37
Calvert and Pederson (1993), particle size variations and the amount of carbonates
and organic matter present in the sediments are primarily controlled by geological
and chemical factors such as provenance, precipitation, oxic/anoxic conditions etc.
Based on this observation, an attempt has been made to understand the processes
involved in the deposition of sediments. The measured particle size variations (sandsilt- clay) of the six selected samples (ST1-NH) are given in Table 1 and result shown
in Fig. 7. The sand-silt-clay ratio determined from these samples shows that the
sand percentage is varying within 71% (ST4) and 95.22% (ST5), silt percentage
varies between 3.06% (ST5) and 15.54% (ST4), and the clay percentage falls within
1.72% (ST5) to 13.46 (ST4). The results are depicted in Fig. 7. The analysed data
suggests that the sand constitutes major part of the soil while clay fraction is generally negligible to minimum. It is at the vertical sections of some lake margins that
fine lamiae of clay are seen. Both the Organic Carbon content and the Inorganic
Carbon as also the variation in the CaCO 3 in the samples is very low (Table 1 and
Fig. 7). This is justified as there are no plant or vegetation constituents that could
contribute towards deposition of Carbon in the sediments.
Fig. 6 Map showing sample locations for trace metal analysis. (After Ravindra et al. 2001)
Table 1 Sample locations and their data of different analysed parameters such as sand, silt, clay,
organic carbon and carbonate percentage
Sample
No.
Latitude
(S)
Longitude
(E)
Sand
(%)
Silt
(%)
Clay
(%)
OC
(%)
IC
(%)
CaCO 3
(%)
ST1
70°45.875′ 11°44.111′
82.81
11.81
5.38
0.00
0.004 0.04
ST2
70°45.937′ 11°44.151′
87.63
9.53
2.84
0.04
0.004 0.03
ST3B
70°45.991′ 11°43.806′
87.72
8.32
3.95
0.06
0.004 0.03
ST4
70°46.083′ 11°43.989′
71.00
15.54 13.46
0.07
0.005 0.04
ST5
70°46.231′ 11°44.178′
95.22
3.06
1.72
0.03
0.005 0.04
NH
–
–
29.96
35.27 34.77
–
–
–
Glacial Sediments of Schirmacher Oasis, East Antarctica and their Characteristics
Calvert and Pederson (1993), particle size variations and the amount of carbonates
and organic matter present in the sediments are primarily controlled by geological
and chemical factors such as provenance, precipitation, oxic/anoxic conditions etc.
Based on this observation, an attempt has been made to understand the processes
involved in the deposition of sediments. The measured particle size variations (sandsilt- clay) of the six selected samples (ST1-NH) are given in Table 1 and result shown
in Fig. 7. The sand-silt-clay ratio determined from these samples shows that the
sand percentage is varying within 71% (ST4) and 95.22% (ST5), silt percentage
varies between 3.06% (ST5) and 15.54% (ST4), and the clay percentage falls within
1.72% (ST5) to 13.46 (ST4). The results are depicted in Fig. 7. The analysed data
suggests that the sand constitutes major part of the soil while clay fraction is generally negligible to minimum. It is at the vertical sections of some lake margins that
fine lamiae of clay are seen. Both the Organic Carbon content and the Inorganic
Carbon as also the variation in the CaCO 3 in the samples is very low (Table 1 and
Fig. 7). This is justified as there are no plant or vegetation constituents that could
contribute towards deposition of Carbon in the sediments.
Fig. 6 Map showing sample locations for trace metal analysis. (After Ravindra et al. 2001)
Table 1 Sample locations and their data of different analysed parameters such as sand, silt, clay,
organic carbon and carbonate percentage
Sample
No.
Latitude
(S)
Longitude
(E)
Sand
(%)
Silt
(%)
Clay
(%)
OC
(%)
IC
(%)
CaCO 3
(%)
ST1
70°45.875′ 11°44.111′
82.81
11.81
5.38
0.00
0.004 0.04
ST2
70°45.937′ 11°44.151′
87.63
9.53
2.84
0.04
0.004 0.03
ST3B
70°45.991′ 11°43.806′
87.72
8.32
3.95
0.06
0.004 0.03
ST4
70°46.083′ 11°43.989′
71.00
15.54 13.46
0.07
0.005 0.04
ST5
70°46.231′ 11°44.178′
95.22
3.06
1.72
0.03
0.005 0.04
NH
–
–
29.96
35.27 34.77
–
–
–
Glacial Sediments of Schirmacher Oasis, East Antarctica and their Characteristics