Archive for May, 2013

Wooster Geologist on the Wasatch Front in northern Utah

May 25th, 2013

WasatchFront052513

SALT LAKE CITY, UTAH–It may be a vacation, but even so, every geologist has the delightful duty of enjoying the local geological setting. The above image is looking south from the University of Utah campus in Salt Lake City along the Wasatch Front and the snow-dappled Oquirrh Mountains. We’re standing along the Wasatch Fault, which extends north-south from southern Idaho to central Utah. It is a large normal fault that marks the eastern edge of the Basin & Range Province. It is a beautiful setting for a campus.

On Our Way to Iceland

May 23rd, 2013

BOSTON, MA – A bleary-eyed Iceland group left Wooster at 4 am this morning to begin the journey to the land of fire and ice. We’ve arrived in Boston and are comfortably checked-in. We are patiently awaiting our flight to Keflavik airport, arguably the most geological airport in the world.

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Proof that we really are leaving for Iceland in two hours! From left to right are Adam Silverstein (’16), Michael Williams (’16), and Alex Hiatt (’13). The gate agent assures us that we’ll see lots of rocks in Iceland. We sure hope so! Follow our adventures on the blog for the next two weeks.

Wooster’s Fossil of the Week: An amphibian from the Permian of Germany

May 19th, 2013

Apateon_pedestris_Odernhelm_Germany_fixedThe above skeleton is of the salamander-like Apateon pedestris von Meyer 1840 from the Lower Permian of Odernhelm, Germany. There are just enough of these tiny little bones to show the ghostly outline of this freshwater amphibian. It is our only amphibian fossil at Wooster, and it is another gift from the George Chambers collection.

Apateon pedestris is in the Order Temnospondyli, a group thought to be ancestral to the modern salamanders. They would have lived much like their descendants today, spending most of their time in creeks and streams and wet leaf litter. It grew to a maximum length of about nine centimeters. Its head was wide and flat, presumably to aid in swimming. Some specimens are preserved with soft tissues intact showing that this species had external gills as an adult, a classic example of paedomorphosis (as my History of Life students will tell you).

homo diluvii testis-1The skull of our tiny specimen reminds me of a younger, larger and much more famous Miocene amphibian that went for a time under the surprising name Homo diluvii testis, meaning “evidence of a human at the time of the Noah’s Flood”. A drawing of the skeleton is shown above.

Johann Jacob Scheuchzer (1672-1733)

Johann Jakob Scheuchzer (above) described and interpreted Homo diluvii testis in Lithographia Helvetica (1726). He was convinced it represented a person (more likely a child) who was drowned in the Flood of Noah and then entombed in the sediments. The critical page from his book is shown below.

HdtJohann Jacob Scheuchzer (1672-1733) was a Swiss medical doctor and somewhat of a naturalist. He certainly had a gift for seeing a human pattern in these bones that is lost on us today — the skeleton is obviously not that of any kind of mammal. It is likely he was far too enthusiastic about finding what he considered solid proof of the Flood and a member of the wicked generation nearly killed off by it. Here is a bit of poetry he included in his fossil description:

Afflicted skeleton of old, doomed to damnation,
Soften, thou stone, the heart of this wicked generation!

homo diluvii testis

Much later the famous French scientist Georges Cuvier (1769-1832) had at Scheuchzer’s fossil (above). He showed that it was, of course, an amphibian. The name for it now is Andrias scheuchzeri — a perpetual honor for its sincere but deluded discoverer.

References:

Fröbisch, N.B., Carroll, R.L. and Schoch, R.R. 2007. Limb ossification in the Paleozoic branchiosaurid Apateon (Temnospondyli) and the early evolution of preaxial dominance in tetrapod limb development. Evolution and Development 9: 69-75.

Fröbisch, N.B. and Schoch, R.R. 2009. The largest specimen of Apateon and the life history pathway of neoteny in the Paleozoic temnospondyl family Branchiosauridae. Fossil Record 12: 83-90.

GPS Training for Summer Fieldwork

May 17th, 2013

WOOSTER, OH – In preparation for the summer field season, some Wooster Geologists are being trained on new GPS equipment.

Wooster Geologists learn to set up the GPS prior to taking it to the field.

Wooster Geologists learn to set up the GPS prior to taking it to the field.

We learned the importance of thoughtfully crafting a data dictionary prior to heading to the field. Features and  attributes were entered into a database that helps us organize our data as we collect it. For Team Utah, we’ll be collecting features like fractures, joints, tumuli, and samples.

