William and Mary


Rolling Deep with the Penrose Conference on Orogenic Systems

April 6, 2014 by

This past week I co-convened a Geological Society of America Penrose Conference focused on Feedbacks and Linkages in Orogenic Systems.   An orogen is a geologic term for a mountain belt, and orogenesis describes the processes at work in mountain belts (derived from Greek- oros for “mountain” and genesis for “creation/origin”).  The world’s great mountain belts include massive modern ranges such as the Himalayas, Andes, and Alps as well as ancient mountain belts such as the Caledonian orogen in Greenland, Scotland, and Scandinavia, the Grenvillian orogen in Canada, and the Limpopo orogen in South Africa.

Cover image from the Penrose Coonference filed guide and technical program.

Cover image from the Penrose Conference field guide and technical program.

The Penrose Conference included structural geologists, petrologists, sedimentologists, geomorphologists, geochronologists, and geophysicists all with a common interest in orogenic processes.  Geoscientists from as far away as China and Poland traveled to Asheville, North Carolina for nearly a week’s worth of discussions, talks, posters, and field trips.  Penrose Conferences are small meetings where the participants are encouraged to present novel or controversial hypotheses and hash out those ideas with colleagues.

Penrose Conferences were first established in 1969 and over the last 45 years these meeting have helped bring forward many major advances in the realm of plate tectonics, ophiolites, and metamorphic core complexes (to name just a few topics).  For me it was a great pleasure to co-convene a Penrose conference, I reconnected with old colleagues and met many new ones.  The National Science Foundation paid the freight that enabled participation by a large contingent of graduate students, the interaction between established scientists and up-and-coming scientists was special.

The Conference honored Bob Hatcher, who first brought a plate tectonic focus to the Appalachians back in the late 1960s and early 1970s.  Today working with his large and eager group of graduate students (aka the Hatchery), Bob continues to make seminal contributions to the field.

We experienced the fickle nature of the southern Appalachian spring on our field excursions.  The first trip started under heavy overcast with a malignant wind and wet snow blanketing the outcrops.  By the last stop on the final field trip day we were broiling in Carolina sunshine.

Views from the field trip: left- snowbound in the Blue Ridge Mountains at the 2nd stop, right- broiling in the Brevard Fault Zone at the last stop.

Views from the field trip: left- snowbound in the Blue Ridge Mountains at the 2nd stop, right- broiling in the Brevard Fault Zone at the last stop.

That evening as our crew of sun-drenched and thirsty geologists pulled to the curb in downtown Asheville and headed straight towards a brewpub, a natty hipster on a skateboard took one look at the group and commented, “Ah, you’re rolling deep.

Rolling deep?  Some of the brightest geologic minds I know were utterly stumped as to just what it meant to be rolling deep.  I’ll use the phrase in a sentence:

“Me and my Penrose posse were rolling deep in the Brevard Fault Zone looking for trouble and some dextral transpression.”

The geologic lexicon is rich with colorful expressions (for instance- there are glacial erratics, faults have both throw and heave, and ocean lithosphere can be obducted).  I have no doubt we can co-opt rolling deep as geologic term with tectonic significance.

Shaded relief map of the Blue Ridge Mountains and adjacent terrain in the Inner Piedmont and Valley & Ridge provinces of western North Carolina and eastern Tennessee.  The Penrose field trip examined rocks across this region.

Shaded relief map of the Blue Ridge Mountains and adjacent terrain in the Inner Piedmont and Valley & Ridge provinces of western North Carolina and eastern Tennessee. The Penrose field trip examined rocks across this region.

I learned much about the linkages and feedbacks at work in mountain belts at this Penrose Conference–from the focused erosion in the Himalayan river systems that drive rapid exhumation to the growth dynamics of garnet porphyroblasts in metamorphic rocks from deep in the interior of thrust belts.  Heady and exciting stuff!

Chaguite, Cuje, Clinic

March 24, 2014 by

We have worried about the value of our annual clinic since we first opened the doors in 2007.  We intended NOT to be a duffle-bag medicine project—arriving with U.S.-based notions about what our patients might need and dropping off short-dated medicines in small quantities.  Eight years later, we’re still trying to find ways to make our clinical efforts smarter, better founded, more integrated with local medical and health efforts, truer to the needs of our partners.  We are encouraged by this year’s meeting with Dr. Blanco.  We hope that our evolving relationship with the Totogalpa clinic will allow us to be more strategic and more attuned to needs defined by those who have responsibility for providing health care on a continuing basis.

