A rite of passage: Geology Junior Independent Study presentations

WOOSTER, OHIO–The College of Wooster requires an Independent Study (I.S.) thesis (or performance) from all of its graduates. These are not just extended literature reviews, but unique research projects crafted for and by each of our students. We devote three semesters to the process. Readers of this blog are well acquainted with Senior I.S. work because we highlight each study with multiple entries. The first I.S. semester, which is usually (but not always) taken in the spring of the junior year, gets far less outside attention. This is because most of the work is preparation for the research to come in the following summer and school year. Students and faculty sort out projects for each junior, narrow and focus their objectives, and then do a thorough library study to form hypotheses to test in the field or lab. Occasionally we have specimens to work on as a preview, or have even done some of the fieldwork during Spring Break. No matter what, though, each student eventually presents his or her research ideas to the faculty and fellow classmates. Last week most of our juniors gave their talks and posters. (Two of our juniors are out of sequence; one presented last semester, the other will this summer.)

This presentation is the first of three that these students will give to the department about their projects. It is always the most difficult because the research is just beginning and the students are new to giving talks. By their senior years these same students will feel like veteran speakers and masters of their topics. As juniors, though, the task is daunting. The faculty make the proceedings a little less formal than the senior presentations (note in the photo above Anna Mudd is giving her talk on paleosols from a cart as a podium!), but our juniors are still facing a group of their peers … and scary faculty charged with evaluating their performances. The students came through this year and did very well.

New to the system this year were posters from the Utah group (explained below). Each of these four students still gave an oral presentation, but rather than all repeating the same basic framework information (location, geological setting, etc.), they began their set of talks with these poster discussions. Above we see Kevin Silver starting to explain the Utah integrated projects, with Whitney Sims ready to do her part at the end.

Four students (and Clare Booth Luce award winner Tricia Hall) are going with Dr. Shelley Judge and Dr. Meagen Pollock to the Black Rock Desert in south-central Utah to explore petrological and structural questions:

Will Cary will be looking at the ballistics of volcanic bombs thrown from the eruptions.
Whitney Sims will examine the petrology and geochemistry of particular lava flows.
Kevin Silver is studying xenoliths in these lava flows.
Matt Peppers will be doing a fracture analysis of the Ice Springs lava flow.

Two of our students will be doing Keck Geology Consortium projects this summer:

Anna Mudd is examining paleosols (ancient soils) developed in the northeastern Oregon.
Joe Wilch is assessing metamorphic core complexes in the northern Snake Range of Nevada.

Two students are traveling with Dr. Mark Wilson to the western islands of Estonia:

Richa Ekka will concentrate on petrology and paleoenvironments of Silurian carbonates.
Jonah Novek will study Silurian paleocommunities and recovery faunas.

Two students will be in Glacier Bay, Alaska, with Dr. Greg Wiles:

Jenn Horton and Lauren Vargo will study the reaction of trees (and their rings) to climate change and isostatic rebound.

Finally:

Melissa Torma is studying Jurassic faunas in Israel with Dr. Wilson.
Kit Price will be examining Ordovician sclerobionts in the Cincinnati region, also with Dr. Wilson.

This summer you will see blog posts from all of the above as they start their senior adventures!

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Wooster’s Fossil of the Week: A giant oyster (Eocene of Texas)

It’s no ordinary oyster, of course, because it comes from Texas. It certainly is the largest oyster I’ve ever seen. Wooster received it as part of a large donation in 2010. (You can see students studying it in this previous blog entry.)

