Figure 7
SEM images of melted AH quartz grain. (a) SEM topographical image of 15-μm-wide grain on the inner wall of an AH glass vesicle. The darker gray central portion of the image is a smooth, melted quartz grain with no apparent crystalline structure. From level 445, sample E301, 405 cm depth. (b) Manually constructed EDS-based phase map with light red representing the aluminosilicate glass matrix, blue representing melted quartz grain, and green representing zone of diffusion of SiO2 into the matrix. The crack was likely caused by thermal contraction during cooling. Percentages of SiO2 range from 100 to 68.0 wt.%). (c) SEM topographical image of melted zircon of melted 8-μm-wide zircon grain embedded in an outer surface of AH glass. (d) Manually constructed EDS-based phase map of same grain with the zircon weight percentage ranging from 100 → 90 → 70 → 0 wt.%. (e) SEM image showing the location of zircon grain in melted 2.7-mm-wide AH glass fragment. From level 449, sample E305, 412 cm depth.
