Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

S. Rajendran ¹, P. Karthikeyan ¹, P. Seralathan ¹

Affiliations
1 Marine Geology Division, School of Marine Sciences, Cochin University of Science and Technology, Kochi - 682 016, IN

Abstract

Size specific abundance of heavy minerals (HM) in sediments of lower Bharathapuzha indicates an increase towards finer sizes, with the average maxima at ASTM +170. HM content in the bulk sample is similar to that of ASTM +60. Opaques, hornblende and pyroxenes are responsible for more than 90% variability. Garnet, monazite, zircon and sillimanite are least abundant. Hornblende, pyroxene and garnet are enriched in ASTM +60 but depleted in ASTM +230, whereas opaques show a reverse trend. HM content of bulk is similar to that of ASTM +60 and +120.

Heavy metal distribution has also been examined and the order of abundance is Fe>Mn>Ni>Cr>Zn>Pb>Cu>Cd. Bulk samples show the lowest content. Mud fraction is emiched in metals, i.e., more than five fold for Zn, Cu and around three fold for Ni, Cr, Mn and Fe. The difference of metal abundance between HM and mud fraction is only marginal for Ni and Pb. In HM, Cd, Cu and Zn content are very low whereas Cr, Mn and Fe are enriched. EF (Enrichment Factor) values of Cu, Zn, Cr and Mn are close to crustal abundance whereas Cd and to a small extent Pb show relatively high values possibly resulting from anthropogenic contributions.

Keywords

Geochemistry, Heavy Minerals, Bharathapuzha, Kerala.

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