Grain Characteristics of Zircons of Beach Sands from Southwest Coast of India

Abstract The mineral beach sands of the southwest coast of India, particularly of Chavara and Manavalakurichi areas, contain 4-6% zircon. Although the general setting of the zircon-bearing sands in these two areas is similar, the zircon grain characteristics show some differences. The Manavalakurichi zircon is coarser than the Chavara zircon and in the former, the grain-size has in general a positive correlation with the aspect ratio, whilst in the latter, the correlation is not straightforward. Zoning is more prominent in the Chavara zircon than in the Manavalakurichi zircon. In contrast to the Chavara zircon, the Manavalakurichi zircon shows statistically significant preferred association of idiomorphic grains with microfractures. The level of inclusions (ilmenite, rutile, monazite, quartz, apatite and fluid), either in single phase or in polyphase, is higher in the Manavalakurichi zircon than in the Chavara zircon. The source rock (s) of these zircons may not have been much dissimilar.