A new paper has appeared: A rugose coral – bryozoan association from the Lower Devonian of NW Spain.

I’m proud to be an author with my two Spanish colleagues, Consuelo Sendino and Juan Luis Suárez Andrés, of a paper just out in the latest issue of Palaeogeography, Palaeoclimatology, Palaeoecology (we call it “Palaeo-cubed”). I’ll let the abstract tell the story (with some embedded links):

“A new rugose coralcystoporate bryozoan association is here described from the Devonian of NW Spain. This is the first evidence of intergrowths between Devonian rugose corals and bryozoans. In this case bryozoans provided a suitable substrate for the settlement of corals, which were subsequently encrusted by the bryozoans. The hypothesis of intergrowth between living organisms is supported by the absence of encrustation of the rugose coral calices by the cystoporates. We suggest that the association was specific and developed through chemical mediation. This symbiosis was facultative for the bryozoans but likely not for the corals. The association provided the bryozoan host with additional substrate for encrustation as well as protection from various predators, and it allowed the rugose corals to grow in a muddy environment and benefit from the feeding currents of the bryozoans.”

The above images show some of these specimens of corals intergrown with bryozoans. The caption from Figure 2: Intergrowth of fistuliporid bryozoans and rugose corals from the Aguión Formation of Asturias, NW Spain. A. General view of DGO12902. B. General view of MMAGE0033. C. Detail of the corallite, MMAGE0032. D. Magnified corallite of the right side, MMAGE0033.

This cartoon from the paper shows the process in which a coral larva (planula) lands on a living bryozoan, somehow survives the encounter, and then the coral grows together with the surrounding bryozoan colony. The fun part is sorting out the biological and evolutionary context of this relationship.

I thank my colleagues Consuelo and Juan for inviting me into this project. I learned a lot that will be applied to similar intergrowing situations in the fossil record.

Sendino, C., Suárez Andrés, J.L. and Wilson, M.A. 2019. A rugose coral – bryozoan association from the Lower Devonian of NW Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 530: 271-280.

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A Wooster Geologist at Austerlitz and other Czech places

Olomouc, Czech Republic –At our very first site, Holubice in the Czech Republic, the Miocene celliporid bryozoans are like baseballs.

The site is in the middle of a vineyard, with the fossils eroding out of the loose sediment at our feet.

This is a shadow-selfie on the fossiliferous ground between the grape vines. As I was taking this artistic image, the field trip bus took off without me! I chased after it but lost hope as it pulled away in the distance. Geez. I had time to consider my few options (my pack with water and passport was on my lonely seat), but then the bus returned for me. My friend the Chinese paleontologist Jun-ye Ma had noticed I was missing. Lesson learned.

The dramatic chapel and memorial for the Battle of Austerlitz (1805) was our next stop. It is situated on one of the critical hills during the battle. The campaign is too complex to summarize here (thus the link), but in short it was a huge victory for Napoleon and it dramatically changed the map of Europe.

The stones in the memorial chapel are rich with Miocene domal bryozoans (the white objects).

Some of the bryozoans are penetrated by borings.

The chapel was constructed during the early 20th century and shows an Art Deco style.

The altar. The chapel doesn’t seem to account for non-Christian fallen soldiers, but that’s not surprising.

The dead from the battle were mostly buried in shallow graves where they fell. The soil of the battlefield continues to yield bones, especially after plowing. The remains are collected and brought to the chapel for eventual burial underneath in a crypt.

The Austerlitz battlefield.

Our first field group photo! We are at the Austerlitz chapel.

This miserable site  is Holubice, where a Miocene bryozoan marl is exposed. The hike in led by Kamil (above) was through a long stretch of high grass and woody brush. The mosquitoes were excited that mammals had suddenly appeared, while nettles stung exposed skin. Plus I didn’t see the bryozoans. I left early to make sure the bus didn’t abandon me here.

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Wooster Geologist in Slovakia and Austria

Mikulov, Czech Republic — We have been very fortunate with the weather on our long IBA field excursion. Dazzling sunlit days and relatively cool evenings. Above is our first stop of the day — the Sandberg site with Miocene fossils in a loosely-bound sand.

This is a cool geological setting where a Miocene shoreline is preserved against Jurassic carbonate cliffs. The Miocene sand is the yellowish unit above superimposed on the blue limestones.

Some of the Jurassic carbonates are exposed as boulders that tumbled down the slopes. This boulder has a surface that was exposed to the Miocene ocean and accumulated round bivalve borings (ichnogenus Gastrochaenolites, which has been seen a lot in this blog).

The limestones also have external molds of snails and bivalves.

Another castle! This one very dramatic in its position commanding the confluence of the Morava and Danube rivers. It is the Devin Castle, which was destroyed by Napoleon himself in 1809.

