The heavy minerals in the sandy shelf sediments around Taiwan consist mainly of magnetite, ilmenite, amphiboles, pyroxenes, olivine, epidote, garnet, zircon, tourmaline, and monazite. The highest concentration of heavy minerals occurs on the eastern Taiwan shelf where average heavy mineral content is about 8%. This abundance of heavy minerals is closely related to the weathering of pyroxene andesite from the Coastal Range. Amphiboles dominate in the heavy minerals from the shelf of northern Taiwan while zircon and monazite are relatively abundant along the southwestern coast.

The manganese nodules dredged by R/V Chiu-Lien from the Philippine Sea consist essentially of akaganeite (ß-FeOOH), birnessite, and todorokite, while the nuclei of the nodules contain phillipsite, illite, and feldspar. The average compositions of 18 nodules analyzed are Fe 14.10%, Mn 12.94%, Ca 0.26%, Mg 0.80%, Na 1.53%, K 0.62%, Co 2,588 ppm, Cr 30 ppm, Cu 1,257 ppm, Li 14 ppm, Ni 2,733 ppm, Pb 1,033 ppm, Sr 80 ppm, and Zn 518 ppm. The (Ni + Cu) contents tend to increase with increasing Mn/Fe ratios which vary from 0.6 to 1.1 averaging around 0.9. According to the criteria given by Toth, the Philippine Sea nodules are not related to hydrothermal activity. These nodules may have originated by catalytic oxidation and absorption of Mn, Fe, and other transition elements upon suitab e submarine surfaces.

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