Te Mata Peak

The fossil rich limestone rocks that make up Te Mata Peak were laid down in the sea about 3.5 million years ago when the area was a fairly shallow submerged ridge. The limestone is made of alternating harder and softer layers that represent changes in sea level due to ice age cycles. At that time, the area that now forms the flat plains of Hawke's Bay to the west, was a channel of deeper water, and the coastline was then along the edge of what are now the Ruahine and Kaweka ranges about 40 km away.
The hills and plains we now see have been uplifted above sea level by tectonic plate collision, which continues to this day. The boundary of the Pacific Plate and the Australian Plate reaches the surface of the crust along the Hikurangi Trough about 120 km out to sea to the east.

Many of the hills and ridges in this part of Hawke’s Bay are formed from limestone similar in character to the Awapapa Limestone here at Te Mata Peak. From the top of Te Mata Peak you can see hills to the south and east that are also made of Awapapa Limestone. The flat plains to the west consist of mudstones that were laid down in deeper water, overlain by more recent river deposits.
There is a map (topograph) showing the names and places that are visible from the summit on a clear day. It is worth having a good look at this and thinking about the relationship of the landscape to its geological history, and processes of uplift and erosion.
If you walk along the ridge just south of the summit, or along some of the walking tracks, you may be able to spot occasional fossils of oysters, scallops, barnacles, brachiopods and coral-like bryozoans. Some of these are broken up due to strong water currents during sedimentation in ice ages when sea levels were lowest.