The Origin of Nanoscopic Grooving on
Vesicle Walls in Submarine Basaltic Glass:
Implications for Nanotechnology
Figure 2
SEI images of other similar vesicles. The vesicle shown in (a)–(d) exhibits grooved features analogous to those shown in Figure 1, but is from a different glass fragment from the same pillow margin sample, and is coated with a 5–15 thick layer of Cr. (a) Overview of the vesicle highlighting a step (S) in the fracture that exposed the vesicle, which formed in lee of it as the propagating fracture opened it from upper right to lower left, and pits (P) along the edge of the vesicle indicating where sulfide spherules once were. (b) Close-up of the vesicle from (a) showing numerous sulfide spherules (SS) and multiple elongate ribbon-like domains that exhibit a wrinkled surface texture (W). Such wrinkled, ribbon-like domains are interpreted as another form of pull-apart viscous deformation contemporaneous with viscous fingering and development of tension gashes (see Figure 7). (c) Close-up of the vesicle from (a) showing where a solitary viscous finger seems to have pulled a U-turn (U) before stopping and spreading out into a terminal bulb as it was shielded by a sulfide spherule (SS). Some faint, more lobate viscous fingers at left are interpreted to indicate shallowing of the boundary layer to perhaps 10 nm there. (d) Close-up of the vesicle from (a) showing where viscous fingers intersect the plane of the fracture that exposed their host vesicle, allowing for a precise estimate of finger depth at 50 nm (arrow). (e) Overview of a portion of a vesicle that is nearby (400m away on the same fragment of glass) to that shown in Figure 1, exhibiting branching grooves of the same size, but with a slightly different form. In this case the nanoscopic grooves lack the distinctive terminal bulbs and lobate forms observed in the other two vesicles (Figures 1 and 2(a)–2(d)), and, instead of viscous fingers, are interpreted to represent brittle radial microfractures that formed in a thin boundary layer surrounding the vesicle. (Sample is coated with 150 of Au.)
