Fig. 4
From: Weathering in a world without terrestrial life recorded in the Mesoproterozoic Velkerri Formation
SEM backscatter and cathodoluminescence images of silica overgrowth cement around quartz grains. a SEM backscatter image showing two 25 µm quartz grains surrounded by clay sized minerals from Urupunga-4. b SEM cathodoluminescence image illustrating 3 to 4 angular quartz grains that have strong luminescence indicating a detrital origin46 with non-luminescent silica cement forming overgrowths that appear as silt sized grains. Scale bar = 10 μm
