Confession of a basalt addict

They say the first step in addiction is to admit it. Okay, I like basalt. I like to travel to see it. I like to know how it has influenced our planetary history. I like how it creates such wonderful scenery so rich in color and texture. I like how it shows that nature bats first, and in many places last and clean-up. In essence I am what you might call a basaltophile.

I realized this recently on a vacation to Hawaii’s big island. This was the second time in less than a year that I spent time on an island of basalt. The first was last year on a trip to Iceland. In each place, basalt dominated the landscape. I don’t use dominated lightly. I mean it in the dictionary definition of “to bear rule over, control, sway; to have a commanding influence on.”

When you travel in Hawaii and Iceland, you quickly learn that basalt is what rules these islands. Drive down a road and you will discover how it weaves through lava flows, unless, of course, it simply disappears under the lava. Read stories about the islands’ histories and you will learn how basalt has shaped the actions of where and how people lived. Look at tourist brochures and you will see how promoters exploit the splendor of basalt to draw in visitors.

[nggallery id=22]Part of the attraction is the beauty of the basalt, but part of it is the raw nature of the rock. On Iceland and Hawaii, you feel the primal personality of the planet. Exploding geysers, bubbling hot springs, oozing molten rock, this is how Earth was in its earliest days. It was a harsh and dangerous place, and yet seeing how life has taken root on these islands, it takes little imagination to envision some form of existence starting to evolve and flourish those billions of years ago.

Because of the youth of the basalt—on Hawaii we saw flows less than a year or so old—both islands have a dynamic feel. On Iceland, we experienced the eruption of Grimsvötn, which shut down the airport and curtailed our travel plans. On Hawaii, the ongoing spewing of toxic gases from Halema’uma’u crater prevented us from hiking several trails. Where else would you see signs that read “Stay on trail. Dangerous earth cracks in park area”?

That dynamic also gives Iceland and Hawaii a raw and unformed feel. The islands are in a constant state of change, growing with new lava flows and disemboweling themselves with eruptions. Hiking around Iceland, I was struck by how moss was often the lone plant life, as if only primitive vegetation veneered a primitive land. Hawaii does have its tropical rainforests, which at times made the island seem far older, but I also saw huge areas devoid of any plant, or even any animal. When driving, I found you could not always trust a map, as some geologic disaster might have simply erased a road or bridge.

The story of basalt is one that stretches back to the earliest days of Earth and continues unabated to the present. It is a story that shapes our planet and our species. It is a story that shows that geology is alive and well, and often kicking some butt. What more could a basaltophile want?


Geology in Iceland

Following on my previous post on Iceland’s building stone, I want to look a little at the country’s landscape. As I wrote previously, every geologist should go to Iceland. We spent about ten days there, traveling along the southern coast and then north of Reykjavik (Reyk meaning smoky or steamy and vik meaning bay) out the Snæfellnes Peninsula (a bit of a redundancy as nes is Icelandic for peninsula). We were also lucky enough to be in Iceland when a volcano erupted; we were just 20 miles or so from Grimsvötn on Friday, the day before the eruption.

In one sense, Iceland is geologically simple. Nearly every rock you see is basalt. You may find a few fossils and a few sediments but you would have to seek them out. This is a place that, as trite as it sounds, is a land of fire and ice. Driving along the south coast, you travel along plains of basalt flows, or glacial outwash. Some are still black and devoid of much vegetation but in many areas, carpets of lush mosses grow thickly atop the flows. A few shrubs sprout but no trees grow, even along streams.

As you look inland, the landscape begins to climb, as scree slopes and more commonly as basalt cliffs, layer upon layer rising straight up. Waterfalls regularly cascade over the cliffs, a product of the gargantuan ice sheets that cover vast swaths of the interior. At Skaftafell National Park (part of Vatnajökull NP), we hiked up the shoulder of Skaftafellshei∂l (fells means mountain(s) and shei∂l equals shield) just west of the Skaftafelljökull icefield (again redundant as jökull means glacier). We did encounter some trees up here, birches and willows, but they were low growing, about as tall as me. In the desert southwest, we call such a woodland a pygmy forest, which I am not sure is PC or not.

Of all the wonderfull geology, two spots stood out. The first was the vast glacial outwash plain or Skei∂arársandur, which stretches for 500 square miles of soil, silt, pebble, gravel, and boulder with little to no vegetation. A two lane road snakes on a berm across the sandur with two, 1/2–mile-long, single lane bridges spanning areas of braided streams.

The day we drove the road the wind blew. A sign we saw showed that wind gusts peaked at 41m/s or about 90mph. (We read one sign that stated “a light breeze is just hurrying by.”) As you might suspect in a landscape lacking vegetation and comprised of rocky bits, the wind became visible as streams of sediment ripping across the road (thank goodness for rental cars!). At times we could barely see in front of us. Fortunately, we didn’t pass any cars at all crossing this stretch of road. At least we didn’t see any other cars.

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When we finally emerged out of the wind, we stopped at a road side table. Signs informed us that in 1996, an eruption of Grimsvotn led to a truly stupendous jokulhlaup (glacial flood) bursting out of the Skei∂arárjökull. The estimated flow was 53,000 m3/s or 1.87 million cubic feet per second. Only one river on earth has an average flow greater than this flood. The Amazon runs at about 180,000 m3/s.

My other favorite spot was Hraunfossar (lava falls), a series of turquoise water falls that emerge as springs on a low ledge above the Hvita (white river). The springs run for about a kilometer with water cascading from the moss-covered basalt down to the river. It was quite stunning.

These are just a few of my impressions of Iceland. I hope to write a bit more in the future.