Wooster’s Fossil of the Week: Small and common orthid brachiopods from the Upper Ordovician of Ohio

August 7th, 2015

Cincinnetina meeki (Miller, 1875) slab 1 585
One of the many benefits of posting a “Fossil of the Week” is that I learn a lot while researching the highlighted specimens. I not only learn new things, I learn that some things I thought I knew must be, shall we say, updated. The above slab contains dozens of brachiopods (and a few crinoid ossicles and bryozoans). I have long called the common brachiopod here Onniella meeki. Now I learn from my colleagues Alycia Stigall and Steve Holland at their great Cincinnatian websites that since 2012 I should be referring to this species as Cincinnetina meeki (Miller, 1875). Jisuo Jin sorted out its taxonomy in a Palaeontology article three years ago:

Phylum: Brachiopoda
Class: Rhynchonellata
Order: Orthida
Family: Dalmanellidae
Genus: Cincinnetina
Species: Cincinnetina meeki (Miller, 1875)
Cincinnetina meeki (Miller, 1875) slab 2 585This slab, which resides in our Geology 200 teaching collection, was found at the famous Caesar Creek locality in southern Ohio. It is from the Waynesville/Bull Fork Formation and Richmondian (Late Ordovician) in age.
Cincinnetina meeki (Miller, 1875) slab 3 585You may see some bryozoans in this closer view. This bed is a typical storm deposit in the Cincinnatian Group. The shells were tossed about, most landing in current-stable conditions, and finer sediments were mostly washed away, leaving this skeletal lag.

Reference:

Jin, J. 2012. Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia. Palaeontology 55: 205–228.

Wooster’s Fossil of the Week: A coiled nautiloid from the Middle Devonian of Ohio

July 17th, 2015

Goldringia cyclops Columbus Ls Devonian 585The above fossil is a nautiloid cut in cross-section, showing the large body chamber at the bottom and behind it to the left and above the phragmocone, or chambered portion of the conch (shell). It is a species of Goldringia Flower, 1945, found in the Columbus Limestone (Middle Devonian, Eifelian) exposed in the Owen Stone Quarry near Delaware, Ohio. It is a nice specimen for both what it shows us about a kind of nautiloid coiling and for clues to its preservation.

This specimen was originally labelled Gyroceras cyclops Hall, 1861. In 1945, Rousseau Flower designated this taxon the type species of Goldringia. I can’t tell if we really have G. cyclops here or some other species, so I’m leaving it at the genus level. The old name lingers, though, in the term for this kind of open coiling: gyroceraconic. It is one of the earliest examples of the nautiloids having the phragmocone positioned above the body chamber, presumably for stable buoyancy.
Pentamerid embedded 071315I like the clues to the early history of this conch after death. The chambers are entirely filled with sediment, a fossiliferous micrite. You can see places where the original shell was broken and larger bits infiltrated, like the whole brachiopod shown above. This brachiopod appears from its cross-section to be a pentamerid. Also visible are strophomenid brachiopods and gastropods.
Winifred GoldringRousseau Hayner Flower (1913–1988) described Goldringia in 1945. He doesn’t directly say who he named it after, but he thanks “Dr. Winifred Goldring of the New York State Museum” in the acknowledgments. We can tell Flower’s story later (and it’s a good one), but this gives us a chance to introduce Winifred Goldring (1888-1971). She was the first paleontologist to describe the famous Gilboa fossil flora (Devonian) in upstate New York, and she was the first woman State Paleontologist of New York (or anywhere, for that matter). (Now there is Lisa Amati in this prestigious position. Congratulations, Lisa!) Goldring grew up near Albany, New York, one of nine children in a very botanical family. She graduated from Wellesley College in 1909 with a bachelor’s degree in geology (very unusual for a woman at the time). She stayed at Wellesley to earn a master’s degree (1912). She also taught geology courses at Wellesley. In 1913 she studied geology at Columbia University with the famous Amadeus Grabau. In 1914, Goldring joined the scientific staff at the New York State Museum as a “scientific expert”. She worked her way up through the many ranks there to become State Paleontologist in 1939. She is best known as a paleontologist for her work with the fascinating Gilboa fossil forest, bringing her early upbringing by botanists to full circle. Along the way she was the first woman president of the Paleontological Society (in 1949) and vice-president of the Geological Society of America (in 1950). A hero of paleontology.

