Indian Journal of Marine Sciences Vol. 28, September 1999, pp. 257-262 Heavy mineral distribution and sediment movement at Kwada and Belekeri Bay Beaches, west coast of India P T Hanamgond Department of Geology, G.S. Science College, Belgaum - 590006, Karnataka, India PB Gawali Indian Institute of Geomagnetism, Colaba, Mumbai - 400 005, India and V C Chavadi Department of Studies in Geology, Karnatak University, Dharwad - 580003, Karnataka, Indi a. Recei ved 7 January /998, revised 3/ March /999 The present study on the heavy mineral assemblage from the sediments of beaches was made in order to understand the spatial, seasonal and longshore distributions, source of the sediment (Provenance) and the sediment movement. The study has indicated the presence of Magnetite, Ilmenite, Hornblende, Tourmaline, Sillimanite, Rutile, Garnet, Zircon, Kyanite etc .; they are enriched in tiner sand fractions. The heavy mineral assemblage of this stretch indicates the mixed provenance or Igneous and Metamorphic rocks with reworked sediments especially at Belekeri bay beaches. The mineralogy of the clastic sediments is important to understand their provenance and transportation history. Each type of source rock tends to yield a dis- tinctive suite of minerals, hence are exceptionally useful clues to the nature and type of source rocks l . 2. Source of sediments and strength/energy of the cur- rent carrying the sediments are claimed to be the in- fluencing factors of grain size characters and min- eralogical composition 3 , and the light minerals such as feldspars are impoverished along the direction of transport 4 • 5 . The present work, aims at the under- standing of the heavy mineral distribution, prove- nance and sediment movement along the study area. Materials and Methods The investigated area is confined to the coastal tract between Aligadde and Harwada beaches (Fig. 1), situated on central west coast of India. The study area includes four beaches of two bays, Kwada Bay (Aligadde Beach and Kodar Beach) and Belekeri Bay (Mudga Beach and Harwada Beach), which lie be- tween latitudes 14° 42'to 14° 47' N and longitudes 74° 9' to 74° 17' E, and are oriented NW-SE (140° w. r. t N) except Aligadde beach which orients E-W (90° w. r. t N). Belekeri Bay is a sheltered and deeply incised type compared to Kwada Bay exhibiting dif- ferent physiographic and geomorphic setup. The beaches are separated by rocky headlands and inter- mittent sandy stretches, especially between Kodar and Aligadde Beach; and between Mudga and Kodar Beach. The entire coast is bordered by Western Ghats on the eastern side and Arabian Sea on the west. Fifteen locations (Fig. I) were selected from th e Kwada and Belekeri Bay Beaches. The heavy miner- als were separated from varying sizes (-60 +80 to -170 +230) of mid foreshore sediment samples co l- lected at all the locations along th e beach during monsoon (August, 1989). As the concentration of heavy minerals was fairly large 6 at Harwada beach, mid foreshore samples collected during postmonsoon 14· 47' N 14· L-------------.: ....... l-:;;7';;;.1::;;-'7. 42' "og, Fig. l--Locati on map of the study area.