Archive for April, 2013

A Beautiful Day at Fern Valley

April 30th, 2013

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A large crowd of community members congregated on Saturday to show their appreciation for the donation of Fern Valley to The College of Wooster as its new field station. Betty and David (retired French Professor) Wilkin donated the tract of land located in northern Holmes County that includes a gorge and a stream (Wilkin Run (unofficial name)).

teamDavid and Betty Wilkin with Lyn Loveless (right, Biology) during the dedication of the Fern Valley field station.

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President Grant Cornwell shows his appreciation for the gift to the College.

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A transdisciplinary group examines the biota and geologic setting of the stream bed. Several classes across the curriculum have visited and collected data from Fern Valley. 

A BRIEF GEOLOGIC SETTING

Geology has begun to install dataloggers and other equipment to monitor streamflow, sediment flux and mass movements at Fern Valley. Photos and the data collected will be archived at the Wooster Digital Resource Commons.

The Geology includes Paleozoic sedimentary rocks overlain by as much as 150 feet of unconsolidated glacial sediments. The water well logs in the area show a buried valley that includes a preglacial lacustrine deposit of several tens of feet of lacustrine clays. The clays were laid down prior to the most recent (~20 ka) advance of the Laurentide Icesheet and the tills and ice contact deposits exposed along the valley walls incorporate these lake clays.  Wilkin Run is now cutting through this sedimentary pile and in many places is now in the lake clays. The lake clays serve as a hydrologic barrier and slip plane for mass movements along the valley.

A Clinton Well drilled in 1950 to a total depth (TD) of 3000 feet  is also on the property and is now part of a natural gas storage field. The current land use in the basin is largely agricultural.

Wilkin Run (below) flows north into Odell Lake. Wooster geologists have cored the lake and together with the ongoing monitoring of sediment flux through Fern Valley; sediment that ultimately ends up in Odell Lake, they can better interpret the sediment cores.

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Dr. Meagen Pollock and Russ along with their dogs enjoying the dedication and geology of Fern Valley.

Wooster’s Fossil of the Week: Tubular drillholes (Upper Ordovician of the Cincinnati Region)

April 28th, 2013

Trypanites_hardground_585_010213

This is one of the simplest fossils ever: a cylindrical hole drilled into a hard substrate like a skeleton or rock. The above image is of a hardground (cemented carbonate seafloor) from the Upper Ordovician of northern Kentucky with these borings cut perpendicularly to the bedding and descending downwards. Each boring is filled with light-colored dolomite crystals. This boring type is given the trace fossil name Trypanites weisi Magdefrau 1932.
Trypanites_Bryozoan_010213_585Trypanites, shown above cutting into a trepostome bryozoan from the Upper Ordovician of southeastern Indiana, is a very long-ranging trace fossil. It first appears in the Lower Cambrian and it is still formed today — a range of 540 million years (James et al., 1977; Taylor and Wilson, 2003). It was (and is) made by a variety of worm-like organisms, almost always in carbonate substrates. Today the most common producers of Trypanites are some polychaete and sipunculid worms. Trypanites was the most common boring until the Jurassic, when it was overtaken in abundance by bivalve and sponge borings. Trypanites was the primary boring in the Ordovician Bioerosion Revolution (Wilson and Palmer, 2006).
Trypanites_Horizontal_585Trypanites is defined as a cylindrical, unbranched boring in a hard substrate (such as a rock or shell) with a length up to 50 times its width (Bromley, 1972). The typical Trypanites is only a few millimeters long, but some are known to be up to 12 centimeters in length (Cole and Palmer, 1999). The above occurrence of Trypanites is one of my favorites. The organisms bored into a bryozoan colony (the fossil in the upper left and center with tiny holes) and down into a bivalve shell the bryozoan had encrusted. The borer then turned 90° and drilled horizontally through the aragonitic and calcitic layers of the shell. The aragonite dissolved, revealing the half-borings of Trypanites.
LibertyBorings_585In this bedding plane view, Trypanites weisi borings are shown cutting into a hardground from the Liberty Formation (Upper Ordovician) of southeastern Indiana. This is a significant occurrence because the borings are cutting through brachiopod shells cemented into the hardground surface. When the brachiopods are dislodged from the hardground, those with holes in them erroneously appear to have been bored by predators (see Wilson and Palmer, 2001).

The simplest of fossils turns out to have its own levels of complexity!

References:

Bromley, R.G. 1972. On some ichnotaxa in hard substrates, with a redefinition of Trypanites Mägdefrau. Paläontologische Zeitschrift 46: 93–98.

