Wooster’s Fossil of the Week: Birch wood with beetle borings (Oligocene of Oregon)

Mark Wilson November 4, 2012 1:31 am

We may be at the Geological Society of America annual meeting today, but that doesn’t stop Fossil of the Week! This week’s fossil is a beautifully-detailed piece of petrified birch wood (Betula) with tree rings and insect borings throughout. It was found in the Little Butte Formation (Oligocene) of Linn County, Oregon. This rock unit consists of thick tuffs and volcanic breccias representing volcanic mudflows and nuée ardente deposits that buried diverse hardwood forests. This formation is known for its spectacular silicified fossil wood.
The beetle borings, shown in closer view above, are very similar to those bored in birch trees today. There is little work done on the ichnotaxonomy of these trace fossils, so I can’t yet give them a name, but at least we can see typical beetle activity in the twists and turns. The holes are apparently filled with a cemented mix of insect feces and wood fragments called frass, just like we find in modern birch wod today.

References:

Beaulieu, J.D., Hughes, P.W., and Mathiot, R.K. 1974. Environmental geology of western Linn County, Oregon. Oregon Department of Geology and Mineral Industries Bulletin, no. 84, 117 p.

Rozefelds, A.C. and De Baar, M. 1991. Silicified Kalotermitidae (Isoptera) frass in conifer wood from a mid-Tertiary rainforest in central Queensland, Australia. Lethaia 24: 439-442.

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First GSA Event: The Paleontological Society Short Course — “Reconstructing Earth’s Deep-Time Climate”

Mark Wilson November 3, 2012 5:21 pm

CHARLOTTE, NORTH CAROLINA–This iPhone snapshot of a dark lecture room may record the time and place, but it hardly does justice to the event, so let’s see an image of the colorful special volume printed for this year’s Paleontological Society Short Course:

Much better. The Paleontological Society has a short course every year at its annual meeting with the Geological Society of America. I’ve been to nearly every one since my graduate school days. They are designed to bring paleontologists up to speed on the latest innovations and ideas in the science. They are also — sometimes in contradiction — supposed to review basic concepts for non-experts in a particular subdiscipline. This year’s course, developed by Linda Ivany (Syracuse University) and Brian Huber (Smithsonian Institution), was even more ambitious than most: it brought together paleontologists and geochemists to address how we deduce ancient climates, and by implication Earth’s history of climate change. As an indication of its interdisciplinary nature, this short course was also sponsored by the Society for Sedimentary Geology (SEPM) and the Cushman Foundation for Foraminiferal Research. Linda and Brian succeeded in not only bringing us introductory level description of paleoclimatological theory and practice, they also showed us some of the most exciting new developments in the field. And unlike every other short course, this one even had food and drink!

I learned a great deal in this course, especially about some geochemical techniques for estimating ancient seawater temperatures such as clumped isotope and lipid paleothermometry, oxygen isotope analysis, and Mg/Ca ratio determination. Each has particular advantages in particular circumstances, and each has significant limitations in other settings. They all produce varieties of what Greg Wiles calls “wiggly lines” open to interpretation as to what they mean about ancient temperature histories. We also saw several examples of how climate analysis actually works with invertebrate, vertebrate and plant fossils. As always, one of the primary lessons was that biological systems are not easily modeled or predicted — that what geochemists call “vital effects” can make complicated natural processes even more convoluted.

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Wooster Geologists at GSA

mpollock November 2, 2012 6:46 pm

Many of the Wooster Geologists have embarked on the journey to Charlotte, NC, for the 2012 National Meeting of GSA. If you’re attending the meeting, be sure to check out one of our presentations:

Don’t miss us at the Group Alumni Reception on Monday at 7 pm in the Westin Grand Ballroom CD. We’re taking our annual alumni photo at 8 pm. GSA President and Wooster Alum George Davis (’64) will also be joining us at 8 pm.

Real-life photos to come!