All we know is that it came from Texas (a notoriously big place) and the Eocene Series. It appears to be the extinct oyster Crassostrea gigantissima (Finch, 1824). Curiously, this is the first fossil species described from the Paleogene of North America (see Howe, 1937). It is worth quoting the entire description:

Fossils. This extensive formation is chiefly composed of a large species of ostrea, which I believe has not yet been described. A specimen of it may be seen in the Philadelphia museum; it is twelve inches long and two and three-quarters wide, and each valve from half to two and a quarter inches thick — Major Ware says they occur larger; on account of their great size I propose to call them Ostrea Gigantissima. The shells appear but slightly changed by their residence in the earth, and are in many parts used for burning into lime. (Finch, 1824, p. 40)

This is what it took to name a new species in 1824! Since then, of course, we have a detailed set of rules for naming animal taxa detailed in the International Code of Zoological Nomenclature. The Lawrence (1991) reference below is an example of what we often have to do in order to bring old names like “Ostrea Gigantissima” up to, well, Code.

The interior of the attaching valve of Crassostrea gigantissima.

The top surface of our giant oyster is riddled with these small holes. They are produced by the boring sponge Entobia, which is the next Fossil of the Week.

References:

Finch, J. 1824. Geological essay on the Tertiary Formations in America. The American Journal of Science and Arts 7: 31-42.

Howe, H.V. 1937. Large oysters from the Gulf Coast Tertiary. Journal of Paleontology 11: 355-366.

Lawrence, D.R. 1991. The neotype of Crassostrea gigantissima (Finch, 1824). Journal of Paleontology 65: 342-343.

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Now this is field trip weather

WOOSTER, OHIO–It is now difficult to believe that we were measuring stratigraphic sections in a sleety thunderstorm on Saturday. Today the Tuesday lab of my Sedimentology & Stratigraphy course visited a local outcrop of the Logan Formation (Lower Carboniferous) to get more practice with stratigraphic techniques. What an enjoyable afternoon!

Students hard at work on the Logan Formation outcrop in Wooster. I’m hoping there’s no poison ivy in there.

Alex Hiatt and Cam Matesich looking very closely at the sandstone like good sedimentary geologists.

A set of male pine cones that have already distributed their pollen.

Andy Nash found this Eastern American Toad (Bufo americanus americanus) and our amphibian expert Ned Weakland captured it. Ned’s advisor Rick Lehtinen picked up a similar toad last semester on a short geology field trip. It made us feel all the more that we were in Spring at last.

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Wooster’s Fossil of the Week: the classic bioclaustration (Upper Ordovician of Ohio)

We’re looking at two fossils above. One is the bryozoan Peronopora, the major skeletal structure. The second is the odd series of scalloped holes in its surface. These are a trace fossil called Catellocaula vallata Palmer and Wilson 1988. They at first appear to be borings cut into the bryozoan colony. Instead they are holes formed by the intergrowth of a soft-bodied parasite with the living bryozoan colony. This type of trace fossil is called a bioclaustration. We gave it the Latin name for “little chain of walled pits”.

My good friend Tim Palmer and I found this specimen and many others in 1987 as we explored the Upper Ordovician Kope Formation in the Cincinnati region. We were collecting bioeroded substrates like hardgrounds and shells, and these features were clearly different from the usual borings. They do not actually cut the bryozoan skeleton, for one thing. For another it is apparent that the bryozoan growth was deflected around whatever sat in those spaces. Tim and I called this kind of interaction “bioclaustration”, meaning “biologically walled -up”.
Catellocaula vallata on the Upper Ordovician bryozoan Amplexopora. Note that the scalloped holes have more lobes than those seen in the lead image. This may mean it was a different species of infesting soft-bodied organism.

The infesting parasite on the bryozoan colony was itself colonial, consisting of small clusters connected by extended stolons. The bryozoan grew around the parasite, roofing over the stolons and making walls on the margins of the clusters. We think the parasite was a soft-bodied ascidian tunicate like the modern Botryllus. If true, it is the earliest fossil tunicate known.

This closer view of C. vallata shows the scalloped margins of the pits and the horizontal connections between them.

Another specimen of C. vallata. This view shows the flat floors of the bioclaustration features.

Acetate peels cut longitudinally through the bryozoan and bioclaustrations. On the left you can see that the bryozoan zooecia (long tubes) were deflected sideways as they grew. On the right is a tunnel connecting two pits, with bryozoan zooids forming the roof. (From Palmer and Wilson, 1988.)

