Mad about Science: Weird volcanism

By Brenden Bobby
Reader Columnist

We learned about funky volcano behavior last year while exploring fumaroles, mud pots and cryovolcanoes. Surely that was all the weirdness that exists in the world of volcanism, right? Wrong!

In the world of hot rocks, there is no limit to the strangeness that can be achieved. Here are a few examples:

Kirkjufell, Iceland

You may recognize the hill of Kirkjufell from multiple scenes of HBO’s Game of Thrones. Located in western Iceland on the Snæfellsnes Peninsula, Kirkjufell is an impressive structure called a nunatak, from an Inuit word describing a peak or ridge that rises out of an ice field or glacier — in this case, two separate glaciers. What’s particularly interesting about Kirkjufell is not that it survived thousands of years of glacial erosion, but that it’s a volcanic structure that isn’t actually a volcano.

Kirkjufell volcano in Iceland. Courtesy photo.

The rock of Kirkjufell is layered in bands from multiple eruptions across millions of years. It’s viewable from three angles on the peninsula and emerges a stone’s throw from a magnificent 54-foot waterfall that drains into the sea. While only standing 1,519 feet tall, it has been the site of numerous fatalities, likely related to the sharpness of its ascent.

Due to the hill’s home in the distant north, visiting during the summer may allow you to experience a midnight picnic in brilliant sunlight. Its location also allows you to view the aurora borealis in vivid closeness.

Ol Doinyo Lengai, Tanzania

Located in northeastern Tanzania in part of the Eastern Rift mountain range, Ol Doinyo Lengai is a curious peak. The summit has an elevation of 9,718 feet, roughly 10,000 feet below that of Tanzania’s Mount Kilimanjaro. Despite its shorter size, Ol Doinyo Lengai has a reputation for presenting a vicious climb. A conical stratovolcano, the trek to Ol Doinyo Lengai’s summit is practically vertical in either direction. Still actively erupting, with an eruption as recently as 2008, much of the ground is actually very loose debris that could result in aspiring hikers meeting the mountain’s namesake: The Mountain of God.

The verticality of the mountain isn’t what makes it so quirky. Most volcanoes erupt and eject red-hot silicate compounds with temperatures exceeding 1,800 degrees Fahrenheit. Ol Doinyo Lengai instead belches out a calcium carbonate mixture that reaches its peak temperature at 950 degrees Fahrenheit. This isn’t hot enough to transform the lava into your typical Mt. Doom-ian red-orange flow. Instead, this mountain expels a slow-moving carbon black sludge that forms wild arcs that look like something from H.R. Giger’s canvas. As this mixture cools the carbon binds with oxygen to create carbon dioxide, leaving white chalky calcium behind. This gives the mountain the illusion of being snowy from a distance. Upon closer observation, it’s very clear that these streaking white patterns aren’t in fact snow.

Those planning to hike Ol Doinyo Lengai can expect a 12-hour journey that begins around midnight and ends around lunchtime. The reason for this is to catch the sunrise from the caldera and see where to put your feet during the near-vertical descent.

Aino Planitia, Venus

If you’re planning a spring trip to the Aino Planitia, I have one bit of advice: don’t.

Despite being considered Earth’s sister, our nearest planetary neighbor is a vapor-choked hellscape with a surface temperature hot enough to liquefy lead and a day that lasts longer than the planet’s year. This weird Alice in Nightmareland planet understandably has some of the most bizarre volcanic activity in the solar system.

Some of the strangest volcanism happens in the Aino Planitia, a low plain on the surface of Venus. These plains play host to a number of active volcanoes, many with features that span up to 100 kilometers wide and one of which is a funky dome 100 km wide and one km high flanked by many thick-fanned lava flows. These flows range in height from 120 to 540 meters high — considerably taller than the Empire State Building at 443 meters. Stranger than these building-sized lava flows is their viscous structure. Viscous lava flows on Earth are formed by a large presence of water and non-basaltic rock.

As we know, the surface of Venus is hot enough to melt lead, so liquid water simply cannot exist here which really leaves scientists scratching their heads about the state of Venus’ weird lava flows. It’s unknown how the extreme atmospheric pressure of Venus combined with its obscene level of heat may affect the volcanic dynamics of the world.

Another curious volcanic feature on Venus is the presence of “ticks.” These structures are large and relatively flat domes spanning up to 70 km wide with a collapsed crater near the center. The plains crack along the edges to create the illusion of spindly tick-like legs around a bulbous body, very closely resembling the parasitic arachnids here on Earth. The biggest difference between Earth ticks and Venus ticks, apart from their size, is that Venusian ticks are loaded with hot magma and completely devoid of horrible bloodborne pathogens.

Everything we understand about Venus’ volcanoes comes from radar imaging. Despite its nearness, relatively few missions have been flown to Venus in comparison to bodies like Mars and Jupiter. We actually possess more knowledge of the workings of very deep space and galactic mechanics than we do of our own next door neighbor. That’s set to change, as NASA currently has three missions in the works to explore Venus — hopefully from the safety of orbit, as the handful of landers that were sent by the Soviets were crushed and melted over the course of hours.

Stay curious, 7B.