Moeraki Boulders … geologically interesting

“The Moeraki Boulders are huge spherical stones that are scattered over the sandy beaches, but they are not like ordinary round boulders that have been shaped by rivers and pounding seas. These boulders are classed as septarian concretions, and were formed in ancient sea floor sediments. They were created by a process similar to the formation of oyster pearls, where layers of material cover a central nucleus or core. For the oyster, this core is an irritating grain of sand. For the boulders, it was a fossil shell, bone fragment, or piece of wood. Lime minerals in the sea accumulated on the core over time, and the concretion grew into perfectly spherical shapes up to three metres in diameter.”

Read more about the boulders here ( includes map)

Maori legend says the boulders are remains of calabashes, kumaras and eel baskets that washed ashore after the legendary canoe, the Araiteuru was wrecked at nearby Matakaea (Shag Point).

Author: Heather - the kiwi travel writer

Nomadic travel-writer, photographer, author & blogger. See more on and Amazon for my books (heather hapeta)

One thought on “Moeraki Boulders … geologically interesting”

  1. I really liked being at this beach, with these boulders, but I wished I weren’t on a bike so I could have gotten there in the evening for sunset. They’re pretty fascinating, and I kind of loved not really knowing how they were formed and just trying to fathom what might have caused them. Of course now that I know, I think they’re pretty great, too. Was this part of your WOMAD trip? Glad that all came together for you, and also it was great to meet you in Christchurch. It seems like a million years ago!


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