 

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Wooster’s Fossils of the Week: Bivalve Borings (Upper Miocene of Spain)

Mark Wilson October 28, 2012 1:50 am

This beautiful object has a complex history. In the center is a gray limestone cobble that eroded from an underwater ridge and rolled free on a shallow coral reef in an area now near Abanilla, southeastern Spain. It was encrusted by a scleractinian coral, which grew thickly all around the cobble because it was turned continually by wave and current action. Larvae of the bivalve Lithophaga landed on the surface of the coral and quickly began to bore downwards, creating the trace fossil Gastrochaenolites torpedo Kelly and Bromley, 1984. They bored in some cases all the way into the cobble nucleus. The whole set was then buried in transgressive sediments of the Los Banós Formation during the Late Miocene. In the summer of 1989, my student Genga Thavi (“Devi”) Nadaraju (’90) found it as part of her Keck Geology Consortium fieldwork for her Independent Study project. It now resides proudly in the trace fossil collection at Wooster.

Closer view of the gray limestone cobble in the center. Note the remnants of Lithophaga shells still in the borings.

The bivalve boring Gastrochaenolites was named in 1842 by a French geologist with a magnificent name: Alexandre Félix Gustave Achille Leymerie (1801-1878). He was a prolific author with a long career spent primarily studying Cretaceous rocks and fossils in France and northern Spain.

References:

Kelly, S.R.A. and Bromley, R.G. 1984. Ichnological nomenclature of clavate borings. Palaeontology 27: 793-807.

Leymerie, M.A. 1842. Suite de mémoire sur le terrain Crétacé du département de l’Aube. Mémoire des Société Géologique de France 5: 1-34.

Mankiewicz, C. 1995. Response of reef growth to sea-level changes (late Miocene, Fortuna Basin, southeastern Spain). Palaios 10: 322-336.

Mankiewicz, C. 1996. The middle to upper Miocene carbonate complex of Níjar, Almería Province, southeastern Spain, in Franseen, E.K., Esteban, M., Ward, W.C., and Rouchy, J.-M., eds., Models for carbonate stratigraphy from Miocene reef complexes of the Mediterranean regions: Tulsa, SEPM (Society for Sedimentary Geology), p. 141-157.

Nadaraju, G.T. 1990. Borings associated with a Miocene coral reef complex, Fortuna basin, southeastern Spain. Third Keck Research Symposium in Geology (Smith College), p. 165-168.

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

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An IS Meeting in the Phoenix Airport

mpollock October 21, 2012 6:53 pm

Phoenix, Arizona – The Wooster geologists hit a little snafu on their return trip from Arizona. Fortunately, they’ve been rebooked on a red-eye and have 12+ hours to spend in the airport. Instead of relaxing with a coffee or shopping for matching Phoenix shirts, these Wooster geologists have decided to hold a marathon IS meeting (lucky Whitney).

20121021-154035.jpg It’s actually the opportune time to debrief after an intense 3-day conference and field trip. Our conversations with physical volcanologists and experts in southwest volcanism have helped us interpret some of the curious structures that we observed in the field. We’re incorporating our new knowledge in Whitney’s GSA poster, which we planned out today.

20121021-154352.jpg This is just a sneak preview. Don’t forget to stop by her poster on Tuesday to see the final version and to learn about the emplacement of Miter lava flows.

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Wooster’s Fossils of the Week: Silicified sclerobionts (Middle Permian of southwestern Texas)

Mark Wilson October 21, 2012 1:57 am

During my work at the National Museum of Natural History last week, I had my research desk amongst the many cabinets housing the famous Permian brachiopod collection made by the eminent paleontologist Richard E. Grant (1927–1995). Most of these specimens are from the Middle Permian of southwestern Texas, and they are preserved in a fantastic way. I peaked into some of these drawers and was just amazed at the beauty and delicacy of these fossils.

