Wednesday, March 23, 2016

The Moeraki Boulders of Koekohe Beach

Moeraki Boulders
The Moeraki Boulders
Moeraki Boulders are just one of the many naturally occurring oddities that are found on Koekohe Beach and surrounding areas in New Zealand. Some have likened the appearance of these boulders to the bowling balls of giants, who have long since abandoned their game. In a way, they do look like bowling balls because some of them are nearly perfectly spherical. This sort of boulder occurs naturally elsewhere, but the number of them in the area and the beauty of the surrounding New Zealand landscape seems to draw people to the Moeraki Boulders in particular.

Roughly 56 million years ago (during the Paleocene Epoch), small bits of wood, fossils and bones on the bottom of the ancient sea floor began to accumulate layers in what is now New Zealand. Over time, these small formations grew larger and larger in much the same way an oyster's pearl grows in size. The large, round stones that resulted from this process are known as septarian concretions. They eventually became trapped in the stunning sheer cliffs that grace the coast of Kohekohe Beach between Moeraki and Hampden, New Zealand.

When erosion began to take its toll on the cliffs, the ancient Moeraki Boulders were freed. Today, they are scattered across the landscape like errant marbles. Some are not spherical, but are oval instead. These Moeraki Boulders look like dinosaur eggs–really big ones, at that. Some of them have cracked open and revealed their softer, eroded interior. Some of these are big enough for a man to sit in, giving the appearance that he has just been hatched from the ancient stone. The biggest of the Moeraki Boulders is close to nine feet in diameter and weighs several tons.

The surfaces of the Moeraki Boulders are cracked, causing them to look like turtle shells. The reason for this cracking is yet unknown to science. We do know that the interiors of the boulders are weaker than the exteriors, yet the exteriors are cracked. Some of the boulders are much smaller than others. The cracked surface makes them look like large turtles half-buried in the sand.

An 1848 drawing by W.B.D. Mantell shows the Koekohe Beach with more of the Moeraki Boulders than are currently there, so we know they are slowly vanishing. However, more are still trapped in the cliffs, as evidenced by those that are only half-exposed today. There is no telling how many of them are still waiting to be revealed.


De Hek, Danny, retrieved 10/28/10,

Facts about Moeraki Boulders, retrieved 10/28/10, moeraki-boulders-facts.php

Evans, RJ, The Mysterious Moeraki Boulders,

Sunday, March 13, 2016

Interesting Facts About Iceland's Volcanoes

Fire spewing out of Eyjafjallajokull
during the 2010 eruptions
Courtesy of Ulrich Latzenhofer
Iceland and its volcanoes have been in the news a lot in the past few years. The Eyjafjallajokull volcano in Iceland was been very active in March and April of 2010. The ash spewing forth from this volcano resulted in the grounding of flights as far away as England, due to the danger it presents to airplanes. Prior to this tantrum, the Eyjafjallajokull volcano had not erupted for nearly 200 years. All of this attention serves to remind us that Iceland is a land of many volcanoes, some of which can have global consequences should they erupt. With that in mind, here are a few facts about Iceland's volcanoes that can give us an idea of what goes on there in the "land of fire and ice."

Hawaii gets a lot of attention for its volcanoes. This is because it was formed by volcanoes. Evidence of their activity is present everywhere there. Nonetheless, there are only two active volcanoes in the State of Hawaii. Iceland has between 20 and 30 active volcanoes. That is more active volcanoes than any other place on Earth.

The most active volcano in Iceland is Hekla. Hekla has an elevation of 4,892 feet. It is a stratovolcano that is located in southern Iceland. Hekla has erupted roughly once every ten years for the past fifty years. A Hekla eruption can come on with little to no warning and can last for weeks or months. Hekla was less active in the past fifty years. However, for some time, there was hardly a century that passed without at least one eruption from Hekla.

Iceland was formed from volcanic activity, like Hawaii. The American and Eurasian tectonic plate boundary goes through Iceland. The two plates pull apart, making it easy for lava to push through the gap. This is how Iceland was formed and why it has so many active volcanoes today.

In the past 500 years, nearly one-third of the Earth's lava output has spewed forth in Iceland. Furthermore, 83% of the world's sub glacial eruptions have occurred in Iceland. To put that into perspective, the area of Iceland is 39,707 square miles of land. The entire Earth has roughly 57,393,000 square miles of land area. Iceland is sure pumping out a lot of lava for such a small portion of the Earth.

From the above, you can clearly see why Iceland is called the "land of ice and fire." Of course, given its position on this Earth, there is a lot of ice in Iceland. However, residents can warm up by taking a dip in the large number of the geothermal spas there. Despite the scary number of active volcanoes, Iceland is easily one of the most beautiful and interesting places on Earth.


Volcanology Highlights, retrieved 4/16/10,

Volcanoes in Iceland, retrieved 4/16/10,

Seach, John, Hekla Volcano, retrieved 4/16/10,