NOPR Collection:

Heavy Metals & Mineralogy in Sediment Cores from a Tropical Coastal Lagoon, Mexico

2016-12-16T11:01:59Z

Title: Heavy Metals & Mineralogy in Sediment Cores from a Tropical Coastal Lagoon, Mexico Authors: Paez-Osuna, F; Fong-Lee, M L; Fernandez-Perez, H; Lozano-Santacruz, R; Villasenor, G Abstract: Concentrations of Fe, Co, Ni and Cd in this lagoon are comparable to similar but affected systems. Cu, Zn, Cr and Pb are, however, lower than those found in contamined estuaries. One core (CP-3) shows an exponential increase of all metals toward the surface. This distribution may lead to erroneous interpretations, attributing it to pollutant input. Clay minerals of the cores consist of kaolinite (41-69%), illite (21-52%), montmorillonite (1-12%) and traces of gibbsite. Variable proportions of illite and kaolinite in the Copala river core can be explained by a depositional environment with varying influence from non-marine to marine conditions. Quartz, feldspar and amphiboles found in the silt fraction of all cores indicate that the sediments in all parts of the lagoon are composed mainly of detrital material. Page(s): 153-158

Some sedimentological aspects of Vembanad Lake, Kerala, West Coast of India

2016-12-16T10:59:47Z

Title: Some sedimentological aspects of Vembanad Lake, Kerala, West Coast of India Authors: Mallik, T K; Suchindan, G K Abstract: Average depth in the Vembanad Lake south of Tannirmukkom bund (lat. 9ᵒ30' to 9ᵒ40'N and long 76ᵒ21' to 76ᵒ26'E) is 3 m while the maximum depth being 8.5 m. Quartz is the main constituent of the sediment which is an admixture of clay, silt and sand. Lesser amounts of muscovite, feldspar, chlorite, heavies, clay minerals and shell fragments are also present. Heavy mineral assemblage indicates that the sediments are derived from the charnockites, granite gneisses, khondalites and pegmatites. Landsat imagery of this area is characterised by number of beach ridges oriented in direction varying from 10ᵒ-190ᵒ to 155ᵒ-335ᵒ. Two main processes are responsible for the formation of Vembanad Lake - an initial tectonic phase followed by natural sedimentation processes affected by waves, currents and tides. Page(s): 159-163

Studies on nearshore processes at Yarada Beach (South of Visakhapatnam Harbour), East Coast of India

2016-12-16T10:57:15Z

Title: Studies on nearshore processes at Yarada Beach (South of Visakhapatnam Harbour), East Coast of India Authors: Chandramohan, P; Rao, T V Narasimha; Rao, D Panakala; Rao, B Prabhakara Abstract: Influence of breakwaters on Yarada Beach, Andhra Pradesh, India (3.5 km length) stability and distribution on wave induced longshore currents in this region were studied. Monthly observations on variation in beach levels, distribution of wave induced longshore currents and visual observations on breaker heights and breaker angles were made at 8 stations from January 1978 to January 1979. There was accretion in Yarads Beach with a net addition of about 12,000 m³ of sand during the study period. Seasonal erosion and accretion patterns differed from place to place along the beach. Wave induced longshore current direction was towards NE from March to September and towards SW from November to February and its speed varied between 0.1 and 0.4 m sec^-1 during study period. Page(s): 164-167

Tidal flow characteristics at Kasheli (Kalwa/Bassein Creek), Bombay

2016-12-16T10:55:22Z

Title: Tidal flow characteristics at Kasheli (Kalwa/Bassein Creek), Bombay Authors: Swamy, G Narayana; Suryanarayana, A Abstract: Tidal flow characteristics of waters at Kasheli, connected to the sea through Thane and Bassein Creeks in Bombay, Maharashtra, India are investigated based on tide and current observations carried out in 1980-81. The results establish that the tidal water enters the channel first through Bassein Creek rather than from Thane side. The currents are strong, (1 m.sec^-1) and are tidal, while during SW monsoon considerable flow towards the Bassein side is noticed. However there is indication that the flood tide water at Kasheli partly escapes into Thane Creek. Page(s): 168-171