The New Zealand Site

The Maori Leap Cave runs through 60 million year old Kaikoura Limestone that’s just dripping with stalactites.

Maori Leap Cave

It’s set into 30 metre cliffs three kilometres south of Kaikoura, close to a large roadside diner. Maori appear to have been unaware of the existence of the cave, and the ‘Maori Leap’ name relates to the actions of a warrior in an inter-tribal battle. He was faced with the choice of being captured and becoming a slave or jumping for freedom. He leapt off the cliffs and supposedly survived, although the story is unclear about what happened to him in the end.

Cave Entrance

The cave was discovered when a quarry was being developed in the area and locals found a hole that lead into the roof of a large cavern. As this didn’t offer very convenient access, an entrance through the base of the cliff was subsequently cut and the hundred metres of the cave lit and fully explored. Tours of the cave are run out of the roadside diner close by and are delightfully low key compared to the packaged patter at more touristy places.

Chert in the limestone

The cliffs under which it runs are made of limestone that was formed around 60 million years ago from the calcium-rich shells of tiny plankton-like creatures that fell in untold billions to the sea floor when they died. Amongst these microscopic creatures were some (the radiolarians and certain diatoms) whose shells and skeletons were made of silica instead of calcium. This silica was dissolved and concentrated to form deposits of chert (pictured) or flint. These can easily be seen in the cave as areas of glassy, dark rock in the creamy-white limestone.

Stalactites and Stalagmites

All of this was raised above the sea within the last couple of hundred thousand years by the process of uplift and mountain building that has also created the Kaikoura ranges which reach two and a half kilometres into the sky. Unlike many limestone caves, this one was cut by the sea before subsequent uplift raised the cliffs beyond the waves’ reach. Underground seepage has created the intricate formations of stalactites, stalagmites and flowstone in the cave.

Rusty stalactite

Water flowing through the soil picks up carbon dioxide and becomes a mildly acidic solution of carbonic acid. This eats away at the calcium of the limestone, dissolving it away and forming caves. As water continues to drip down from the sides and roof of caves, the dissolved calcium carbonate settles out of the water, forming stalactites with corresponding stalagmites growing up below them. In the Maori Leap Cave, deposits of iron in the limestone turn some of the stalactites a deep orange color, caused by dissolved iron oxide (also known as rust). It looks a lot better in the stalactites than it does in my car!

Stalactites and straws

In most cases material is deposited on the outside of the stalactites, forming those pointy, carrot-like shapes, but sometimes the water flows down through a tube and the dissolved calcium carbonate builds up long thin straws that can often grow at strange angles. They’re very delicate and years of growth can easily be destroyed by handling them.

Tours take about 40 minutes and run several times a day (hardhats supplied). It’s a dark, quiet and refreshing break from the sea-based activities that most people visit Kaikoura for.

No related posts.