References:

Flower, R.H. 1945. Classification of Devonian nautiloids. American Midland Naturalist 33: 675–724.

Goldring, W. 1927. The oldest known petrified forest. Scientific Monthly 24: 514–529.

Koninck, L.G.D. 1880. Faune du Calcaire Carbonifere de la Belgique, deuxieme partie, Genres Gyroceras, Cyrtoceras, Gomphoceras, Orthoceras, Subclymenia et Goniatites. Annales du Musee Royal d‘Histoire Naturelle, Belgique 5: 1–333.

Wooster’s Fossils of the Week: A Silurian encrinite from southwestern Ohio

May 22nd, 2015

BrassfieldEncrinite585_041915The above rock was collected on our Sedimentology & Stratigraphy class field trip last month. It is an average piece of weathered Brassfield Formation (Early Silurian, Llandovery) from Oakes Quarry Park near Fairborn, Ohio (N 39.81472°, W 83.99471°). It is made almost entirely of crinoid fragments, and has a pleasant pinkish hue, most of which comes from the crinoid bits themselves. If you look closely you can see crinoid thecal plate fragments as well columnals and pluricolumnals.

This kind of limestone in which echinoderm ossicles make up the bulk of the grains is known as an encrinite. I first learned about encrinites from my colleague Bill Ausich of The Ohio State University, who has written the best assessments of encrinites on a regional scale. Encrinites are well-washed biosparite grainstones typically deposited between fair weather and storm wave bases on shallow shelves in low latitudes. They are surprisingly common from the Ordovician into the Jurassic, but then the disappear from the rock record as crinoids declined in abundance in shallow environments.

We’ve seen encrinites before in this blog from the Silurian of Estonia, the Triassic of Poland, and the Jurassic of Utah.

References:

Ausich, W.I. 1986. Early Silurian inadunate crinoids (Brassfield Formation, Ohio). Journal of Paleontology 60: 719-735.

Ausich, W.I. 1997. Regional encrinites: a vanished lithofacies. In: Paleontological events: stratigraphic, ecologic and evolutionary implications, p. 509-519. Columbia University Press, New York.

Ausich, W.I. and Deline, B. 2012. Macroevolutionary transition in crinoids following the Late Ordovician extinction event (Ordovician to Early Silurian). Palaeogeography, Palaeoclimatology, Palaeoecology 361: 38-48.

Hunter, A.W. and Zonneveld, J.P. 2008. Palaeoecology of Jurassic encrinites: reconstructing crinoid communities from the Western Interior Seaway of North America. Palaeogeography, Palaeoclimatology, Palaeoecology 263: 58-70.

Tang, C.M., Bottjer, D.J. and Simms, M.J. 2000. Stalked crinoids from a Jurassic tidal deposit in western North America. Lethaia 33: 46-54.

