Archive for June, 2012
mpollock June 8th, 2012
FILLMORE, UTAH – [Guest Bloggers Matt Peppers and Will Cary]
On the morning of the 8th, all seemed well. Much like days before, we all arose and began to pack our lunches for the day. However, as we piled into the car, an ominous light started to blink on the dashboard. Low tire pressure. Concerned, Dr. Judge pulled us into a nearby gas station and checked the tires. Much to our dismay, the left rear tire was 10 psi lower than it should be, a repeat occurrence from a few days earlier. Not wanting to jeopardize our upcoming Mystery Fun Day, Drs. Judge and Pollock made the decision to take the car into a repair shop to have the problem diagnosed. While they were gone, they left us to wreak havoc upon the KOA Kampground. We started by swimming and relaxing by the pool, and ended by swimming and relaxing by the pool. All before lunchtime. We retired to our individual cabins to enjoy the lunches we had packed a few hours earlier in glorious air conditioned komfort.
Around 1 pm, the professors returned and it was business as usual. Even though we had lost half of our day to a small hole in the tire (curse you, basalt!) we rushed out to mob Kevin’s project for the afternoon. Arriving on the cinder cone at peak temperature made for a challenging work environment (especially after having spent most of the day in a sun-induced stupor) but we turned the afternoon into a very productive, albeit rushed, day. After reviewing the wall Kevin had used to map his xenoliths, we spread out and tried to collect as many of the 16 different types as we could find. After a few small injuries, stumbles, artistic work with a rock hammer, and some sore hands trying to pry the xenoliths out of the uncooperative host rock, we amassed a small mountain of samples for Kevin. As Whitney struggled to bag and record the samples in the gusting wind, the rest of us made one last sweep of the area for any xenoliths to claim.
We trooped back down the van, and made the dusty trek back to the kampsite, just in time to shower and recover before we left for dinner at six. After a quick stop to pick up a package containing some hardier field notebooks we went of to dinner followed by a stop for ice cream, where the professors revealed the Fun Trip they had planned for Saturday. We will be driving down to Bryce Canyon on the morrow to spend the day in the park. None of us have been there, so it promises to be a unique experience for us all!
mpollock June 8th, 2012
FILLMORE, UTAH – [Guest Bloggers Whitney Sims and Kevin Silver]
As we arose for our fourth day of field study, the morning was chilly. However, this was to be short lived. A clear day unleashed the full power of the sun upon the Black Rock Desert as we parked our van and began our trek onto the lava flows once again. It was Whitney and Matt’s day to lead again and the group was split in two to assist each of them.
Matt’s group was comprised of Dr. Judge, Kevin, and Will. Their goal was to look at the walls of the lava channel to find any structural features and to study the islands of basalt that were scattered across the floor of the lava channel. From there, they were planning to travel west towards a portion of the map that showed faulting near the end of the lava channel. Instead, they quickly deviated from the plan as the floor of the lava channel closer to the cinder cone showed great promise. Their day was spent tracking and measuring fissure fractures that ran both perpendicular and parallel to the walls of the lava channel. Many of these fissures were found to run right through the basalt islands. In addition, a large fault was discovered above the cliff face. Due to the wealth of data and the absolute lack of shade the study site provided, the work was very tedious and many of us, most noticeably the fairest-skinned of us, began suffering from exposure. It was a most joyous occasion when our two groups were reunited once more and were heading back to the van. Despite her preconceptions of horror, Dr. Judge found that accompanying the three boys in the field was nothing but pleasant interactions and behavior on the most professional of levels.
Whitney’s group was comprised of Dr. Pollock, Tricia, and Whitney. Their goal was to collect samples from different sections of the lava channel while travelling west to determine where the lava channel ended. They came upon what is believed to be the western breach of the flow that showed significant promise to Whitney’s project. Upon their trek, they came across a major fault that Dr. Pollock was really excited about.
The day was very productive and rich in data. It has become apparent that Matt currently holds the equivalent of three I.S. projects in his data and thus will not graduate in 2013. Whitney’s project is proving to be quite complex as Ice Springs is proving to hold some unusual structure and complexity within its flows. There is no certainty what future days in the field will reveal.
mpollock June 7th, 2012
FILLMORE, UTAH – What do volcanic bombs, xenoliths, and giant gypsum crystals have in common? Not much, except that we saw them all during our long and productive day. We met to pack lunches at 7:30 am and finished with student-faculty meetings at 10 pm, so we’re all ready for a good night’s rest, but we thought we’d give you a quick update on our progress.
