42
Six quartz grains (1a, 2a, 2b, 3a, 3b and 3c) were selected from ST-1 glacial
surface for SEM studies (Fig. 12). The microphotographs were taken at 350 to 800
magnifications. The picture at ‘1a’ shows an irregular grain boundary with sharp
edges. The surface has few deep breakage areas, which are characteristics of splitting/chipping off. At ‘2a, 3a, 3b and 3c several planes show fractures and broken
fragments sticking on to the surfaces, which is the indication of high energy erosion.
Figure  12 (2b) shows well developed cleavage surfaces parallel to the foliation
plane. All these photomicrograph especially the Fig. 12 (3a), show conchoidal fractures and splitting surfaces very prominently. The Multiple crushing episodes are
indicated from this scenario.
The micrographs pertaining to sample ST2 (Fig.  13) show multiple events of
glacial crushing with overprinting of recycled features. Characteristic conchoidal
fractures at different scales, indicating glacial flurry and chipping off is seen in
Fig. 13 (1a). In addition to these features, the Fig. 13 (1a and 1c) show some chemi0
ST1 ST2
ST4
ST5
NH
ST3B
ST1 ST2
ST4
ST5
NH
Clay (%)
CaCO 3 (%)
IC (%)
OC (%)
Silt (%)
Sand (%)
ST3B
Sampling Stations
Sampling Stations
a
b
Sampling Stations
Weight (%)
2
4
6
8
10
20
30
40
50
60
70
80
90
100
0.000
0.005
0.010
0.015
0.040
0.080
0.120
0.160
0.200
Fig. 8 Bar Diagram
illustrating comparative (a)
sand-silt-clay percentage,
and (b) concentration of
organic carbon (OC),
inorganic carbon (IC) and
carbonate (CaCO 3 ) in
percentage for different
samples (ST1-NH)
R. Ravindra