A review of heavy minerals in clastic sediments with case studies from the alluvial-fan through the nearshore-marine environments

Heavy mineral analysis can play an important part in unraveling the extrabasinal (e.g., source area weathering) and intrabasinal processes (e.g., hydraulic processes) that influence the formation of clastic rocks. Various clastic (conglomerates, wackes, arenites, siltstones) and pyroclastic rocks (tuffs, ignimbrites, lahars) spanning the interval from the Upper Carboniferous through the Early Tertiary SE Germany (Bavaria) and the North German Basin were investigated for their transparent and opaque heavy minerals. The samples have been taken from drill cores, percussion holes and outcrops of various environments of deposition which are representative of a cross-section from the basin edge to the basin center (alluvial fan, braided streams, meandering to anastomosing fluvial drainage patterns, swamps, lakes, estuarine and nearshore-marine deposits). Routine heavy mineral analysis may be applied to heavy mineral separates in the grain size fraction from 0.020 mm to 0.200 mm, using heavy liquids of 2.95 g ml−1. The results furnish evidence that the strong points of this method lie in the fields of provenance analysis, paleoenvironmental analysis, and the study of volcanism and hydrothermal alteration. Routine heavy mineral analysis using the petrographic and ore microscope may successfully be combined with trace element analysis using ICPMS (e.g., REE, Th, U, Zr) and isotope studies (e.g., U, Pb). Radiometric age dating and the determination of the chemical composition of detrital apatite in late Paleozoic arenaceous rocks helped to pinpoint the type of source rocks and constrain the age of intrusion of the granites in the provenance area, from which the apatites were derived. This sedimentological method may be of interest to academicians and geologists working in the various fields of applied research alike (e.g., geoengineering, hydrogeology, exploration for hydrocarbons, uranium, coal and placer deposits).