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What we learned in Climate Change (Geology 210, Spring 2016)

May 31st, 2016

boulder

A dedicated group of geologists, physicists, archaeologists, political scientists, biologists, english and history majors joined forces to learn a bit about Climate Change in the natural laboratory of Northeast Ohio. Here they surround a glacial erratic in Secrest Arboretum of the OARDC – where The Ohio State University and the National Weather Service has meteorological records extending back to the late 1800s CE. The Arboretum also has an extensive collection of stands of trees from around the world that are used in our climate studies below (special thanks to Joe Cochran (OSU) for permission to work at Secrest).

The first project: the glacial transition in a sediment core from  Browns Lake Bog

rundown

Dr. Thomas Lowell gives the rundown at Browns Lake Bog – Tom is a professor at the University of Cincinnati and long-time collaborator and the core boss.

lab

Initial description of the 5 meter core – we obtained two radiocarbon ages, measured magnetic susceptibility, loss on ignition, in addition to core description and sediment analyses.

The Upshot of the Lake Work – The two ages were chosen at transitions in the character of the peat and mineral matter – we identified a major shift at the time of the Bolling – Allerod warming and at the cooling of the Younger Dryas.  The abrupt climate changes (ACCs) and discussion of how the world moves from the Pleistocene to the Holocene is brought home to Ohio in this core (Figure below). It is exciting to explore how these ACCs affected NE-Ohio’s ecosystems and physical landscapes.

master_bog

Project 2: Tree Ring Dating of the Biggio Barn

rundown

The barn owner gives the rundown on the history and possible ages of the hand hewn timber frame. The dating of the barn project introduced the class to the science of tree-rings.

vincent

Hong Kong dendrochronologist, Vincent shows the class how by standing on two milk crates he cores a beam – the instructor adds a stabilizing foot to Vincent’s precarious sampling strategy.

The upshot of Barn Dating: Ten of the beams from the Biggio Barn were cut in the spring of 1840 CE. The building then was likely constructed shortly after that cut date.  A copy of the report to the owner from the class can be found here. The ring-width data obtained in this study are used in drought studies below. The Wooster Tree Ring lab has dated over 60 barns and houses in Ohio and PA (this video describes the process and some of the science).

Project 3a: Extracting a Temperature Proxy Record from Larch in Kamchatka
Vincent Hui, Abbey Martin, Sarah McGrath, Matthew Shearer, Ann Wilkinson

The purpose of this study was to analyze Kamchatka larch (Larix cajandery Mayr.) tree ring widths from Fareast, Russia. The team standardized the chronology using two methods, (1)  negative exponential, and (2) regional curve standardization (RCS), and they then compared how the standardization technique influenced correlations. Both standardized series were correlated with meteorological records showing high positive correlations for summer temperatures. The RCS showed stronger correlations and was used for NTREND comparison, temperature reconstruction, and spectral analysis. Together these correlations and comparisons showed the larch primarily responds to summer temperature and can be used to reconstruct summer temperatures.

kamchatka

The Kamchatka team of researchers (without Vincent) who did the study. They are posing at Wooster Memorial Park where a recent planting of 700 trees and prairie will sequester more carbon in the future than the previous agricultural land use at the site.

Figure2

ntrendConclusions: 
1 – The Kamchatka larch tree-ring widths are most sensitive to summer (May through September) temperatures.

2 – The team recommends the region curve standardization method) RCS method for standardization with a sample size of 190 series.

3 – The RCS series showed similar trends as the NTREND series, suggesting the Kamchatka site follows the same trends as much of the northern hemisphere.

4 – Ring-widths show a general increase in temperature over the last 350 years for the interior of Kamchatka. This is unprecedented over the past 300 years and is consistent with other proxies such as glaciers.

