46
(Mahaney 1995). Secondary precipitation within the depressions can be noticed.
Smooth grain surface, prior to the mechanical breakage, is still preserved on the
southeast corner of the micrograph along with some silica precipitation in the top
northeast corner. The cleavages are closely spaced in the Fig. 15. Two grains shown
in Fig. 15 (3b) from this surface expose sharp conical shapes with closely spaced
conchoidal fractures that indicate impact of the forceful breaking on the grain.
Figure 16 shows a fresh cleavage surface that has markings of secondary deposit.
Fig. 12 SEM microphotographs for glacial surface ST-1
R. Ravindra