Tertiary

Until relatively recently, the paucity of easily-dated marine rocks onshore, and the low economic potential of Tertiary strata in general, had militated against their systematic stratigraphic study and the development of regionally applicable correlation schemes. Several factors have now altered this state of affairs to the point that during the last decade the traditional, and inadequate lithostratigraphic classifications have been in a state of flux from which no consensus has emerged. These factors include: the application of micropalaeontological studies (especially planktonic foraminifera and calcareous nannofossils) to the onshore outcrops; the recognition, classification and mapping of extensive, relatively thick and comparatively complete Tertiary sequences on the continental shelf; and the realization that the Tertiary may not be as economically barren as previously thought. On the last point, minerals worthy of economic assessment include glauconite (K 2 O), phosphatic rocks (P 2 O 5 ), diamondiferous and metal enriched sediments (particularly along the west coast), as well as manganese-rich nodules in some of the deep sea areas. In addition drilling for hydrocarbons in the pre-Tertiary has provided considerable incidental knowledge on the overlying cover.