Fantastic Weather Makes Productive Field Days

May 28th, 2013

ICELAND – Team Iceland made the most of the beautiful weather over the last two days. After spending all day in the field yesterday, we went back after dinner;  the lighting was just right to take GigaPan images of the field site.

Aleks ('14, Dickinson) and Ben (Dickinson) set up the GigaPan to take a panoramic image of the quarry.

Aleks (’14, Dickinson) and Ben (Dickinson) set up the GigaPan to take a panoramic image of the quarry.

This is a simple panorama made of three images stitched together. The GigaPan system allows us to merge over 100 images to produce a high-resolution image.

This is a simple panorama made of three images stitched together. The GigaPan system allows us to merge over 100 images to produce a high-resolution image.

Our plan is to couple the high-resolution GigaPan images with elevation information from the laser range finger. Here, Michael ('16, Wooster) and Ellie ('14, Dickinson) are recording the elevations of contacts along the quarry walls.

Our plan is to couple the high-resolution GigaPan images with elevation information from the laser range finder. Here, Michael (’16, Wooster) and Ellie (’14, Dickinson) are recording the elevations of contacts along the quarry walls.

Meanwhile, the rest of us are mapping and sampling the different units. Adam ('16, Wooster) and Aleks ('14, Dickinson) are ready to sample a glassy pillow lava.

Meanwhile, the rest of us are mapping and sampling the different units. Adam (’16, Wooster) and Aleks (’14, Dickinson) are ready to sample a glassy pillow lava.

Alex ('14, Wooster) describes a volcanic breccia unit.

Alex (’14, Wooster) describes a volcanic breccia unit. Photo Credit: Aleks Perpalaj

Liz ('16, Dickinson) carefully describes the mineralogy and vesicularity of a sample.

Liz (’16, Dickinson) carefully observes the mineralogy and vesicularity of a sample. Photo Credit: Aleks Perpalaj

Ben and I are having a blast working in the quarry (no pun intended).

Ben and I are having a blast working in the quarry (no pun intended). We’ve seen a number of interesting features that have our minds racing. Photo Credit: Aleks Perpalaj

We're currently puzzled over these large, light gray, columnar jointed features.

We’re currently puzzled by these large, light gray, columnar jointed features.

 

The puzzling features are associated with these steeply dipping pillow lavas, which might lead to some insights into their origin.

The puzzling features are associated with these steeply dipping pillow lavas, which might lead to some insights into the origin of the features and enhance our understanding of the formation of subglacial pillow ridges.

Mission Possible: Mapping the Quarry Walls

May 27th, 2013

ICELAND – We spent Sunday morning discussing all of the features that we’ve seen during our reconnaissance investigations. After comparing notes, we defined several lithofacies, or mappable units with specific lithologic features. Our coherent lithofacies include pillow lavas, dikes, and intrusions while our fragmental lithofacies are units like volcanic breccia and lapilli tuff. By the end of the morning, Team Iceland was ready for their first group assignment: map a section of the quarry wall.

The students worked diligently to record comprehensive field notes.

The students worked diligently to record comprehensive field notes.

Image of a pillow lava that shows some of the features the students were looking for: radial columnar joints, glassy rind, interbedded hyaloclastite.

Image of a pillow lava that shows some of the features the students were looking for: radial columnar joints, glassy rind, and interbedded hyaloclastite.

The students celebrated the completion of their mission with lunch by large mining equipment.

The students celebrated the completion of their mission with lunch by large mining equipment.

 

 

Theory to Practice (Classroom in the Quarry)

May 26th, 2013

ICELAND – Team Iceland is investigating the formation of subglacial pillow lavas on the Reykjanes Peninsula in southwest Iceland.

We are working on a an elongated pillow ridge, which erupted along a fissure system when the peninsula was glaciated.

Google Earth image showing the elongated pillow ridge that we are working on. The pillow ridge erupted along a fissure system when the peninsula was glaciated. 

Quarries along the ridge expose the internal structure of the subglacial deposits, revealing complex sequences of pillow lavas, intrusions, and fragmental units.

One of the active quarries graciously allowed us to use their break room for a morning overview.

Ben Edwards discusses the  geological goals of the project.

