Genesis of host rock in the Tamusu Mudstone pre-selected area in Northwest China for high-level radioactive waste geological disposal purposes

Abstract Mudstone characterized by typical structures and mineral assemblages in the Tamusu pre-selected area, Inner Mongolia, Northwest China, has been selected as a potential host rock for China’s high-level radioactive waste (HLW) repository purpose. Based on indications of petrological geochemical characteristics, hydrothermal sedimentary geneses are well discussed from perspectives structures, environments, model. The results show that rocks have characteristics low-temperature "white smoke" rocks. developed dry, anaerobic reducing saline lake environment with transient oxidation dry–wet evolution. 100–120 Ma tectonic activity Altun fault may main factor controlling process exhalative, which provided migration pathway water–rock reactions contributed to formation assemblages. is new kind argillaceous serves rock, will provide insights into suitability evaluations mudstone properties promote site screening area HLW disposal