Archive for June, 2013

A visit to ancient Syracuse

June 12th, 2013

1. Theater061213CATANIA, SICILY, ITALY–One of the treats of many small scientific meetings, like the International Bryozoology Association conference I am attending now, is that we can have a variety of short field trips for all participants. Today we packed into two buses and spent the afternoon and evening in the city of Syracuse south of Catania.
2. TheaterTop061213Syracuse was founded by Greek colonists (primarily Corinthians) over 2700 years ago. It was the home of Archimedes. He was famously killed there by a Roman soldier when the city was captured in 212 BCE. Cicero called Syracuse “the greatest Greek city and the most beautiful of them all”. The Syracusan tyrant Hiero I (who ruled from 478 to 466 BCE) built the outdoor theater shown at the top of this page. (Don’t call it an “amphitheater”!) Just above is a view of the ancient entrance to the theater above the seats. Greek engineers diverted a stream here to fill fountains and pools and eventually flow down to the front of the theater for refreshment and sometimes to be part of the performances. The theater is still used, so wooden seats have been fixed over much of the ancient stone.
3. SyracuseQuarry061213Behind the theater is this large ancient limestone quarry. You can make out a couple of pillars left in place on the quarry floor, along with characteristic vertical walls and square corners. The sturdy rock here was used to build the city and its walls.
4. QuarryPrisonSyracuse061213On one side of the quarry is this unusual cave called The Ear of Dionysius. It is 23 meters high and goes back about 65 meters. It has an uncanny resemblance to a human ear, hence at least one possible reason for the name. Inside it has smooth walls and a serpentine curve much like a meandering stream. The acoustics are unusual. Apparently even whispers inside can be heard at certain points above the cave’s entrance. The tyrant Dionysius is said to have placed his prisoners in there so that he could listen to their secrets (or to their tortured screams). There is considerable debate (which was repeated in our group) about whether this was all carved by quarriers or is a natural water-eroded slot canyon then modified for human use.
5. CarlPaulSyracuse061213Carl Simpson and Paul Taylor showing stylish Italian straw hats on our trip.
6. SyracuseHarbor061213At dinner this evening we had this wonderful view of the ancient harbor of Syracuse as the sun set and moon appeared above. Across the water on the end of the promontory is the Castello Maniace, which was originally completed as a fortification in 1240. King Ferdinand III gave this structure to none other than Admiral Horatio Nelson in 1799 for services rendered to the Kingdom of Naples. It stayed in private English hands until 1982 when it was given to the province of Catania.

I would describe the dinner, but you probably wouldn’t believe how many various Sicilian treats we had, including the inevitable octopus. It was a memorable evening in the middle of our intense conference.

Scientific Outreach in Iceland

June 12th, 2013

ICELAND – Team Iceland is nearly ready to return to the states, but not before we share what we’ve learned with the Icelandic community. Our home-away-from-home, the Hraunbyrgi guesthouse, is also home for the Hafnarfjörður scouts. To celebrate the end of their season, the scouts are having a large, nationwide camp-out at a site just south of the pillow quarries. So, for their final meeting, the scouts met with Team Iceland to learn about our research.

Dr. Ben Edwards shows the local scouts a sample of a pillow basalt.

Dr. Ben Edwards shows the local scouts a sample of pillow basalt.

The scouts learned that they’ll be camping along a ridge made of pillow basalts, which formed when lava erupted under a glacier. They also heard about the kinds of information that we can learn from the pillow basalts, like how the upper portion of the ocean floor is formed and how thick the ice was that once covered the Reykjanes Peninsula.  The scouts returned the favor and taught Team Iceland a few new Icelandic words. What a fantastic way to end a successful field season!

Team Utah Version 2.0

June 11th, 2013

UTAH – Field work has officially begun for Team Utah, Version 2.0. The team consists of three Wooster seniors (Kyle Burden ’14, Cam Matesich ’14, Candy Thornton, ’14) and two Wooster sophomores (Adam Silverstein ’16, Michael Williams ’16). Tricia Hall (’14) is a returning member who has graciously agreed to stay in Utah after her IS field work to help us with our data collection. This year, we’re also joined by Dr. Thom Wilch and two senior geologists (Ellen Redner ’14 and Ben Hinks ’14) from the Albion College Department of Geological Sciences. Needless to say, we’re a small army, and we’re ready to find the answers to questions raised during last year’s reconnaissance investigations of Ice Springs Volcanic Field in the Black Rock Desert.