Ben Edwards discusses the geological goals of the project. Photo Credit: Jim Ciarrocca

We spent most of the rest of the day working in the inactive part of the quarry.

Team Iceland examines the base of a wall of pillow lavas and discusses the formation of hyaloclastite, the glassy fragmental material that spalls off the pillow rims.

Team Iceland examines the base of a wall of pillow lavas and discusses the formation of hyaloclastite, the glassy fragmental material that spalls off the pillow rims.

As we explored the walls, we found a lava cave. Alex Hiatt ('14) snapped a photo of the hibernating lava bears for Dr. Wilson.

As we explored the walls, we found a lava cave. Alex Hiatt (’14) snapped a photo of the hibernating lava bears for Dr. Wilson.

Aleks ('14, Dickinson) uses a GPS and a laser range finder to "shoot" the quarry walls.

Aleks (’14, Dickinson) uses a GPS and a laser range finder to “shoot” the quarry walls.

Adam Silverstein ('16) points out features on the wall for Aleks to shoot.

Adam Silverstein (’16) points out features on the wall for Aleks to shoot.

The day ended with some reconnaissance work in the active parts of the quarry after the workers had left.

Team Iceland poses with a a fantastic columnar jointed basalt they found on their reconnaissance investigation.

Team Iceland poses with a a fantastic columnar jointed basalt they found on their reconnaissance investigation.

 

 

 

Pizza on the Pillows

May 25th, 2013

ICELAND – Team Iceland has arrived! We have been joined by our collaborators from Dickinson College and now number 9 strong. The Dickinson crew arrived early on Friday morning, so we spent much of the day recovering from our overseas travel and preparing for fieldwork. In addition to obtaining vehicles and food, we met our Icelandic collaborator, Steinunn Hauksdóttir, at the Iceland Geosurvey (ISOR) to discuss logistics. (Steinunn also showed us their latest geological map of the northern volcanic zone. We promptly offered to map the rest of Iceland for them in exchange for bread and Skyr).

When the group awoke from their jet-lagged slumber, they were hungry for food and geology. So, we thought we’d try a twist on the introduction to the field area: Pizza on the Pillows. In a spur of the moment decision, we thought it might be fun to have an informal dinner at the quarries where we’ll be studying the formation of subglacial pillow lavas. We picked up pizzas and headed to the field.

Unfortunately, when we arrived at the field, the weather was perfectly Icelandic. Although you can't see it, the wind and rain would have made our pizzas soggy.

Unfortunately, when we arrived at the field site, the weather was perfectly Icelandic. Although you can’t see it, the wind and rain would have made our pizzas soggy. We got the cliff notes version of the overview instead.

We are creative bunch, though, and were still able to have a different kind of Pizza on the Pillows back at the hostel.

Team Iceland and their "Pizza on the Pillows" in the dry hostel dining room. Pictured from left to right: Michael ('16, Wooster); Aleks ('14, Dickinson); Ellie ('14, Dickinson); Liz ('16, Dickinson); Dr. Ben Edwards; Alex ('14, Wooster); Adam ('16, Wooster); Jim Ciarrocca (GIS, Dickinson).

Team Iceland and their “Pizza on the Pillows” in the dry hostel dining room. Pictured from left to right: Michael (’16, Wooster); Aleks (’14, Dickinson); Ellie (’14, Dickinson); Liz (’16, Dickinson); Dr. Ben Edwards; Alex (’14, Wooster); Adam (’16, Wooster); Jim Ciarrocca (GIS, Dickinson).

On Our Way to Iceland

May 23rd, 2013

BOSTON, MA – A bleary-eyed Iceland group left Wooster at 4 am this morning to begin the journey to the land of fire and ice. We’ve arrived in Boston and are comfortably checked-in. We are patiently awaiting our flight to Keflavik airport, arguably the most geological airport in the world.

20130523-121853.jpg
Proof that we really are leaving for Iceland in two hours! From left to right are Adam Silverstein (’16), Michael Williams (’16), and Alex Hiatt (’13). The gate agent assures us that we’ll see lots of rocks in Iceland. We sure hope so! Follow our adventures on the blog for the next two weeks.