Project 3b: Past climate inferences using data from Johnson Woods
 Sharron Osterman, Annette Hilton, Cameron Steckbeck, Gina Malfatti, Amineh AlBashair

  • tst
  • The Johnson Woods team assembled a newly compiled data set originally sampled in 1985 by Dr. Ed Cook (LDEO), by the Wooster Tree Ring Lab in 2003 and most recently updated by Dr. Justin Maxwell (Indiana State University). They found there was a marked release in the tree ring record across northern Ohio about the time of European Settlement in the region. This may be in part due to the disturbance in the record, however it could also persist due to the positive response that tree growth has to summer precipitation.
  • Slide2
  • Slide1Above is a histogram showing the correlations of the Johnson Woods ring-width series and monthly precipitation and temperature records from the OARDC spanning 1880 to 2014 CE. The trees are a record of summer precipitation (positive correlation) and favor wet summers. These trees are negatively correlated with high summer temperatures.

One Question on the final exam:
What is the Climate response of European Larch to climate of Ohio – Secrest Arboretum (and why might this exploration be relevant?).

  • coring1

Obtaining high quality cores for ring-width chronologies from European Larch at Secrest Arboretum.

coring2

 The upshot here is the ring-width chronology below. The class worked on this as part of the final exam and found that similar to the oaks in the region, the European Larch is sensitive to summer precipitation and is stressed by high summer temperatures. The tailing off of the ring-widths during recent decades could be the result of warmer summer temperatures – a hypothesis that needs testing. The relevance of this study is that as climate changes in the high latitudes of Europe and Asia, where these larch dominate – it may be the case, that warming may stress the species leading to decreases in bioproductivity – these ideas need further work to test if this is a viable hypothesis.

Plot 1

jw

A day in Johnson Woods – the full class in the rain.

jw

danWe also learned that Dan Misinay (’16) is a pretty fair teaching assistant.

milling

The class wanders around the gas power plant on the Wooster campus – three years ago the college transitioned from coal burning to natural gas – the carbon dioxide emissions on campus have been cut in half. However, now the College buys its power for cooling (air conditioning) off campus from the grid, where much of the electricity is powered by coal, but with a growing portfolio of clean energy sources (special thanks to Lanny Whitaker who showed us the plant and explained where our energy comes from – thank you). We also thank Nick Wiesenberg (our able Geology Technician) for his knowledge of trees, barn dating and general troubleshooting,  Tom Lowell and his students for the high quality sediment cores, our TA Dan and a host of tree-ring scientists who contributed data to our efforts in this course. Special thanks too – to the Secrest Arboretum. A portion of the Kamchatka tree-ring record was supported by NSF- AGS – 1202218.

Wooster’s Fossils of the Week: Echinoderm holdfasts from the Upper Cambrian of Montana

May 27th, 2016

Pelmatozoans051216The white buttons above are echinoderm holdfasts from the Snowy Range Formation (Upper Cambrian) of Carbon County, southern Montana. They and their hardground substrate were well described back in the day by Brett et al. (1983). We have these specimens as part of Wooster’s hardground collection. (The largest collection of carbonate hardgrounds anywhere! A rather esoteric distinction.)

These holdfasts are the cementing end of stemmed echinoderms, conveniently called pelmatozoans when we don’t know if they were crinoids, blastoids, cystoids, or a variety of other stemmed forms. I suspect these are eocrinoid attachments, but we have no evidence of the rest of the organism to test this.
Snowy bedThe hard substrate for the echinoderms is a flat-pebble conglomerate, a distinctive kind of limestone found mostly in the Lower Paleozoic. They are in some places associated with limited bioturbation (sediment stirring by organisms) and early cementation, but there are other origins for these distinctive sediments (see Myrow et al., 2004).
Snowy crossThis particular flat-pebble conglomerate was itself cemented into a carbonate hardground, as seem in this cross section. The pelmatozoan holdfasts are just visible on the upper surface.

These pelmatozoans are among the earliest encrusters on carbonate hardgroounds and thus have an important position in the evolution of hard substrate communities.

References:

Brett, C.E., Liddell, W.D. and Derstler, K.L. 1983. Late Cambrian hard substrate communities from Montana/Wyoming: the oldest known hardground encrusters: Lethaia 16: 281-289.