Wooster’s Fossil of the Week: A ptilodictyine bryozoan from the Silurian of Ohio

May 15th, 2015

Phaenopora superba Brassfield 585The fossil above was found by Luke Kosowatz (’17) on our Sedimentology & Stratigraphy class field trip last month. We were measuring and sampling the Brassfield Formation (Early Silurian, Llandovery) near Fairborn, Ohio, and Luke pulled this beauty out of the rubble. This limestone is full of echinoderms and corals, so this lonely bryozoan was immediately a star.
Peela 050815This is the specimen that we sectioned and made an acetate peel from last month. The interior view, shown above, was critical to its identification. This peel was made perpendicular to the surface. It shows that the bryozoan is bifoliate, meaning it has two sides with zooids (the filter-feeding bryozoan polypides) and stood upright on the seafloor like a fan or leaf. Both sides had the characteristic bumps called monticules.
Phaenopora closerThe next critical view is this close-up of a slightly weathered surface of the bryozoan. It shows a regular arrangement of the larger zooecia (autozooecia) with two smaller zoooecia (metazooecia) between each pair. These clues enabled my friend Andrej Ernst, a paleontologist and bryozoan expert in the Department of Geosciences at the University of Hamburg, to identify this bryozoan as the ptilodictyine Phaenopora superba (Billings, 1866).
CNSPhoto-GEOLOGISTElkanah Billings (1820-1876) originally described this bryozoan species in 1866. He was Canada’s first government paleontologist, and he very much looked the part. Billings was born on a farm near Ottawa. He went to law school and became a lawyer in 1845, but he gave up dusty books for the life of a field paleontologist. In 1856 Billings joined the Geological Survey of Canada. He named over a thousand new species in his career. The Billings Medal is given annually by the Geological Association of Canada to the most outstanding of its paleontologists.

References:

Billings, E. 1866. Catalogues of the Silurian fossils of the island of Anticosti: with descriptions of some new genera and species. Dawson brothers.

Ross, J.P. 1960. Larger cryptostome Bryozoa of the Ordovician and Silurian, Anticosti Island, Canada: Part I. Journal of Paleontology 34: 1057-1076.

Ross, J.P. 1961. Larger cryptostome Bryozoa of the Ordovician and Silurian, Anticosti Island, Canada: Part II. Journal of Paleontology 35: 331-344.

A beautiful day for Wooster Geologists in the Silurian of Ohio

April 18th, 2015

aDSC_5072FAIRBORN, OHIO–It’s field trip season at last for the Wooster Geologists. Several geology classes have now been out in Ohio, taking advantage of windows of spectacular weather. Today was one of those days for 25 students in the Sedimentology & Stratigraphy class. We returned to the Oakes Quarry Park exposures in southwestern Ohio (N 39.81472°, W 83.99471°). Three years ago here in April it was 37°F and raining. This year the conditions were perfect. We studied outcrops of the Brassfield Formation (Early Silurian, Llandovery) in the old quarry walls. The students measured stratigraphic columns of these fossiliferous biosparites as part of an exercise, and then explored the glacially-truncated top of the unit.

bDSC_5079The Brassfield is intensely fossiliferous. Large portions of it are virtually made of crinoid fragments. In the random view above you can see columnals, as well as a few calyx plates. This is why this unit is very popular among my echinodermologist friends at Ohio State.

DSC_5056Kevin Komara, Brian Merritt and Dan Misinay (Team Football) are here contemplating the quarry wall, planning how to measure their sections.

DSC_5063One of our Teaching Assistants, Sarah Bender, is here pointing out one of the many thin intercalated clay units in the Brassfield biosparites.

DSC_5065Fellow Californian Michael Williams directed the action. No, actually he’s doing the time-honored technique of following a measured unit with his finger as he finds a place he can safely climb to it and the units above. He is holding one of our measuring tools, a Jacob’s Staff. Why do we call them “Jacob’s Staffs”? Read Genesis 30:25-43. (Yes, today’s students are mystified by Biblical references.)

DSC_5066Here’s Rachel Wetzel, giving me a heart attack. Don’t worry, insurance companies and parents, she’s fine.

DSC_5068Rachel is again on the left. Team Ultimate Frisbee (Meredith Mann and Mae Kemsley) are in the front, and Sharron Ostermann is above. This is the recommended way to get to the top of the exposure!

DSC_5070We carried our lunches in “to go” boxes from the dining hall. Our Teaching Assistants Sarah Bender and Kaitlin Starr enjoyed a sunny picnic on the rocks.

yDSC_5077The top level of the quarry was cleared of soil and brush many years ago to expose a glacially truncated and polished surface of the Brassfield. Looking for glacial grooves and fossils here are (from the left) Tom Dickinson, Jeff Gunderson (another Californian!), Andrew Conaway, and Luke Kosowatz (who seems to also be making a little pile of rocks as a memorial to a great day).

zDSC_5074One of the many corals we found in the top of the Brassfield was this halysitid (“chain coral”), an indicator fossil for the Late Ordovician and Silurian.

