Planning for a Day in the Field

I officially started my summer field work today! Unfortunately, here in West Chester, PA, it rained all day. That didn’t keep us from being productive, though. Lee Ann and Tim (from West Chester University) and Loretta (from Lock Haven University) and I began the day by visiting the quarries that we’ll be working in tomorrow. We spent the afternoon developing a plan for the rest of the week. It goes a little something like this:

The Plan

This really isn't the plan, but it is a map of all of the sites that we're interested in.

Lee Ann set out all of her samples from these locations and let us play in the lab all afternoon. We immersed ourselves in diabase, so much so that we nearly forget to break for dinner!

Diabase samples

A table topped with diabase hand samples, thin sections, maps, and chemical data = heaven.

Diabase thin section

Action shot of Lee Ann adjusting the microfiche viewer to get the best image of a diabase thinsection.

You would think that a day of discussion would clear things up, but I’m more overwhelmed than ever! I realize that I have so much to learn about the emplacement and evolution of these rift-basin dikes and sills. I typically think of these large intrusions as composite structures, formed by multiple pulses of magma, but I wonder if I’ll be able to recognize evidence of this in the field? How did the complex plagioclase-pyroxene layers form, and why are they different in different parts of the sill? And what are the mafic channels that cut across the plagioclase-pyroxene layers? Fortunately, I have wonderful and experienced (not to mention patient) colleagues who are seeking answers to the same questions. Some insights, I hope, will be gained by whole-rock geochemistry (as long as my sampling strategy works). Whew! Are all new projects as exciting as this?

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Knowing how to pick your field day

Compare these happy and warm Sed/Strat students to the freezing Petrology group in the previous post. It is all a matter of choosing the right part of April for fieldwork in Ohio. Comes with experience, I suppose.

Andrew Collins, Nick Fedorchuk and Travis Louvain measuring a section of the Logan Formation (Mississippian) in the Miller Lakes area of Wooster. The striped sticks are low-budget Jacob Staffs divided into tenths of meters.

Houston Hoskins, Megan Innis and Sarah Appleton also measuring and describing the Logan Formation at Miller Lakes. This is a class exercise to learn how to construct a simple stratigraphic column.

Sarah Appleton reaching high as she describes a portion of the Logan Formation with interbedded very fine sandstones and quartz-pebble conglomerates. These beds were deposited in the proximal portion of a deltaic complex with the conglomerates representing distributary channel sediments. Marine fossils such as crinoids, brachiopods and bivalves are found in both the sandstones and conglomerates.

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Tough Field Trips

I heard that the Sed-Strat field trip was canceled today due to rain. Hmm… I seem to remember a certain Wooster Geology course taking a field trip on a cold, snowy Saturday just a week ago.

Who's that out in the field on a cold, snowy Saturday in April? Petrology.

Yep. Hard Rock = Hard Core! Just saying.

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Science Day and Expanding Your Horizons

The Geology Department has been busy reaching out to the community lately. On Saturday, April 17, the College hosted its annual Science Day. GeoClub invited the community to dig for dinosaurs in a sand pit and witness an erupting volcano. See the story in the April 20 edition of the Wooster Daily Record (here’s a link if you happen to have a subscription).

After 4 years of a Wooster Geology education, senior Palmer Shonk ('10) demonstrates his ability to play in the sand.

Today, local middle school girls joined Geology faculty Meagen Pollock and Shelley Judge and several Geology majors to see if they could outrun a dinosaur. The girls measured the stride and size of dinosaur footprints to calculate the speed, then raced to see if they could beat it.

The situation: T-Rex chases Stegosaurus.

Ana helps one of the girls measure the size of the T-Rex footprint.

Melissa helps one of the girls measure the stegosaurus' stride.

Afterward, we played with rocks, minerals, and fossils. The girls got to choose one to take home.

Shelley Judge talks rocks with the Expanding Your Horizons Girls.

Polished stones and agates were today's momentos.

We even had time to demonstrate the use of a rock hammer.

And time to tell (bad) Geology jokes!

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Wooster Geologists Participate in the Senior Research Symposium: A Celebration of Independent Study

WOOSTER, OHIO–Several of our senior geology majors gave poster and oral presentations in the 2010 Senior Research Symposium today.  We are very proud of their accomplishments and the skills they have in articulating their projects to a very diverse audience.  It was a good day for the department.

Kelly Aughenbaugh delights in answering questions about her topic: "Reconstructing Late Holocene Glacial Movement in Muir Inlet Glacier Bay, Alaska."

Colin Mennett gave an oral presentation on his project: "Decline in Alaskan Yellow-Cedar: Tree-Ring Investigations into Climatic Responses and Possible Causes, Glacier Bay, Alaska."

Bill Thomas presented: "Petrographic and Mapping Analysis of Volcanic Tuffs in the Green River Formation Cuestas, Sanpete Valley, Utah."

Palmer Shonk explains to Anna Mudd his research: "Paleoecological Reconstruction of the Late Silurian (Pridoli) Äigu Beds of Saaremaa Island, Estonia."