Myrow, P. M., Tice, L., Archuleta, B., Clark, B., Taylor, J.F. and Ripperdan, R.L. 2004. Fat‐pebble conglomerate: its multiple origins and relationship to metre‐scale depositional cycles. Sedimentology 51: 973-996.

Sepkoski Jr, J.J. 1982. Flat-pebble conglomerates, storm deposits, and the Cambrian bottom fauna. In: Cyclic and event stratification (p. 371-385). Springer, Berlin Heidelberg.

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

How we measure the chemical composition of Earth materials

May 25th, 2016

San Diego, CA – If you’ve been following our adventures, you know that we’ve started a project on Black Mountain with our collaborators at the University of San Diego. We’ve dedicated a significant portion of our time in California to sample preparation, and today we see the results of all of our hard work.

In order to address our research questions, we need to understand the compositions of the minerals, rocks, and soils that are present at the field site. To analyze mineral compositions, we are using a scanning electron microscope equipped with an energy-dispersive detector (SEM-EDS). The electron beam interacts with a polished rock specimen to produce characteristic X-rays. The detector separates those X-rays by energy, correlates the energy to specific elements, and maps the distribution of elements in the sample. This technique allows us to determine the compositions of individual minerals in our rocks.

Elizabeth Johnston (USD graduate student) and Dr. Beth O'Shea (USD) are examining mineral compositions using an SEM-EDS.

Elizabeth Johnston (USD graduate student) and Dr. Beth O’Shea (USD) are examining mineral compositions using an SEM-EDS.

Dr. Beth O'Shea (USD) and Amineh AlBashaireh ('18) examine soil samples and discuss analytical strategies.

Dr. O’Shea and Amineh AlBashaireh (’18) examine soil samples and discuss analytical strategies.

To analyze the bulk compositions of our soil samples, we’re using a benchtop X-ray fluorescence spectrometer (XRF). The XRF uses an X-ray beam to generate X-rays from the samples. The generated X-rays are characteristic of specific elements, which the XRF measures and compares to a calibration curve to calculate a concentration. This XRF model is equipped with several modes for analyzing soil or ore samples and allows us to analyze bulk compositions without destroying the sample.

Amineh is analyzing her soil samples with the benchtop XRF. She will use these data to guide her analytical work when we return to Wooster.

Amineh is analyzing her soil samples with the benchtop XRF. She will use these data to guide her analytical work when we return to Wooster.

Construction of the new Life Sciences building begins, and the geologists welcome our new biologist labmates

May 24th, 2016

Mateer May 2016Wooster, Ohio — The College of Wooster community will soon say goodbye to Mateer Hall (above), which has housed the Biology Department for decades. It will be demolished next month to make way for the new Ruth Williams Hall of Life Science. I haven’t heard anyone yet say they will miss the creaky and undersized Mateer. The new Life Sciences building, which will be joined to the existing Severance Hall (chemistry), will be beautiful, spacious, and filled with the finest of scientific equipment and facilities.

Scovel 216 052416In the meantime the biologists (sensu lato, including neurobiologists, biochemists and so on) have to go somewhere with all their stuff for two years. Scovel Hall will be home for some of the biology labs, so the geologists have been making room throughout the building. I thought I’d record the process at its most chaotic in Scovel 216 (above) and Scovel 219 (below). The biologists have to move everything out of Mateer in just a few days, so our lab tables and just about every other flat surface in Scovel is occupied by specimens, equipment, and massive bottles of distilled water. I especially like the stuffed animals (including a small bear), the crocodile skulls, and the human skeleton in an ancient tall display cabinet.

Scovel 219 052416We are looking forward to spending quality time with our biologist friends. We’re each going to learn a great deal about how the other group works, and we’ll have new appreciation for our disciplines. Science marches forward!