Cole, A.R. and Palmer, T.J. 1999. Middle Jurassic worm borings, and a new giant ichnospecies of Trypanites from the Bajocian/Dinantian unconformity, southern England. Proceedings of the Geologists’ Association 110 (3): 203–209.

James, N.P., Kobluk, D.R. and Pemberton, S.G. 1977. The oldest macroborers: Lower Cambrian of Labrador. Science 197 (4307): 980–983.

Taylor, P.D. and Wilson. M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62 (1-2): 1–103.

Wilson, M.A. and Palmer, T.J. 2001. Domiciles, not predatory borings: a simpler explanation of the holes in Ordovician shells analyzed by Kaplan and Baumiller, 2000. Palaios 16: 524-525.

Wilson, M.A. and Palmer, T.J. 2006. Patterns and processes in the Ordovician Bioerosion Revolution. Ichnos 13: 109–112.

Sed/Strat goes local with its field trip: the Meadville Shale and the Logan Formation (Lower Carboniferous)

April 27th, 2013

MeadvilleB042713WOOSTER, OHIO–The traditional spring field trip in the Sedimentology & Stratigraphy course at Wooster is taken several hours south, usually in Jackson County or, as last year, in a soggy quarry outside of Dayton. This time, though, we stayed nearby, measuring and describing the local bedrock: the Meadville Shale Member and the Logan Formation, both in the Lower Carboniferous. We had a spectacular day with the best weather Ohio can offer.

Our first location, shown above, was in Lodi Community Park about 20 miles north of Wooster. A tributary of the Black River (the East Fork Black River) flows through a small valley, exposing the Meadville Shale in its steep sides. The Meadville is a member of the Cuyahoga Formation and is late Kinderhookian in age. The students above are beginning to measure the unit with their Jacob’s staffs.

MeadvilleA042713Candy Thornton and William Harrison are here at the exposed base of the Meadville. They’re taking a break from geology to examine a salamander they found on this fine spring morning.

Spiriferid042713 The Meadville is in part very fossiliferous. We found crinoids, bryozoans, bivalves and brachiopods like this nice spiriferid above.

FluteMarks042713 An interesting feature on the soles of some thin siltstones are these long, parallel grooves called flute marks. They were made when shells were dragged across a muddy substrate, leaving scour marks. We think they represent the basal unit of thin turbidites formed by sediment slurries that flowed across the seafloor.

SarahF042713Sarah Frederick climbed high on the outcrop with a measuring staff to describe the transition from a silty shale to a very fine sandstone.

PicnicTable042713Here a group of Wooster geologists compares notes as they construct their stratigraphic columns. Yes, this sunlight felt very good to us.

Logan042713Our afternoon stop was in southeastern Wooster along the onramp from north Route 83 to east Route 30. The Logan Formation exposed here is a Lower Carboniferous (early Osagean) very fine sandstone and conglomerate. This site is near what was once known as “Little Arizona” to older Wooster geologists. That exposure was mostly removed when this new onramp was constructed.

Conglomerate042713The base of the Logan has an extensive conglomerate sometimes referred to as the Berne Member. As you can see, it mostly consists of rounded quartz and chert pebbles, making it a very mature sediment.

Dewatering042713One of the distinctive features of this Logan outcrop are these large dewatering structures. These form when a water-rich slurry of sediment is forced upwards through the sediment above. Vertical channels are made between the rounded bases of sandstone bodies. One interpretation of these structures is that they were produced an earthquake shaking the water-saturated sediment. If this was the case, we would call these seismites.

LoganGroup042713Here a happy group of geologists is returning to the vans with various fossil and rock specimens. Now it’s time to write the reports!

 

 

Wooster Geology poster session at the 2013 Senior Research Symposium at The College of Wooster

April 26th, 2013

Joe_Wilch_2013WOOSTER, OHIO–It was a bit of a crowded room in Andrews Library for our geology seniors (and all their friends, family and faculty), but it was a very happy place. Joe Wilch (above) escaped the crowd, though, because he is a double math and geology major and thus presented his poster in Taylor Hall. His title: “Insights into the tectonic evolution of the northern Snake Range metamorphic core complex from 40Ar/39Ar thermochronologic modeling results, northern Snake Range, Nevada.” Much math ensued in that project. I told Joe to look grim — anyone can smile for the camera. This was the best he could do. Joe recently gave a poster at the Keck Geology Symposium. He seems to be still wearing the same shirt.

Will_Cary_2013Will Cary, a member of Team Utah, presented his poster on “Ballistics analysis of volcanic ejecta: Miter Crater, Ice Springs Volcanic Field, Black Rock Desert, Utah.” He had lots of bright Wooster sunshine behind him. This was fitting because he’s a Wooster boy.