Theory to Practice: An Early GSA Abstract

May 11th, 2012

This semester, I’ve had the pleasure of teaching a special topics lab course in geochemistry. Given our new lab facilities, I decided to approach the class as an analytical geochemistry course. We explored sampling strategies, data quality, and the theory and techniques behind X-ray methods (XRF), electron-beam methods (SEM-EDS), and mass spectroscopy methods (ICP-MS).  Unlike a typical survey course, our course was entirely research-based. We actually became analytical geochemists by conducting an authentic research project on a suite of Icelandic basalts. Our goal was to investigate the development of a structural basin in northern Iceland by interpreting the petrogenesis of lavas that were erupted during different phases of basin construction. This week, we’ve accomplished our goal and have written an abstract to submit to the Fall 2012 meeting of GSA.

Here is the text of the abstract:

A GEOCHEMICAL ANALYSIS OF THE VATNSDALFJALL STRUCTURAL BASIN, SKAGI PENINSULA, NORTHWEST ICELAND

Matthew Peppers, Sarah Appleton, Lindsey Bowman, Andrew Collins, Whitney Sims, Melissa Torma, Meagen Pollock

Vatnsdalfjall, in northwest Iceland, exposes the upper ~700 m of crust formed ~7 Ma ago at the extinct Hunafloi-Skagi rift zone. In general, the lava flows dip gently westward toward the abandoned rift axis, but are interrupted by a local area of steeply dipping lava flows known as the Vatnsdalur Structural Basin (VSB). The VSB is composed of three sequences of lava flows emplaced before, during, and after subsidence. Using the geochemistry (XRF, ICP-MS) of samples gathered in the field in 2006 and 2007 and previous data from Ackerly (2004) and McClanahan (2004), we were able to establish a basic eruptive history for the sequences. Major element analysis shows diverse rock types, including basalt, basaltic andesite, dacite, and rhyolite. Sequence 1 shows the greatest diversity and was primarily affected by mineral accumulation, while Sequences 2, 3, and the dikes follow the trend of a shallow level fractional crystallization model based on a modified parent magma from Sequence 1. Trace element ratios suggest the presence of 1 (or 2) parent magmas, although the intermediate to silicic lavas appear to be generated by a separate process. Sequence 1 contains various lava flows, each with a uniform thickness, emplaced on relatively flat terrain. Sequence 2 was emplaced on top of Sequence 1 as subsidence of the basin was occurring, creating lava flows that thicken toward the basin interior. Intermediate to silicic rocks are absent during this interval and dikes cut Sequence 1 to feed lavas in Sequence 2. After a period of erosion, Sequence 3 was erupted above Sequence 2. Dikes that feed Sequence 3 cut through Sequence 2. The development of the VSB may have been associated with a waning period in the magmatic system, where magmas cooled and evolved (following an evolutionary trend controlled by fractional crystallization) and there was little partial melting of the crust (given the lack of intermediate to silicic lavas).

And some key figures:

Geologic map that shows the location of our samples on Sequence 1 (green), Sequence 2 (pink), and Sequence 3 (blue).

CaO vs. MgO (wt%). Symbols for dikes and Sequences 1, 2, and 3 are as shown on the geologic map. Previous data outlined by the dashed line. Fractional crystallization model shown by the black like. Arrows indicate effects of mineral accumulation. Plagioclase (pentagons) and clinopyroxene (stars) are also shown.

Schematic model (not to scale) for the development of the basin.

I applaud all of the students for their excellent work. They really took ownership of this project and deserve all of the credit. Look for us at GSA in the fall!

Wooster Geologists: Communicating New Knowledge

April 7th, 2012

AMHERST, MA – Congratulations to Wooster Geology Seniors Katharine and Andrew for their excellent presentations at today’s Keck Symposium! Andrew presented the results of his remote sensing investigation of channels on Ascraeus Mons on Mars. Andrew compared his channels to those on Pavonis Mons and in Hawaii. He characterized his channels as volcanic in origin based on their spatial distribution, surface stratigraphy, and geomorphological relationships.

Andrew poses by his poster during a rare quiet moment at the poster session.

