Whitney Houston took a car ferry from Britain to Ireland to attend her concert, rather than flying. Barack Obama has canceled his trip to a state funeral in Poland. A very large magical snake protects a canyon in south Africa. These things are connected a lot more closely than you might think.
Eyjafjallajoekull1 is the volcano in Iceland that is making all the mess in Europe, shutting down most Western European airports. Iceland as a whole is a volcanic feature that sits atop the Mid Atlantic Ridge.
The Atlantic Ocean is a huge rift valley, in some ways similar to the famous rift valleys of Africa, but very very wide. The African rifts sit on a continent, but were they to continue to spread, the space between the rift walls would become an ocean. There was a time when the Atlantic Ocean was a rift valley narrow enough to see across, presumably with lakes and dinosaur filled fern forests (or whatever) within. (The current Atlantic opened up starting about 65 million years ago.)
The continental level rifting can be seen in the basin structure of southern Africa as well. The seaward edge of the subcontinent tends to retain an upward slope. At one time, the faces of these slopes were the edges of rifts separating what is now Africa from South America and Antarctica. The upward slope is caused by the elevation that tends to accompany rift systems (which, in the case of Iceland, leads to Iceland sticking up out of the water, and along the mid Atlantic Ridge, leads to … it being a ridge.)
With the continent sloping upwards towards the sea, the interior was filled with giant inland bodies of water, which trapped the sediment that later would become, for instance, the Kalahari sands (which are a thick and major feature from the Orange River of South Africa to the left bank of the Congo River). Subsequent breaching by major rivers, typically forming modern day canyons or very deeply entrenched valleys, emptied those inland seas, and in some cases created huge off-shore deposits. The sand bar at St. Lucia, South Africa, formed in the Miocene of the output from the Limpopo River, is probably the largest sand bar in the world, measured in terms of volume of sand (this is subject to revision, but that is my impression).
Let me give an example that may be closer to home for some of you. If you live near the Hudson River, you may know about the Taconics and the Catskills. You would know of the Catskills as reasonably impressive mountains, and the Taconic Hills as a line of funny little bumps, large hills on the other side of the river from the Catskills. What you may not know is this: The Taconics are the basal remnants of uplift caused by an early closing up of the Atlantic ocean, that caused a huge mountain range to form much like the Himalayas have been formed by the closing of the gap between India and the rest of Asia. The ramming together of continents, as it were. To the west of those mountains formed a great sea, which was filled with sediment from erosion, that erosion being caused by the uplift. The Himalaya-size Taconics essentially eroded into the sea, forming a vast and complex region of sediments to the west. Subsequently, erosion has cut though those sediments and what is left behind is the Catskills. The Catskills are not really mountains … they are an eroded plain, and they are made up of relatively flat (considering how old they are) sediments from across the more recently formed Hudson.
Meanwhile, back in Africa, and much much earlier in time, one of the interior basins formed by rift-ridging around the edge of the continent was presumably breached by the Orange River, which flows all the way from the relatively better watered eastern side of the continent to the west. The river flows through the very arid lands of the southern Kalahari. Even if the river was not used in irrigation, it would still become smaller and smaller as it went west, because of evaporation. And, in reaching the sea, it cuts through a series of canyons.
One of those canyons starts with a high waterfall. The canyon below the waterfall is said to be the home of a giant snake, a very large powerful demonic snake. This snake is the main reasons people (who believe in the snake) will not travel through the area. That maybe somewhat less rational than air traffic controllers refusing to allow planes fly through the ash plume of Eyjafjallajoekull. So the connection, I admit, is tenuous at this level: The snake story and the grounding of the planes are both caused, directly or indirectly, by the rifting process.
But I find a different aspect of this to be more interesting. The average person spends their entire life living in, or frequently visiting, a region without knowing a single thing about it’s geology and related biogeography. Does any American who visits Jamaica or any of the Caribbean Islands know why those islands are there? Does the average Englishman know why the White Cliffs of Dover are in Dover, are white, or are cliffs? (Those may be three different questions … but the answer to one of them is related to rifting!) And now, all these people are wandering around a large chunk of Europe wondering when the ash is going to stop falling, when what they should really be doing is marveling at the fact that they are taking place in a major geological event! Granted, their role in the event is to become part of the sedimentary record (if they stop moving and the rate of ash fall increases enough!). And, in fact, as geological events go, this is not huge. But nonetheless, it is humbling and fascinating at the same time. If you let it be.