References:

Bromley, R.G., Beuck, L. and Taddei Ruggiero, E. 2008. Endolithic sponge versus terebratulid brachiopod, Pleistocene, Italy: accidental symbiosis, bioclaustration and deformity. Current Developments in Bioerosion, Erlangen Earth Conference Series, 2008, III, 361-368.

Palmer, T.J. and Wilson, M.A. 1988. Parasitism of Ordovician bryozoans and the origin of pseudoborings. Palaeontology 31: 939-949.

Tapanila, L. 2006. Macroborings and bioclaustrations in a Late Devonian reef above the Alamo Impact Breccia, Nevada, USA. Ichnos 13: 129-134.

Taylor, P.D. and Voigt, E. 2006. Symbiont bioclaustrations in Cretaceous cyclostome bryozoans. Courier Forschungsinstitut Senckenberg 257: 131-136.

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A very damp field trip

FAIRBORN, OHIO–I actually used to brag about the great weather on my class field trips. The hubris! Today Shelley Judge and I took our combined Sedimentology & Stratigraphy and Structural Geology classes to Oakes Park Quarry near Dayton for a field trip. (Location = N39.81401°, W083.98374°.) We planned to describe and measure the exposure there of the Brassfield Formation, and then assess the joint fabric and the direction of glacial grooves on its top surface. I took three students there last week to test the concept. Since this is the last weekend of the semester, there was no do-over, so we went rain or shine.

It was 38°F and breezy when we arrived. That’s when I took my first and last picture, shown above. (It is of Tricia Hall and Scott Kugel in the middle of their stratigraphic task.) The rain came slowly at first. Not too bad. Then we heard the thunder and were quickly overwhelmed by a serious downpour. Near-freezing temperatures and a thunderstorm? That’s spring in Ohio. I haven’t been so cold and wet since I was in this place. This is why I very much prefer my field areas to be very warm and very dry.

The students were great sports, though, and we collected just enough data so that we could retreat to the bus with some geological honor intact.

The summer can’t come fast enough back here for the Wooster geologists!

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Wooster Geologists at the 2012 Senior Research Symposium

WOOSTER, OHIO–Six Wooster geology seniors presented their research to the campus and public this morning in Kauke Hall on the College of Wooster campus. They were among the first posters in the annual Senior Research Symposium in which Independent Study projects are highlighted and celebrated. They did very well — their geology faculty advisors are proud indeed. Here they are with their presentations:

Sarah Appleton ’12: Dating of the Mid-Holocene History and Glacial Stratigraphy of the Wachusett Inlet, Glacier Bay National Park and Preserve, Southeast Alaska. (Links to Sarah’s work on the Wooster Geologist’s blog.)

Lindsey Bowman ’12: Geochemical and Field Relationships of Pillow and Dike Units in a Subglacial Pillow Unit, Undirhlíðar Quarry, Southwest Iceland. (Links to Lindsey’s work on the Wooster Geologists blog.)

Andrew Collins ’12: A Comparison and Analog-Based Analysis of Sinuous Channels on Rift Aprons of Ascraeus Mons and Pavonis Mons Volcanoes, Mars. (Links to Andrew’s work on the Wooster Geologists blog.)

Nick Fedorchuk ’12: Stratigraphy and Paleoecology of the Wenlock/Ludlow Boundary on Saaremaa Island, Estonia. (Links to Nick’s work on the Wooster Geologists blog.)

Rachel Matt ’12: Paleoecology of the Hilliste Formation (Lower Silurian, Llandovery, Rhuddanian) on Hiiumaa Island, Estonia: An Example of a Shallow Marine Recovery Fauna. (Links to Rachel’s work on the Wooster Geologists blog.)

Katharine Schleich ’12: A Geochemical and Petrographic Analysis of the Hrafnfjordur Central Volcano, Westfjords, Iceland. (Links to Katharine’s work on the Wooster Geologist blog.)