Everyone returned safely to Wooster with their completed stratigraphic columns, lithological descriptions, and a few fossils. Thank you to Mark Livengood, our bus driver. Good luck to the other field trip groups later this month!

Wooster’s Fossil of the Week: A molded brachiopod from the Lower Carboniferous of Ohio

February 20th, 2015

Syringothyris bored Wooster CarboniferousWe haven’t had a local fossil featured on this blog for awhile. Above is an external mold of the spiriferid brachiopod Syringothyris typa Winchell, 1863, from the Logan Formation (Lower Carboniferous, Osagean, about 345 million years old) of southeastern Wooster, Ohio. The outcrop is along the onramp from north Route 83 to east Route 30. Older Wooster geologists may remember this area was called “Little Arizona” because of the large roadcuts made for a highway bypass that was never completed. That original outcrop was destroyed several years ago, but the same rocks are exposed in this new section. This is the area where Heather Hunt (’09) did her Senior Independent Study work, and long before her Brad Leach (’83) worked with the same fossils.

The Logan Formation is primarily fine sandstone, with some subordinate conglomerates, silts and shales. It was likely deposited in the proximal portion of a prodelta at or below wavebase. The fossils in the Logan are mostly these large Syringothyris and the bivalve Aviculopecten, along with scattered crinoids, gastropods, bryozoans, nautiloids and ammonoids. This fauna needs more attention. Funny how the fossils in your own backyard are so often ignored.

This brachiopod was first buried in sediment and then the shell dissolved away, leaving an impression behind. Since it is an impression of the exterior of the shell, it is called an external mold. Curiously, all the external molds (and the internal molds as well) in the local Logan Formation have an iron-rich, burnt orange coating much finer than the fine sand matrix. This means that details are preserved that are of higher resolution than the matrix alone would allow. In the case of this fossil, that coating extended down into long, narrow borings in the shell, casting them (see below).
Syringothyris borings 585These borings are odd. Most of them are parallel to the ribs (plicae) of the brachiopod, and appear to have been excavated from the shell periphery towards its apex. This was in the opposite direction of brachiopod shell growth. I suspect they were made by boring annelid worms that started at the growing edge of the shell where the mantle ended. These traces need attention, like most other aspects of this local fossil fauna.

References:

Ausich, W.I., Kammer, T.W. and Lane, N.G. 1979. Fossil communities of the Borden (Mississippian) delta in Indiana and northern Kentucky. Journal of Paleontology 53: 1182-1196.

Bork, K.B. and Malcuit, R.J. 1979. Paleoenvironments of the Cuyahoga and Logan formations (Mississippian) of central Ohio. Geological Society of America Bulletin 90 (12 Part II): 1782-1838.

Leach, B.R. and Wilson, M.A. 1983. Statistical analysis of paleocommunities from the Logan Formation (Lower Mississippian) in Wayne County, Ohio. The Ohio Journal of Science 83: 26.

Wooster’s Fossils of the Week: Beautiful trace fossils from the Upper Ordovician of southern Ohio

December 19th, 2014

Trace fossils Bull Fork Ordovician OH 585Every year we highlight at least one of the fossils found and studied by Wooster’s Invertebrate Paleontology class as part of their field and laboratory exercises. This year it is this nice slab of trace fossils collected by Curtis Davies (’15) on our August 31 field trip to the emergency spillway in Caesar Creek State Park. I didn’t even notice it at the time Curtis picked it up. I only saw its full glory when he photographed the rock as part of a paleontological essay.
CurtisGalen083114aCurtis Davies is the smiling, bearded guy in the back (with Galen Schwartzberg) at the Caesar Creek outcrop. The rain had finally stopped and everyone was happy.

