The Mid-Atlantic Ridge above sea level in Iceland.
On my recent trip to Iceland, I had to seize the opportunity to take pictures of plate tectonics at work. Imagining oceanic plates drifting apart is quite difficult, and Iceland is one of the few places in the world where a mid-oceanic ridge reaches above the water level.
We first went to Thingvellir, but since I wanted pictures with no wandering tourists on them except for us, we had to continue the search for the perfect rift valley.
I don’t really know all that much about plate tectonics, but from what I read in various places, the plates here don’t converge continually, but in episodes. Apparently, the last big event and subsidence of the valley floor occurred with an earthquake in 1789.
Hydrothermal springs that you can visit without a deep-sea submersible.
When teaching about hydrothermal springs, I usually use a video a friend of mine took of hydrothermal vents on the mid-Atlantic ridge on the WHOI submersible Alvin. But being on Iceland now, there is much better material available which students can even go and experience themselves.
I am too chicken to take my camera under water in the Blue Lagoon to film the hot springs, but there are other hot springs all over Iceland that are less scary, for example this one that my friend Astrid found in the middle of a meadow.
And here I even dared take my camera under water.
Granted, this is not quite as impressive as a black smoker or the Blue Lagoon. But the water in the whole little lake was warmer than about 40 degrees Celsius, and the hot spring is sitting randomly in a field. That’s hand-on geothermal heating for you!
See? When I said “very simple” I meant “very simple”. But it does help explain why sometimes rock layers are not nice and horizontal.
This demo works really well with a piece of paper towel, too, especially if that is grabbed from a dispenser in the lecture theatre during the lecture and hence the impression is conveyed that it is a spontaneous visualization rather than one that was carefully planned…