Chapter 13 Geochemistry of Heavy Minerals

This contribution provides an insight into the use of mineral chemistry in provenance research, and demonstrates how studies, by using microbeam techniques on several detrital heavy mineral species, benefit from continuing technological advances. Virtually all detrital heavy minerals can now be subjected to sophisticated geoanalytical techniques that can determine their major and trace element compositions and identify their crystal chemistry. Petrogenetic controls impart distinctive elemental signatures to mineral phases in igneous and metamorphic rocks that are preserved in mineral grains eroded from them, and can be used as a genetic tool to help decode their parageneses. Of particular interest are those heavy minerals that are widespread in sediments with compositions that are suitable for routine geochemical analysis. In this review, the geochemistry of garnet, tourmaline, chrome spinel, apatite, pyroxenes and amphiboles and its application to specific geological problems is discussed in detail; brief references are given to minerals that have not been used frequently in provenance studies. It is important to emphasise that a particular species, chosen for geochemistry, is generally associated with other minerals that are also carriers of information. Therefore, mineral chemical data need to be integrated with information from the whole assemblage to ensure that the conclusions are truly comprehensive.