Like a big snow storm but you can put some of it in a small plastic box and keep it for your grand kids.
1Eyjafjallajoekull means “My fingers are on the wrong keys on the keyboard” in Icelandic.
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“Eyjafjallajoekull means “My fingers are on the wrong keys on the keyboard” in Icelandic.”
Well put.
Oh, geology is just too geekily interesting! In most of Europe, I hear (from my daughter in Paris) the skies are blue, and ash isn’t visibly falling- though, in Iceland it’s another story, judging by the pictures on tv….also, in Iceland you can actually see the Atlantic rift! I’ve seen it, and floated around in the geothermal lagoon formed in the middle of it….just too cool for words!
I sure know I am living on top of schist, because it supports the new 35-floor tower that blocks sunlight from my garden, and rocked my quiet home with blasting from 8AM to 6PM for 3/4 of a year. The Second Avenue tunnel construction is rapidly approaching my block – so a replication will occur soon. If only the schist had remained silt, Manhattan would still be a beautiful quiet island. But I agree: most people have no idea about the natural setting in which they live or work.
Ash and jet turbines do not play well together. The probability of seizing is small, but not the result. I’m with the euros on grounding flights.
OK, here’s what I know (accurate or not) about my local geology. Southern Michigan, where I live, is and AFAIK has always been a basin; sometimes covered by water, sometimes not. Of course we all know here that the area has been glaciated during the ice ages and that the Great Lakes date from the last glaciation. The nearest volcanoes are long gone; they were in what is now the Upper Peninsula and Isle Royale, the latter being mostly basalt ridges sticking up out of Lake Superior (I backpacked there in my youth).
I once (long ago) read that there is something called a “failed triple juncture” deep under Lake Erie; if I understood correctly it’s the intersection of multiple ancient but abortive rifts. Now and then it supposedly still causes small earthquakes. But maybe my memory is faulty. Any Midwestern geologists out there?
Mi’s lower pennisula has been a basin for about 500 million years. Before that in the 1.2 billion year time frame there was a continental collision in the region the Grenville collision, (which shows well on the north side of lake Huron). The failed triple junction is related to the rocks of the kewenaw pennisula in the UP, with one branch dieing off in S mich and the other going into Kansas (the mid continent gravity high) Btw the center of the Michigan Basin is north of Lansing, and the north edge occurs in the eastern UP. The Grenville collision BTW extends from Canada down thru Texas and into Mexico.
Amy: I think there is ash falling in England. I prefer to imagine a thick layer of ash falling on all of europe as every one trudge around in hats for a few days. But yes, I think the main problem is air planes at altitude, and perhaps a bit of extra caution because they really don’t know.
Excellent geology! I would just add that the great lakes were probably carved out over a few glaciations, not just the last one, and that it is very complex (and for pre-Wisconsin glaciation very difficult to interpret because of the effects of later glaciation)
I won’t question your Icelandic expertise, but it looks suspiciously like it should mean “Island Mountains’ Glacier”.
Greg, as far I know, there’s no ash falling here in England. I thought there was none in the UK but, after doing a bit of reading, apparently there’s a bit in Scotland. Don’t refer to Scotland as England, it makes them angry 🙂
(Wonderful article and blog though, keep up the good work!)
For the record, the Atlantic is a system of two large oceans, which opened in two separate (and potentially three) events, rather than one. While the African Rift Valley system is an accurate model for this, it is only accurate for the southern Atlantic in this regard, and only if you look at the entire Rift system in Africa (which is about 1/4 the length of the continent).
The northern Atlantic, east of Greenland, opened up during the Early Jurassic, while forming a shallow sea spotted with various non-volcanic islands. On its western edge, the Icelandic-based North Atlantic Sea Ridge began spreading much later, during the Middle to Late Jurassic, before America and Europe were completely split off from one another (Gondwana is still intact). By the early Cretaceous, two separate rifts opened between South America, leaving a narrow bridge between the two. This would be completely severed, but biogeographic evidence suggests it reconnected, severing the ocean, before splitting again in the mid Cretaceous. At this point, to whole Southern Atlantic opened up, and the northern and southern oceans connected. The consequences of this event are interesting in and of themselves. This thus starts from about 140mya to 95 mya (rough guesstimation).