Thinking like a scientist

May 24th, 2016

San Diego, CA – Thinking like a scientist is a challenging and important learning goal for the Wooster Geologists, and one of the primary reasons that we engage our students in undergraduate research. Although science is often portrayed as a collection of facts or as a series of exercises designed to prove something that is already known, our research students learn that science is a way of thinking. It is a method of inquiry that involves creativity, examining a question from multiple perspectives, and understanding uncertainty. Science requires hypotheses that are testable, data that can be collected and interpreted, and explanations that are supported by evidence. Today, our Black Mountain research group focused on these aspects of science as we developed our research goals and plans for the rest of the summer.

Amineh AlBashaireh ('18) filled the whiteboard with an impressive set of ideas and questions, which jump-started our research discussion.

Amineh AlBashaireh (’18) filled the whiteboard with an impressive set of ideas and questions to prompt our research discussion. On the left are “broad impacts” that define the significance of the research and put the research into context of the larger society. On the right are sources of “potential error,” which Amineh is recognizing and attempting to minimize.

Eventually, we developed a couple of research questions that Amineh will be able to address this summer. We formulated hypotheses for the answers to these questions and designed a research strategy that will generate the data necessary for testing our hypotheses. In the end, we created a research plan that is both achievable (given the constraints of time, expertise, resources, etc.) and flexible enough to allow the research to evolve as Amineh discovers new findings and develops new questions.

For an excellent resource on the process of science, check out the Visionlearning module by Anthony Carpi and Anne Egger. It’s an incredible resource for teachers and students alike.

References:

Carpi, A., and Egger, A.E. 2009. The process of science. Visionlearning POS-2 (8).

Geochemists know preparation is key

May 22nd, 2016

San Diego, CA – While the University of San Diego celebrated their commencement, we commenced lab work on the Black Mountain Project. We began by drying and sieving the soil samples that we collected earlier in the week.

Amineh AlBashaireh ('18) is removing her soil samples from the drying oven.

Amineh AlBashaireh (’18) is removing her soil samples from the drying oven.

Her soil samples display variety of colors and compositions.

Her soil samples display variety of colors and compositions.

Dr. Beth O'Shea (USD) and Amineh discuss the Munsell System for classifying the color of soil.

Dr. Beth O’Shea (USD) and Amineh discuss the Munsell System for classifying the color of soil.

While her samples dry, Amineh is helping prepare samples for analysis on the scanning electron microscope (SEM-EDS). Doesn't she look like a happy geochemist?While her samples dry, Amineh is helping prepare samples for analysis on the scanning electron microscope (SEM-EDS). Doesn’t she look like a happy geochemist?

Field Work on Black Mountain

May 21st, 2016

San Diego, CA – Amineh AlBashaireh (’18) and I are working with USD scientists, Dr. Bethany O’Shea, Elizabeth Johnston, and Eric Cathcart on the geology of Black Mountain in San Diego, CA.

Black Mountain Open Space Park is a popular hiking and mountain biking destination.

Black Mountain Open Space Park is a popular hiking and mountain biking destination.

The Santiago Peak Volcanics are exposed in the park. These rocks are early Cretaceous in age (~110 Ma) and are thought to represent the volcanic arc associated with the Peninsular Range batholith (Herzig and Kimbrough, 2014).

Slightly metamorphosed andesites and basaltic andesites are present as gray to dark gray aphanitic (fine grained) rocks with scattered phenocrysts (crystals) of plagioclase.

Slightly metamorphosed andesites and basaltic andesites are present as gray to dark gray aphanitic (fine grained) rocks with scattered phenocrysts (crystals) of white plagioclase.

There are also volcaniclastic rocks like this tuff breccia that include large clasts of andesites, basaltic andesites, and other fragmental rocks.

There are also volcaniclastic rocks like this tuff breccia that include large clasts of andesites, basaltic andesites, and fragmental volcanic rocks.

Outcrops of lapillistone contain accretionary lapilli, or rounded sphere of volcanic ash, that hint at the more turbulent and explosive nature of this volcano.

Outcrops of lapillistone contain accretionary lapilli, or rounded spheres of volcanic ash, that show evidence of the more turbulent and explosive nature of this volcano.