Dr. Shelley Judge gives a brief overview of the local and regional geology before heading out to the field.

Dr. Shelley Judge gives a brief overview of the local and regional geology before heading out to the field.

We began the morning at the top of the cinder cone and found a new exposure that was uncovered in the last year.

We began the morning at the top of the cinder cone and found a new exposure that was uncovered in the last year.

I know what you’re thinking…it looks like a wall of pillow lavas. (By the way, Team Iceland’s work on pillow lavas continues.)

It's actually a wall of welded bombs and spatter.

It’s actually a wall of welded bombs and spatter. These blobs of lava were ejected explosively during an eruption and fused to one another on the rim of the cone.

Kyle Burden ('14), shown here taking careful notes, will be working on the welded bomb wall using an approach similar to the one Team Iceland used on pillow lavas. He'll be collecting high-resolution images with a GigaPan and making careful measurements of bombs across the exposure.

Kyle Burden (’14), shown here taking careful notes, will be working on the welded bomb wall using an approach similar to the one Team Iceland used on pillow lavas. He’ll be collecting high-resolution images with a GigaPan and making careful measurements of bombs across the exposure.

After a morning on the cinder cones, we descended into the lava fields.

Candy Thornton ('14) contemplates her field area. She'll be documenting features in the lava flows to determine whether they inflated as they were emplaced.

Candy Thornton (’14) contemplates her field area. She’ll be documenting features in the lava flows to determine whether they inflated as they were emplaced.

One of the features that Candy will be studying are these striae, which are grooves that formed on the sides of a mound called a tumulus. The striae indicate that the interior of the mound moved up relative to the outer crust while the lava was partially molten.

One of the features that Candy will be studying are these striae, which are grooves that formed on the sides of a mound called a tumulus. The striae indicate that the interior of the mound moved up relative to the outer crust while the lava was partially molten.

 

 

Sediments, fossils and vistas at the Capo Milazzo Peninsula, Sicily

June 9th, 2013

1. Capo Milazzo 060913CATANIA, SICILY, ITALY–This was the last day of our International Bryozoology Association pre-conference field trip through Sicily. We had an excellent time and covered an extraordinary amount of territory on this large Mediterranean island. We started our final day on the Capo Milazzo Peninsula in the northeastern portion of Sicily. The view above is looking north from the base of the with the main lighthouse on the right and bay on the left. Just peeking around the headland in the distance is one of the Aeolian Islands. We climbed down to study the rocks in the middle distance.
2. Eckart Conglomerate 060913One of the most striking units we saw was this Pliocene conglomerate at the base of a small paleobasin cut into a Paleozoic metamorphic complex. The clasts are a variety of metamorphic rocks, from high-grade schists and gneisses to low-grade greenstones. Eckart Hakansson for scale.
3. Closer conglomerate 060913This is a closer view of the conglomerates. The matrix is a foraminiferan-rich marl almost identical to the marl which lies above it (see the next image).
4. Foram Marl 060913This Pleistocene (Gelasian) marl above the conglomerates is almost 95% planktonic foraminiferans, or at least it looks that way with a handlens. There are some other fossils (see below) and a few sand-sized lithic fragments, but otherwise this is a foraminiferan ooze deposit.
5. Pliocene marl octocorals 060913Besides the foraminiferans, the most common fossils in the Pliocene marls on the Capo Milazzo Peninsula are these stick-like objects. They are gorgonian octocoral internodes, probably from the species Keratoisis melitensis. I grabbed a handful and thereby tripled Wooster’s collection of fossil octocorals.
6. Pleistocene bored Miocene 060913Included in the marls are these cobbles and boulders of Miocene limestones slumped in from the slopes above. They often have large borings from lithophagid bivalves (producing Gastrochaenolites) and a smaller background boring by clionaid sponges (making Entobia).
7. Stromboli 060913There are spectacular views from Capo Milazzo. This is looking north at the volcanic island of Stromboli. We spent a long time staring at it because every half-hour or so it spouts steam and smoke for a few seconds. I didn’t get to see an event, but there was a continual very light plume blowing from the right to the left.
8. Mark Stromboli 060913This is the only time I handed my camera to a colleague and asked for my picture taken. I couldn’t resist a view with Stromboli in the background. I also wanted to show off my new Italian hat. (I lost my regular and well-worn field hat somewhere along the way.)
9. Etna Smoking 060913As we were leaving the peninsula, Mount Etna to the south let out a large puff of steam and gases into the murky air.
10. Hotel in Milazzo 060913Finally, a few shots from today to show a bit how our field trip worked. Above is our hotel in Milazzo, typical of the places we stayed around Sicily. Note all the little Fiat cars. In every city and town these cars were constantly buzzing by.
11. Bus interior 060913This is a view from my seat in our bus. Our intrepid leader Antonietta Rosso from the University of Catania is speaking in the microphone. We are very grateful to her for her planning, energy and good humor. My legs here, by the way, are extending well into the aisle because they just did not fit in these tiny Italian seats.
12. Field trip lecture 060913Antonietta Rosso is here giving us a field lecture before we descend down to the Capo Milazzo outcrops. The man taking photographs in the background is a keen Italian amateur who was very helpful. I wish I caught his name. He said one lifetime isn’t enough to enjoy all the wonders of this planet — and then there’s space!
13. Milazzo Castle 060913Just before lunch we had the requisite castle visit, this one in Milazzo. The Milazzo Castle suffered some bombing damage in World War II. The Germans and Italians used Milazzo and its port as a supply center for the Afrika Korps, and then later as a communications center for their resistance to the Allied invasion in 1943. The walls we are looking at here were built by the Spanish (Aragonese) in the 15th Century.
14. Messina Strait 060913Finally we passed by the Strait of Messina, with mainland Italy visible through the haze. This narrow body of water is extraordinarily deep and its sides continue to be uplifted by tectonic activity. These waters have wicked currents and have been known as a navigational hazard since antiquity. When we saw this strait we knew we had rounded the corner of Sicily and nearly completed our journey around the entire island.

