Heavy minerals

Abstract

A wide range of detrital minerals may sometimes be observed in minor amounts in marine sediments. These include zircon, tourmaline, kyanite, sillimanite, rutile, anatase, epidote, garnet, andalusite, staurolite, sphene and many others. These minerals are generally uncommon in deep-sea sediments reflecting their low abundances in rocks and/or their relative instability in the marine environment. However, when they do occur, they may be exceptionally useful as clues to the nature of the source rocks and may be especially valuable in determining the source of turbidite beds. Many of these are termed ‘heavy’ minerals as they have specific gravities greater than 2·9 and hence sink in bromoform. This forming the basis of a separation technique which allows such dense minerals to be separated from the bulk of the sediment.