Figure 2: Phreatomagmatic versus plinian eruptive products.
From: Determining volcanic eruption styles on Earth and Mars from crystallinity measurements
Representative groundmass diffraction patterns (a,c) and scanning electron microscope back-scatter images (b,d) for a phreatomagmatic eruption (Surtsey) and basaltic plinian eruption (Tarawera). Grey regions in a,c represent the area under the diffraction pattern associated with the amorphous (Amorph., glass) component from 10–40° 2θ. Bragg peaks, identified here by X-ray count rates above background, represent the diffraction of X-rays off various lattice planes within minerals in the sample, and therefore represent the crystalline component. White scale bars, 20 μm (b,d).