Well done, Wooster Geologists!

 

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Wooster’s Fossil of the Week: a nestling bivalve (Pleistocene of The Bahamas)

This weathered and encrusted shell was pulled from a round hole bored in a Pleistocene reef (about 125,000 years old) exposed on San Salvador Island, The Bahamas. It is Coralliophaga coralliophaga (Gmelin 1791), a derived venerid bivalve (a type of heterodont, meaning that it has cardinal and lateral articulating teeth inside its valves.) I collected it back in 1991 while studying an inter-reef unconformity that recorded a drop and rise of sea level (Wilson et al., 1998; Thompson et al., 2011).

Coralliophaga means “coral eater”, which is a bit of a bum rap for this clam. It is found inside borings in coral, true enough, but those holes were drilled by some other types of clams. C. coralliophaga only occupies the holes after the original dweller is dead and gone (Morton, 1980). We call this kind of behavior “nestling“, which seems a polite way of saying “squatting”. These bivalves grew to adulthood in these cavities protected from most predators as they filtered the seawater for food.
The trace fossil Gastrochaenolites torpedo (the elongate borings) with a nestling (and broken) C. coralliophaga in the lower right corner.

The posterior ends of these shells are encrusted by a variety of calcareous algae and other organisms during life, so they look a bit rough on their outsides. Often the encrustations are so thick that the shells are difficult to extract from the holes, so getting a nice complete shell like the one at the top of this entry is rare.
C. coralliophaga was named by Johann Friedrich Gmelin (1748–1804) in 1791. Gmelin was an accomplished naturalist from Tübingen, Germany. He received an MD degree in 1769, with his father (Philipp Gmelin) as his advisor. He taught at Tübingen and the University of Göttingen, writing many textbooks in fields from chemistry through botany. He published the 13th edition of Systema Naturae by Carolus Linnaeus, inserting his new taxa in the text, including our new friend Coralliophaga coralliophaga.

References:

Gmelin, J.F. 1791, in Linnaeus, C. Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. 13th Edition, Lyon : J.B. Delamolliere Tom.

Morton, B. 1980. Some aspects of the biology and functional morphology of Coralliophaga (Coralliophaga) coralliophaga (Gmelin, 1791) (Bivalvia: Arcticacea): a coral-associated nestler in Hong Kong. pp. 311-330, in: Morton, B., The Malacofauna of Hong Kong and southern China. Proceedings of the First International Workshop on the Malacofauna of Hong Kong and Southern China, Hong Kong, 1977. Hong Kong: Hong Kong University Press.

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.

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.

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Wet and Cold Wooster Geologists in the Silurian of Central Ohio

DAYTON, OHIO–It was 37°F and raining this morning as three stalwart Wooster Geology students and I worked in a muddy quarry near Fairborn, Ohio (N 39.81472°, W 83.99471°). Our task was to scout out a beautiful exposure of the Brassfield Formation (Early Silurian, Llandovery) for a future field trip by the Sedimentology & Stratigraphy class. Until today this week was sunny and warm in Ohio. Nevertheless, our students persevered and efficiently measured and described the exposed units, and then they searched for glacial grooves and truncated corals on the top surface.

Abby, Steph and Lizzie during a relatively dry moment. The striped stick, by the way, is a Jacob’s Staff divided into tenths of meters. We use these large and simple rulers to measure the thickness of rock units. Our technician Matt Curren made us nice set of these this semester. Previous Wooster students may remember the long dowels we had in the past that Stephanie Jarvis discovered one day were not very precise! Why do we call them “Jacob’s Staffs”? Read Genesis 30:25-43. (This must be the first biblical reference in this blog!)

Dolomite at the base of the Brassfield with a pervasive fabric of burrows. These trace fossils were probably produced by shrimp-like arthropods tunneling in the seafloor sediments.

A well-sorted encrinite (limestone made almost entirely of crinoid skeletal fragments) from the lower third of the Brassfield Formation. These are mostly stem and arm pieces. The articulated portion on the left is a small stem.