Then we went to the quad to learn how to collect different types of features.

Then we went to the quad to learn how to collect different types of features.

It was a gorgeous day to be training in the field. We learned to collect points, lines, and areas. We also learned about data accuracy and how to ensure that our data are high quality.

Tricia Hall ('14) and Dr. Shelley Judge work together to map a sidewalk.

Tricia Hall (’14) and Dr. Shelley Judge work together to map a sidewalk.

After two days of training, we’re ready to collect GPS data on the cm-scale. This summer, we’ll be able to produce high-resolution maps of our field area and test hypotheses about lava emplacement.

 

Wooster’s Fossils of the Week: Embedded cornulitids from the Lower Silurian of Estonia

May 12th, 2013

Cornulitids_Strom_051113At first specimen this looks like a series of holes drilled into a small, smooth substrate (like Trypanites), but then you notice that the substrate has grown up around the holes, and on the far left you can make out two cones. These are cornulitid tubes that lived on and then inside a living stromatoporoid sponge. Jonah Novek (’13), a Wooster geologist graduating tomorrow, found these in the Hilliste Formation (Rhuddanian, Llandovery) during his Independent Study work on Hiiumaa Island in Estonia.

My Estonian paleontologist friend Olev Vinn is the expert in bioclaustrated (embedded in a living substrate) cornulitids, as you can see from the papers listed below. These fossils are an excellent example of endosymbiosis, or the living relationship of one organism embedded within the skeleton of another (see Tapanila and Holmer, 2006). We can’t tell yet without a thin-section, but the cornulitid here is probably very similar to the Sheinwoodian (Wenlock) Cornulites stromatoporoides Vinn and Wilson, 2010. The specimen shown above is already in the mail to Estonia for further analysis. This specimen is the earliest example of cornulitid endosymbiosis in the Silurian.
Closer_Cornulitids_Strom_051113A closer view of the embedded cornulitid tubes. The tubes in these holes appear to have dissolved away, at least in their distal parts. Some of the details of the stromatoporoid substrate are just visible.

Jonah_MW_Richa_071213Fond memories of the 2012 Wooster-Ohio State University expedition to Estonia. Jonah Novek (’13), me, and Richa Ekka (’13) on the top of the Kõpu Lighthouse, Hiiumaa Island, Estonia. Photo by our friend Bill Ausich (OSU).

Congratulations to Jonah on his find, and best wishes to all the senior Wooster Geologists on this graduation weekend.

References:

Tapanila, L. and Holmer, L.E. 2006. Endosymbiosis in Ordovician-Silurian corals and stromatoporoids: A new lingulid and its trace from eastern Canada. Journal of Paleontology 80: 750-759.

Vinn, O. and Wilson, M.A. 2010. Abundant endosymbiotic Cornulites in the Sheinwoodian (Early Silurian) stromatoporoids of Saaremaa, Estonia. Neues Jahrbuch für Geologie und Paläontologie 257:13-22.

Vinn, O. and Wilson, M.A. 2012a. Encrustation and bioerosion on late Sheinwoodian (Wenlock, Silurian) stromatoporoids from Saaremaa, Estonia. Carnets de Géologie [Notebooks on Geology], Brest, Article 2012/07 (CG2012_A07).

Vinn, O. and Wilson, M.A. 2012b. Epi- and endobionts on the Late Silurian (early Pridoli) stromatoporoids from Saaremaa Island, Estonia. Annales Societatis Geologorum Poloniae 82: 195-200.

Dreaming of San Onofre Beach

May 9th, 2013

SAN ONOFRE STATE BEACH, CA – The warm spring weather in Wooster, OH has us dreaming of the beach rather than finals week. Some lucky Wooster Geologists had a recent beach fix when they visited San Onofre State Beach in southern California during the Keck Symposium. Symposium attendees had two options for the traditional Friday Field Trip: San Onofre Beach or Mecca Hills. It was a difficult choice, but the prospect of spending a warm day on the Pacific coast in April was quite persuasive for this midwest geologist.

Keck Symposium participants at San Onofre Beach.

Keck Symposium participants at San Onofre Beach.

The fantastic cliffs along San Onofre Beach consist of the late Miocene San Mateo sandstone overlain by much younger alluvial sediments. Notice the bags on beach for scale.

The fantastic cliffs along San Onofre Beach consist of the late Miocene San Mateo sandstone overlain by much younger alluvial sediments. Notice the bags on beach for scale.

The San Mateo sandstone is a well-sorted marine unit with highly rounded grains that was likely deposited in a submarine fan setting. Although the sandstone itself is beautiful, what really caught our eye was the well-exposed Cristianitos Fault and associated deformation.

