How Did Timaru’s Land Form?

Millions of years ago, Timaru’s land was shaped by nature’s forces! Our region has rocks from the ocean floor, volcanic eruptions, and layers of wind-blown dust that has shaped where we live and Caroline Bay.

The layers in the mound, represent the loess layers in Timaru's special cliffs.

CPlay's "Floor Is Lava" obstical course. For some friendly competition two people could race each other by starting at the ninja wall going down one side of the course and running back up the other side to race up the catch the flag 4m high pole. For an easier challenge you could trying moving up and down the course by only stepping on rock to avoid the lava. - South Canterbury Drone Photography

From the Sea to the Hills

• A long time ago, Timaru was underwater! Layers of sand and shells settled on the seabed.

• Earthquakes and movements deep inside the Earth pushed up the land, creating hills and valleys.

• You can still find fossils of ancient sea creatures at Pareora River today!

Fiery Volcanoes

• Around 2.5 million years ago, lava flowed slowly from volcanic eruptions at Waipouri Mt Horrible.

• This lava flowed like fingers down to where the coastline is today, it cooled and formed the basalt rock and reefs we see around Timaru.

• These volcanic rocks help protect the coast from erosion.

The Power of Ice and Wind

• During the Ice Ages, huge glaciers carved out valleys and carried rocks and dust.

• Strong winds blew dust called loess, which built up thick layers over the land.

• John Hardcastle, a Timaru geologist, wrote an internataionally important scientific paper on the loess cliffs at Caroline Bay, and how it shows layers of dust giving us a record of climate change.

How Did Timaru’s Coastline Form?

• Rivers carry gravel and sand from the mountains to the sea.

• Waves and currents move these stones north, forming the stony and sandy beaches we see today.

• Caroline Bay was once a small stony beach, but thanks to human efforts of constructing the Port, it changed the way sediment moved up the coast, trapping the sand and creating the shallow and sandy Caroline Bay.

Rocks Around Timaru

• Limestone (from ancient sea creatures) is found in places like Kakahu and Craigmore.

• Basalt (hardened lava) is used for roads, bridges, buildings and even early water race and stormwater networks.

• Gravel from old riverbeds is great for construction.

Why Does This Matter?

Understanding our land helps us:

• Understand what is impacting Timaru’s coastline changes.

• Use rocks and soil wisely for building and farming.

• Learn about Earth’s past and changing climate through studying fossils and rock layers.

Timaru’s landscape tells an incredible story—next time you see a rock, think about how it got there!

View north up the Timaru District coastline showing an interruption by the Timaru basalt formation. It forms the first hill south of the Canterbury Plains where Timaru's Hilton Highway ends (named after Timaru's first woman Mayor of Timaru City 1959-62). Photography courtesy of Geoff Cloake 2012.

Basalt was quarried from lava that flowed from Wapouri / Mount Horrible.It was positioned along the Caroline Bay and Benvenue Cliffs to reduce the erosion. 

The rock being transported to the Port of Timaru. Here you can see wagons that were operated by the Timaru Harbour Board's Otupua Tramway which ran from the Eastern Extension to the quarries in what is today's Scnenic Reserve they date back to 1900. The Tramway closed in 1958. The "six wheeled tipping wagons" are now on display at the Pleasant Point Railway Museum.

Loess layers at Dashing Rocks - South Canterbury Drone Photography

Loess layers at Benvenue Cliffs - South Canterbury Drone Photography

The basalt at Dashing Rocks flowed here from Wapouri / Mount Horrible.

 1947 - View to the south Canterbury town of Timaru with Caroline Bay with Evans Street in foreground looking south over the CBD and outer suburbs. You can see the stream running to the sea. Aerial photograph taken by Whites Aviation. Tiaki IRN: 720135. Tiaki Reference Number:: WA-06402-F - PA-Group-00080: Whites Aviation Ltd: Photographs