Figure 7.
Microstructures of antigorite bare surfaces. (a) Photomicrograph showing dark striations on slip surface at low normal stress: Run 727, σn = 8.8 MPa. (b) SEM micrograph of dark band from sample from Run 727 showing melt-like tendrils and bulbous features on the slip surface. (c) Photomicrograph showing glass-like band on cut section of the slip surface at higher normal stress: Run 733, σn = 19.5 MPa. (d) Magnified region from Figure 6c showing glassy luster and transparent nature of the material. (e) SEM micrograph from polished glassy surface shown in Figure 7d. (f) Enlargement from Figure 7e showing gray ultra-fine-grained matrix with bands of nanometer-scale iron-rich minerals that are too fine-grained to resolve.