The traces are exposed here on the bottom of a bed of argillaceous limestone. They are preserved in what trace fossil workers (ichnologists) call convex hyporelief, which means simply that they stick out on the base (or sole) of the rock slab. These were tunnels originally excavated in soft mud by worm-like animals. The tunnels were filled with sediment that cemented up more resistant than the surrounding matrix, and thus were weathered in this relief.
Taenidium serpentinum Heer, 1877Most of the trace fossils here are the simple unlined burrow called Planolites, one of the most common traces in the Ordovician of the Cincinnati area. The trace labelled with the red “T” above, though, is rare here. Note that it is formed by a series of pulse-like movements that produced segments in the sediment infill. My estimate is that this trace can be classified as Taenidium serpentinum Heer, 1877. It is not common in the Ordovician.
Heer, Oswald, 1809-1883Oswald Heer (1809-1883), the scientist who named Taenidium serpentinum, was a Swiss geologist and botanist. As was the case for many educated Europeans, he started as a clergyman, even signing up for holy orders. The natural world captivated him, though, and starting with insects he worked his way up to become a naturalist and professor of botany at the University of Zürich. He was one of the key figures in the establishment of paleobotany (the study of fossil plants).
Taenidium serpentinum Heer, 1877 image 585Here is Heer’s figure of Taenidium serpentinum from Plate XLV in his 1877 book, Flora fossilis Helvetiae (Fossils Plants of Switzerland). You see the irony already. Heer described this trace fossil as a plant, inadvertently becoming one of the early figures in ichnology, the study of trace fossils.

Oswald Heer published many books and papers, becoming well known for his geological and paleontological explorations and descriptions. He was awarded the prestigious Wollaston Medal from the Geological Society of London in 1874. He was an earlier advocate of using fossils to sort on problems of paleogeography. He knew, for example, that Miocene fossils in Europe and North America were very similar, so he suggested in those days before Plate Tectonic Theory that the two continents were connected by a “land bridge“. This was called the “Atlantis Hypothesis”, and you can imagine the confusion that name caused among various cranks and pseudoscientists looking for Plato’s mythical continent. Heer died in Switzerland in 1883.

References:

D’Alessandro, A. and Bromley, R.G. 1987. Meniscate trace fossils and the Muensteria-Taenidium problem. Palaeontology 30: 743-763.

Heer, O. 1877. Flora fossilis Helvetiae: Die vorweltliche flora der Schweiz. Zürich, J. Wurster & Company. 182 p.

Keighley, D.G. and Pickerill, R.K. 1994. The ichnogenus Beaconites and its distinction from Ancorichnus and Taenidium. Palaeontology 37: 305-338.

Keighley, D.G. and Pickerill, R.K. 1995. Commentary: The ichnotaxa Palaeophycus and Planolites: Historical perspectives and recommendations. Ichnos 3: 301-309.

Last Fieldtrip for Climate Change

November 13th, 2014

GROUP

As the weather cools – the Wooster Geology Climate Change class ventured out in the field one more time. For the remainder of the semester we will try to get some work done. Two sites were visited – the Cedar Creek Mastodon Site and the OARDC.

excavationTwo weeks ago a pit was dug from our coring sites to the Mastodon excavation site. The mission was to link the cores to the archaeological site.

pit

The general stratigraphy of the mastodon site. The muds have a high calcium carbonate content that helped preserve the bones and tusk. Note the plow horizon about 25 cm down – the trip also focused on the agricultural history of Ohio and the role it plays in climate change.

anomalyJeff Dilyard, who hosted us at the site, explains to the class that a GPR (ground penetrating radar) survey identified an anomaly at this location. Isabel probed the area (see below) and “clunked” on a tile.

probingIsabel above used a tile probe to investigate the subsurface (note the chin method she is employing).

tileWhat is a “tile”? above is an old drainage tile from the site. This one is plugged with mud and the plugging was the reason the mastodon was discovered. New tiles were installed last year and the digging brought up the original tooth of the mastodon. Tile and draining of the Midwest allowed for our great agricultural history. In addition, the tile and draining allowed widespread plowing that released the carbon in naturally sequestered organic rich wetland soils to the atmosphere.

in_pitThe crucial end of the backhoe pit where probing and sampling links the bog cores to the mastodon site.

group_no_till

A quick stop ate the Triplett-Van Doren Experimental Plot. For over 50 years a variety of experiments have been underway here. We discussed the side-by-side no-till and mold board plowed sites and their ability to sequester carbon. Not plowing (no-till) sequesters carbon and mitigates erosion. Less carbon dioxide to the atmosphere and less sediment flux on the landscape.

no_till

A darker colored soil in the core barrel above shows more carbon in the soil relative to the one below.