Although it was long and challenging, the cool temperatures and partly cloudy skies made for a pleasant day in the field. Back to the lava fields tomorrow to check out some scarps and map flow boundaries. Wish us luck!
mpollock June 6th, 2012
FILLMORE, UTAH – Whitney and Matt took charge today, leading us on an investigation of the lava flows that extend westward from the Miter cinder cone.
We picked our way across the sharp, rubbly flow surface and learned the importance of careful observation. Although we weren’t looking for bombs and xenoliths, we found both along our path.
Whitney had a successful day of mapping the margins and morphology of a couple of complicated lava flows.
Matt’s productive day included finding a spectacular fault exposure, where he made lots of measurements on the fault and associated joints.
Overall, it was a strong start to the field project, despite the searing sun and blinding wind storm.
We were rewarded for all of our hard work.
We hope every day of our field season is just like this one (minus the wind).
Mark Wilson June 5th, 2012
Fort Ligonier was built by the British in 1758 during the French and Indian War (or Seven Years’ War) along the Loyalhanna River in what is now Westmoreland County of southwestern Pennsylvania. It is a spectacular site today with a fully reconstructed fortification and an excellent museum. It gives us a chance to see how a military engineer used the local geology to build a successful fort in a difficult terrain.
The purpose of Fort Ligonier was to serve as the forward base for the capture of the French Fort Duquesne at the forks of the Ohio River. This was the most strategic site on the western frontier. The French and their Indian allies desperately wanted to preempt this attack by destroying the advancing British columns in the woods before they could assemble. The British and American colonists needed a robust road through the wilderness approaching Fort Duquesne, along with defensible strongholds. Fort Ligonier was the most critical of these positions, then, for both sides.
You would expect a fort to be built on the highest ground, yet Fort Ligonier is in a valley surrounded by commanding heights. The British knew, though, that the French and Indians did not have significant artillery in this theater. They could give up the heights so that they could use the Loyalhanna River as a defensible barrier against the inevitable infantry attacks. The site of Fort Ligonier also has small ravines on its other sides, forming a kind of moat. Most importantly, sandstone cliffs on the river side provide an unbreachable wall and an overview of the most likely approaches to the fort by the enemy. The British placed their largest cannon at the top of this cliff, surrounding them with an elaborate wooden stockade and sharpened obstacles.
The exposed rock of the Fort Ligonier cliffs is the Casselman Formation, a Late Carboniferous (about 300 million years old) mixture of shale, siltstone, sandstone and occasional coal beds. The particular unit here is a fine micaceous sandstone with cross-bedding. It was formed in an ancient river system. The cross-bedding and abundance of mica is a clue to this environment: the cross-bedding shows high-energy seasonal flooding; the mica flakes (the white grains seen below) show ebbs in water energy to near zero.
The French and Indians attacked Fort Ligonier on October 12, 1758, and very nearly took it. The British artillery sited on the sandstone cliffs was the deciding factor, though, and the besiegers retreated. Fort Ligonier swelled in population as British troops assembled for the attack on Fort Duquesne. In fact, in November 1758 it was the second largest city in Pennsylvania! (Among the British forces was the young George Washington.) The French saw the score and retreated from Fort Duquesne. The British captured this most strategic location and renamed the site “Pittsburgh”. Building and defending Fort Ligonier was key to this victory. By March 1766 the fort had served its purpose and was decommissioned.
Fowler, W.M., Jr. 2005. Empires at War: The French and Indian War and the Struggle for North America, 1754–1763. Walker & Company, 360 pages.
Sipe, H.C. 1971. Fort Ligonier and Its Times. Ayer Company Publishers, 699 pages.
Stotz, C.M. 2005. Outposts of the War for Empire: The French and English in Western Pennsylvania: Their Armies, Their Forts, Their People, 1749-1764. University of Pittsburgh Press, 260 pages.
mpollock June 4th, 2012
FILLMORE, UTAH – [Guest bloggers Kevin Silver and Tricia Hall]
The alarms sounded in the early morning sun, early enough for the outside air to chill the bones. After our standard yogurt and cereal breakfast, we piled into the van and made our way to the Ice Springs volcanic field, the site of our field work for Independent Study. By chance, we met the manager of the quarry along the narrow road in a near head on collision before making our way up the winding road of the cinder cone with the manager’s warnings of careless truck drivers at the forefront of our minds. Once we arrived at the top of the cinder cone, we were able to enjoy the incredible views of the surrounding valley. The first feature we came to was the Crescent crater. As we viewed the expanse of the lava flow below us, it became quite clear at this point that trying to map the entire field would take much longer than the two short weeks that we have to work in Ice Springs.