Hikers and bikers who visit Black Mountain may be less familiar with its volcanic history and more familiar with its mining history. In the 1920s, this area was briefly mined for arsenic. The arsenic was used in pesticides at the time.

Hikers and bikers who visit Black Mountain may be less familiar with its volcanic history and more familiar with its mining history. In the 1920s, this area was briefly mined for arsenic. The arsenic was used in pesticides at the time (Stewart, 1963).

Our research group is exploring one of the abandoned mines.

Our research group is exploring one of the abandoned mines.

In the mine waste, you can see shiny gold specs of aresenopyrite (FeAsS). Arsenopyrite is a sulfide mineral in which some of the sulfur is replaced with arsenic.

Amineh is studying trace element concentrations in the soils on Black Mountain. Here she is collecting samples. In the next few days, and over the course of the summer, we'll show you how she processes these samples in the lab.

Amineh is studying trace element concentrations in the soils on Black Mountain. Here she is collecting samples. In the next few days, and over the course of the summer, we’ll show you how she processes these samples in the lab.

This was a small (~30 cm) rattlesnake that we saw earlier in the day, and we take field safety seriously, so when we heard a rattle coming from the tall grass, we ended our sampling and called it a day.

This was a small (~30 cm) rattlesnake that we saw earlier in the day, and we take field safety seriously, so when we heard a rattle coming from the tall grass, we ended our sampling and called it a day.

It was an exciting, productive, and safe day in the field. More to come in the next few days as we start on our lab work.

References:

Herzig, C.T. and Kimbrough, D.L. 2014. Santiago Peak volcanics: Cretaceous arc volcanism of the western Peninsular Ranges batholith, southern California. GSA Memoirs 211: 345-363.

Stewart, R.M. 1963. Black Mountain Group in Weber, H.F., Geology and mineral resources of San Diego County, California: San Francisco, California Division of Mines and Geology, 49-50.

Wooster Geologists in San Diego, CA

May 20th, 2016

San Diego, CA – Wooster Geologists don’t waste any time getting to work on their summer research. Amineh AlBashaireh (’18) and I have made our way to the University of San Diego to start on a new research project with our collaborators in the Department of Environmental and Ocean Sciences. Our trip began with a tour of the department’s facilities in the impressive Shiley Center for Science and Technology.

The grand and welcoming entrance to the Shiley Center, which houses USD's science programs.

The grand and welcoming entrance to the Shiley Center, which houses USD’s science programs.

Visitors to the Department of Environmental and Ocean Sciences are greeted with this stunning display of a donated coral collection.

Visitors to the Department of Environmental and Ocean Sciences are greeted with this stunning display of a donated coral collection.

A favorite lunch spot is the Strata Plaza. The plaza was designed to represent the local stratigraphy and includes regional fossils, stones, and shells.

A favorite lunch spot is the Strata Plaza. The plaza was designed to represent the local stratigraphy and includes regional fossils, stones, and shells.

Our tour ended in the lab, where Dr. Bethany O'Shea and her graduate student, Elizabeth Johnston, gave us an overview of their work. Looks like they mean business!

Our tour ended in the lab, where Dr. Bethany O’Shea and her graduate student, Elizabeth Johnston, gave us an overview of their work. Looks like they mean business!

We’re looking forward to a full week of field and lab work. Stay tuned for more posts from sunny San Diego!