DR

A quick stop at Secrest Arboretum to view the famous Dawn Redwoods. Under the proper conditions these trees can grow a meter each year. Our tree-ring data from this stand helps define the optimum conditions for their growth. Planting trees sequesters carbon and helps out in lots of other ways as well.

weather

In addition to the no-till fields and trees at Secrest – there is a meteorological record that spans more than 120 years (note how Tom – far left, seems to be the only student listening to the instructor). These instruments have been keeping track of climate and we will use it to compare with our tree ring study. Our tree ring project asks the question: during the time of European Settlement in Ohio what were the climate conditions like? (precipitation and temperature) and could the widespread deforestation and tile and draining of the region have perturbed the climate (see this video for more on this subject). This question is relevant to the ever-present striving of climate scientists to investigate the relative roles of natural climate variability and anthropogenic change.

 

 

 

 

Wooster’s Fossils of the Week: Upper Carboniferous seed casts from northeastern Ohio

October 31st, 2014

Trigonocarpus trilocularis Hildreth 1838We haven’t had a paleobotanical fossil of the week for awhile, so here are a couple of nice seed casts from the Upper Carboniferous Massillon Sandstone exposed near Youngstown, Ohio. They fall within the “form genus” Trigonocarpus Brongniart 1828. A form taxon is one that may not have any systematic or evolutionary validity, but it is a convenient resting place for taxa that share a particular morphological pattern but can’t be easily classified elsewhere. Trigonocarpus consists of seed casts that are “radially symmetrical, decorticated, and have their surface marked by three prominent ridges” (Gastaldo and Matten, 1978, p. 884). These particular seeds appear to be Trigonocarpus trilocularis (Hildreth, 1837). The taxa here are problematic, of course, because these seeds belong to larger plants that have their own names.
Trigonocarpus trilocularis Hildreth 1838_585These seeds appear to be from medullosalean trees, which were small relatives of today’s cycads. They were common in wetlands throughout North America and Europe during the Carboniferous, especially the Late Carboniferous. The seeds we have were likely attached to small stalks. You can see what appears to be a circular attachment scar above.
Samuel Prescott Hildreth (1783–1863)
Dr. Samuel Prescott Hildreth (1783-1863) was a physician and historian with a keen eye for natural history, especially including fossils and rocks. He was born in Massachusetts of strong Patriot stock and moved to the dangerous territory of Ohio in 1806, settling in Marietta in 1808. Dr. Hildreth is often cited as one of the first scientists in the country west of the Alleghany Mountains. His prolific writing is fast-moving, diverse and interesting, so he must have been a great traveling companion. Dr. Hildreth served in the Ohio Legislature and was on the first Ohio Geological Survey.
HildrethNutThe above is a figure from Hildreth (1837, p. 29) showing the fossil seed he named Carpolithus trilocularis. He wrote that “[t]his nut is probably the fruit of some antediluvian palm”, which is not far from what we think now (apart from the Flood reference!).

References:

Gastaldo, R.A. and Matten, L.C. 1978. Trigonocarpus leeanus, a new species from the Middle Pennsylvanian of southern Illinois. American Journal of Botany 65: 882-890.

Hildreth, S.P. 1837. Miscellaneous observations made during a tour in May, 1835, to the Falls of the Cuyahoga, near Lake Erie: extracted from the diary of a naturalist. American Journal of Science and Arts 31:1-84

Zodrow, E.L. 2004. Note on different kinds of attachments in trigonocarpalean (Medullosales) ovules from the Pennsylvanian Sydney Coalfield, Canada. Atlantic Geology 40: 197-206.