After becoming oriented with the area, we made our way to Miter crater and came across extensive exposures of xenoliths. We paused for a snack and to reapply sunscreen before heading out onto the lava flows, and it was here we realized a harsh reality. The lava flows are very complex, but luckily provided better footing than the cinder of the crater slopes. Assessing the lava flows led us to the flows breaching Miter crater. The ascent back up Miter crater proved to be more challenging than expected, but we were truly independent minds working together to find flat ground. Once everybody caught their breath, we wandered back toward the van to make our way back down the cinder cone. We then made an attempt at circumnavigating the volcanic field using the rather primitive roads that were more attuned to cattle herds than cars. This feat proved to be futile as nothing less than an ATV could navigate the rough terrain we encountered. Upon our misfortune, and the near loss of our bumper, we decided to head back to camp. Along the way, we all took a nap, leaving poor Dr. Judge and Dr. Pollock to navigate our group safely back to the camp site in silence.
Once back in our accommodations, the kozy kabins, we all went our separate ways for some R&R. We each met individually with the professors to discuss our project ideas once again following our initial introduction to our field site.
Around 5:30 pm, we all piled into the van once more to scavenge for nutrients at the quality establishment known as 5 Buck Pizza. We had 4 of them. They were good. Will and Matt guzzled 8 pieces of pizza each, leaving the rest of us starving.
mpollock June 3rd, 2012
FILLMORE, UTAH – [Guest bloggers Matt Peppers and Will Cary]
As Dr. Wilson so kindly stated in his last blog post, the Utah group arrived safely at Salt Lake City International Airport on Saturday, June 2. After stopping briefly at a Target to get various essentials, we finished our two-hour drive at Fillmore (see here for how the drive went), the town we will reside in for the next two weeks. We are staying at a KOA Kampsite in some kozy little kabins. After getting acquainted with the campsite layout, we explored some of the finer cuisine options, finally settling on Larry’s Drive-In Diner across the road. Will tried a marshmallow milkshake that gave him enough sugar to power through the jet lag associated with the time zone change. After a filling meal, the group headed back to the campsite for a quick group meeting to go over the schedule for Sunday, which promised to be an orientation day to the Black Rock Desert and what we could expect. Following the meeting, everyone felt the effects of travel and promptly retired to their respective cabins for the evening.
The next morning, the group met at 9:30 to pack lunches for the day followed by an overview of equipment and safety precautions that we would need for our fieldwork. With backpacks set up, we gathered as much water as we could carry and set out to our first meeting with the Black Rock Desert. We drove directly west out of Fillmore and, although we couldn’t get onto it, saw Ice Springs, our future field site. We drove around the flow front boundaries and were impressed by how distinct and steep the boundaries actually were. Because today was an orientation day, we set out to find some lava tubes in the Tabernacle Hill lava field. Although we were unsuccessful in locating them, we had some good experience using the GPS units. In addition, we spent a lot of time looking at pressure ridges in the lava field, which adds additional complexity to some students’ projects.
Admitting defeat in finding the lava tubes (and questioning the signage that lead us to that area), we drove on to White Mountain, a hulking mass of gypsum sand a few minutes away. Looking for a place to get out of the 93° heat to eat our lunches, we headed to the one tree we had seen in the entire trip. Stepping out of the car almost had us believing we were in the Bahamas, and the white sand proved a pleasant place to sit. As we moved under the shade of the tree, two small owls flew out from its branches. Waiting cautiously in the leaves above us were three more owls, who seemed upset that we interrupted their lunch with our lunch (3 dead mice taunted them from next to where we were sitting).
After getting back into the car, we asked Dr. Judge and Dr. Pollock what our next stop would be. Getting only a, “Classified” as a response, all we could do is bounce around in the back of the car down a dusty road. We were pleasantly surprised when the trip ended at a natural hot spring. We eagerly climbed out of the car and jumped in.
We continued our first full day by taking a quick stop back at the campsite for a change into dry clothes before heading to meet Dr. Wilson’s, aunt, Ms. Sylvia Huntsman. She graciously welcomed us into her house where we played with her two dogs, Zeke and Bogey and ate delicious apple cobbler. When eyes started to droop from too much time sitting in a comfortable air-conditioned house, we excused ourselves to go eat more food. The fine cuisine of Fillmore proved itself once again at the “Garden of Eat’n.”