Jenn_Horton_2013Jenn Horton discussed her project: “Dating the First Millennium AD glacial history of Adams Inlet, Glacier Bay National Park and Preserve, southeast Alaska.” She had many adventures in the Alaskan wilderness this summer leading to this warm and dry session back in Old Woo.

Anna_Mudd_2013Anna Mudd is here passionately presenting her poster: “Clay mineral analysis and paleoclimate interpretation of a middle Miocene paleosol in the Powder River Volcanic Field, northeast Oregon.” Like Joe Wilch, she also discussed her work at the 2013 Keck Geology Symposium meeting in California. You can see here an image of Anna as a Junior I.S. student last year as she began her research journey.

Jonah_Novek_2013Jonah Novek did his fieldwork in the Baltic with the well-remembered Richa Ekka (a member of this class who graduated early). Jonah’s title: “Analysis of a Rhuddanian (Llandovery, Lower Silurian) sclerobiont community in the Hilliste Formation on Hiiumaa Island, Estonia: a hard-substrate-dwelling relict fauna.” I’m pleased that he didn’t wear his tuxedo today.

Matt_Peppers_2013Matt Peppers is another Team Utah member. His title: “Analysis of Ice Springs Volcanic field structures, Black Rock Desert, Utah.” Matt is looking dapper in an increasingly warming room.

Kit_Price_2013Kit Price did her fieldwork in southern Indiana, and then loads of paleontological lab work back in Wooster. Her project is titled: “A description of cryptoskeletozoan communities and growth analyses of cryptic Cuffeyella arachnoidea and Cornulites from the Upper Ordovician (Richmondian) of Ohio and Indiana.” She appears to be explaining her poster to Johnny Cash.

Whitney_Sims_2013Whitney Sims is yet another Team Utah member. She had the extra experience of attending a conference on volcanism with her advisors. Whiteny’s title: “Geochemical and geospatial analysis: mapping Miter’s lava flows in Ice Springs Volcanic Field, Black Rock Desert, Utah.”

Melissa_Torma_2013Melissa Torma went on an excellent spring trip to the Negev in southern Israel over a year ago for her I.S. fieldwork. She clearly enjoyed it! Her title: “The paleoecology of a brachiopod-bearing marly subunit of the Matmor Formation, Israel: A Middle Jurassic marine environment near the equator.”

Lauren_Vargo_2013bFinally, Lauren Vargo got one more presentation today after her morning talk. Her title: “Tree-ring evidence of north Pacific volcanically-forced cooling and forcing of the Pacific Decadal Oscillation (PDO).” Gotta love those wiggly lines!

We are very proud of our Wooster Geology seniors. Well done, young geologists!

 

Lauren Vargo (’13) starts off the Wooster Geologists in the 2013 Senior Research Symposium at The College of Wooster

April 26th, 2013

LaurenVargo042613WOOSTER, OHIO–The College of Wooster has an annual celebration of Independent Study after all the theses are done and (most) of the oral examinations. It is much fun as our students present their research to the community, which often includes people from the town and quite a few family members. The amount and quality of student research is astounding.

The first Wooster Geologist of the day was Lauren Vargo (above) talking about her I.S. project: “Tree-ring evidence of north Pacific volcanically-forced cooling and forcing of the Pacific Decadal Oscillation (PDO)”. Hers was a special presentation because she received an Honorable Mention for the Independent Study Research Prize in Sustainability and the Environment. This new prize was established by The College of Wooster Libraries and Gale-Cengage, an e-research and educational publishing company, to encourage undergraduate research in sustainability. You will remember Lauren as one of our video stars, as well as for her fieldwork in Alaska, including this epic blogpost.

The other Wooster seniors are presenting posters this morning and afternoon. We will see them here soon.

Wooster’s Fossil of the Week: A pentamerid brachiopod from the Lower Silurian of New York

April 21st, 2013

Pentamerus oblongus Sowerby, 1839Another brachiopod this week. This simple fossil is an internal mold of the brachiopod Pentamerus oblongus (J. de C. Sowerby, 1839). It was a very common and widespread taxon throughout North America and Europe in the Early Silurian. This particular specimen was found in a dolomite of the Clinton Group of New York State. This species has been an important fossil for reconstructing Early Silurian paleocommunities, and it is useful in biostratigraphy as well.