Many years ago I received a block of limestone from the Road Canyon Formation (Middle Permian, Roadian, about 270 million years old) found in the Glass Mountains of southwestern Texas. This rock was from an ancient reef system and so nearly completely filled with fossils. The fossils are replaced with very fine-grained quartz (“silicified”), yet the rock matrix around them is limestone (composed of calcium carbonate). The trick, then, is to dissolve away the limestone in hydrochloric acid and watch the delicate replaced fossils emerge. I did this with the Road Canyon Formation rock and recovered hundreds of extraordinary specimens. One set is shown above. Previous Fossils of the Week have included an aberrant brachiopod and a set of reef-forming brachiopods.
While at the Smithsonian, Kathy Hollis showed me a polished block of original Road Canyon Formation limestone (above) and then next to it the results after dissolving a similar block in acid (below). The complex mass of bryozoans, corals and brachiopods is preserved in exquisite detail.
Now, back to the Wooster specimens at the very top of this entry and just above. The platform is the wavy outer layer of a bivalve shell. Attached to it are encrusting organisms (sclerobionts). The long, gorgeous tube is a rugose coral. At its base is a ribbed athyrid brachiopod. Also in this vignette are bryozoans, additional corals and some really tiny productid brachiopods. Beautiful.

References:

Cooper, G.A., and Grant, R.E., 1964, New Permian stratigraphic units in Glass Mountains, West Texas: American Association of Petroleum Geologists Bulletin 48: 1581-1588.

Cooper, G.A., and Grant, R.E. 1966. Permian rock units in the Glass Mountains, West Texas, In: Contributions to stratigraphy, 1966: U.S. Geological Survey Bulletin 1244-E: E1-E9.

Olszewski, T.D. and Erwin, D.H. 2009. Change and stability in Permian brachiopod communities from western Texas. Palaios 24: 27-40.

 

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A Different Kind of Conference

mpollock October 19, 2012 12:10 am

Flagstaff, Arizona – The Volcanism in the American Southwest conference is different from any meeting that I’ve attended. First, most of the participants are geologists at academic institutions or government agencies, but there are also a good number of emergency managers, social scientists, aviation specialists, and meteorologists. We’ve come together to discuss the potential volcanic hazards and how best to mitigate them. I’ve learned so much about emergency response planning and how decisions are made. Did you know that each state has an emergency response plan? If you’re a scientist and you’d like to get involved in your state’s mitigation planning, you can join your Emergency Management Association.

Second, the Arizona Shakeout took place this morning during a convenient coffee break.

20121018-210132.jpg Most of us hid under tables or ducked, covered, and held at 10:18 am as we simulated an earthquake. There were even sound effects and shaking (notice the blurry photo). I can honestly say I’ve never crawled under a table with other people at a conference before.

20121018-210630.jpg Finally, our poster session was held outside under Arizona’s blue skies. Whitney, on the far right, is learning about the Smithsonian’s Global Volcanism Program. The sun was almost too bright and too warm for an outdoor poster session, but given that it’s mid-October, I’m not complaining.

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A Visit to Meteor Crater

mpollock October 18, 2012 12:26 am

ARIZONA – A short drive east of Flagstaff will bring you to a fabulous view of the San Francisco Peaks and a Natural Landmark called Meteor Crater.

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Meteor Crater was named as one of Smithsonian Magazine’s “ten most spectacular geological sites.” With a diameter of over 4000 ft and a depth of ~550 ft, the nearly perfect circular crater is truly impressive. According to the tour guide, the crater floor could host 20 simultaneous football games while 2 million fans watch from the crater walls!

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The crater was formed by an impact about 50,000 years ago and pieces of Fe-Ni meteorites have been found in the surrounding area since the late 1800s.

20121017-210325.jpg Here I am in the bottom of the crater searching for meteorites. Actually, that’s a backdrop in the museum.