“Eyjafjallajoekull means “My fingers are on the wrong keys on the keyboard” in Icelandic.”
No, no, it means: “Where’s Language Log when I need it?”
😉
There is no ash visibly falling from the sky here in the Netherlands. Perhaps the sunsets in the last few days have been a little more colorful than usual.
But who knows… Apparently, the last three times Eyjafjallajökul erupted, Katla, a much larger volcano, did too. In 1783 it killed tens of thousands of people in Europe and the effects of the eruption lasted until 1788. “By day, a paltry sun emitted little more light than the moon did by night. Only at sunset and sunrise did it turn a deep crimson red.”
Nice work, Thanks.
Now I can sit back,sip coffee and wait for the “see, volcanoes disprove global warming” nonsense to begin.
Or not.
DLC: I’ve already heard it from an acquaintance: “The world got cool after the volcano down near Taiwan exploded in the late 1800s [I assume he meant Krakatoa, but who knows?] and volcanoes make lots of CO2 so global warming is a hoax. Just watch how cooler it gets with the volcano in Denmark exploding and dumping CO2 in the air.”*
A few minutes later, after I pointed out that ash is the culprit for the cool summers and brutal winters after some volcanoes, and he said, “No, not the ash. It’s the CO2. They won’t let jets fly through it because there is so much CO2 that there isn’t enough oxygen for the jets to burn.”*
A half hour later, I was significantly dumber and he was still an idiot. I took two aspirin and a scotch.
* Very close to exact quotes.
@lyle #5: Thanks! The Grenville collision fault is dramatically visible in Killarney Provincial Park (Ontario CA) north of L. Huron as you said. There’s a long narrow lake (have forgotten the name & don’t have maps handy) that according to the guidebook I was using lies along the fault having been subsequently gouged out by glaciers. On one shore the rocks are pink granite; the other, white quartzite.
Beautiful country, rugged hiking, lousy fishing (the inland lakes are pretty sterile).
Um, that’s Ontario CAnada, not CAlifornia, of course! :/
Jaime A. Headden: yes indeed, and thanks for putting those details in a comment (they certainly were not going to fit in my post!)
Irene: Proof that that is not really a langauge!
That major geological event in Iceland just caused my dissertation defense to get temporarily cancelled, with my parents flying up to New York for nothing now and unable to come back for whenever it’s rescheduled for. All because one of my dissertation readers is in England this week. So, a volcanic eruption in Iceland forces my New York dissertation defense to be postponed. I never imagined such a thing would happen.
Well, I know the geological makeup of my region! The Pacific NW is full of volcanoes, and that’s because it’s more or less on the edge of two tectonic plates. The most famous example of this confluence of forces is the eruption of Mount St. Helens in 1981. Oh, BTW, much of Western Washington was buried under two miles of ice during the Pleistocene. Which has had a considerable impact on the landscape, in some areas. Eastern Washington was what is now called “steppe tundra” and woolly mammoths roamed there once upon a time.
Anne G
You can trace the path of a hot spot, similar to the one that produced the Hawaiian Islands, through New Hampshire a few hundred million years ago. The hot spot left a few hills behind. Montreal’s eponymous hill is one of them, as is Mont Orford to the east. The line then turns more southerly; it includes Mount Washington (which was subsequently built up further when the Appalachian Mountains were built) and several other hills near the NH-ME border. Mount Agamenticus in York, ME (about half an hour from where I live) is the last one on land. There are several more underwater, the last of which is an active volcano that marks the hot spot’s current location.
Thanks for the post, very informative.
Living in Iceland and being a geology enthusiast and the out-doorsy type, is fantastic. Just wish I knew more about it. But I know enough to impress fellow hikers:)
And Eyjafjallajokull does indeed mean the glacier on the islands mountains. Named either after Vestmannaeyjar, which is a group of islands that lie due south of the coast. Or the area west of the mountains that is called Landeyjar (land islands, dont ask, long story). Oh and those islands are also volcanically active (as most places here). Last eruption there was 1973.
“Does the average Englishman know why the White Cliffs of Dover are in Dover……”
It would be interesting if the white Cliffs of Dover were in Aberystwyth. They are presumably in Dover because they are not the White Cliffs of anywhere else.