I chose this specimen because it has the preservation I have seen in almost every pentamerid brachiopod I have collected: it is an internal mold formed when sediment filled the calcitic shell, was cemented, and then the shell dissolved. We are looking at an impression of a sort of the interior surface of the brachiopod. The posterior (hinge region) of the brachiopod is at the top of this view. You can see a straight slit that represents the ventral muscle field complex (spondylium) that was part of the ventral valve. This was a kind of shelly septum on the floor of the brachiopod interior. we would not see this feature (or rather what is left of it) if the exterior shell had not been removed.
Pentamerus_drawingThe above is a drawing of Pentamerus oblongus as it looked with its original shell. In this view, unlike our specimen, we are looking at the dorsal valve with the ventral valve visible beneath it.
James_d_c_SowerbyThe genus Pentamerus was named in 1813 by James Sowerby (1757-1822), a prolific scientist we met earlier with our specimen of the Cretaceous bivalve Inoceramus. The species Pentamerus oblongus was fittingly named by his eldest son, James de Carle Sowerby (1787-1871), in 1839. J. de C. Sowerby is shown above in his latter years. The younger Sowerby was an unusual combination of a paleontologist, botanist and mineralogist. He was a friend of the extraordinary scientist Michael Faraday (1791-1867), so he would have had encouragement to be an accomplished polymath. He is said to have conceived one of the first classification of minerals by their chemical compositions. In 1838, J. de C. Sowerby and his cousin Philip Barnes founded the Royal Botanic Society and Gardens (now part of Regent’s Park, London). On top of all this, he was a spectacular scientific illustrator. How many such diverse scientists do we have today?

References:

Johnson. M.E. 1977. Succession and replacement in the development of Silurian brachiopod populations. Lethaia 10: 83-93.

Johnson, M.E. and Colville, V.R. 1982. Regional integration of evidence for evolution in the Silurian Pentamerus-Pentameroides lineage. Lethaia 15: 41-54.

Ziegler, A.M., Cocks, L.R.M. and Bambach, R.K. 1968. The composition and structure of Lower Silurian marine communities. Lethaia 1: 1-27.

Keck Symposium Warmup for Wooster’s IS Symposium

April 19th, 2013

Wooster’s Senior Research Symposium is exactly a week away, so many seniors will be spending this weekend practicing their poster presentations. Two senior Wooster Geologists have had a recent poster presentation warmup; In early April, Anna Mudd (’13) and Joe Wilch (’13) presented their Independent Studies at the 26th Annual Keck Symposium. The Keck Geology Consortium provides opportunities for Wooster geologists to work on a variety of projects with faculty and students from many other institutions. Keck projects involve an intense four-week summer experience followed by a year-long guided research project at the home institution. The symposium represents the culmination of the project, bringing the Keck team back together to synthesize their results and present their work.

This year, Anna worked on the Northeast Oregon project. She studied the clay mineralogy of paleosols in the Powder River volcanic field. By identifying the clay species, she was able to interpret the climate at the time of soil formation, approximately 14 million years ago.

Anna Mudd ('13) presented her work on paleosols in the Powder River volcanic field.

Anna Mudd (’13) presented her work on paleosols in the Powder River volcanic field.

While Anna was in Oregon, Joe  was in the Northern Snake Range in Nevada. He used 40Ar/39Ar thermochronology of muscovites and K-feldspars to understand how the footwall of a detachment fault was exhumed.

Joe Wilch ('13) presented his work on the thermochronology of muscovites and K-feldspar in the Snake Range.

Joe Wilch (’13) presented his work on the thermochronology of muscovites and K-feldspar in the Snake Range.

Best of luck to Anna, Joe, and the other geology seniors who will be presenting their research next week. If you’re in the area next Friday, you should definitely try to make it to the symposium. Most of the geology posters will be in the Writing Center in Andrews Library between 1 and 3 pm. Joe’s poster will be presented with the mathematicians on the third floor of Taylor between 9 and 11 am.

Wooster’s Fossil of the Week: A terebratulid brachiopod from the Middle Triassic of southern Israel

April 14th, 2013

Coenothyris oweni Anisian 041013 585Sure, I could have picked a pristine shell from our collection, but I like the rugged character of this one. It is the terebratulid brachiopod Coenothyris oweni Feldman, 2002, from the lower Saharonim Formation (Middle Triassic) of Har Devanim, southern Israel. I picked it up, along with a dozen others, during our 2010 Israel expedition.

Above we have a dorsal view of this brachiopod. The posterior is at the top, anterior at the bottom. The round hole is the pedicle opening in the ventral valve. (The pedicle is a fleshy stalk the brachiopod uses to attach to a substrate.) As with all brachiopods, you can see the bilateral symmetry of the shell with the plane perpendicular to the hinge between the valves. Terebratulids are still around.

