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.

2.5 Million years ago, lava flowed like fingers from the Waipouri / MtHorrible area to what is now the coastline of Te-Tihi-Omarua Timaru.

This is the most recent volcanic activity in the South Island and is believed to be dormant.

It was formed in a single event, which is an uncommon characteristic of volcanic systems. 

Rather than a big cone shape volcano, Waipouri (Mt Horrible) was more like a line of fishers.

The lava flowed down a slope. The sea was probably nowhere near the erupting lava but has advanced occasionally, eroding the basalt and helping to form the current coastline.

Waipouri (Mt Horrible) to the sea and helped form the terrain, reefs and wetlands of Te Tihi o Maru's coastline.

Today you can see the lava as an “apron” at the foot of Dashing Rocks. The basalt below the Benvenue was quarried and placed there to mitigate erosion.

Basalt was used as a construction material and the “blue stone” blocks can be seen in many of Timaru’s heritage buildings, homes, bridges.

The rock was also quarried to help construct Timaru’s artificial harbour.

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

The sandy beach at Caroline Bay is an area of reclaimed land, shaped since the 1880s by currents and the city’s changing coastline.

A volcanic reef shapes the natural harbour, wetlands and coastline of Te Tihi-o-Maru Timaru. It was formed over 2 million years ago, when lava flowed like fingers down sloping plains to the coast, helping to shape the terrain of Kā Poupou-a-Rakihouia (the South Canterbury coastline) as it is today.

Over time, the coast and shoreline has continued to change and evolve. 200 years ago, the sea directly met the rocky shoreline and loess cliffs along Timaru’s coast. Pohatu-koko Stream ran from the bottom of what is now the bottom of Wai-iti Road to the sea. Wetlands and coarse gravel beaches eventually gave way to a new sandy shore, and the Pohatu-koko Stream is now underground, piped beneath the current playground to the sea.

The construction of the Timaru Port breakwater in the 1880s changed the shape of the bay, and in doing so interrupted the flow of sediment up the coastline. Tides ground the gravel to sand, which then swept into the bay forming the sandy beach we know now. The changing shape of the coast also accelerated coastal erosion further north, affecting Waimataitai Lagoon (now Ashbury Park) and Waitarakao Washdyke Lagoon. 

Lava once flowed from somewhere west of Claremont (Wapouri / Mount Horrible) down a gentle sloping plain. The sea was probably nowhere near the erupting lava but has advanced occasionally, eroding the basalt and helping to form the current coastline. Diagram courtesy of Geoff Cloake.

The Timaru loess cliff is an important geological feature located in Timaru, New Zealand. The cliff is made up of loess, a windblown sediment that was deposited during the last ice age. The loess is over 20 meters thick in some places and is one of the thickest and most extensive deposits of its kind in the world. The history of the loess cliff can be traced back to around 20,000 years ago when the Canterbury Plains were covered in glaciers. As the glaciers retreated, they left behind a layer of gravel and sand. Strong winds blowing across the plains then picked up the fine sediment and deposited it on the leeward side of hills and mountains, forming the loess cliffs. The characteristics of the loess layers, such as thickness, grain size, and mineral content, can provide information about past wind and climate conditions. This information can also be used to develop models to predict future climate change and its potential impacts.

John Hardcastle was a amateur geographer who worked at the Timaru Herald. He conducted extensive studies in Timaru, New Zealand. His research focused on the geography, geology, and geomorphology of the region, with a particular emphasis on the loess cliffs of Timaru. His study of stratigraphic features of loess deposits provides information about past climates and can give an indication about what to expect in the future. In addition to his work on the loess cliffs, Hardcastle also conducted studies on the rivers and drainage patterns in the region, as well as the agricultural and land use practices of local farmers. His research helped to deepen our understanding of the physical and cultural landscape of Timaru and its surrounding areas.  In 1991 scientists from all over the world met in Beijing to discuss the work of John Hardcastle – in particular his discovery of the geological relationship between loess deposits and climates of past years.