The town of Dover is named after the stream that runs through it, the Dour. Dover is at the cliffs rather than the other way round – I think the accepted view is that they were there first. It is near the narrowest point of the English Channel, and at a gap in the whitish cliffs, and is therefore a rather convenient harbour for travellers to and from the continent.
Kinda like why Buffalo NY is called Buffalo.
There’s a series of books written for general audiences called Roadside Geology. They have them for most of the USA.
They are organized by highway, so that as you travel along, you (hopefully a passenger!) can read about the geology you are seeing.
http://geology.com/store/roadside-geology.shtml
Very cool post. Thanks. It just motivated me to learn a bit about the geology around me (if I could ever find the time).
@20, Anne G: Actually, there are three tectonic plates here because Vancouver Island is on its own small plate, and that makes our area along the Oregon/Washington/BC coast one of the most geologically diverse in the world. We also have great variance in climate (yes, climate, as well as weather) because of the geology. We have two distinct mountain ranges, the Cascades and the Olympics. Because of the large altitude differences we also have several different climatic zones, ranging from our rare northern rainforest to subarctic alpine.
As far as weather, there is great local variance. For instance I live on the island inside Lake Washington called mercer island, and I if I want a change of weather, I can either drive 10 miles west to Seattle or 10 miles east to the Sammamish plateau.
Where the people are situated on the tectonic plates and what altitude they live at determines their climate and overall weather patterns, and there is great variance of those even within a 100-mile radius around here.
Plus we have the mother of all volcanoes in the lower 48, Tahoma (Thunder Mountain) a.k.a. Mt Rainier. The towns Enumclaw and Buckley are sitting atop the volcanic ash plains from previous eruptions, and will likely be in the direct path of the lahar if Tahoma blows again anytime soon.
If the Paradise (= northwest) face of the volcano blows, the force of the eruption will be directed in the direction of Seattle, although prevailing winds might turn the plume back inland. Apparently this is what happened in the last big eruptions, which is why the volcanic plain spread northwest from Rainer towards Tacoma.
Acutally, nobody knows why Buffalo is called Buffalo, though there are a couple of theories. (I once heard that Buffalo came from the Iroquois word for chicken wing. ;)) There is some pretty cool geology in the area, though. The Niagara escarpment alone makes the geology cool.
I think that we know, but “knowing” in this case relies on accepting some oral history as reasonable. The problem these days (in the Wikipedia days) is that all oral history has been relegated to the “it’s not real evidence” pile. But, if all you have is chickens, you are going to eat a lot of chicken.
The oral history on this isn’t bad, especially since “buffalo creek” was once called “buffalo’s creek” strongly suggesting that it was named after a person, as creeks in NY once were often named. Collaboratively, there was an Indian named “Buffalo” according to oral history. Other evidence suggests that the city was named after the creek. So, it is perfectly reasonable to say that the most likely source of he name “Buffalo” for the city is the creek, and in turn, the man named Buffalo. There is one story as to how he got his name …. he reminded people of a buffalo … but in a culture where people often get named after animals, that is less clear and less important, and that is probably just an add on for the white people who accept that they name themselves with little consideration for the meaning of the name but often demand of other cultures that we get a detailed explanation.
It is important to note that there is no evidence to support the idea that the city was named “Buffalo” because the animal roamed the vicinity at the city’s founding.
Manhattan would still be a beautiful quiet island. But I agree: most people have no idea about the natural setting in which they live or work
Isn’t that the volcano in Journey to the Center of the Earth? Or do all those names look alike. R R
Mike:
q.v.…
It is so fascinating to learn about the geology under your feet. I’m from Minnesota, and there are some very interesting pieces of geology around here. Glaciation in some areas, areas untouched by glaciers elsewhere, moraines, sedimentary rock dating back to the Permian…. And up north, volcanic rock dating back to the beginning of life itself!
I live on the verge of one of the more awesomely named bits of geography that most people don’t notice: the Driftless Area. There are some quite beautiful vistas in the region, which is named for its lack of glacial deposits. Rivers, including the Mississippi, cut deep bluffs into the surrounding terrain, and tributaries cut surprising canyons. Almost immediately next door to all that are massive glacial deposits; I live on what is essentially a gigantic moraine, and there’s a lovely valley nearby (Rich Valley) which is bordered by two moraines.