Archive for June 4th, 2013

20 Bags, Two Geologists, Plenty of Mountains

June 4th, 2013

EPHRAIM, UTAH — After no sleep, Tricia Hall (’14) and I had to get up at 3 am to catch our early flight to Utah.  It is a good thing that we arrived at the airport in plenty of time (thanks, Patrice, for the schedule!!), because one of our many equipment bags was searched several times.  Apparently the Schmidt Hammer (“Schmidty”) caused some concern.  But, it is not always that you have concrete strength testing equipment in your carry-on.

After a good night’s sleep, we were bright-eyed and ready for “reconn day” up Sixmile Canyon, just east of Sterling, UT.  Tricia will be working on her I.S. within the Cretaceous Sixmile Canyon Formation, which is exposed in all its glory near the mouth of the canyon.  Her focus is to investigate the wonderful deformation bands within the formation and their relationship to local structures.  To get a good overall perspective of some of the deformation in the area, we investigated two major faults that are exposed near the base of the formation.

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Here’s Tricia, admiring the fault plane and noticing the upturned Flagstaff Limestone on the downthrown block.

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After examining the faults, we decided to have some lunch.  Our view of the Sanpete Valley was gorgeous.  The sun was warm, with few clouds…and there was just enough breeze to make lunch very relaxing.  Take a look at the photo above, which shows a view toward Ninemile Reservoir and the infamous Arapien Shale that forms the core of the Sanpete-Sevier Valley Anticline.

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The photo above is of the Sixmile Canyon Formation, which contains deformation bands of various types and sizes, along with traditional joints.  The formation at this locality is a medium- to even coarse-grained sandstone that shows the obvious impacts of fluid flow and iron-stained surfaces.

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We had a great reconn day.  However, in the photo above, Tricia is looking out for mountain lions, which apparently are a little problem in the canyon!!  Lucky for us, we were able to get access to a southern exposure of the formation and had a great conversation with the landowner about all of the bears and mountain lions and recent “kill sites” that he has seen in the area.  We are psyched.

Sicilian fossils at last!

June 4th, 2013

FieldStopOne060413CATANIA, SICILY, ITALY–After lunch our International Bryozoology Association field trip actually collected fossil bryozoans. We visited a quarry exposure of Lower Pleistocene cemented marls rich in the bryozoan Celleporaria palmata (Michelin), along with many other species. These were apparently from a thicket of bryozoan colonies broken up in a storm and deposited as a debris flow down slope. The location is south of Catania at Pianometa.

Celleraria060413Lower Pleistocene Celleporaria palmata fragments at Pianometa. This was a very rapid-growing, branching bryozoan colony easily fragmented by storm currents.

Volcaniclastic060413Below those bryozoan-loaded beds is this unusual sequence. The darker layered units are volcaniclastic sediments derived from early eruptions from the Mount Etna complex. Occasionally boulders would roll downslope and be deposited as xenoliths (“foreign rocks”) Later the cemented sediments cracked repeatedly due to the intense earthquake activity associated with this tectonic boundary between the European and African plates. Those cracks filled with marly sediment from above.

SheepCheeseFarm060413The last visit of the day was to a sheep cheese farm. One sheep produces about a liter of sheep’s milk. The cheese we sampled (some more than others) is very soft — like cottage cheese without the lumps, or a soft ricotta. Interesting (and unpasteurized). We watched four rams beat each other bloody in an ongoing context monitored by large black dogs. I suppose it is part of the herding process, grim as it is.

Products of an angry giant

June 4th, 2013

SicilyCyclopeanIslands060413CATANIA, SICILY, ITALY–They may look like impressive sea stacks to you, but it turns out these are three huge stones thrown by the aggrieved and wounded cyclops Polyphemus at Odysseus as he escaped that infernal cave. Who knew?

This morning we traveled north of Catania to the Ciclopi Marine Protected Area near Aci Castello and Aci Trezza to look at the evidence of the ancient volcanic activity that led to Mount Etna, and to snorkel and dive on the life-encrusted rocks in the blue, blue waters.

Island060413We took a boat ride all of about 300 meters across the bay to the tiny island of Lachea, shown above. Notice that there is a crack running through the rocks seen just above the boat. This is an active fault that runs through the middle of the island. Also note that there is a mix of light and dark rocks visible.

IslandBasalticIntrusion060413Lachea is a combination of whitish marls and claystones above with black basalt injected from below. This is the very beginning of volcanic activity in this region as hot magma began to work its way into the overlying sediments of a shallow sea. When the lava erupted onto the seafloor, masses of pillow basalts formed (see previous post). The cyclopean rocks in the top image are eroded roots of the massive basalt flows. They show beautiful columnar jointing.

Etnafromisland060413From Lachea we can see the glowering outline of Mount Etna, the true giant in our story.

StationSign060413The island of Lachea and its surrounding rocks has been the site of a research station for over a century. The fauna and flora of both the island and the seafloor down to 110 meters are protected by law.

IslandLizard585This pretty green lizard is common on Lachea and apparently endemic (found only there). It is Podarcis sicula ciclopica. Its mating season of three months is about to begin, so there was much lizardly activity.

Grotto060413One of the first places we visited on the island was this tiny historical grotto. Only five of us could crawl into this completely dark chamber at a time. Once inside you can carefully stand up and (at least some of us) touch your head on the ceiling. That turned out to be a mistake because the guiding biologists then show you the unique cave spiders hanging on their webs about your ears!

Lunch060413Finally I must show you at least one of our large Sicilians lunches, this one back in Catania after our morning marine excursion. We are eating well, if a bit later than usual — and with much more time in the process!

 

Pillow basalts for Dr. Pollock

June 4th, 2013

PillowsCastle060413CATANIA, SICILY, ITALY–These are Dr. Meagen Pollock’s favorite kind of rocks: pillow basalts. Above we have a spectacular example of pillow basalts exposed in cross section below a castle ruin in Aci Castello a few kilometers north of Catania. The pillows (more are shown below) are in the middle of this natural outcrop carved by the sea.

Pillow basalts are formed when basaltic lava is erupted underwater. The surface of the flow quickly cools and begins to solidify as the interior fills with lava. The result is a flattened spheroid of basalt with chilled margins. The castle, by the way, was built in 1076 by conquering Normans.

Megapillow060413The light was not great for this shot, but you should be able to make out in the lower right a large body of basalt with columnar joints radiating from the center. This is, I was told, a “megapillow’ of basalt from a large flow.

PillowWall060413Here we have a closer view of the pillows in the wall shown above. On several of these pillows you can just make out a fine-grained chilled margin.

PillowBed060413This is a view of the wave-eroded platform below the castle showing the pillows form the top. I left the roasting Europeans in the frame for scale. Note that while these pillows appear with almost circular outlines in cross-section, they are actually serpentine in shape.

These pillow lavas were formed with the beginning of volcanic activity roughly 600,000 years ago that led to the present Mount Etna complex. They show the submarine phase of eruption before the eruptive center was uplifted above sea level. They are the most spectacular pillows I’ve ever seen.