Mineralogical compositions of fault rocks from surface ruptures of Wenchuan earthquake and implication of mineral transformation during the seismic cycle along Yingxiu-Beichuan fault, Sichuan Province, China

Structural fabrics of carbon grains in a natural fault gouge reactivated by the 2008 Wenchuan earthquake

“…The skin materials were two layers of small (<1 cm) white and yellow clasts on the west and east side, respectively (Figure 2c–e). The white vein was composed of almost pure quartz (~96 wt%) and the yellow vein contained ~80 wt% carbonate minerals (calcite and dolomite) (Dang et al, 2018; Yao et al, 2013). The brownish breccia occurred along the uncovered co‐seismic slip plane and the shattered quartz vein clasts were locally mixed with shattered brownish clasts (Figure 2d,e).…”

“…The brownish breccia occurred along the uncovered co‐seismic slip plane and the shattered quartz vein clasts were locally mixed with shattered brownish clasts (Figure 2d,e). This means that the shear strain of recent fault movements was focused on the BGG (Chen, Yang, Ma, & Spiers, 2013; Dang et al, 2018; Yao et al, 2013; Zhang & He, 2013). The samples analysed in this study were collected specifically from the BGG layer (red stars in Figure 2).…”

“…Three kinds of rock units occurred in the damage zones overlying the fault core, including shattered black-grey breccias, fractured grey breccias, and weakly fractured sandstone from west to east. The parent rocks of the breccias in the damage zones were sandstone (Dang et al, 2018).…”