Saharonim061010

The layered units at the top of this ridge of Har Devanim are the lower part of the Saharonim Formation (Anisian, Middle Triassic). Micah Risacher (’11) is just visible.

CoenothyrisBedding061010

Coenothyris oweni was named in 2002 by my friend Howie Feldman. He also wrote a 2005 paper on the paleoecology of this species in the Saharonim Formation of southern Israel. The brachiopods are sometimes found in obrution deposits, meaning they were buried alive by storm-driven sediments (see above).

Combined_Douville

The genus Coenothyris was named by Joseph Henri Ferdinand Douvillé in 1879 (above as a young man and older). He was a French paleontologist and geologist who worked first as a mining engineer and then a professor of paleontology at the École des Mines (School of Mines). His research took him around the world, but his most prominent papers were on French fossils and geology. In 1881 he became president of the Société géologique de France; in 1907 he was elevated to the Académie des Sciences.

References:

Feldman, H.R. 2002. A new species of Coenothyris (Brachiopoda) from the Triassic (Upper Anisian-Ladinian) of Israel. Journal of Paleontology 76: 34-42.

Feldman, H.R. 2005. Paleoecology, taphonomy, and biogeography of a Coenothyris community (Brachiopoda, Terebratulida) from the Triassic (Upper Anisian-Lower Ladinian) of Israel. American Museum Novitates, no. 3479: 1-19.

Expanding Your Horizons in Geology

April 13th, 2013

Wooster, OH – The Wooster X-ray Lab hosted girls from the Expanding Your Horizons program, a series of workshops aimed at encouraging young women to pursue careers in the sciences. The geology workshop focused on minerals and their wide variety of uses. One popular use of minerals is in beaded jewelry.

These colorful beads are made of minerals.

These colorful beads are actually polished pieces of minerals.

Our goal was to figure out which minerals each bead represented. To do this, we used the X-ray Diffractometer (XRD).  The XRD zaps the minerals with X-rays, which get reflected off of the atomic layers in the minerals, giving us information about their structures. Each mineral has a unique set of reflections, sort of like a fingerprint, which allows us to identify the mineral.

One of the girls prepares a sample for the XRD.

One of the girls prepares a sample for the XRD.

While we were waiting for the samples to run, the girls made bracelets out of the beads.

While we were waiting for the samples to run, the girls made bracelets out of the beads.

Someone made a bracelet that said, "Science Rocks!"

Someone made a bracelet that said, “Science Rocks!” We love the geology pun.

By the end of the workshop, we learned that three of our beads were actually varieties of quartz: Tiger’s Eye Quartz, Amethyst, and Jasper. Our dark blue bead was Sodalite. Maybe the most surprising result was the bead that looked like Turquoise. It was actually Calcite!  Tricky, tricky!

 

 

 

Virtual Cascades Volcano Observatory in Wooster

April 11th, 2013

Wooster, OH – We hosted a virtual visitor in today’s GeoClub seminar. Dave Ramsay, a geologist from the Cascades Volcano Observatory, connected with us via the web to tell us about the geology of Crater Lake.

Shelley Judge and Dave Ramsey bumped into eachother at the conference on Volcanism in the American Southwest. Both are alumni of the same undergraduate geology program!

Shelley Judge and Dave Ramsey bumped into eachother at the conference on Volcanism in the American Southwest. Both are alumni of the same undergraduate geology program!

Dave and his colleagues have done fantastic work mapping the floor of Crater Lake. Crater Lake formed from the explosive eruption of Mount Mazama about 7700 years ago. On most geologic maps, Crater Lake is a blue body of water. But Dave and his colleagues used multibeam swath echo sounders and a human occupied submersible to map the geology of the lake floor.

Map of Crater Lake showing features of interest on the lake floor. Klimasauskas, E., Bacon, C., and Alexander, J., 2002, Mount Mazama and Crater Lake: Growth and Destruction of a Cascade Volcano: U.S. Geological Survey Fact Sheet 092-02.

Dave took us on a fly-through tour of the geology and told us stories about how many of the geologic features developed. He and his colleagues found that Wizard Island is much bigger than we may have expected, and that it erupted both under and above water while Merriam Cone erupted exclusively under water.

Snapshot of the geology of the floor of Crater Lake.  Here, Wizard Island (gray peak) extends below the water (green). (Photo Credit: David Ramsey).

Snapshot of the geology of the floor of Crater Lake. Here, Wizard Island (gray peak) extends below the water (green). (Photo Credit: David Ramsey).

Many thanks to Dave for talking to us first thing this morning (west coast time) and for giving such an engaging and entertaining seminar.

 

 

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