Coesite from the Richat Dome, Mauritania: A Misidentification

Science  10 Oct 1969:
Vol. 166, Issue 3902, pp. 228-230
DOI: 10.1126/science.166.3902.228


The "shattered sandstone" from Richat reported to contain coesite is a tectonic breccia and probably represents a shear zone developed during the structural doming. An optical and x-ray examination of concentrates from this breccia demonstrated that the supposed x-ray reflections of coesite are actually due to barite, introduced into the permeable crushed zone by groundwater.