Patterns of Clay Minerals Transformation in Clay Gouge, with Examples from Revers Fault Rocks in Devonina Niqiuhe Formation in The Dayangshu Basin

The role of authigenic clay growth in clay gouge is increasingly recognized as a key to understanding the mechanics of berittle faulting and fault zone processes, including creep and seismogenesis, and providing new insights into the ongoing debate about the frictional strength of brittle fault (Haines and van der Pluijm, 2012). However, neither the conditions nor the processes which clay minerals transformations are well understood. Moreover, understanding of these mineral transformations is required to predict the mechanical and seismogenic behavior of faults. Here, we present a systematic study of clay gouge mineralogy from devonina Niqiuhe formation in the Dayangshu basin, located in the Arong Banner and Oroqen Banner, east of Inner Mongolia, on the east part of Daxinganling orogenic belt. It is in a long narrow shape, with the NNE trending and next to Songliao Basin to the east. Dayangshu Basin experienced multistage deformations, which were characterized by widely develops of fractures (Liu, et al., 2008). Significant differences in clay mineral assemblages and chemical composition were identified in rocks from the fault gouge, through a series of analytical techniques including X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF). The analysed fault gouge is exposed in the silty mudstone in devonian Niqiuhe formation in the Dayangshu basin. The fault gouge we obtained is dozen centimeters in thickness, and we examined the clay mineralogy of the fault gouge vertical to fault strike and fault plane, the relative samples that obtained by equal interval sampling method were labeled as XY0, XY1, XY2, XY3, XY4, XY5 (Fig. 1). The samples were hand-crushed and grounded to powder, and then the <2