Sureau, Experimental investigation of clogging of fissures and pores in granite, Mineral

ABSTRACT. Fluid flow through a fractured granite core and leaching experiments ongranite powder (at constant temperatures of 50 and 100 ~ and during cooling from 100 to 50 ~ indicate that the dissolved silica content of the fluids originates from the dissolution of feldspars and phyllosilicates. The dissolution of quartz is not ruled out but it should be a minor phenomenon. The precipitation of quartz may control the dissolved Si content during constant temperature leaching. During cooling from 100 to 50 ~ chalcedony, alumino-silicates, and chlorite are all capable of precipitation, possibly leading to some clog-ging or sealing of fissures. KE V WO R D S: granite, fluids, fissures, ilica. STORAGE in geological formations is presently considered to be one of the most realistic mean