Thank you again to our University of Catania leaders, especially Antonietta Rosso and Rossana Sanfilippo. Now we have a few hours to rest before the official International Bryozoology Association Conference begins tomorrow morning.

Wooster’s Fossil (and Mineral) of the Week: Marcasite worm burrows from Bolivia

June 9th, 2013

MarcasiteBurrowsBoliviaFixedHere’s a type of fossil I’ve never seen: worm burrow casts made entirely of the mineral marcasite. These come from the George Chambers (’79) gift collection, so we know only that they were found in Bolivia. Despite the lack of information about them, they’re curious enough to be featured in our series.

As best as I can figure out, these started as tunnels burrowed into a muddy substrate by worms of some kind. Iron sulfide, in the form of the mineral marcasite, precipitated within the abandoned tunnels, eventually filling them completely. Later the mud matrix was eroded away, leaving these intertwined tubes of silvery marcasite.

The tunnel walls were probably coated with an organic slime from the original worms or later bacteria. Sulfate-reducing bacteria may have then colonized the organic material, precipitating the pyrite in a manner described by Schieber (2002) and Virtasalo et al. (2010). The marcasite would ordinarily have converted to the more common (and stable) form of iron sulfide, pyrite (see Murowchick, 1992), but for some reason this did not happen here.

A cool combination of mineralogy and paleontology!

References:

Murowchick, J.B. 1992. Marcasite inversion and the petrographic determination of pyrite ancestry. Economic Geology 87: 1141–1152.

Schieber, J. 2002. The role of an organic slime matrix in the formation of pyritized burrow trails and pyrite concretions. Palaios 17: 104–109.

Virtasalo, J.J., Löwemark, L., Papunen, H., Kotilainen, A.T. and Whitehouse, M.J. 2010. Pyritic and baritic burrows and microbial filaments in postglacial lacustrine clays in the northern Baltic Sea. Journal of the Geological Society 167: 1185-1198.

