Knowing what I know, I am assuming this image was standardised and then normalised (fancy stats algos to keep things in the same visual range) while stitching it together, and the final product enhanced a lot of colouration (saturation). They’re subtle or undetectable to the naked eye, but they exist. They are reflected in the different minerals present. I’ve done this stuff (raster stitching) with different imagery. Op was active in the comments with info, but I didn’t read up on it.