20121017-210812.jpg This is what the center of the crater floor looks like: fenced remnants of an abandoned drill shaft. In the early 1900s, a Philadelphia mining engineer named Daniel Barringer drilled the crater floor searching for a potential ore body, which he never found because researchers think that the meteorite was destroyed during the impact.

In the mid 1960s to early 1970s, NASA used the crater to train Apollo astronauts. If you look closely at the fence, there’s an American flag and an astronaut figure in the near-right corner that honors those Apollo astronauts.

Meteor Crater is definitely worth the trip. Take the guided rim tour and ask for Eduardo; he’s very knowledgeable and will have you laughing at each stop.

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My First Trip to the Grand Canyon

mpollock October 16, 2012 11:55 am

ARIZONA – Contrast Dr. Wilson’s view in the Smithsonian with my view in Arizona:

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Believe it or not, this was my first trip to the Grand Canyon, and it didn’t fail to impress. It was a perfect day to hike the South Kaibab trail.

20121016-080012.jpg The trail begins with steep switchbacks through the ~270 million year old Kaibab Limestone and Toroweap Formation.

20121016-081141.jpg It then winds past the fantastically cross-bedded Coconino Sandstone to a place called “Ooh Ahh Point”.

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20121016-082002.jpg The view certainly inspired oohs and aahs. That’s O’Neill Butte in the center foreground.
Within an hour, we were eating lunch on the ~280 million year old Hermit Shale overlooking O’Neill Butte.

20121016-083053.jpg Despite the ominous signs, we made it out of the canyon in time to hike some of the rim and visit other viewpoints.

20121016-084053.jpg We arrived at the Desert View Watchtower just in time to witness a fabulous sunset. The Watchtower was designed by architect Mary Colter in the 1930s, who was meticulous about incorporating the Hopi culture and even hand selected the stone blocks for their shape and color. Overall, it was a fantastic ending to a memorable first-time visit.

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Wooster Geologists at the Smithsonian

Mark Wilson October 15, 2012 7:03 pm

WASHINGTON, D.C. — It is Fall Break at the College of Wooster, so some of the geologists have taken the opportunity to get out of town. Dr. Meagen Pollock is under the bright blue skies of the gorgeous state of Arizona. I am now under a string of fluorescent lights between two rows of cabinets deep in the Smithsonian National Museum of Natural History (above) in overcast and gray Washington, D.C. We are both having fun in some very different ways!

I am here on a project studying some enigmatic encrusting fossils from the Paleozoic. Paul Taylor and I want to sort out the mysterious systematic identities of Allonema, Ascodictyon and related forms commonly inhabiting hard substrates, especially in the Devonian. All we can say for certain now is that they are not bryozoans! The specimen above, for example, is USNM 43129 Allonema fusiforme (Nicholson & Etheridge, 1877) figured as Ascodictyon fusiforme in the Treatise of Invertebrate Paleontology, pt. G, p. G35, Fig. 9-3. It was collected from the Devonian of Michigan. It doesn’t look like much more than bubbles of calcite under a light microscope, but later Paul Taylor will show its glories through scanning electron microscopy. I am the advance member of the team, looking through specimens to find the best for Paul to borrow when he visits later this month. We’ll have much more to say about these fossils later.

Above are the specimen boxes for species of the genus Allonema. Note how much information is packed into the small space on the top of each box. Paul and I go through these boxes and examine the specimens they contain with light microscopes in the museum galleries.

There is some humor in the dry world of systematic paleontology.

This is my work station while at the museum. Note the nice photographic tube on the microscope, the comfortable chair, and the lack of any distractions!

I’ve saved the best part for last. Why the plural “Wooster Geologists” in the title? Because the Collections Manager of this world-class paleontological museum is one of my former students — Kathy Hollis (’03). Here is happy, efficient, uber-competent Kathy in her office, clearly in her element. We are very proud of her at Wooster. It is so cool to see her at work in one of the most paleontologically exciting places you could be. Makes up for the gray skies!

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