This is the Maiden Tower, a cultural symbol of Slovakia.

River confluences are so cool. The Morava on the right is joining the Danube.

At this important confluence, at the border between what was Czechoslovakia and Austria during the Cold War, is a moving memorial to the over 400 people shot while trying to escape through the Iron Curtain.

The long list of names of those killed by the Soviets and their allies along the border.

The last stop of the day was the type section of the Hartl Formation (Middle Miocene, Badenian) near Eisenstadt, Austria. It is another loose sand, this time with common brachiopods and some bryozoans. This section is eroded back, forming a cave. The roof will collapse some day.

These are beach sands with spectacular cross-beds. I collected some sediment to challenge my sedimentology students next year.

Tonight we stay in the historic Czech city of Mikulov on the border with Austria.

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New publication on an Alaskan glacier – coauthored by a Wooster student, staff and faculty member

Dr. Ben Gaglioti (Lamont-Doherty Tree Ring Lab and University of Alaska – Fairbanks) just published an article entitled: Timing and Potential Causes of 19th-Century Glacier Advances in Coastal Alaska Based on Tree-Ring Dating and Historical Accounts. Three of the coauthors include Wooster Earth Scientists and Tree Ring Lab workers, Josh Charlton (’19), Nick Wiesenberg (Department technician) and Dr. Wiles (Earth Sciences faculty). This contribution describes the Little Ice Glacier History of LaPerouse Glacier on the outer coast of Glacier Bay National Park and Preserve.

Dr Gaglioti did a great job putting together the glacial chronology for the site, and then coming up with some new ideas explaining why this glacier advanced to its Holocene maximum between CE 1850 and 1890. This was a time when it was not as cold as some other times within this broad interval (~ CE 1250-1850) we call the Little Ice Age. Dr. Gaglioti draws on some new and not-so-new proxy records that show a strengthening of the Aleutian Low over the past several 100 years and he suggests that the cooler summer temperatures aided by increased winter snowfall forced this glacier to its maximum extent. His methods and presentation in this paper are new and provide some excellent possibilities for future work by Wooster students. We look forward to continuing our collaboration with Dr. Gaglioti.

The photos below are from Dr. Gaglioti and show (top) the location of the glacier, (middle) the setting of the buried forest he discovered, and (bottom) what the amazing pristine trees look like as the ice retreats. Within this buried forest is also the first Alaskan Cedar paleo-forest that has been discovered. Here is a link to a National Geographic sponsored blog describing some of the field work. Special thanks to Lauren Oakes for her excellent blog. The project was partially supported by the National Geographic Society, the Lamont-Doherty Earth Observatory and the National Science Foundation.



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Wooster Geologist in the High Tatras Mountains of northern Slovakia

Bratislava, Slovakia — Today our continuing IBA field trip adventure started in the High Tatra Mountains at this spectacular glacial lake called Štrbské pleso. This is  very popular ski destination in central Europe. The sharp mountain peaks are granitic.

Another view of Štrbské pleso.

This was our modernistic hotel near Štrbské pleso. Excellent views.

We stopped for a tour of Bojnice Castle after leaving the mountains. It has essentially been built and rebuilt since the 11th century and is currently popular in films and weddings needing a fairy-tale castle background. It is ostentatious, of course, with ridiculous sums of money spent by generations of aristocrats to encrust it with gold and artworks.

The castle didn’t impress me, but the fact that it overlies a natural cavern did!

I like my castles in dramatic ruins, and Beckov Castle in western Slovakia  fits that bill well. The castle sits on a limestone klippe, which is an erosional remnant of a thrust sheet.

We went way, way high up through the ruins to the castle’s top.

The bedrock is integrated into the castle walls, as we’ve seen often.

This was the last stop of the day before we reached Bratislava and our next hotel.


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Wooster Geologist in Hungary and Slovakia

Štrba, Slovakia — Today our field party drove from Budapest through northern Hungary into Slovakia. The day was brilliantly sunny. Our first stop was at a holy well near Szentkút, Hungary, to examine Miocene fossils (mostly bryozoans). High up in the surrounding hills is a shelf where the mrl is best exposed. Long ago a community of monks established living quarters and a chapel by carving the soft stone. Our outcrop was well exposed because of their work.

Our leader Kamil emerging from one of the stone rooms.

There is some sedimentology and structural geology going on here as well as paleontology. Inside one of the rooms the walls cut through soft-sediment deformation and a normal fault oblique to the corner.

The bryozoans are numerous and well-preserved in the stone walls.

Szentkút was especially religious on the day we visited. It was Pentecost for the Greek Catholic faith, so there were large crowds and colorful clerics around the shrines. I hope we were not noticed walking through.

In case you wondered what a border crossing between Hungary and Slovakia looks like.

We next stopped in Fiľakovo, a Slovakian town with a magnificent castle. We will see a lot of castles on this trip, and as Kamil told us, most were built in the 13th century and destroyed in the 16th. This castle was most impressive to me because of the bedrock it is built on: a Miocene ignimbrite, which is a rock resulting from volcanic eruptions. Most geologists would call it a welded tuff. he Miocene volcanoes still ring the town as wooded hills.

A close view (with my field trip roommate Hans Arne Nakrem for scale) shows the complex stratigraphy of the unit.

There are numerous volcanic bombs and other volcaniclastic bits in the welded tuff.

A view of the town from the castle. When the Ottoman Turks were here I’m sure they couldn’t imagine having a Catholic church in sight.

One of the Miocene volcanoes.

Our last stop of the day was near Štrba, Slovakia, for this small outcrop of Miocene bryozoan marl. ots of high grass.

The High Tatra Mountains of northern Slovakia and southern Poland are now in view! We’ll look at these in more detail tomorrow.


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A Wooster Geologist in Budapest

Budapest, Hungary — This month I have the privilege of attending the 18th meeting of the International Bryozoology Association (IBA) in Liberec, The Czech Republic. As is the tradition, there is a pre-meeting field trip, this time to sites in four countries: Hungary, Slovakia, Austria, and The Czech Republic. There are 11 participants in a chartered bus setting off for a week of fossils and history, led by that excellent bryozoologist and good fellow, Kamil Zágoršek. We begin in Budapest with a classic view of the beautiful Danube River as it flows past our hotel. It is sunny and very warm.

There will be plenty of fancy views, but fr the local feel I want to include an image of just a regular Budapest block near our hotel.

Our first stop was at the Hungarian Natural History Museum in Budapest. It was established in 1802, and as our guiding museum scientist told us, the first 154 years were “normal” (at least for this part of the world), but in 1956, during the Soviet suppression of the Hungarian Revolution, a Russian tank fired into the museum, causing extensive damage. Shortly afterwards a Soviet jet dropped an incendiary bomb on the building. Tens of thousands of specimens were lost in the ensuing fires. The collections have still not recovered the numbers they had prior to the attacks.

Bryozoologists all love natural history museums, especially when we can open the drawers.

This particular museum doesn’t have a lot of bryozoans (a few drawers), but does have extensive vertebrate collections, fossil and modern.

Every natural history museum I’ve visited has a basement floor with hundreds of stuffed animals that are no longer in fashion for public displays.

The public part of the museum is diverse and well organized. I wouldn’t use Noah’s Ark as the initial theme for biodiversity, but it works here!

Our first locality was an Eocene bryozoan-rich marl site near Mátyashegy, Hungary, just outside Budapest. The bryozoans are numerous, but tiny little critters for my camera!

The second site is another bryozoan marl and sand, this one Miocene near Fót on the outskirts of the Budapest city center.

Our first group dinner was in the center of Budapest, ironically at an American restaurant. Our leader Kamil is at the head of the tables.

That evening we walked up Gellért Hill in the center of the city to see the amazing lights. My phone camera wasn’t up to the challenge, but you may be able to make out Buda Castle here.

At the top of the hill is a massive Soviet monument originally dedicated to the Soviet defeat of the Nazis in Budapest in 1945. The tall structure is the Liberty Statue. After the Soviets left the country (in 1989), the Hungarians removed some statuary and rededicated the monument to “those who sacrificed their lives for the independence, freedom, and prosperity of Hungary”, which includes thousands killed by the Soviets during their occupation.

On my first day in Budapest I was alone, so I visited the former Hungarian Secret Police headquarters, now a museum called The House of Terror. It is a grim but highly informative look at Hungarian life under fascist and then communist rule.

Photography was not allowed inside. The outside of the building has what seems to be an endless row of photos of Hungarians who were executed here. Quite moving. In one of the displays inside is a wall of photographs and names of the “victimizers”, the agents (Russian and Hungarian) who perpetrated these crimes. The point is that we don’t see these atrocities as simply results of a system but also the actions of individuals.

This artwork outside the museum entrance is simply called “Iron Curtain“. The link has a full description and more images.




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Wooster and Dickinson students team up for geochemistry research

[Wooster, OH] – A team of students from Wooster and Dickinson are working together on geochemistry research this summer. We’re using the compositions of Earth materials to understand geologic processes. Our main goal is to study the formation of volcanic ridges that were erupted beneath glaciers in Iceland, but we have a few other projects that we’ll be working on, too.  Thanks to Sherman Fairchild funding, we have 8 weeks to learn a lot of different lab techniques and travel to Iceland to get more samples.

We began our work with a weeklong marathon of preparing samples for analysis in the Wooster X-ray and Dickinson SEM labs.

Kendra and Layali prepared geochemical samples by melting powdered rocks and forming them into glass disks.

Marisa is examining samples of volcanic glasses under the microscope, selecting the freshest chips.

Kendra and Hannah are in the first stages of polishing the fresh glass chips so that they are perfectly smooth. This will let us analyze their compositions on Dickinson’s scanning electron microscope. We can also use the polished glass chips to measure the water contents later in the project.

Layali is tracing images of thin sections. We’ll use the tracings to do some quantitative mineralogical analyses.

It looks she is having fun doing all of this hard work!

The team has been working so hard that they have needed reminders to take breaks. So what to do on a break? How about a game of lab-bench-dino-mancala?


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Dundee Falls: A beautiful waterfall in northeastern Ohio

Dundee, Ohio — One of the joys of summer for a geologist is the time to take short trips in the neighborhood to explore nature. This afternoon Greg Wiles, Nick Wiesenberg, Greg’s adventurous dog Arrow, and I drove about 45 minutes into Tuscarawas County to visit Dundee Falls, which is in the Beach City Wildlife Area. It was a gorgeous day. The falls are formed by a creek rushing into a gorge walled by the Dundee Sandstone (= Massillon Sandstone), part of the Pottsville Series of Upper Carboniferous age. I hadn’t heard of this place until Alexis Lanier (’20) recommended it.
The vertical sandstone walls are impressive. This particular face is used by rock climbers. I learned on this visit that the climbers occasionally scrub the cliff face with wire brushes to remove slippery moss and the inevitable graffiti.

The sandstone shows several sedimentary structures, including dramatic cross-bedding. These are like lateral accretion deposits from meandering streams in a delta complex.

The sandstone has layers of iron oxide concretions reminiscent of the Moqui Marbles we saw in the Navajo Sandstone on our Utah Expedition this spring.

Nick”s right hand is on a quartz-pebble conglomerate within the sandstone. These core beds are common throughout the Pottsville Series. They likely represent braided stream deposits and classic molasse. The reddish color is what remains of spray-painted graffiti.

The unscrubbed, unpainted walls host a wonderful moss-fern flora.

One of the goals of this hike was to determine the ages of the oldest trees. Nick and Greg (and Arrow) are here scoping out the woods for the largest oak trees.

Greg and Nick worked hard inserting their coring devices. The process makes some incredible squawking noises as the bit is screwed into the tight wood. I also learned that taking the corer out of the tree can be much harder than putting it in! So far the dendrochronology team found trees only about 200 years old, which is too young to interest them.

Arrow the Dog was a great companion as always! He seems to have a very good time on these outings.

Update from Dr. Wiles, ace dendrochronologist: “Nick worked up the five cores we took and below is the Dundee Ring Width Series – inner ring 1823, second growth. Looks like a slow release up until 1900 and then a big release – selective logging and the big logging at 1900? Maybe the quarry was set up ~1900.”


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Constructive & Destructive Landforms at Mount Rainier National Park

One common frame used to introduce landforms in introductory Geology courses is the idea of constructive and destructive forces that create and change them. (See, for example some K-12 resources here and here.) Constructive processes like the the deposition of sediment and extrusion of lava build landforms by adding material at the surface. Destructive processes like weathering and erosion and explosive volcanism shape the surface by removing material.

If you go to the Paradise Visitor Center in Mount Rainier National Park, you can observe this dichotomy at work just by comparing the north and south. Looking to the north is the park’s namesake: Mount Rainier. The smooth, rounded shape of this composite stratovolcano is primarily the result of layered ash, rubble, and lava over the past 500,000 to a million years, piling up over 14,000 ft high (NPS). There are glaciers eroding the flanks of Mount Rainier, but the recent volcanism of the past few thousand years means the overall shape is more reflective of volcanism than glaciation.

View to the North: Mount Rainier

Contrast this with the view to the south. Rather than a single smooth and rounded profile, the Tatoosh Range is characterized by several jagged peaks with names like “The Castle” and “Pinnacle Peak”. This mountain range is the result of extensive weathering of an ancient pluton, which was originally emplaced in the Miocene (14 million years ago; USGS 1963; Mattinson 1977). The Tatoosh pluton was exposed at the surface and actively eroded by Pleistocene glaciers long before Mount Rainier existed.  With millions of years of erosion at work, destructive forces are more obvious in the Tatoosh Range than on Mount Rainier. It displays classic glacial features like the horn of Pinnacle Peak, the col between Plummer Peak and Denman Peak, and the converging U-shaped troughs below Plummer Peak.

View to the South: Tatoosh Range (Paradise Visitor Center in foreground).

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