A poorly-sorted encrinite. Here you can see a much greater range of bioclast size than in the previous image. There are also some brachiopod shell fragments mixed in.

The Brassfield Formation is a critical one in stratigraphy because most of the other Silurian carbonates in northeastern North America have been altered by dolomitization, which destroys the original fabric and texture of the rock. Fossils become mere ghosts in dolomitized limestone, but here they are superbly preserved.

It may have been a damp and chilly day, but how bad could it have been if we had limestones and fossils in it?

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Expanding Horizons in Geology

WOOSTER, OH – The Wooster Geologists are pleased to be part of the Expanding Your Horizons Program, a science workshop aimed at encouraging young women to consider science as a career. This year’s topics ranged from sunscreen to marshmallow-spaghetti towers. Our workshop focused on minerals in common household products. We’ve ran this workshop once or twice before, but now that the X-ray lab is fully established, we’ve (mostly) worked out the kinks.

The girls began the workshop by guessing which minerals were in which products based on physical properties of the minerals.

We tested their hypothesis for toothpaste by running a sample in the XRD, which provides us with a "fingerprint" of the minerals in the sample.

This particular toothpaste contained a mixture of two minerals, so the girls needed to do some detective work to figure out which parts of the fingerprint belonged to which mineral.

The girls were expert geologists, correctly matching each of the minerals to their products. A special thanks to Wooster Geology Major Anna Mudd for guiding the girls through their experiment!

 

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Wooster’s Fossil of the Week: A scale tree root in its own soil (Upper Carboniferous of Ohio)

Last week a local man, Larry Stauffer, brought in the above fossil for identification and then kindly donated it to the department. It is part of the root system of Lepidodendron, the “scale tree” of the Carboniferous Period. What is especially cool about it is that the rootlets, thin ribbon-like perpendicular extensions, are still attached. Usually they were lost quickly when the root was dislodged from its bed.

The well-preserved rootlets show that this bit of root is still in its original soil. Such a fossil soil is called a paleosol. These features are important in the rock record because they show ancient climate conditions, weathering profiles and sedimentation rates. Carboniferous paleosols like this are called seat earth.

The roots of Lepidodendron were given a separate generic name in 1822 by the French naturalist Alexandre Brongniart (1770-1847). He called them Stigmaria because of the regularly-spaced holes called stigmata. (You may know “stigmata” from an entirely different context!) The name was superseded by Lepidodendron once it was figured out how the roots, trunk, and leaves were connected.

Diagram of “Stigmaria ficoides”  from “Elements of Geology: The Student’s Series” by Charles Lyell (1871).

Brongniart is best known to me as one of the first biostratigraphers. He worked out the first divisions of the Tertiary Period (now known as the Paleogene and Neogene Periods) using fossils to mark time intervals. He also was the first to systematically study the trilobites at the other end of the geologic time scale. Brongniart did original geological mapping with the famous Georges Cuvier in the Paris region as well. He was a professor at the École de Mines and director of the Sèvres porcelain factories. I think he looks rather friendly in a Frenchy way.

References:

Brongniart, A. 1822. Sur la classification et la distribution des végétaux fossiles en général, et sur ceux des terrains de sédiment supérieur en particulier. Soc. Philom., Bull., pp. 25-28 and Mémoires Du Muséum d’Histoire Naturelle 8: 203–240, 297–348.

Frankenberg, J.M. and Eggert, D.A. 1969. Petrified Stigmaria from North America: Part I. Stigmaria ficoides, the underground portions of Lepidodendraceae. Palaeontographica 128B: 1–47.

Jennings, J.R. 1977. Stigmarian petrifications from the Pennsylvanian of Colorado. American Journal of Botany 64: 974-980.

Rothwell, G.W. 1984. The apex of Stigmaria (Lycopsida), rooting organ of Lepidodendrales. American Journal of Botany 71: 1031-1034.

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