Fig. 9
From: Artificial weathering of rock types bearing petroglyphs from Murujuga, Western Australia
source power, < 5 mW on the sample surface) was used and each point was measured 2 times 10 s
Hyperspectral Raman image from an area a of a pristine granophyre cube and b after it was artificially weathered for 4 months. Both images show the distribution of quartz, iron oxides (mainly hematite and magnetite), anatase, and calcite. The images reveal no significant changes in mineralogy. One calcite crystal seems to have disappeared on image b and some anatase crystals seem to have formed, which can be attributed to repositioning errors, which are in the same order of magnitude as the crystal sizes. The 632.81 nm laser with 17 mW power (