Katharine presented her study of the Hrafnfjordur central volcano in the West Fjords of northwest Iceland. She found a complicated sequence of eruptive units that includes pyroclastic material, basalt, andesite, and dacite. Using geochemistry, Katharine determined that the units fall on different, genetically unrelated trends, suggesting that the Hrafnfjordur central volcano has a complex magmatic history.

Katharine enthusiastically explains her study to a thoughtful listener.

Overall, the Keck students are truly a motivated and talented bunch. It’s amazing to see what these students have accomplished over the course of a year. The symposium is not only a celebration of their achievements, it’s a powerful moment in which these students officially become part of the Keck alumni family.

The 2011-2012 Wooster Keck alumni.

Field Trip Friday

April 6th, 2012

AMHERST, MA – If you were following our adventures last summer, you’ll remember that Wooster helped lead a 6-student Keck trip to the West Fjords in northwest Iceland. You may not know that we also had a Wooster presence on the Keck Mars project. Now, after nearly a year of hard work, all of the Keck students are coming together at the Keck Symposium to share their findings and celebrate their accomplishments. This year, we’re at Amherst College in Massachusetts. The symposium kicked off today with glorious weather and a local field trip featuring “The ABV’s of Valley Geology: Arkose, Bedrock, and Varves.”

Our first stop was in the Moretown Formation. These early Paleozoic rocks were originally deposited on the edge of the continent and were subsequently deformed during the Taconic and (perhaps) the Acadian Orogenies. The outcrop consisted of interbedded schist and quartzite that had been metamorphosed to upper greenschist – lower amphibolite facies. We observed tight folds that showed fantastic crenulation cleavage, which developed as a result of multiple folding events.

Side-view of the crenulation cleavage, almost looking down the cleavage crenulation hinge.

The light reflects off of the wavy surface of micaceous schist layers. The pen is nearly aligned with the cleavage crenulation hinge.

Garnet porphyroblasts in the Moretown Formation.

After a brief stop at the Yankee Candle Company (what’s not to like about hot coffee, clean restrooms, and plentiful scented candles?), we made our way to Mt. Sugarloaf. Here, we visited the type locality for the Triassic Sugarloaf Arkose, a feldspar-rich sandstone and matrix-supported conglomerate. The arkose was deposited in the Deerfield rift basin during the opening of the Atlantic. Abundant orthoclase suggests that the sediment was close to its source. Most of the sediment was deposited by debris flows, but there is some evidence for reworking by a braided stream system.

Conglomeratic section of the Sugarloaf arkose.

We hiked to the top of Mt. Sugarloaf for a scenic lunch stop, where we had a breathtaking view of the Mesozoic rift valley in which the Sugarloaf arkose was deposited.

View from the top of Mt. Sugarloaf.

After lunch, we traveled back to 15,000 years ago, when the rift valley was filled with proglacial lake Hitchcock. The lake was over 200 km long, stretching from upstate Vermont to central Connecticut. Seasonal layers of silt and clay were deposited on the lake bottom, forming varves. It’s the flat-lying varves that make the valley floor so flat. The annual layers were also critical in the development of the New England Varve Chronology, which suggest that the lake existed for over 4,000 years.

Lake Hitchcock varves.

Close-up view of the annual layers in the Lake Hitchcock varves.

Our last stop of the day was to see the trace fossil Eubrontes (aka dinosaur footprints). The three-toed tracks are subparallel. If the tracks are the same age, then they may have recorded a passing herd. If the tracks are on different bedding planes, then this area may have been on a migration route. The Amherst College Beneski Museum of Natural History hosts the largest collection of dinosaur tracks world, primarily collected by Edward Hitchcock (also of the proglacial lake, third president of Amherst College, 1845-1854).

Three-toed dinosaur footprint. Do you see it?

It was nice of the dinosaurs to outline their footprints in chalk to make it easier for us to see!

We finished the evening with a reception at the museum (a drool-worthy collection that will be the focus of a future post). After a quick pizza dinner, the Iceland group is meeting for the last time to work on tomorrow’s presentations. It’s a bittersweet meeting; it’s fun to bring everyone together to compare findings and pat ourselves on our backs for a job well done, but it’s a bit sad to know that our Keck experience is coming to an end.

The Iceland crew on the Keck Field Trip.

