Page 5 - Bulletin 2 1998

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Middle to Late Miocene Epoch (13 – 6 million years ago (mya))

The earliest preserved remains are of plants, mainly pollens, from peat found in a borehole in

the Noordhoek area. This revealed the existence of palm forests such as only occur on
Madagascar nowadays. Commercial excavations on the Cape Flats sometimes expose a

clayey surface on which are preserved trunks of trees and other macro remains, which
indicate the presence of marshes and forests with tropical trees such as palms and yellow

woods. Ocean cores suggest that upwelling existed by about 12 mya, although the scale of

upwelling only reached modern proportions by about 3 mya. Our south-easterly winds force
nutrient-depleted surface water off-shore, to be replaced by cold, clear deep water that wells

up in its place. This provides nutrients that provide the food which sustains the fisheries of

the west coast.

The earliest fossil animals come from the Langebaanweg site near Saldanha and are between
10 and 7 million years old. For much of this time the area was under the sea and fossils

include sharks’ teeth (also of the extinct giant white shark) and sea shells of species which
indicate warmer water temperatures than at present. Other animals found are skates, rays,

mussel cracker, tortoise, penguin, seal and whales. The few vertebrate fossils, which include

the three-toed ancestor of the horse, a grazer, indicate that the earlier terrestrial environment
of extensive forests and woodlands was being replaced by more open woodlands, savannas

and grasslands.

The end of the Miocene, about 6 mya, and the beginning of the Pliocene epoch were
associated with the development of the Antarctic ice cap, significant changes in global

climates, and the evolution of animals and vegetation forms more similar to those of modern

times. Notable among these was the emergence of our earliest bipedal ancestors. There are no
remains of these earliest hominids from our region.