Ancient Muriwai lava megapillows gain global recognition

Publish Date : 16 Sep 2024

Unique formations of megapillow lava flows at Muriwai, that are millions of years old, are now listed among the world’s most significant geological sites by the International Union of Geological Sciences

Only 200 features around the world are recognised as Geological Heritage Sites by this scientific group, for their value and significance to early geological history – including the Giant’s Causeway in Northern Ireland and the Devil’s Tower in Wyoming, United States. 

West Auckland’s megapillows, located in Muriwai Regional Park were added to the prestigious list in August 2024 and fall under the care of Auckland Council. 

Councillor Richard Hills, chair of Auckland Council’s Policy and Planning Committee, says having an Auckland attraction recognised as one of the best in the world and by one of the largest scientific organisations is huge validation for the work that the council is doing.  

“This special site at Muriwai is one of many taonga natural features that we care for in the regional parks network, to ensure that visitors can enjoy them for generations to come.”  

“It’s also one of around 250 important geological sites in the region that are recognised and scheduled for protection in the Auckland Unitary Plan,” Cr Hills adds.

Auckland Council’s Geologist and Natural Features Specialist, Kate Lewis, says Muriwai is considered by far one of best locations to see lava pillows, with three connected sites showing spectacular examples of this rare volcanic pattern at Maukatia Bay. 

From the beach, visitors can see giant fans of lava pillows stretching 20 metres high and 30 metres wide, across the main cliff face. Each fan provides a cross-sectional view of the pillows themselves and also the vent or feeder tube that once supplied fresh lava to the pillows that surround it, says Kate. 

“These shapes emerged after a massive underwater volcano erupted close to Waitākere 17 million years ago. When flowing lava is cooled quickly by the ocean, it forms a surface crust over bulbous folds that look like pillows. The liquid inside the lava flow pushes forward, and pressure from behind the crust cracks it, so more lava pushes out to form adjacent folds,” she explains.

“Muriwai’s examples have earned the title of megapillows, due to their impressive size - up to 3 metres in diameter. They are extremely rare,” Kate adds.

Megapillow lava flows can also be found in Iceland, Sardinia, Spain, and Tasmania, but none match the size and complexity of the Muriwai megapillow flow – nor are they as accessible. 

Auckland Council Parks Manager Scott De Silva says that while Muriwai Regional Park is often admired for its natural beauty, not all visitors are aware of the geological significance of this remarkable landscape. 

“We are thrilled to see these features receive such widespread recognition. It will enable more people to learn about the history of this area and continue to help us protect it.” 

Four other New Zealand attractions have been selected by world renowned geologists to join the IUGS celebrated list of 200 Geological Heritage Sites. Those sites are the fjords and towering seacliffs of Fjordland, Ruapehu volcano, Rotorua’s geothermal fields (Ahi-Tupua), and the impressive Maruia Falls.  

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