Return to the Pliocene at Altavilla Milicia, Sicily

June 8th, 2013

9. Altavilla Milicia 060813Our last stop of the day on the IBA field trip was to a classic fossil locality on the north coast of Sicily about an hour east of Palermo. These are fine sandstones and marls preserving a diverse array of mollusks from the Pliocene, including the bivalves shown below. Over 130 bryozoan species have been recorded from this site since 1921. The most interesting features to me were the numerous sclerobionts, including shallow worm and barnacle borings and encrusting bryozoans and barnacles.
10. Altavilla Milicia fossils 060813From here it was a long drive to the beautiful and ancient city of Milazzo to prepare for our last day of the field trip.

A Phoenician island city and its lagoon

June 8th, 2013

1. Mozia south harbor 060813MILAZZO, SICILY, ITALY–The pre-conference field trip of the International Bryozoology Association has now almost completely circled Sicily. We are in the far northeastern corner of the island on a rocky cape jutting into the sea towards mainland Italy. The drive here along the very steep and rocky north coast of Sicily was fantastic, especially the seaward views of the volcanic Aeolian Islands (including the famous Stromboli).

Our day started on the furthest western part of Sicily. We took a short boat trip into the Stagnone di Marsala lagoon to the ruins of the ancient Phoenician walled city Mozia. The top photo is a view of the silted-up south harbor of the island with remnants of its guard towers on either side of the narrow entrance. Mozia was settled in the 8th Century BCE as a commerce center. It was well-suited to the Phoenician way of life with its small but safe ports and a defensible interior. The island is in the middle of an extensive lagoon which protects it from the ravages of the open sea (and invaders — for awhile). The site is still being actively excavated and studied.

2. Mozia Museum 060813There is a small museum on the island full of artifacts. It appears that the lagoon itself has abundant deposits of detritus from this active community, so items are continually dredged up.

3. Necropolis Mozia 060813Mozia has a considerable necropolis, as you would imagine. Many of the best sarcophagi and other memorial stones are in the museum.

4. Mask Mozia 060813There is a collection of terra cotta masks in the museum of apparently ceremonial use. This one seems delightful until you learn tat one of those ceremonies was human sacrifice, primarily of children. Now this character looks far more sinister.

5. Burned guardhouse Mozia 060813Greeks under the tyrant Dionysius captured the island and is city after a siege in 397 BCE. The fall of Mozia is recorded subtly by remnants of literally last ditch earthworks and fires. The stones of this guardhouse along the wall on the southern coast were reddened when the associated wooden structures were burned either during or just after the siege.

6. Greek attack Mozia 060813The island museum has a diorama depicting the final breaching of Mozia’s walls by the Greeks in 397 BCE.

7. Lagoon 060813The Stagnone di Marsala lagoon was formed during the Pleistocene as an abraded marine platform cut into fossiliferous marls and soft limestones. In this view from the island to the mainland you can see six whitish piles of salt on the distant shore. These are harvested from low ponds with walled enclosures (see below). The windmills, iconic for this area, pump water from one pond to another to control the mineral phases of the precipitates. This salt production goes back to antiquity.

8. Lagoon salt ponds 060813

George Davis (’64), meet Tricia Hall (’14)

June 8th, 2013

EPHRAIM, UTAH — Generations of Wooster geologists were united today over a common interest:  deformation bands of Utah!!

George Davis (Regents Professor Emeritus and Provost Emeritus, University of Arizona) researched the deformation bands of the Colorado Plateau region of Utah and wrote several very detailed manuscripts.  As we work on a structural analysis of the Sixmile Canyon Formation, we have been using two of his publications rather extensively this past week:  “Structural Geology of the Colorado Plateau Region of Southern Utah, with Special Emphasis of Deformation Bands”…and…”Conjugate Riedel Deformation Band Shear Zones”.

I actually thought that it was a unique twist of fate that Tricia and I were pouring over two of George’s publications last night…and putting our knowledge into use today in the field.

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Above is a view of the Sixmile Canyon Formation, the focus of Tricia’s study.  It contains wonderful deformation bands and joints, and it just happens to be located next to two characteristic antithetic normal faults that cut the Wasatch Plateau.

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Tricia and I stumbled upon these deformation bands early in the morning…

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…and these later in the afternoon.  With all of the deformation bands in the area, we felt like “measuring machines”.  Indeed, we could have used help in the field today from fellow Brunton-lovers!!

