Stream sediment chemistry reflects chemical variations in rock complexes, and many element distribution patterns can be related to known lithological features. Although the rock exposure rate is generally very high in Greenland, there are inland areas in West Greenland where overburden and vegetation create problems for geological mapping. The geochemical maps helps to outline rock boundaries in such a surface environment. Also where high-grade metamorphism has obscured original textures and boundaries between lithological units, the geochemical maps may contribute valuable information. This is the case in central West Greenland where high-grade Archaean and Palaeoproterozoic gneiss complexes cannot be distinguished in the field. However, the younger gneiss has a strong geochemical signature, which is reflected in the maps of Ba and Sr. Thus an approximate outline of the younger gneiss can be drawn, based on the geochemical data. Several other cases are known from West and South Greenland, where stream sediment geochemical patterns have drawn the attention to rock complexes that had not previously been recognised.

The geochemistry of a rock unit, and its trace element signature, in particular, is an important factor in determining its origin. Many trace elements are hosted in scarce, fine-grained minerals in the rocks, e.g. apatite, zircon and monazite. These minerals are resistant to weathering with the effect that their abundance is upgraded in the stream sediments relative to their abundance in the source rocks. Again, because the stream sediment data cover regions with little or no geochemical data on rocks, the stream sediment chemical maps may assist in identifying rock complexes of a certain origin.