The first day ended with a final meeting back at the campsite to set a schedule for Monday (the 7 am departure time was a harsh return to reality) and a beautiful sunset.
Mark Wilson June 3rd, 2012
The summer field season has started for Wooster geologists. Greg Wiles is now in southern Alaska with his students doing dendrochronology and geomorphology. Meagen Pollock and Shelley Judge are running an integrated project in west-central Utah with their students doing structural geology, geochemistry, vulcanism and petrology. Watch these pages for their reports!
As for me, I’m on a short vacation. A geologically-rich vacation, of course! My wife Gloria and I are visiting the Shenandoah region of Virginia. We started today in Shenandoah National Park, driving south down Skyline Drive along the Blue Ridge. The weather is spectacular as you can tell from the above image. This is a view near Mile 61 looking west across the Valley and Ridge Province.
The Blue Ridge Province has a bedrock made of igneous and metamorphic Grenville basement rocks up to a billion years old. The Blue Ridge itself, which runs north-south from Pennsylvania to Georgia, is mostly an eroded anticline overturned westward. Directly west is the Valley and Ridge Province. In the image above, the “A” is at the spot where the top photograph was taken. You can easily pick out the physiographic and geological provinces.
Most of the rocks exposed along Skyline Drive in Shenandoah National Park are metabasalts of the Catoctin Formation (Ediacaran, about 570 million years old). A metabasalt is a basalt that has been metamorphosed (unsurprisingly). The original basalts of the Catoctin were erupted during the rifting open of the Iapetus Ocean, a precursor of the Atlantic. Many of these eruptions were on this early seafloor, forming pillows and thick flows. The total basalts in this formation piled up in layers to almost 800 meters thick.
The metabasalt of the Catoctin has a greenish color in many places, giving it the common name “greenstone”. Veins of green minerals, primarily epidote and chlorite, run through the rock, especially in the northern part of the Blue Ridge. This greenstone is occasionally mined to produced chemical-resistant lab surfaces and facing stones.
The dramatic geology was accompanied by beautiful wildflowers. The rocks, flowers, views and weather combined to make an extraordinary day of natural history. Tomorrow we’ll explore how this geology affected human history in very direct ways.
Mark Wilson June 3rd, 2012
Our version above of the bivalve Inoceramus is actually rather small compared to how big it can get. The record holder is a specimen 187 centimeters in diameter (over six feet) in the Geological Museum of Copenhagen. This Wooster Inoceramus is from the Pierre Shale of South Dakota, a unit my colleague Paul Taylor and student John Sime once explored in some detail.
Inoceramus means “strong pot”, which I assume must refer to its unusually thick shell with calcite prisms oriented perpendicular to the surface. They also had concentric “wrinkles” that make them easily identifiable even in small fragments. In fact, we can even recognize the isolated prisms of inoceramids in thin-sections of sedimentary rocks. This genus was widespread during the Late Cretaceous, being found from British Columbia to Germany. The had very large gill systems that enabled them to live in poorly-oxygenated waters. It makes sense that they are so common in the dark, carbon-rich sediments of the Pierre Shale.
Inoceramus was named by the dapper James Sowerby (above) in 1814, so it is a genus we have known for a very long time. Sowerby (1757-1822) was an Englishman skilled in natural history as well as scientific illustration. He named the first species of the genus as Inoceramus cuvieri to honor the French scientist Georges Cuvier. His illustration of I. cuvieri is below.
Inoceramus was one of the first invertebrate fossils to be the subject of an evolutionary study in a modern way. Woods (1912) studied various species of Inoceramus in the Cretaceous, noting that it apparently underwent rapid intervals of change. My former student Colin Ozanne and his advisor (and my friend) Peter Harries studied Inoceramus and its relatives in the Western Interior Seaway. Their study, published in 2002, showed that inoceramids were greatly stressed by parasites and predators before their final extinction in the Maastrichtian.
Ozanne, C.R and Harries, P.J. 2002. Role of predation and parasitism in the extinction of the inoceramid bivalves: an evaluation. Lethaia 35: 1–19.
Sowerby, J. 1822. On a fossil shell of a fibrous structure, the fragments of which occur abundantly in the chalk strata and in the flints accompanying it. Transactions of the Linnean Society of London XIII: 453-458. Plate XXV.
Woods, H. 1912. The evolution of Inoceramus in the Cretaceous Period. Quarterly Journal of the Geological Society 68: 1-20.