The loess (looks like clay) has layered over time. And gives us a record of changes in our local climate.

ABOVE LEFT: Distribution of Late Pleistocene Loess. You can see that Timaru has a "very thick" layer. Loess Section exposed at Dashing Rocks, Timaru.
ABOVE RIGHT: Four loess layers overlie the eroded surface of the Timaru Basalt. - Nature and distribution of loess in Canterbury, New Zealand This is sediment that has been blown here, is dust from glacial carving periods.

Dashing Rocks is a volcanic rock headland topped with a loess cliff. Loess is wind-blown silt from the mountains that was deposited 9000-11,000 years ago as the glaciers from the last ice-age began disappearing.’ John Hardcastle was an amateur geologist who made an internationally significant climate change contribution by studying Timaru's coastal cliffs, which revealed past climate changes.

Looking in a northerly direction down from a terrace towards Caroline Bay. The beach and a large low building are in the middle distance. The Southern Alps are in the background.- Barton, Cranleigh Harper, 1890-1975 A-227-335/349: Barton, Cranleigh Harper 1890-1975 :[Scenes from Geraldine to Oamaru] [ca 1950?]

View of township looking across water to foreshore with Southern Alps in background.  Pencil and watercolour (A-157-018) by Arthur Lagden Haylock (1860-1948) c1878. Arthur probably created this when he worked in Timaru as a cadet in the Lands Office. Courtesy of Alexander Turnbull Library, Wellington, New Zealand.

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

The CPlay team were inspired by the local geology to create an obstical course themed on lava. Features 4m catch the flag, 3m ninja wall, double sided triple rockwall, 3m ninga finger wall, horizontal totem pole, and an up and over climbing net. A fitness area has also been designed to help people build their fitness, co-ordination and strength.

1. Physical development: This obstacle course has been designed to challenge kids and adults physically, requiring them to run, jump, crawl, climb, balance, and perform other movements that improve physical fitness, coordination, and motor skills. 

2. Mental development: People can problem-solve, strategize, and use critical thinking skills to navigate through the course. This can help develop mental resilience and adaptability.

3. Emotional development: Overcoming obstacles can give people a sense of accomplishment, which can improve self-esteem and confidence. It can also help develop resilience and the ability to manage stress and anxiety.

4. Social development: Obstacle courses can be done individually or as a team, encouraging individuals to work together, communicate effectively, and build social skills. There are two sides that are the same, so people can race each other, cross over and run back down the course. They can race up the flag pole and catch the flag to win.

The Timaru Harbour Board once owned much of the land at Centennial Park, which was worked as a quarry in the late 1800s to provide a source of harbour-protection rock for the development of the Port of Timaru. Several quarries were operated, one at the Gleniti end of the reserve and others throughout the stretch of the gully, each supplying rock via a railway leading from Otipua Rd. The last of the lines was dismantled in late 1959. The Moa bones were found when rock was being removed for the building of the North Mole by Palliser and Co. The bones are believed to be the oldest discovered to date with the clay found under the bones being described as being from the Pliocene Age (2 to 7 million years ago).

During 1934-35 negotiations took place between the Timaru Harbour Board, representative of the estate of J King, and the Timaru Borough Council to acquire land for a reserve in the western sector of the borough. The land lay from Claremont Rd stretching east to the end of Quarry Rd. About 32 hectares was bought for the equivalent of $1060. However, the harbour board maintained its right to quarry in the reserve until 1975. 

About the time the reserve was created, George Bowker, a local real estate man, donated 6.5ha of land adjoining the Otipua Rd reserve. That enabled a central accessway to the site in the area of the large bluestone Bowker Gates opposite Church St. In 1938 it was formally opened and named the Scenic Reserve; however, by 1940 it had been renamed Centennial Park marking the centenary of the signing of the Treaty of Waitangi.

Basalt (cooled lava) being quarried at Centenial Park. - Harbour Board Quarry, Timaru, New Zealand, by Muir & Moodie. Te Papa (C.014398)

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.