Figure 3
From: Fracture-matrix fluid exchange in oil-bearing unconventional mudstones
Top row: optical images (diameter ~ 3.81 cm) with elemental map (~ 1 cm × 2.5 cm) overlay showing that the primary compositional variation is an evolution of the silt/carbonate ratio, where the legend on the right indicates color scheme used in the elemental map. Middle row: Magnified view of highlighted region on elemental maps showing fine resolution (~ 5 μm) of EPMA technique and variation in breadth of grain size. Bottom row: SEM micrographs with energy dispersive x-ray spectroscopy (EDS) at various points to verify changes in composition and grain size.