In addition to looking for conjugate deformation bands that George describes from his work in southern Utah, we were also trying to identify characteristic “ladder structures” that he identified in the Sheets Gulch area.  Tricia is sampling the deformation bands for further thin section analyses to determine if they show any sign of cataclasis.  Ultimately, she would like to classify the deformation bands, using one of the kinematic classification schemes proposed in the literature.

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Here’s Tricia gathering what she considers to be a “small” sample from a prominent deformation band.  You can tell how excited she is about her I.S.!!

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One characteristic of this part of the Sixmile is the interesting iron “concretions” that are everywhere.  The photo above shows how abundant that they can be within the unit.

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Aren’t these awesome??!!  These iron “chimneys” rise right out of the rock.  Tricia and I will be further investigating the abundance of morphologies of these concretions tomorrow, as we try to tackle some interesting paleo-fluid fronts within the Sixmile.  The past two days have been rather safe in the field, because we saw few mountain lion prints at our localities.  But, tomorrow is another day, and we are hiking back up to the areas where we saw extensive mountain lion “trace fossils”.

The ancient Greek city of Selinunte

June 7th, 2013

8. Temple Selinunte Mid 7th BCE 060713MARSALA, SICILY, ITALY–During the afternoon the field party of the International Bryozoology Association drove south out of the Sicilian mountains back to the southern coast to visit the ruins of an entire Greek city founded in the 7th Century BCE and captured by the Carthaginians after a siege in 409 BCE. It is rare to have so much of an ancient city still in place. It was like being in Greece itself. Above is a partially reconstructed temple on the acropolis (a high worship center) opposite the city center across a valley.
9. Selinunte ruined temple 060713Next to the reconstructed temple are two other temples still in ruins. They are a wondrous tangle of columns and blocks.
10. Selinunte column runins Steve 060713Steve Hageman is standing by one of the largest toppled columns. We thought it looked a lot like a very, very large disarticulated crinoid column. (You may have to be a paleontologist to appreciate that viewpoint!)
11. Selinunte Agora destroyed 409 BCE 060713I hiked over to the remains of the agora, or administrative center. It is surrounded by a wall augmented by later inhabitants but still mostly original. It has a spectacular (and strategic) view of the sea.
12. Acropolis viewed from Agora 060713From the agora you can look back to the northeast and have the view of the acropolis temples that the inhabitants must have cherished. I very much like the style of some reconstruction amidst the dramatic and evocative ruins.

A surprising bit of Permian in central Sicily

June 7th, 2013

1. Sicilian Mountains 060713MARSALA, SICILY, ITALY–This morning the pre-conference field trip of the International Bryozoology Association headed into the mountains of central Sicily. The roads were steep and windy, as one would imagine, and the views of mountainsides, villages and fields spectacular. We were high enough to be in some small woods and scrub forests. Our goal was to see some mysterious blocks of Permian limestone seemingly out of place on an island dominated by Cenozoic sediments.
2. Palermo Geologists 060713We met a team of friendly geologists from the University of Palermo in the Sosio Valley near Palazzo Adriano. They were well prepared to tell a complicated story of tectonics in the classic geological manner: maps and charts held by students as a professor lectures. It was very effective, aided by the superb weather and amazing views.
3. Geological cross-section 060713In this geological cross-section, the Permian rocks are shown as blue. Already you see something odd with the same color of rock above and below the blue, showing that it is tectonically bounded. It is part of a melange (in the geological sense) of blocks of rock broken and thrust about during the tectonism of the Miocene. The Permian rock was recognized as such by its fossil content, which includes distinctive conodonts, fusulinids, brachiopods, bryozoans and corals. It sits surrounded by much younger Miocene sediments, demonstrating the complex tectonics leading to this unusual setting.
4. Permian melange fragment MioceneAbove is the Permian outcrop in the Sosio Valley. It stands out as very different from its surroundings by its lithology alone. I admire the geologists, though, who found diagnostic fossils within it — I saw just a very few highly recrystallized fusulinids and corals.
5. Museum Palazzo Adriano 060713For lunch we went to the city museum in Palazzo Adriano and had delicious sandwiches and cakes. There we saw some of the best fossils from the Permian outcrops on display.
6. Palazzo Adriano Church 060713This is one of the churches in Palazzo Adriano on the city square. It looks to be neglected on the exterior, but inside …
7. Palazzo Adriano Church Interior 060713… it is elaborate and well-maintained.

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