Experimental studies of He and Ar degassing during rock fracturing

We studied degassing of He and Ar from granite, basalt and volcanic tuff samples which were subjected to uniaxial compression. From the samples which were fractured in the dilatant region He was always degassed, while degassing of Ar dependent not only on the dilatancy, but also on the type of rock and the compressional conditions such as wet, room dry or vacuum conditions. It is concluded that degassing of rare gases from the compressed samples depends primarily on the generation of new surface area by dilatancy.