Fig. 2
From: Artificial weathering of rock types bearing petroglyphs from Murujuga, Western Australia
Photographs of the rock varnish on the surface of a the gabbro and b the granophyre samples from Murujuga. Cubes from a the more coarsely grained gabbro and b finely grained granophyre. The weathered rind of the gabbro is more porous compared to the weathered rind of the granophyre. The recesses on the lower right-hand side (red arrow) have been engraved to facilitate repositioning of the cubes for all analytical measurements performed