of the late‐stage base metal sulfide mineralisation and its relationship with the regional deformation in Ambaji–Deri, South Delhi Terrane, North‐West India

“…Then intrusion of G3 granite and mineralised quartz veins occurred along these brittle structures. It is observed from the palaeostress study of G3 and quartz veins that NW–SE extension was responsible for the brittle deformation (N. K. Sharma & Biswal, 2020; Tiwari & Biswal, 2019b) (Figure 13d). This extensional vein can only be developed at elevated fluid pressure where veins are parallel to maximum compressional stress ( σ 1 ).…”

“…These veins were formed in an extensional stress regime where P f value exceeded the σ 2 stress condition ( σ 2 < P f < σ 1 ) (Figure 14b). The stress ratio ( φ = 0.90) and driving pressure ( R ′ = 0.95) value indicate that dilation of foliations and fractures occurred at very high P f in multiple directions of orientation (N. K. Sharma & Biswal, 2020). The G3 granite vein shows a similar values of driving pressure ( R ′ = 0.92) and stress ratio ( φ = 0.82) (Tiwari & Biswal, 2019b).…”

“…Quartz vein palaeostress analysis (a) Contour plot of the pole to quartz vein orientations; (b) 3D Mohr plot of quartz vein orientations (N. K. Sharma & Biswal, 2020)…”

“…From the orientation of the fold and fractures, it was elucidated that the NW–SE compression superseded by the NE–SW compression played a major role in structural transformation in the SDT. The brittle structures are formed by NW–SE extension (N. K. Sharma & Biswal, 2020; Singh et al, 2010; Tiwari & Biswal, 2019a, 2019b).…”

“…Then intrusion of G3 granite and mineralised quartz veins occurred along these brittle structures. It is observed from the palaeostress study of G3 and quartz veins that NW-SE extension was responsible for the brittle deformation (N. K Sharma & Biswal, 2020;.…”