Heavy Minerals in Beach Sands of Gopalpur and Paradeep Along Orissa Coastline, East Cost of India

Indian Journal of Marine Sciences Vol. 32(2), June 2003, pp. 172-174 Short Communication Heavy minerals in beach sands of Gopalpur and Paradeep along Orissa coastline, east cost of India P. Behera Deprtment of Geology, Utkal University, Bhubaneswar-751 004, Orissa, India [ E-mail : [email protected] ] Received 29 March 2001, revised 27 February 2003 Selective sand samples were collected from Gopalpur and Paradeep beaches and studied for their heavy mineral assemblage. Beachsands of both the areas contain heavy minerals like sillimanite, ilmenite, garnet, pyroxene, rutile, sphene, biotite, hornblende, zircon and monazite. At Gopalpur, the percentage of concentration of sillimanite is the highest followed by limonite, garnet, pyroxene, rutile, sphene, biotite, hornblende, zircon and monazite. At Paradeep, almost similar trend was observed with some exceptions, i.e., concentration of pyroxene and biotite is more here. The mineral sphene was absent at Paradeep, whereas tourmaline was negligible at Gopalpur. Higher grade percentage of heavies at Gopalpur is linked with many favourable factors and is being mined by IREL whereas low grade percentage at Paradeep discourages mining. [ Key words : Beach sands, Gopalpur beach, heavy minerals, Orissa, Paradeep beach ] The state of Orissa is one of the important littoral coastal tract of Orissa around the village Gopalpur states of the eastern sea board due to concentration of (Fig.1). Sand samples, about 2 kg by weight were heavy minerals at different places particularly from collected from Gopalpur and Paradeep sea beaches. 1 the south of Mahanadi mouth to Orissa – A.P. border . Twelve samples each were collected from Gopalpur Atomic Minerals Directorate for Exploration and and Paradeep covering a distance of about 6 km. The Research (AMD) of the department of Atomic Energy sampling points were located at an interval of is exploring and assessing the potential of the Orissa beach placers since 1958-59. The exploration work was mostly confined to southern Orissa coast, between Orissa-Andhra Pradesh state border and Mahanadi delta1. A number of potential fields have been discovered between Rushikulya river in north and Pedda-lakshmipuram village near Orissa Andhra border in the south cover a distance of 43 km. Of these, the northern 18 km long strech between Rushikulya river and Gopalpur town is known as “Chatrapur Mineral Sands Deposit”, currently being explored by Indian Rare Earth Limited (IREL)1. The occurrence of coastal sand dunes containing monazite, zircon, ilmenite, rutile, and sillimanite in south Orissa on the east coast of India, especially along Ganjam coast is known since a long time2, 3. Recent work along Puri coast has identified wider sand bodies with significant heavy mineral concentration, which requires detailed exploration for their heavy reserve potential1. The purpose of the present paper is to study the heavy minerals of Paradeep and Gopalpur beaches and assess the economic viability for mining at Fig. 1 — Map showing the study area and coastal segments of the Paradeep. (Fig.1). The area under study is a part of Orissa coast Short communication 173 500 m. A hand operated sand augur having one and mining. From this result it is found that costly heavies half inch diameter was used to collect the samples. like ilmenite and monazite occurring as 18.94 (wt %) Collection of the samples was done in the pre- and 0.59 (wt %) respectively give some hope for monsoon period, i.e. in the month of May, 2001. In mining in future. However a detailed study over a both the beaches the samples were collected mostly long stretch of beach covering large area may bring from the back shore region from a depth of 0.75 m. some conclusive and positive result. Each sample was washed and exposed to sun for six Mineralogical assemblages in beaches vary from hours and then dried up in an oven at 200oC for two one region to another depending on a number of hours. The samples were sieved through a set of factors like host rocks in their provenance, climatic ASTM sieves having numbers +60, +80, +120, +170 conditions prevailing in the area, agents and and +230 followed by standard bromoform separation mechanism of transport and hydraulic conditions technique4. All the size fractions of 60, 80, 120, 170 during deposition6. The sediments that are delivered and 230 sieve samples were subjected to bromoform into the sea by the river will be redistributed by the separation. The coarser fractions 60, 80, 120 did not waves and currents according to their densities, size yield any heavy mineral concentration whereas the and shape7. The concentration of heavy minerals finer fractions of +170 and +230 yielded heavy depends on the hydrodynamic conditions like minerals. Slides were