An Epic Geologic Competition in Cuyahoga Valley National Park

October 26th, 2014

VIRGINIA KENDALL, CUYAHOGA VALLEY NATIONAL PARK (CVNP) — What an absolutely awesome day for geology in the field!!  One of my geologic mentors once told me that “every day in the field is a day of vacation”, and today proved to be just that day.  Late October…temperatures above 60 degrees…with the fall colors everywhere!!  I could not have asked for a better day to take my Structural Geology class to “The Ledges”, part of Virginia Kendall, which is only about an hour north of campus.  Essentially, we have a National Park right in northeast Ohio, and fall is the best time to visit the area.

However, we were not just going there for a day hike.  We were on a mission.  I set up a scenario for my class:  CVNP exposes strata that in the subsurface is rich in oil and gas.  The goal for the students was to undertake a complete geologic study (including the stratigraphy, sedimentology, structure, and geomorphology) of the exposed rock in the area as an analog in order to better assess oil and gas fluid migration in the subsurface.  The class was split into two teams — seniors vs juniors.  Each team is not permitted to talk to one another about data collection, analysis, or synthesis.  Eventually, these Research and Development (R&D) Teams will share their findings with Wooster’s Production Experts (Drs. Pollock, Wiles, and Wilson) via a poster presentation later in the semester.

So, while there were literally hundreds of people out for a day hike near The Ledges, Wooster’s geologists were busy at work.  The Ledges is located just south of Happy Days Visitor Center and southeast of Peninsula, OH.

lock-29-location-map_585blogThe area between State Route 303 and Kendall Ledges Road (where there are all the green hiking trails) was our field area for the day.

DSC01285_585blog

The R&D Teams quickly noticed the amazing joint sets that are exposed all along The Ledges.  Essentially, we have ledges in this area due to the large fracture system (i.e., joints) affecting the rocks.  These joint sets are very easy to measure and to access due to a wonderful trail system next to the exposures in Virginia Kendall.  Notice above that these joints can be at various orientations and that those in the photo above appear to be nearly perpendicular to one another.

DSC01271_585blogLet me introduce the R&D Team of Woo seniors (’15), from left to right: Coleman Fitch, Zach Downes, Willy Nelson, and Leo Jones.  It appears that they are discussing their team’s strategy early in the day.  Michael Williams (’16), of the opposing team, is in the background.  Is Michael trying to eavesdrop on the opposing team?

DSC01269_585blogTwo members of our R&D team of Woo juniors (’16) are taking notes on this rock exposure.  Eric Parker (left) and Kaitlin Starr (right, white hat) appear to be focused on the gorgeous geology.

DSC01276_585blogThe other two members of the R&D team of Woo juniors (’16) were found hiding in a dark “slot canyon” among the joints.  Michael Williams is in the front, while Adam Silverstein is in the orange hoodie, peeking out from deep inside the “canyon”.  It appears that the juniors are separated from one another!!  It is OK; everyone had maps and GPS units, so perhaps their strategy for the day was to divide and conquer?

DSC01274_585blogWow!!  Check out this entrance to Ice Box Cave, which was formed by the intersection of several joint sets.  Unfortunately, we were not able to go any closer to the cave entrance than this, because…

DSC01273_585blog…the National Park Service is trying to save the bats, which are susceptible to White-Nose Syndrome.

DSC01278_585blogNow, I could not just end the blog without showing you such a wonderful photo.  Check out the amazing set of cross-beds that you can see exposed in the upper half of the photo.  These rocks, which are some of the youngest rocks exposed in CVNP, have been interpreted to be deposited by ancient stream deposits.  Superimposed on the cross-bedding is the characteristic honeycomb weathering that affects many of the sandstone exposures along The Ledges.  And, notice that some of the rocks appear to be more brown or rust colored; some scientists have identified limonite and pyrite (two iron-rich minerals) in the unit.

What an awesome day to be a geologist!!  Who else gets to spend a great fall day with friends, enjoy the weather, learn a little more about rocks, and measure joints along the way?  Geology rocks.

 

 

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