Rob McConnell and his poster titled: "Paleoenvironmental analysis of the Silurian Jaani Formation on the island of Saaremaa, Estonia."

Travis Brown describing his work: "Directly-controlled lichen growth curves for western Spitsbergen, Svalbard."

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A pleasant spring afternoon of geology in Ohio

The College of Wooster 2010 Sedimentology & Stratigraphy class in Spangler Park near Wooster, Ohio. Small classes are such a delight!

WOOSTER, OHIO–I let my Sedimentology & Stratigraphy class talk me into an afternoon field trip to Spangler (or Wooster Memorial) Park just west of town. It was a perfect day of sunshine and cool breezes. While I made plans to measure sections and do other formal geological work, we ended up just enjoying the creek, birds, flowers, rocks, fossils, trees and other delights of Ohio in the spring. We could not have found a better way to celebrate Earth Day.

With the fancy nails of Megan Innis for scale, this is a granitic dropstone in a greenstone known as the Gowganda Tillite. In one of those wonderful geological twists, this rock is a glacial deposit formed in Ontario, Canada, 1.8 billion years ago. It was much later carried to Ohio by a Pleistocene glacier. The dropstone is thus at least twice-removed by ice from its original source.

The class crossing Rathburn Run which flows through the park. The creekbed has many fossiliferous pieces of sandstone, shale and limestone.

An Eastern Garter Snake (Thamnophis sirtalis sirtalis) on an oak leaf in Spangler Park.

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Lava pour!

A cauldron of lava poured onto an angled surface at Syracuse University. Photograph courtesy of Jeff Karson, Department of Earth Sciences at Syracuse.

SYRACUSE, NEW YORK–Today I gave a presentation at Syracuse University as part of the fifth annual Central New York Earth Sciences Student Symposium.  My topic was the rise of modern marine ecosystems in the Jurassic.  Exciting enough, of course, but the real fun was in an event which caught me by surprise: a “lava pour” organized by Professor Jeff Karson with the Sculpture Department at Syracuse.  (This is a type of interdisciplinarity I hadn’t seen before!)

The pour, as they call it, began with the addition of about 100 pounds of basalt (collected in Oregon where they have plenty of it) into a hardened steel cauldron.  The cauldron is then lowered into a below-ground furnace and heated for about four hours until all is incandescent.  Several people in protective gear (it would not protective enough for me, though!) open the furnace and attach a winch to the cauldron and lift it to the surface.  At this point the crowd (including me) had been pushing as close as allowed to the furnace.  We immediately backed up when the blast of heat from the cauldron — which was glowing like the sun — struck us.  Molten rock is serious stuff.

A bit of the lava was first poured into a porcelain pipe bent like an elbow with the lower part ending in a large basin of water.  The pipe had been plugged at the base with wax so the lava would build up before flowing through to the water.  The idea was to make a lava pillow, a type of flow structure made when a natural flow meets water as under a glacier, in a lake or in the ocean.  (See the natural pillow lavas studied last summer by the Wooster Iceland Team.)  The wax immediately and explosively ignited, sending a spout of flame upwards which took everyone by surprise (including the crew).  The fire was short-lived, though, as the lava flowed through into the now-boiling water.

The second pour was onto a cold rock monitored by a digital remote thermometer to record its cooling rate.  This time the lava poured out like syrup, making a flat, bubbling sheet which quickly grew a dark crust which spattered tiny glass shards as the cooling bubbles burst.

The third and final pour was onto blocks of dry ice, apparently to simulate the surface of Mars.  (Really.  Not just to “see what happens”.  This is professional geology, after all!)  The lava hit the dry ice with an extraordinary hiss and then skittered off onto the sand below.  Apparently the vapor built up immediately by the rapidly-sublimating ice did not allow the lava to stick or even stay on the ice itself.  The result was ropy strings, droplets and “angel hair” of cooled lava.

Afterwards, when the cauldron had been scrapped empty and the heat had dropped to a tolerable level, we gathered around the three pour sites and marveled.  The flow on the rock slab continued to bubble and crack, producing some exquisite brown fragments of almost-transparent glass.  We picked up a few cooled pieces and tried to imagine this process scaled up to natural proportions.

Thank you to Jeff Karson for such an innovative idea, this lava pour, and sharing it with all of us.  Way cool.  Mike Cheatham has posted a webpage of photos showing our lava pour in its stages.

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Dr. Whitey Hagadorn presents “The First Animals on Land” for the 29th Annual Osgood Memorial Lecture at Wooster

WOOSTER, OHIO–This evening Dr. Whitey Hagadorn, an assistant professor of geology at Amherst College, gave the 29th Annual Richard G. Osgood Memorial Lecture to a large crowd of students, faculty and community members in Wishart Hall at The College of Wooster.  His topic was “The First Animals on Land”, which was an account of research he and his students did with remarkable Cambrian trace fossils (tracks, trails and burrows) in sandstones in Wisconsin.

