The heavy mineral assemblage is the result of the type of source rock, weathering and hydraulic sorting. An understanding of these controls forms the basis of some interesting applications of the technique. The main applications are listed below:
Based on the relative abundance of different heavy minerals the source areas of the sediment can be deduced. For example when a heavy mineral concentrate contains many minerals like kyanite and sillimanite, it is likely that the source area consists mainly of high-grade metamorphic rocks. On the other hand chrome spinel is very typical for the presence of ultrabasic rocks in the source area.
As the heavy mineral assemblage provides information of the source areas, it can be used as a tool for detecting the origin of certain trace minerals. For example a mineralization of scheelite (CaWO4) can be detected by sampling upstream in a drainage area. At each river fork you continue in the direction of the highest concentration and this should eventually bring you at the ore body.
By hydraulic sorting and weathering some valuable minerals might become enriched in a deposit (placer). The distribution of this mineral enriched deposit can be determined by systematic sampling and determination of its grade. Based on the distribution and grade of a mineral deposit, the reserves can be estimated and whether or not extraction is feasible. Think of enrichments of economically valuable minerals like cassiterite, monazite, zircon and ilmenite.
Additional advantage of an understanding of the sediment provenance is the application of heavy mineral analysis in correlation studies. Imagine a sedimentary basin with changing river sources over time. These changing river sources built up a sedimentary sequence of varying heavy mineral content. In the exploration for oil and gas or geothermal resources these varying heavy mineral contents can be used for correlation between boreholes.