L - Cochin University of Science and Technology
L - Cochin University of Science and Technology
L - Cochin University of Science and Technology
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in deeper depths no change has taken place. Off Veraval region silty clay at 30 <strong>and</strong><br />
50 m was replaced by clayey silt <strong>and</strong> clayey s<strong>and</strong> at 75 m also changed to clayey silt.<br />
S<strong>and</strong> in the deeper station showed no change as that <strong>of</strong> previous transect. Off<br />
Dwaraka, shallow depth recorded no change in the texture, but in deeper station silty<br />
clay has changed to s<strong>and</strong>y clay. In general shallow stations have high clay<br />
percentage <strong>and</strong> deeper stations sustained more <strong>of</strong> s<strong>and</strong> during both the seasons. S<strong>and</strong><br />
percentage decreased to north during both seasons however, during post-monsoon<br />
season the decrease was not as gradual as pre-monsoon.<br />
Statistical analysis based on Student's t test showed that significant difference<br />
between two seasons observed in the shallow depths <strong>of</strong> 30 m <strong>and</strong> 50 m only (Table<br />
2). Silt <strong>and</strong> clay showed significant difference in the 30 m while only clay showed<br />
considerable di fterence between two seasons at 50 m zone.<br />
4.1.3. Discussion<br />
The results <strong>of</strong> the study revealed transect wise <strong>and</strong> depth wise variations in the<br />
texture during the two seasons. Southern part sustained coarser fraction whereas<br />
northern part showed fine texture. Depth wise, shallow areas sustained more clay<br />
content <strong>and</strong> deeper stations had more s<strong>and</strong> content. Six types <strong>of</strong> sediment textures<br />
were obtained during both the seasons, in which silty clay dominated during post<br />
monsoon while silty clay, clayey s<strong>and</strong> <strong>and</strong> s<strong>and</strong>y sediment were predominant during<br />
pre-monsoon.<br />
Occurence <strong>of</strong> fine sediment texture in the shallow areas <strong>and</strong> coarser sediment<br />
in the deeper depths is comparable to that <strong>of</strong> earlier reports. Nair <strong>and</strong> Pylee (1968)<br />
showed that inner shelf (40m) <strong>of</strong> west coast <strong>of</strong> India are floored with poorly sorted<br />
silty clay <strong>and</strong> further southwards a zone <strong>of</strong> fine to medium s<strong>and</strong> exist. Kidwai <strong>and</strong><br />
Nair (1972) pointed out that outer shelf <strong>of</strong> Mumbai is generally coarser <strong>and</strong> inner<br />
shelf is finer with silt <strong>and</strong> clay. Nair (1975) while elucidating the textural<br />
characteristics <strong>of</strong> western continental shelf (<strong>of</strong>f Mumbai to Karwar) <strong>of</strong> India, reported<br />
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