Sedimentary structures In Upper Cambrian sandstones, Wisconsin, USA. On the left are ripples with raindrop imprints; on the right is an intertidal channel. Photographs courtesy of Whitey Hagadorn.

Dr. Hagadorn showed in his presentation how he and his team first recognized ancient shoreline deposits by tracing sedimentary structures such as ripples, channels and raindrop imprints on extensive sandstone bedding planes in quarries.  They could then follow trace fossils of mollusks, worms and arthropods out of the water onto what were sandy beaches in the Cambrian.  Some of those organisms seem to have been carrying shells with them as protection from desiccation in the dry air.  Dr. Hagadorn answered many questions after his lecture from the audience and from a good crowd at the following reception.  We were impressed not only with the beautiful trace fossils and what they tell us about early land life, but also how such significant work could be done with simple tools and clever analyses.

Trace fossils in Upper Cambrian sandstones, Wisconsin, USA. Photographs courtesy of Whitey Hagadorn. More details are available on his website linked in this post.

Dr. Hagadorn will be leaving Amherst College this summer to become the Curator of Earth Sciences at the Denver Museum of Nature and Science.  We wish him well.

The Richard G. Osgood, Jr., Memorial Lectureship in Geology was endowed in 1981 by his three sons in memory of their father, a paleontologist with an international reputation who taught at Wooster from 1967 until 1981. Funds from this endowment are used to bring a well-known scientist interested in paleontology and/or stratigraphy to the campus each year to lecture and meet with students.

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The Mojave Desert Field Trip and Wikipedia

Tertiary debris flow at Resting Spring Pass near Shoshone, California. This is an image from the field trip now posted on Wikipedia.

WOOSTER, OHIO–One of the primary joys of being a geologist is the opportunity to see so many interesting sights in the field.  We can share a bit of the pleasure and advance public knowledge by posting some of our photographs on the free online encyclopedia Wikipedia.  Here are some linked Wikipedia articles which have been improved with public domain images from this month’s Mojave Desert field trip:

Amboy Crater
Aztec Sandstone
Barstow Formation (a new page)
Lake Manly
Calico Ghost Town
Conglomerate
Curtis Howe Springer
Debris Flow
Desert Pavement
Desert Studies Center
Dune
Kelso Dunes
Lake Manix
Lake Tuendae
Mojave River
Pluvial Lake
Red Rock Canyon National Conservation Area
Syncline
Tuff
Volcanic Bomb

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Wandering in the wilderness one last time

ZZYZX, CALIFORNIA–This was our last full day in the Mojave Desert, at least for this trip. Technically it was our coldest start yet (40°F), but the bright sun and lack of wind made it seem like our warmest. The day was mostly unstructured because we were going to try to find a geological site none of us had seen here: the lava tubes in the cinder cones area of the Mojave National Preserve. It was a good thing we left our schedule open because we missed not one turn, not two turns, but three crucial turns before we finally entered the tubes. I’ll take full responsibility, although in my defense I must point out that the Preserve is very coy with their signage and directions!

While exploring the desert during our lost phase today, Rob McConnell found this excellent volcanic bomb on one of the cinder cones. Note the streamlines formed as the molten lava cooled as it was thrown into the air. We can even tell which end hit the ground as it landed (the left).

Rob Lydell at the entrance to the lava tube complex in the cinder cones region of the Mojave National Preserve.

Michael Snader, Andrew Retzler and Stephanie Jarvis (looking very straight up!) inside one of the lava tubes with light behind them shining through a hole in the roof.

This light shaft is outlined by eolian dust it is passing through.

After another delicious lunch packed for us by the Desert Studies Center staff (a shout-out to the world-class cook, our friend Eric), we drove north to Resting Springs Pass to study a famous exposure of a welded tuff.  Our last stop was a descent through the 500,000 year-old beds of ancient Lake Tecopa to China Date Ranch where we looked around the oasis and had the famous (and expensive .. and over-rated) “date shakes”. (Think flurry with little date bits thrown in.) The students and other faculty enjoyed them, though, and they were in their eccentric way a fitting end to our Mojave adventure.

Wooster geologists on the welded tuff at Resting Springs Pass.

Adam Samale, Megan Innis, and Rob McConnell sampling the hottest part of the welded tuff series at Resting Springs Pass. (Oh those youthful days of casually perching on cliffsides!)

Andrew Retzler is standing on the down-dropped block on the left side of a fault at Resting Springs Pass, and Stephanie Jarvis is on the upthrown side. What kind of fault is it?

Travis Brown at the front of the store at China Date Ranch near Tecopa, California.

Proof that the date shakes at China Date Ranch were popular. From the top left, clockwise: Andrew Retzler, Micah Risacher, Greg Wiles, Rob McConnell.

Unless my colleagues surprise me this evening, this will be our last post from the Mojave. We will have many more entries for this field trip, though, as we sort through student images and observations back on campus. We will also add more technical notes about the sites we saw, and maybe even throw in a video or two. It has been an extraordinary trip which will live in our departmental memory for a very long time.

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