prepared from +170 and +230 sediment influx from the hinterland, wave energy and fractions and point counting was done. About 300 its velocity, long shore current and wind speed which grains in each slide were identified and counted using control littoral transport, sorting and deposition of the line method5. The number percentage of each placer minerals in suitable locales1. In present case heavy mineral was then computed and converted into mostly aeolian and marine actions have played a weight percentage by multiplying with the specific significant role and the shape of coastal gravity of the respective minerals. geomorphology have played important role in the The study of minerals of +170 fraction of Gopalpur concentration of heavy minerals. The distribution (Chatrapur) by point counting indicates that minerals pattern exhibited by ilmenite, garnet, sillimanite and like sillimanite, ilmenite, garnet, pyroxene, rutile, pyroxene suggest that differences in specific gravity, sphene, biotite, hornblende, zircon and monazite were settling velocity and differential transport have played found in order of decreasing abundance (Table 1). a major role in their distribution7 at Gopalpur and The heavy minerals of Paradeep are very much Paradeep. identical to that of Gopalpur. The heavy mineral The heavy minerals of both the beaches have been concentration (wt %) in +170 size fractions varies derived from the same Eastern Ghat Group of rocks from 0.44 to 2.92 %, in +230 fractions varies from comprising granites, gneisses, and metasediments of 0.23 to 2.15 % and total weight percentage varies Archaean to Proterozoic age and Gondwanas exposed 1 from 0.25 to 4.42 % at Paradeep beach after in the hinterland . The coast between the Devi river in bromoform separation. The average comes around the south to the Mahanadi river in the north forms the 2.23 % which does not seem to be promising for Paradeep sector with deltaic sediments of the Mahanadi river system. The coastal area is low lying and marshy with mangrove forests and traversed by Table 1 — Heavy minerals at Gopalpur and paradeep sea beaches numerous back water channels and lagoons. Wider Mineral Gopalpur Gopalpur Paradeep Paradeep sand bodies are found both in the barrier beach and (no %) (wt %) (no %) (wt %) along western margin towards inland1. Mahanadi Sillimanite 50.5 43.7 42.5 37.18 delta is a composite prograding delta. Three major Ilmenite 18.7 23.7 14.7 18.94 generations of deltaic sediments have been mapped8 Garnet 13.7 15.37 22.0 25.07 from the lower portion of Mahanadi. These deltaic Biotite 0.9 0.72 3.2 2.60 sediments are underlain by Gondwana sediments and Rutile 4.0 4.48 2.8 3.19 have a minimum thickness of more than 2400 m and Pyroxene 7.7 6.78 12.0 10.74 Tourmaline Nil Nil 0.69 0.57 2000 m near Konark (mouth of Devi river) and 9 Monazite 1.1 1.49 0.43 0.59 Paradeep respectively . Eleven abandoned delta lobes Zircon 0.91 1.1 0.22 -- and three strand lines have been identified in coastal Hornblende 0.86 0.7 0.74 -- plains of the Mahanadi delta10. The poor presentation Sphene 2.0 1.87 Nil Nil of beach ridges has been attributed to dominant 174 Indian J. Mar. Sci., Vol. 32, No. 2, June 2003 fluvial action. Delta progradation has resulted 2 Pascoe E H, A manual of geology of India and Burma, Vol. 1 recession of sea with development of a number of (Govt. of India Press, Calcutta) (1950), pp. 483. palaeo-strand lines deep inland. A number of palaeo- 3 Rao Babrubahan K, Origin and evaluation of sand dune sand ridges of 10-15 km inland from present day deposits of Ganjam coast, Orissa, India, Exploration and Research for Atomic minerals, 2 (1989) 133-146. shore lines is seen above the cultivated land attaining 1 4 Hubbert J F, Analysis of heavy mineral assemblages, in: heights of more than 10 m. Procedures in sedimentary petrology, edited by R E Carver, 1 Atomic Mineral Division’s survey of some palaeo- (Wiley Inter Science, New York) 1971, pp. 453-478. sand ridges showed heavy mineral grade range 5 Galehouse J S, Counting of grain mounts number percentage between 2 and 64 % (average 16.47 %). However, the vs number frequency, J Sed. Petrol., 39 (1969) 812-815. present study area in Paradeep beach does not show 6 Borreswar Rao C, Beach erosion and concentration of heavy promising result. A detailed study for a long strech of minerals, J.Sed. Petrol., 27 (1957) 143-147. beach is required before commenting on the economic 7 Komar P D & Wang Chi, Processes of selective grain viability for mining. The minerals are mined at transport and the formation of placers on beaches, J.Geol. 92(1984) 637-655. Gopalpur (Chatrapur) by Indian Rare Earth Ltd. 8 Ghosh R N & De S K, Sedimentological analysis of coastal (IREL) because of high concentrations of sillimanite, sands Mahanadi Delta, Geol. Survey of India, Sp.

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