Keck Mission Accomplished

August 7th, 2011

WOOSTER, OH – After a month of hard work, the Iceland Keck group parted ways on Saturday. We arrived in Wooster immediately after returning from Iceland and put in a solid week of work in the lab, preparing our samples for thin sections and XRF analyses. In one week, the students produced over 120 thin section billets, powders, and pressed pellets, and almost as many glass beads. Even though the work was tedious and the hours were long, I think we’re all glad that we’ll have data at the start of the school year. Well done, team!

A dessicator full of pressed pellets ready to analyze on the XRF.

 

Challenges of lab work. We tracked the number of samples that were prepared. This student prepped 20 pressed pellets "of varying degrees of brilliance + some epic failures."

Katharine works her magic on the scale.

Erica grinds the saw marks off of her sample.

Nina presses a brilliant pellet.

Thad oxidizes his samples in the muffle furnace.

Emily celebrates a glass bead that hasn't cracked.

Brennan and Katie troubleshoot the GIS file.

Of course, our work isn’t complete. Once we have the chemistry and thin section observations, we can put the data into the context of the mapped field relationships to understand the volcanic history of one of the oldest central volcanoes in Iceland. We’ll have much to present at the Keck Symposium in the spring and are already looking forward to our reunion.

A Keck Adventure at 66 North

July 28th, 2011

West Fjords, Iceland – We’re happy to report that the 2011 Iceland Keck crew has safely completed a productive field season. Nearly two weeks ago, a boat dropped us off in Hornstrandir, a nature preserve that encompasses most of the northern portion of the West Fjords. Our field area centered around Hrafnsfjordur, or Raven Fjord, in the southern extent of Hornstrandir. We had no idea that Hrafnsfjordur was a popular destination; it’s one of the primary drop-off and pick-up points for backpackers in the region. We must have seen at least half a dozen hikers during our stay. Hiking trails snake their way around the fjord and over the passes, which was fortunate for us since we had to access all of our field areas on foot.

A very still day in Hrafnsfjordur.

After a couple of days of recon hiking as a group, the students selected their projects and went to work. Most students chose to map a portion of the fjord, although one student focused on mapping and sampling dikes. Students worked in teams of two, each team being assisted by a faculty member.

A very sunny day in Hornstrandir.

Field work was challenging. Like our Alaskan colleagues, we had dramatic stream crossings, treks across snow, and hikes up steep terrain. Although we never saw a bear, we spotted an arctic fox in the distance. Thankfully, the fox wasn’t interested in our food. Dehydrated meals at the end of a long field day never tasted so good!

Coast guard performing drills outside our hostel in Isafjordur.

The weather was mostly good, by Iceland standards. It seems as if we were constantly confronted with either bugs, wind, or rain, but always just one at a time. Whenever Emily worked in her area, though, the sun would shine!

Hiking up snow to reach the peak.

We took a chartered boat back to Isafjordur on Wednesday and spent one last day in the field mapping a local mountain called Sauratindur. Now that we’re finished with field work and have returned to civilization, we realize how thankful we are for hot showers and soft mattresses. Still, there are some things that we’re already missing: the view from our tents, the sound of the waterfall (especially at night), the soft moss, our own private fjord, the hot cocoa, our special treat at the end of each day, and the freshness of the air.

Our Keck adventure in Hrafnsfjordur, in Hornstrandir.

Tomorrow, we start our long journey back to the states (via Reykjavik). We’re eager to get back to Wooster to start processing our samples. Hrafnsfjordur offered us an amazing amount of what we think are intermediate lava flows, which would be unique for Iceland. Dominated by basalt with local regions of rhyolite around central volcanoes, intermediate lavas are relatively sparse. Our field mapping, thin section observations, and geochemical analyses should yield some insights into the formation of Hrafnsfjordur’s central volcano. Stay tuned!

Panorama from the top of Manafell in Hrafnsfjordur.

Students playing a game of rock while waiting on the boat.

Textbook hanging valley in Isafjordur.

The boat that came to pick us up- one trip for gear and rocks!

The view from my tent in Hranfsfjordur, Keck.

Familiar scene for geo types- hiking up waterfall cuts for good exposure.

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