Mark Wilson June 16th, 2013
CATANIA, SICILY, ITALY–The very last field trip stop — and final event — of the International Bryozoology Association Conference was a trip to the south side of Mount Etna. We drove to a spot that had significant activity in 2000 and 2001. Several lateral craters appeared on the side of the mountain, and the lava flows buried parts of a restaurant and shop complex. They threatened to destroy the base of a cable car system, but firefighters with hoses managed to divert the flow by cooling it with water.
My Belgian friend Hans De Blauwe and I decided to choose one of these smaller craters and hike to it within our allotted visit time. We picked this one in the center because of its symmetry and the flows that streamed from it. All of these features in and around this cone formed in 2001.
We soon saw that our cone was the first of at least three cones descending in a row down the slope. The lava flow shows very distinct levees on its sides where the lava lapped over its banks and cooled, creating a walled channel.
There are many car- and house-sized boulders of non-vesicular basalt scattered about. I assume these were thrown from the throats of explosive craters.
We found this very cool lava tube, indicated first by a long walled channel that apparently represents a collapsed portion of the tunnel. A lava tube is formed when the periphery of a flow cools into hard rock and the still-fluid interior empties. We explore a beautiful ancient example on our Mojave Desert field trips.
Our lava tube is open at both ends. Here Hans is crouching in the larger of the entrances.
I took a flash image of the interior. You can see small “lavasicles” (cooled drips of lava) on the ceiling, along with a white crust of some sulfurous minerals.
Here Hans is picking his way through the aa flow. In the lower right is another lava tube that extends back about three meters.
The flowers on this volcanic slopes are very interesting. Hardy pioneers, they are. There are numerous clusters of these mounds of greenery. It appears that the plants settled on a bit of ash and then grew centripetally. The surrounding ash was eroded away, but the roots of these plants held onto their patches, eventually producing mounds as the surrounding sediment was removed.
The mounds are made mostly of this spiny flowering plant. Maybe Hans will provide me with names later.
These purple flowers often form in rings around the bases of the mounds.
Nice white flowers on the 2001 ash layers.
Somehow there are always daisies around, even in the most surprising places.
Finally, here is a view from our craters toward Catania and the coast. A 2001 lava flow is directly below us. In the middle distance you can see a series of small cones, many of which were active in historical times. Catania is certainly in a volcanic hazard zone. The geologists, though, worry far more about earthquakes here than eruptions. An eruption, after all, gives you much more warning than a sudden and devastating ‘quake. Considering all this, and despite the occasional tornado and blizzard, Ohio looks like one of the safest places on Earth.
And to beautiful and much wetter Ohio I now return.