The San Mateo sandstone is riddled with textbook examples of deformation bands and faulting.

The San Mateo sandstone is riddled with textbook examples of deformation bands and faulting.

Underlying the San Mateo sandstone is the mid Miocene Monterey Formation, a layered marine siltstone locally interbedded with volcanic ashes. Slumps occur in the Monterey Formation all along the coast.

Tilted beds in a slump in the Monterey Formation. The white layer is a poorly lithified tuff. The width of the field of view is less than a meter.

Tilted beds in a slump in the Monterey Formation. The white layer is a poorly lithified tuff. The width of the field of view is less than a meter.

Much discussion was had about the stability of the nuclear power plant just up the beach, given the evidence for local faulting and mass wasting.

Much discussion was had about the stability of the nuclear power plant just up the beach, given the evidence for local faulting and mass wasting.

Above the marine units is a thin, flat-lying cobble-rich layer. The cobbles were deposited on an ancient marine terrace ~125 ka. They littered the beach, so we had a chance to look at them up-close. What we observed were gorgeous hard-rock cobbles from the Cretaceous Catalina Blueschists and the Peninsular Ranges Batholith.

The colorful blue cobbles are Catalina Blueschists and the salt and pepper cobbles are from the Peninsular Ranges Batholith.

The colorful blue cobbles are Catalina Blueschists and the salt and pepper cobbles are from the Peninsular Ranges Batholith.

Wooster’s Fossil of the Week: An asaphid trilobite from the Middle Ordovician of the Leningrad Region, Russia

May 5th, 2013

Asaphus lepidurus Nieszkowski, 1859aThis weathered trilobite is nothing like the gorgeous specimens of this genus you can buy at various rock shops around the world and on the web, but it has sentimental value to me. I collected it on an epic field trip in Russia in 2009. We hacked our way through the woods to an exposure of the Frizy Limestone (Volkhov Regional Stage, Darriwilian Stage, Middle Ordovician) where the local people had a side industry of quarrying out these trilobites for international trade. This specimen was the best I found, and it was probably abandoned by other collectors as too damaged. Still, it makes a nice reminder of my Russian experience and I keep it on a cabinet in my office. (By the way, I did not make a Cold War mistake in referring to the “Leningrad Region“. This oblast retains the old name of the city now known as St. Petersburg. Apparently the residents voted to keep it that way after the Soviet Union collapsed.)
Asaphus lepidurus Nieszkowski, 1859bThis is the asaphid trilobite Asaphus lepidurus Nieszkowski, 1859. This group is known for having fantastic eyes, some on long stalks and others with calcareous “eyeshades” above them. This species has more conventional eyes, but they’re still cool.
Asaphus lepidurus Nieszkowski, 1859cA. lepidurus studies us with a cold, dead eye. From this perspective the facial suture is visible as the curved, raised line running from the near eye to the periphery of the cephalon (head). This is a line of weakness the trilobite used to split its exoskeleton for molting (ecdysis). These sutures often have diagnostic value for distinguishing trilobites, especially at the species level.

A. lepidurus was first described and named by Jan Nieszkowski (1833-1866), a Polish paleontologist (and naturalist and medical doctor). He was born in Lublin, Poland, son of an army captain. He studied at the University of Dorpat (now the University of Tartu in Estonia) and soon became an avid and productive paleontologist. He then participated in the January Uprising of Poles against the occupying Russians in 1863. He was captured and exiled to the Russian city of Orenburg, where he died at a young age of typhus.

This little trilobite brings back memories of my Russian adventure, and it is also a reminder that science is never done in a political vacuum. Here’s to the Polish patriot and scientist Dr. Jan Nieszkowski.

References:

Dronov, A., Tolmacheva, T., Raevskaya, E., and Nestell, M. 2005. Cambrian and Ordovician of St. Petersburg region. 6th Baltic Stratigraphical Conference, IGCP 503 Meeting; St. Petersburg, Russia: St. Petersburg State University.

Ivantsov, A.Y. 2003. Ordovician trilobites of the Subfamily Asaphinae of the Ladoga Glint. Paleontological Journal 37, supplement 3: S229-S337.

Nieszkowski, J. 1859. Zusätze zur Monographie der Trilobiten der Ostseeprovinzen, nebst der Beschreibung einiger neuen obersilurischen Crustaceen. Archiv für die Naturkunde Liv-, Ehst-, und Kurland, Serie 1: 345-384.

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