Wooster’s Fossil of the Week: A phyllocarid crustacean from the Middle Cambrian Burgess Shale of British Columbia, Canada

May 20th, 2016

Canadaspis perfecta Burgess Shale 585We are fortunate at Wooster to have a few fossils from the Burgess Shale (Middle Cambrian) collected near Burgess Pass, British Columbia, Canada, including this delicate phyllocarid Canadaspis perfecta (Walcott, 1912). This species is one of the oldest crustaceans, a group that includes barnacles, crabs, lobsters and shrimp. Please note from the start that I did NOT collect it. The Burgess Shale is a UNESCO World Heritage Site, so collecting there is restricted to a very small group of paleontologists who have gone through probably the most strict permitting system anywhere. I had a wonderful visit to the Burgess Shale with my friend Matthew James in 2009, and we followed all the rules. (The photo below is of the Walcott Quarry outcrop.) Our Wooster specimen was in our teaching collection when I arrived. I suspect it was collected in the 1920s or 1930s and probably purchased from a scientific supply house.

walcottquarryMarrellaSuch a dramatic setting, which is perfect for the incredible fossils that have come from this site.

Canadaspis perfecta drawing

Canadaspis perfecta has been thoroughly studied by Derek Briggs, the most prominent of the paleontologists who have studied the Burgess Shale fauna. The above reconstruction of C. perfecta is from his classic 1978 monograph on the species. He had spectacular material to work with, including specimens with limbs and antennae well represented. Our specimen is a bit shabby in comparison! Nevertheless, we can still make out abdominal segments and a bit of the head shield.

Briggs (1978, p. 440) concluded that C. perfecta likely “fed on coarse particles, possibly with the aid of currents set up by the biramous appendages”. This is a similar feeding mode to many of the trilobites who lived alongside.

References:

Briggs, D.E. 1978. The morphology, mode of life, and affinities of Canadaspis perfecta (Crustacea: Phyllocarida), Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 281: 439-487.

Briggs, D.E. 1992. Phylogenetic significance of the Burgess Shale crustacean Canadaspis. Acta Zoologica 73: 293-300.

Wooster’s Fossil of the Week: A Recent Sponge Boring from South Carolina

May 13th, 2016

1 Coral on bored bivalveWe’re not actually looking at fossils here, but this bivalve-coral-sponge assemblage from the very modern Myrtle Beach in South Carolina is to cool not to share. Jacob Nowell (Wooster ’18) picked it up while on Spring Break this year and donated it to the collections. This is a bit of very worn bivalve shell punctured by clionaid sponge borings and encrusted by a columnar scleractinian coral.

2 Bored bivalve hingeHow do we know the shell remnant is from a bivalve? This is what’s left of the hinge region, the thickest part of the shell. We can tell this is a heterodont bivalve, probably of the common genus Mercenaria. The shell material is calcite.

3 Coral over EntobiaThe coral is aragonitic and exquisitely preserved. It did not make the long tumbling journey the bivalve shell did. At its encrusting base you can see that it partially covers some of the sponge borings, showing that it attached after the sponge was at least partly gone. The round structures on the coral are the corallites, each of which housed a coral polyp. The corallites have radiating vertical septa inside in the classic scleractinian manner.

4 Entobia gallery 041316 585The sponge boring is the star here. This is a side view showing the interconnected galleries and tunnels excavated by a clionaid sponge like Cliona. As a trace fossil this structure would be known as Entobia. It is very common in the fossil record, especially in the Cretaceous and later.

Bronn 041616Entobia was named and described by Heinrich Georg Bronn (1800-1862), a German geologist and paleontologist. He had a doctoral degree from the University of Heidelberg, where he then taught as a professor of natural history until his death. He was a visionary scientist who had some interesting pre-Darwinian ideas about life’s history. He didn’t fully accept “Darwinism” at the end of his life, but he made the first translation of On The Origin of Species into German.

References:

Bromley, R.G. 1970. Borings as trace fossils and Entobia cretacea Portlock, as an example. Geological Journal, Special Issue 3: 49–90.

Bronn, H.G. 1834-1838. Letkaea Geognostica (2 vols., Stuttgart).

Tapanila, L. 2006. Devonian Entobia borings from Nevada, with a revision of Topsentopsis. Journal of Paleontology 80: 760–767.

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

Wilson, M.A. 2007. Macroborings and the evolution of bioerosion, p. 356-367. In: Miller, W. III (ed.), Trace Fossils: Concepts, Problems, Prospects. Elsevier, Amsterdam, 611 pages.

 

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