Heavy mineral analysis

Heavy minerals (minerals with a density greater than 2.89 g/cm3) have highly variable stabilities with respect to transport/weathering but the combined effects of chemical weathering, transport and diagenesis (and overall maturity) tend to decrease their percentage in the whole rock. Therefore, the average heavy mineral yield in sandstones is about 1% but can be a lot lower in old/recycled sandstones. The individual properties of heavy minerals being very different from one another and their relative abundance being a direct proxy of the nature of the source terranes and transport/recycling mechanism, heavy minerals have been used since the 19th century as a provenance tool.
History.
The first published provenance analysis is often considered to be the study of the Dutch-Coast sand dunes by J.W. Retgers who combined petrography and chemical analysis of opaque minerals to assess provenance patterns in the basin. This study was followed a year later by the complementary investigations of J.L.C Schroeder Van Der Kolk who used heavy minerals to study the provenance of Quaternary sandstones of “alluvial or diluvial” origins.
Separation.
Heavy minerals are often extracted from large samples (2-4 kg) as they represent a very limited fraction of old and weathered sandstones. Common procedure involves :
Popular heavy mineral ratios.
Among the most used heavy mineral ratios are: