Carbonate hardgrounds at Wooster

Mark Wilson September 25, 2024 1:34 pm

On the second floor of Wooster’s Scovel Hall, in a room behind the main teaching laboratory, are six cabinets completely full of labelled rocks and fossils (see below). There is even an additional set of specimens too large for the cabinets stored under the eaves in the attic space on the third floor, and in various other cabinets are suites of fossil hard substrates. This is The College of Wooster’s carbonate hardground collection, unique in the world for its size and diversity.

Carbonate hardgrounds are rock surfaces that were once cemented calcareous sediment layers on seafloors (Palmer, 1982; Wilson and Palmer, 1992). The top image of this post shows a hardground from the Upper Ordovician of southwestern Ohio. It is a limestone distinguished by a surface with encrusting organisms, borings, and nestlers in cavities showing it was an ancient lithified seafloor — a rocky substrate in a shallow Ordovician sea. The cementation of carbonate hardgrounds is synsedimentary, meaning they were formed by precipitation of carbonate crystals between sediment grains on the seafloor itself, not long afterwards following deep burial (Erhardt et al., 2020).

Even though the process of forming a carbonate hardground is geochemical, they are most often recognized by biological phenomena that show they were hard marine seafloors with associated hard substrate-dwelling organisms (sclerobionts). These sclerobionts include encrusting organisms (such as bryozoans, crinoids, oysters, barnacles and the like), borings (often made by polychaete worms, clams, snails and sea urchins), and nestlers that lived in cracks, crevices and caverns of these rocks. In the image above you can see two rugose corals that nestled in shallow concavities on the hardground surface. (It is a closer view of the Ordovician hardground pictured at the top.)

Brett and Liddell (1978, fig. 9, p. 344) constructed this beautiful diagram reconstructing a Middle Ordovician hardground found in southern Ontario, Canada. It shows encrusting bryozoans, stemmed echinoderms, and cross-sections of borings cut into the rock surface.

The origin story for Wooster’s hardground collection begins in 1984. My wife Gloria and I were exploring sites in northern Kentucky for an upcoming Wooster paleontology course field trip. We stopped by a muddy exposure in Boone County and I immediately saw the above flat cobble weathered out of the outcrop. It was encrusted with beautiful fossils, and had many cylindrical borings. There were hundreds of similar cobbles scattered about. Most were encrusted and bored on both sides, so I knew there was a paleoecological narrative here.

Here is a close view of another of these Ordovician cobbles in Kentucky. The fine branching network is the bryozoan Corynotrypa, and the stellate encruster is an edrioasteroid echinoderm (Cystaster stellatus). I was enchanted with this little hard substrate community and wrote a paper about how they show a rare example of ecological succession in the fossil record (Wilson, 1985). I wanted to pursue more research on these sclerobionts (even though that term was yet to be coined!).

Shortly after that Kentucky work, I took my first research leave in 1985 to Oxford University in England. I told my host in the Department of Earth Sciences that I was interested in the paleoecology and evolution of hard substrate communities. He quickly recommended that I meet two young paleontologists. The first was Tim Palmer at Aberystwyth University on the western coast of Wales. I contacted Tim and he generously invited me and my little family to his home. Meeting Tim changed my life. Tim had done pioneering work on carbonate hardground communities in the 1970s, resulting in several classic hardground papers (e.g., Palmer and Fürsich, 1974; Palmer and Palmer, 1977) and the first summary of hardground communities through time (Palmer, 1982). During his North American work, he and his wife Caroline collected an astonishing number of hardground samples from Paleozoic and Mesozoic strata. They deposited this material in the US National Museum in Washington, DC, and in the early 1980s it was transferred to Wooster to form the nucleus of our hardground collection. Tim and I, along with other colleagues and students, have added to that collection ever since.

The second English paleontologist I was encouraged to meet in 1985 was Paul Taylor of the Natural History Museum in London. As with Tim Palmer, Paul and I quickly became close colleagues and friends. Paul specializes in bryozoans of all types, as well as other organisms found encrusting and boring hard substrates. In fact, it was Paul and I who invented the term sclerobiont (Taylor and Wilson, 2002 and 2003). Over the decades, Paul also contributed to the Wooster hardground collection, as well as to other suites of sclerobionts on other hard substrates. I can’t say enough about what fantastic friends and colleagues Tim and Paul have been for me, and how much they influenced paleontology at Wooster through their work with many of our students. (And yes, they both seem to have fancied pink shirts for fieldwork!)

About 20 years I met the remarkably productive Estonian paleontologist Olev Vinn, currently an Associate Professor of Paleontology at the University of Tartu. We have common interests with hard substrate communities and very quickly began to look at hardground faunas in the Baltic (for examples, see Vinn and Wilson, 2010a and 2010b; Vinn et al., 2015). Samples from these and other Baltic Ordovician hardgrounds have been added to the growing Wooster collections. Olev and I have since done diverse work on sclerobionts, especially borings and tube-dwellers. Lately we’ve been concentrating on symbiotic relationships in hard-substrate faunas. Much of this work has recently included our Estonian colleague Ursula Toom.

Ordovician (Katian) hardground in cross-section from the Vasalemma quarry in Estonia (GIT 222-499). The borings are the ubiquitous Trypanites. From Figure 9 of Vinn et al. (2015).

Also at the turn of the century I met another English paleontologist: Caroline J. Buttler, currently Head of Collections Development at Amgueddfa Cymru-National Museum Wales. (Image from her museum staff profile.) We share a passion for bryozoans, especially big lumpy trepostomes from the Ordovician. She headed a project describing an Upper Ordovician hardground complex from northern Kentucky in which the hardgrounds were eroded and undermined on the seafloor to form caverns with hardground roofs (see below). Samples of these hardgrounds are in several drawers of Wooster’s hardground collection. The roadside outcrop from which they were collected no longer exists, so these specimens are the only record.

One of the cave-forming hardgrounds from the Upper Ordovician of northern Kentucky described by Buttler and Wilson (2018). The large lump on the surface is a trepostome bryozoan colony. The vertical holes are the boring Trypanites. This looks like a typical bored and encrusted carbonate hardground, but in this image it is upside-down!

This is the actual orientation of the Buttler and Wilson (2018) hardground. It is the roof of a small cavern. The bryozoan was attached to the ceiling and hung down into the little cave. The borings were actually excavated upwards into the limestone roof. Pretty cool story.

Many other professional colleagues, amateur collectors, and Wooster students have added to the Wooster carbonate hardground collection, as well as to other fossil hard substrate assemblages. I wish I could name them all!

Here are some highlighted carbonate hardgrounds represented in Wooster’s collections. Above is a hardground from the Upper Ordovician of southeastern Ohio. We can identify it as a hardground by the abundant small holes punched into the surface (which are the common Trypanites borings). What is notable in this specimen are the irregular cavities, including the straight cone at the top. These are molds of aragonitic shells like those of many bivalves, gastropods, and cephalopods. (The conical one is from a straight nautiloid cephalopod.) This specimen represents a critical observation that these aragonite shells dissolved on the seafloor, producing fluids that precipitated calcite crystals in the sediments, forming the hardground that was later bored and encrusted. This process, a feature of Calcite Sea geochemistry, was described by Palmer et al. (1988).

This slab shows an Upper Ordovician hardground surface in southwestern Ohio with the ovoid borings of bivalves. These borings were described as Petroxestes by Wilson and Palmer (1988).

This is an encrusted hardground from the Middle Ordovician Kanosh Shale of west-central Utah. Most of these encrusters are eocrinoids, an early echinoderm. This hardground series was described by Wilson et al. (1992).

The above hardground sample is also from the Kanosh Shale. The large lump on the left is the encrusting bryozoan Nicholsonella.

This hardground is from the Carmel Formation (Middle Jurassic) of southwestern Utah. The light-gray layer above the ruler shows numerous bivalve borings known as Gastrochaenolites. It was described and interpreted by Wilson and Palmer (1994) and Wilson (1998). The Carmel Formation has been a popular topic for Wooster Independent Study students over the past 30 years. Search for it in this blog!

This is a polished cross-section of a Carmel Formation hardground. The layered unit below is the hardground, complete with Gastrochaenolites borings. The top half shows layers of encrusting oysters.

This is a bivalve-bored carbonate hardground in the Ora Formation (Upper Cretaceous, Turonian) near Makhtesh Ramon in the Negev of southern Israel. It makes a very distinctive marker horizon in the Cretaceous of this region.

I want to end this tour of the Wooster Carbonate Hardground Collection with a specimen that is not technically a carbonate hardground, but interpreted by its common features with hardgrounds. This is a “rockground”, which is an informal term for a sedimentary hard substrate that was encrusted and bioeroded as a rock surface, not a cemented seafloor. This is a wave-eroded coral surface from the Pleistocene exposed on the coast of San Salvador Island, The Bahamas. The small holes are borings formed by clionaid sponges and given the name Entobia. A scleractinian coral encrusts the surface at the upper right. This eroded surface records sea-level changes during the Last Interglacial highstand (White et al., 1998; Wilson et al., 1998; Thompson et al., 2011). You can read the story in this earlier blog post. It was a project that took the lessons of studying carbonate hardgrounds into a bit of paleoclimatology research.

This is thus a description of the Wooster Carbonate Hardground Collection, which because of its diverse history is unique in the world. If you are ever on the second floor of Scovel Hall, take a peek in the cabinets to see these wonderful rocks and fossils. They have been at the center of my geological and paleontological research program, and thus also for generations of Wooster Independent Study students.

 

References:

Brett, C.E. and Liddell, W.D., 1978. Preservation and paleoecology of a Middle Ordovician hardground community. Paleobiology 4: 329-348.

Buttler, C.J. and Wilson, M.A. 2018. Paleoecology of an Upper Ordovician submarine cave-dwelling bryozoan fauna and its exposed equivalents in northern Kentucky, USA. Journal of Paleontology 92: 568 – 576.

Erhardt, A.M., Alexandra V. Turchyn, A.V., Dickson, J.A.D., Sadekov, A.Y., Taylor, P.D., Wilson, M.A. and Schrag, D.P. 2020. Chemical composition of carbonate hardground cements as reconstructive tools for Phanerozoic pore fluids. Geochemistry, Geophysics, Geosystems 21(3): e2019GC008448 (https://doi.org/10.1029/2019GC008448).

Palmer, T.J., 1982. Cambrian to Cretaceous changes in hardground communities. Lethaia 15: 309-323.

Palmer, T.J., and Fürsich, F.T., 1974. The ecology of a Middle Jurassic hardground and crevice fauna. Palaeontology 17: 507-524.

Palmer, T.J., Hudson, J.D., and Wilson, M.A., 1988. Palaeoecological evidence for early aragonite dissolution in ancient calcite seas. Nature 335: 809-810.

Palmer, T.J., and Palmer, C.D., 1977. Faunal distribution and colonization strategy in a Middle Ordovician hardground community. Lethaia 10: 179-199.

Taylor, P.D. and Wilson, M.A. 2002. A new terminology for marine organisms inhabiting hard substrates. Palaios 17: 522-525.

Taylor, P.D. and Wilson, M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1-103.

Thompson, W.G., Curran, H.A., Wilson, M.A. and White, B. 2011. Sea-level oscillations during the Last Interglacial highstand recorded by Bahamas corals. Nature Geoscience 4: 684–687.

Vinn, O. and Wilson, M.A. 2010a. Microconchid-dominated hardground association from the late Pridoli (Silurian) of Saaremaa, Estonia. Palaeontologia Electronica 13(2):9A, 12 p.

Vinn, O. and Wilson, M.A. 2010b. Early large borings from a hardground of Floian-Dapingian age (Early and Middle Ordovician) in northeastern Estonia (Baltica). Carnets de Géologie / Notebooks on Geology, Brest, Note brève / Letter 2010/04 (CG2010_L04).

Vinn, O., Wilson, M.A. and Toom, U. 2015. Bioerosion of inorganic hard substrates in the Ordovician of Estonia (Baltica). PLoS ONE 10(7): e0134279. doi:10.1371/journal.pone.0134279.

White, B.H., Curran, H.A. and Wilson, M.A. 1998. Bahamian coral reefs yield evidence of a brief sea-level lowstand during the last interglacial. Carbonates and Evaporites 13: 10-22.

Wilson, M.A. 1985. Disturbance and ecologic succession in an Upper Ordovician cobble-dwelling hardground fauna. Science 228: 575-577.

Wilson, M.A., 1998. Succession in a Jurassic marine cavity community and the evolution of cryptic marine faunas. Geology 26, 379-381.

Wilson, M.A., Curran, H.A. and White, B. 1998. Paleontological evidence of a brief global sea-level event during the last interglacial. Lethaia 31: 241-250.

Wilson, M.A., and Palmer, T.J. 1988. Nomenclature of a bivalve boring from the Upper Ordovician of the midwestern United States. Journal of Paleontology. 62: 306–308.

Wilson, M.A. and Palmer, T.J. 1992. Hardgrounds and Hardground Faunas. University of Wales, Aberystwyth, Institute of Earth Studies Publications 9: 1-131.

Wilson, M.A. and Palmer, T.J., 1994. A carbonate hardground in the Carmel Formation (Middle Jurassic, SW Utah, USA) and its associated encrusters, borers and nestlers. Ichnos 3, 79-87.

Wilson, M.A., Palmer, T.J., Guensburg, T.E., Finton, C.D., and Kaufman, L.E. 1992. The development of an Early Ordovician hardground community in response to rapid sea-floor calcite precipitation. Lethaia 25, 19-34.

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A Wooster Geologist visits Fort Meigs, Ohio

Mark Wilson September 20, 2024 8:54 pm

Today my wife Gloria and I visited the reconstructed Fort Meigs in the northwestern corner of Ohio in Perrysburg, just south of Toledo. It was a beautiful day and we practically had the place to ourselves. It was our first trip since I started my retirement from The College of Wooster. It felt a little naughty to be there during a work day! The above image is of one of the reconstructed fort blockhouses from the outside. Fort Meigs is sited on “Ohio’s War of 1812 battlefield”.

This inside view of another blockhouse shows the basic construction of the fort — blockhouses with cannon and rifle gunports connected by a strong wooden palisade. The fort is reconstructed as it would have appeared in 1813

This reconstruction gun position overlooks the Maumee River, which is very difficult to see through all the vegetation.

Fort Meigs was constructed by American troops during the bitter winter of 1813. It was designed to be a supply depot for military operations north into Canada and Michigan, as well as for protection of Ohio from invasion by British and Native American forces to the north. General William Henry Harrison was the American commander. The British commander was General Henry Procter, and the Indian warriors were under Chief Tecumseh. On April 28, 1813, the British and Indians began a siege of Fort Meigs, and a significant and bloody battle was fought outside the walls on May 5th. The Americans held the fort during that siege and a second siege attempt in July 1813. The British and Indians retreated and ended the last invasion threat to Ohio.

This post is not to describe in detail the battles at Fort Meigs, but to discuss the geological reasons Fort Meigs was built in this particular place.

This map shows the geography, towns and forts in the Detroit region during the War of 1812. Fort Meigs is shown in the southwest corner of the map on the Maumee River. The river is key to this story. It was a major transportation artery from Lake Erie into northern Indiana. The Maumee River watershed was otherwise difficult to traverse because of the Great Black Swamp, now entirely drained.

Here in this 1813 map we see the position of Fort Meigs overlooking the Maumee River. The British siege batteries of April and May 1813 are shown to the north and east of the fort. Note that the river flows to the northeast. Critically, just upstream from the fort are “Rapids”. Boats traveling upriver must unload and portage around these rapids. Fort Meigs is situated at this critical point where anyone continuing upriver is subject to cannon and gunfire.

This is another 1813 map of the Fort Meigs area. The Maumee River was sometimes called the “Miami”, which is confusing in Ohio because there is another Miami river.

Today Fort Meigs still overlooks the Maumee River, bit of course the topography and hydrology here has been highly engineered since 1813. The rapids still exist, though, upstream from the fort and are not visible because of high water levels at the time of this Google Earth image.

So why do rapids appear at this interval of the Maumee River? Here’s where the geology comes in. In the above map from Ehlers et al. (1951), we see a contact between two geological units at the downstream boundary of the rapids. The red arrow indicates where the river flows off the Tymochtee Dolomite onto the underlying Greenfield Formation. Both of these are Silurian carbonate units. Critically, the Tymochtee Dolomite is more resistant than the upper beds of the Greenfield Formation. The riverbed on the Tymochtee is therefore more rocky, thus producing the rapids. Fort Meigs, at the small blue “x” on the map, took advantage of this change in the navigability of the river. Geology controlled this War of 1812 battlefield.

We didn’t go down to the rapids today, so I got the above image of the rapids from Google Maps. Slabs of the Tymochtee Dolomite are visible in the riverbed and banks. A much more evocative image of these carbonate rocks can be seen here. I learned a new word for a biome through this research: alvar. These flooded, flat carbonate exposures support a unique flora and fauna that is periodically wet and dry. The rapids here are part of the Maumee River alvar.

Reference:

Ehlers, G.M., Stumm, E.C. and Kesling, R.V. 1951. Devonian rocks of southeastern Michigan and northwestern Ohio. Stratigraphic field trip of the Geological Society of America, Detroit Meeting (November 1951)

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And sometimes it rains.

Mark Wilson July 17, 2024 7:42 pm

Today I took Peter, Lauren and Evie on another afternoon local field trip, this time to Wooster Memorial Park (Spangler). We wanted to repeat the enjoyable exploration we had last week in Lodi Community Park. This time, though, we got thoroughly drenched by a small thunderstorm cell that just seemed to hover over us. The students managed to get these images.

It started out well! Evie and Lauren found salamanders in the creek bed.

But then the rain got serious!

It was a steady downpour, forcing us to exit once we were thoroughly soaked.

The trails became streams on our hike back to the car. Still, it was a fun adventure, if a bit short!

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Klawock to Ketchikan

gwiles July 17, 2024 3:48 pm

Guest bloggers: Amanda Flory and Mihalis Protopapadakis

Carnivorous sundews found in Balls Lake muskegs.

On our last full day at Prince of Wales Island, we explored the trail around Balls Lake, in Tongass National Forest. The AYS team helped us core trees of several different species. We then returned to the AYS headquarters in Klawock and taught them how to mount tree cores and analyze them under the microscope. We also celebrated Nick’s birthday!

The following morning we took the ferry back to Ketchikan and spent the day climbing Dude Mountain. There, we collected more cedar samples in a muskeg and a bear trail along the edge of a cliff. We spent the final day of our trip exploring the city of Ketchikan and the nearby beaches.

Bob and Dr. Wiles searching for cedars in the rainforest.

Salmon-spawing stream flowing out of Balls Lake.

Gary supervising tree-core collection at a Forest Service site.

The Wooster team and AYS group deep in the woods of Balls Lake.

Gary’s cedar cookie showcasing abnormal ring characteristics.

Freshly picked blueberries.

The team hiking along the Balls Lake trail.

The team skillfully balancing on a slippery log.

Teaching the AYS group how to process and examine tree cores back at headquarters.

The team sharing excitement over dendrochronology.

Celebrating Nick’s birthday with a delicious cake that David baked.

Happy Birthday Nick!

A bald eagle spotted on the drive to Dude Mountain.

Couple of dudes on Dude Mountain.

The view from the bear trail along the cliff.

Amanda and Proto coring a yellow cedar.

The famous Creek Street boardwalk in southern Ketchikan.

The view from the team’s airbnb.

On the final day, the team visited tidal pools along the coast.

A starfish saved from low tide.

This trip was a wonderful experience. Thank you to all the great people we met along the way! Also a big thank you to Dr. Wiles and Nick for their guidance and these great memories. A big thank you to Bob Girt and the Alaska Youth Stewards Group in Klawock who hosted our trip on Prince of Wales Island. This work was supported by Grant NSF P2C2-2002454 and the Department of Earth Sciences at Wooster.

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54 cm Core from Brown’s Lake Bog Reveals …

Mark Wilson July 17, 2024 9:30 am

Guest Bloggers: Evie Sanford and Peter Rothstein

Summer diatom research continues at The College of Wooster. Building on last summer’s work by Garret Robertson, Minnie Pozefsky and Dr. Mark Wilson, as well as that of other previous IS students Justine Paul Berina and Richard Torres, we have been analyzing the diatom communities at Brown’s Lake. Brown’s Lake is well known among Wooster geology students as the site for many IS projects, research expeditions and class field trips. Located within a Nature Conservancy protected area, the lake is a remnant from glacial ice left behind from retreating glaciers ~15,000 years ago.

A LIDAR map of Brown’s Lake Bog Nature Preserve.

After a hot, muddy expedition to the lake in mid-June, we ended up with a sediment core from the edge of the lake. Thanks to Dr. Wiles and Nick Wiesenberg for helping us out with obtaining the core!

The 54 cm core retrieved from Brown’s Lake.

The core we ended up with is 54 cm long, and composed of mostly peat. The core has not been dated, but likely extends to around the mid-19th century based on a more silt-heavy composition in the lower sections of the core. Last year’s team was able to match this silt deposition to effects of European-American settlement in the area. Our objective was to further investigate the impacts that this silt deposition and anthropogenic impacts had on diatom communities in Brown’s Lake by surveying their abundances over different depths.

Evie took the lead on making smear slides, following the procedure from Richard Torres’ IS. Taking a sediment sample every 5 centimeters and isolating the silicates. This left behind the diatom skeletons and sponge spicules we wanted to study.

Scientific marbles!! (boiling our hydrogen peroxide and homogenized water-soil sample to kill the organics).

Spinning the samples in the centrifuge to isolate diatoms within the leftover solution.

Our slides prepared for inspection.

After isolating all of the diatoms, we got started on counting them. Peter looked at each smear slide by looking over it 3 times and recording the diatom genera that were intact enough to make an identification. In total 461 individual diatoms and 17 genera were found within the 54 cm core. We found that diatom abundance and diversity peak at a depth of 5 cm to 10 cm and decrease significantly with core depth.

Total diatom count by depth.

Common diatom genera found in BLB smear slides.

In addition to measuring abundance and diversity of diatoms, we looked at the Biological Condition Gradient of the diatom genera observed. Biological Condition Gradient is a conceptual measurement of ecosystem function/disruption. It ranges from 1-6, with 1 being a wholly natural community structure and 6 being extreme ecosystem disruption. During the section of the core with high silt deposition, Melosira and Navicula are the most common genera. Melosira is largely present in environments with BCG 4 and Navicula are generalists, spread from BCG 1 to 5. However, in the peaty layers near the top of the core, BCG ratings for diatom genera that are usually only present in ecosystems with BCG of 3 or lower. This would indicate that the Brown’s Lake ecosystem has rebounded from the previous environmental disruption.

Diatoms weren’t the only siliceous microfossils present in the core. We also found the occasional sponge spicule:

This core is important to ongoing research at The College of Wooster because it is a subrecent core containing the most recent sediment including diatom skeletons (frustules) and sponge spicules.

Acknowledgements

We thank Nick Wiesenberg for his help both in the field and retrieving the core and instruction in the laboratories. Additionally, we thank Dr. Greg Wiles for his experience and leadership on this project. Previous College of Wooster students Justine Paul Berina, Richard Torres, and Garrett Robertson, as well as Williams College student Minnie Pozefsky, developed and refined many of the techniques used in this work. This investigation was funded by the National Science Foundation grant #2039939.

 

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A local geological field trip on a midsummer’s day: Return to the Lower Carboniferous of Lodi, Ohio

Mark Wilson July 12, 2024 10:28 pm

Wooster, Ohio– This afternoon three industrious summer research students and I took advantage of the brilliant weather to drive 30 minutes north of town to Lodi Community Park in Medina County, Ohio. We wanted to take a break from lab work and writing to explore for interesting rocks and fossils. I also wanted to revisit the outcrops because of some new interest in the fossils by colleagues. I was last at this site eleven years ago with a Sedimentology & Stratigraphy class.

Lodi Community Park has a narrow valley through which flows the East Fork of the Black River. (The depth of the valley indicates it was originally cut by a much larger river in the waning days of the Pleistocene ice sheets.) Along the cutbanks of the river are exposures of the Meadville Shale, a member of the Cuyahoga Formation. It is Lower Carboniferous (Mississippian) of the Kinderhookian Stage. The stream bed contains rocks derived from the cliffs on each side, along with the occasional glacial erratic.

Three of our ace summer research students went with me to Lodi for this short trip. From the left, Peter Rothstein, Lauren Segura, and Evie Sanford. Peter and Evie are currently working on diatoms and sponges in Brown’s Lake, and Lauren is in the Wooster Tree-Ring Lab this summer. Behind them is an outcrop of the Meadville Shale, which here consists of poorly-resistant gray shale at the base and layers of micaceous quartzose siltstones that are more resistant. The wooden pole in the background, by the way, is a Jacob’s Staff used to measure stratigraphic columns. Each interval is 10 cm. I painted this staff when I was a new professor because I couldn’t find any metric versions in the United States!

Evie is here scanning the stream bed for fossils and interesting rocks. (Thank you again for driving, Evie!)

Lauren was almost always in the water when I looked.

Peter  was very intent in his rock-scanning. All three students made interesting finds.

This is a typical siltstone from the Meadville Shale at Lodi. It is full of branching bryozoan colonies (zoaria).

The underside of this siltstone slab shows numerous trace fossils. Their preservation is termed convex hyporelief.

Siderite beds and concretions are common in these Lodi exposures. In this loose boulder we can see the red-brown siderite with trace fossils at the base overlain by thin beds of fine calcareous fossil debris.

This is an internal mold of a productid brachiopod. It has just a little bit of original calcite remaining from the shell. The arrow indicates hollow spines, which are characteristic of productids. It is rare to have them preserved since they are very fragile. The scale is in millimeters.

There were a few small solitary rugose coral skeletons with their original calcite. On the right is another productid brachiopod, this time as an external mold with some original calcite remaining. Some spines are visible.

This could have been the specimen of the day but for the vagaries of preservation. This is a siderite concretion with a nearly complete crinoid. Its articulated stem (column) is easy to see on the left above the scale bar. On the right are the remnants of what would have been an entire crown with multiple feeding arms. Unfortunately this crown is eroded into a vague cross-section. It is preserved in the same manner as this contemporary specimen described in this blog.

This post gives me a chance to mention how this Lodi fossil locality began my career as a paleontologist. The fossil above, shown as a reversed stereo-pair, is an external mold of a trilobite cephalon. It was found in 1977 by College of Wooster student Mary Beidler. I was also a Wooster student at the time, so Mary gave it to me to identify. I was thrilled because Carboniferous trilobites are uncommon. I could, though, only classify it to the genus Brachymetopus. Turns out it was a new species, which I named in a short 1979 paper as Brachymetopus nodosus. This was my first publication. Thank you again, Mary!

There were some big spiders under the rocks! (Photo by Evie.)

Another change since my last visit — a fancy new bridge over the stream! Back in the day it was a low concrete weir that flooded quickly, sometimes trapping people in the park. This nice bridge was opened just a couple of months ago.

Thanks again to Peter, Lauren and Evie for a great afternoon of field geology!

Reference:

Wilson, M.A. 1979. A new species of the trilobite Brachymetopus from the Cuyahoga Formation (Lower Mississippian) of northeastern Ohio. Journal of Paleontology 53: 221-223.

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Ketchikan to Klawock

gwiles July 11, 2024 2:00 am

Guest Bloggers: Mihalis Protopapadakis and Amanda Flory

This year the College of Wooster Tree Ring Lab flew to Ketchikan for our 2024 Alaska trip. July 6th and 7th were spent in Ketchikan, where we collected samples from Deer Mountain after a rigorous hike. On July 8th we took a ferry to Prince of Wales Island, where we collaborated with Alaska Youth Stewards in the city of Klawock to create a new tree-ring record of the region. While in Klawock, we had the opportunity to bond with the AYS team and explore the local Tlingit culture.

The city of Ketchikan on a rare sunny day.

The Wooster team in front of a Tlingit totem pole.

The view from halfway up Deer Mountain.

Dr. Wiles riding the saddleback of two cedars.

The Wooster team hard at work.

Sun-rays peeking through remnants of possible staurolite crystals in the phyllite bedrock.

The Deer Mountain tree-ring data up to 1998. The chronology highlights the volcanic eruptions of the 1690s and 1809, extending the tail-end of the Little Ice Age. The team collected samples to update the record with the last 25 years.

Kite surfer catching the waves of the ferry to Prince of Wales island.

Meeting the AYS team and other collaborators in Klawock.

The team after a hard day’s work, in front of a magnificent yellow cedar.

The Wooster team coring a dead cedar deep in the mountains.

The AYS experts coring a cedar.

Bob, the instructor of the AYS group, posing with style.

The temperate rainforest around Klawock.

A beautiful moth posing on cedar.

Old logging road on the way to our second site of the day.

Monument of chainsaws by the team’s airbnb.

We spent our third day in Klawock at the Craig Tribal Association’s Culture Camp.

Nick and Proto carving traditional halibut hooks.

After the Culture Camp, we visited Sealaska’s totem tree yard to collect more samples.

Marked totem log, soon to be sent off to Alaskan artist DB.

Proto coring an enormous cedar log (could not reach the middle).A big thank you to Bob Girt and the Alaska Youth Stewards Group in Klawock who hosted our trip on Prince of Wales Island. This work was supported by grant NSF P2C2-2002454 and the Department of Earth Sciences at Wooster.

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Two Environmental Geoscience majors featured in Wooster Magazine

Mark Wilson July 1, 2024 8:09 am

We are proud of all our graduating seniors. When their Senior Independent Study projects are described outside the department, we highlight their excellent work for a larger audience. Corey Knauf (shown above) and Athena Tharenos (shown below) were both featured in the Summer 2024 edition of Wooster Magazine. We hope you can read their IS stories at the link. These beautiful images were taken by our ace college photographer Matt Dilyard.

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Buggin’ Out at Apple Creek

gwiles June 27, 2024 4:18 pm

 

Guest Bloggers: Evie Sanford and Peter Rothstein – On June 11, the 2024 Scovel Summer Research Team visited Apple Creek with Trout Unlimited to analyze the water quality through a macroinvertebrate survey. This study was performed because macroinvertebrates are often used as biological indicators of stream quality due to their response to pollution. Special thanks to Carrie Elvey from OSU CFAES for teaching us about the area, the method, and what it all means for conservation efforts.

Our 2024 collection team!

The team used the kick seine method and dip nets to collect macroinvertebrates from the stream.

In addition to nets, we flipped over rocks to find organisms like leeches, water pennies, and macroinvertebrate larvae.

Carrie taught us about the types of organisms we found.

Final tray for site one

Rainbow Darter (Etheostoma caeruleum)

Mayfly Nymph

Water Penny (Psephenidae sp.)

Site 1 Pollution Tolerance Index by year for the past 12 years. The lowest rating was 27, meaning PTI was excellent for every year measured.

 

Site 2 Pollution Tolerance Index by year for the past 12 years. The lowest value recorded, November 2013, had a value of 21, indicating good water quality. Other than that, the stream recorded excellent or better water quality throughout the recorded measurements.

Original data sheets were collected for sites 1 (left) and 2 (right).

The stream continues to receive a ranking of excellent – the highest possible rating. This excellent stream health rating for Apple Creek indicates a bright future for the stream.

In addition to the macroinvertebrate survey and our calculated pollution tolerance index, we compiled data from data loggers installed in the stream.

 

Apple Creek graph showing temperature in blue (ºC) and water levels in black (kPa) measured from a data logger in the stream channel itself. As expected, temperatures fluctuate by season, while water levels change over a shorter time frame. Note that storm events (peaks in water levels) are associated with warmer temperatures in the warm summer months and colder temperatures in the winter/early spring. These data were taken every hour.

 

Apple Creek 2 showing the temperature in blue (ºC) and water levels (kPa) when a new logger was implemented into a well casing that was installed into the stream bank approximately 10 feet from the channel and about 5 feet deep. In the coming years keeping track of the physical aspects of water flow and temperature should add to the story of environmental and water quality of Apple Creek monitoring efforts by Trout Unlimited, CFAES, and The College of Wooster.  

 

 

 

 

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James Parkinson, Paleontologist

Mark Wilson June 20, 2024 8:33 am

Ann Arbor, Michigan — This morning I gave a talk at the North American Paleontological Convention (NAPC) about the extensive contributions that the English physician James Parkinson (1755-1824) made to the rapidly growing field of paleontology in the early 19th century. This was initially a surprise to me. I had earlier this year looked up details on the life of Parkinson because he is the namesake for Parkinson’s Disease, but was astonished to learn that he had published extensively on fossils. I joined with co-authors Bill Ausich (The Ohio State University) and Caroline Buttler (National Museum Wales) to explore Parkinson’s life and work and bring him to the attention of a new generation of paleontologists. We saw that Parkinson has been nearly forgotten in modern paleontology despite numerous prescient ideas. I’ve taken the PowerPoint slides of the presentation, removed the animations, and made it into the series of images here. I think they have enough text to convey an outline of Parkinson’s paleontology.

Thank you to my Israeli friend and colleague Yael Leshno Afriat for taking this image of me speaking at the NAPC session. This is the first talk I’ve ever given anywhere without a tie and jacket!

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