Our community-based approach inclines us to learn as much as possible from those who live in the communities we intend to serve with health care efforts. Our work in Chaguite has provided us with systematic information and increasing understanding of the health and health care needs of residents of that community.  We know better than to generalize these understandings to residents of the remaining communities that comprise Cuje—the micro-region served by our annual clinic.  We envisioned a Cuje-level Comite de Salud (CdS; Health Committee) that would comprise representatives of residents of each of the communities.  We imagined collecting information from brigadistas in each of the communities and we hoped that we might, through snowball sampling and sociometric techniques, identify such a group as a start for consulting with residents about ways to make our clinic more responsive.

In pursuit of that goal, we reprised our satellite-sites approach to the annual clinic this year.  The objective was to take each day’s clinic as close as possible to the geographic center of the remote communities of Cuje.  Working from those locations, we would dispatch team researchers to conduct interviews with the communities’ brigadistas and with members of randomly selected households to identify community residents who might be (1) interested in participating in discussions about improving the clinic services; (2) trusted to represent residents’ beliefs and needs.  After the first day’s efforts, student researchers reported that there is something wrong with the questions we’re asking or with the respondent-selection process.  Respondents usually were able to identify their community’s brigadistas or other leaders, but they routinely reported that these people did not represent their interests, did not understand their needs, and did not work with them or on their behalf.  We tweaked the questions and the general strategy and tried again the next day.  The results were unchanged.

None of the students on the current MANOS team participated in the first round of interviews in Chaguite.  We were asking very similar questions then—and we got answers very similar to what we are hearing this year in other communities.  That seems nearly impossible to believe now and, seen from our now customary view of collaboration in Chaguite, these other communities seem desperately (1) unfamiliar (because they are) and (2) lacking in social infrastructure (which they may be).  I have the benefit of historical perspective.  I recall residents of Chaguite who were able to identify two or three key leaders (some of whom were brigadistas) — and I remember the same residents saying that they do not work with these leaders and that these leaders do not represent their interests.  I remember the leaders saying that they try to hold community meetings but that residents will not attend and will not collaborate in projects with potential value for the whole community.

This year’s effort to “sample” our way into some rough understanding of the other communities and their social infrastructures was a well-intended effort to find a short-cut for gaining information from residents throughout Cuje.  We want to hear their voices as we think about how our clinic can be more than duffle-bag medicine.  At this moment, it does not appear that there is a short-cut, no substitute for the years of work in the community, on the ground, in the homes, working with good social science methods to learn, using the resulting information and knowledge to build relationships.

Dr. John Showalter (M.D., Knoxville, TN) played a significant role in our follow-up conversation with Dr. Blanco (Totogalpa Clinic Director).  His understanding of our approach and shared frustration with the apparent limited value of our annual clinical efforts were crucial to the discussion.  Speaking medical professional to medical professional, Dr. Showalter was able to convince Dr. Blanco of our determination to be more than another itinerant bunch with good intentions.  We will do all we can to build on this step forward.

Dr. Showalter joined us at the end of the week in two additional meetings, one at a medical school in Managua and the second at the American Nicaraguan Foundation (more on that in a later post).  Through inquiries by Kristina Ripley, we have been in contact with a professor of medicine at this university.  We toured the medical school, talked briefly about our projects in Cuje, and learned about our host’s interests in extending health services to the under-served in Managua.  Dr. Showalter inquired about good strategies for short-term, annual clinical projects and about sources of medicines that would be appropriate for the Cuje population.  His participation in the discussions clearly elevated the seriousness with which are efforts are regarded by this local medical professional.

Baby steps—but they seem to be in a good direction.  We don’t know yet how to make our clinic more responsive and more responsible.  We’ll add more research on brigade and short-term, international clinical approaches to our work for the remainder of the semester and it will top the list of topics for next fall’s seminar.

It’s Not Linear; 2/28/14

March 24, 2014 by

In November 0f 2009, I wrote that SHC was becoming MANOS and that the timing seemed more than incidental.  (And, it happened even before Chrissy Sherman joined the team.)  It seemed clear to me then that the project was evolving from the “service learning” group of 2006 and was finding its way.  The new name, Medical Aid Nicaragua: Outreach Scholarship, was in part a proclamation of  vision: to learn, to research, to engage with, to be mindful of presumptions about what we’re doing and how it may be received by those with whom we intend to partner.

In a post dated March 11, 2010, I noted that we would begin this year to focus our community efforts in Chaguite.  We estimated that there are about 40 houses in this community and by the end of the 2010 March trip, we were close to completing interviews in all of the homes.  From the same trip, I described meeting with a local “brigidista.”  His name is Ysidro and it’s clear that he works very hard to care for his family and still finds time to serve in a volunteer capacity that involves “looking after” the health and health care needs of the community.

And so it is 2014, and we keep coming back—now routinely three times each year, in some fashion:  Small teams in January (like the one this year that facilitated community meetings with representatives of our newest partners from the Engineers Without Borders chapter at Cal Poly – Pomona);  the full team each March; and a team of three to eight students in the summers.  The work proceeds—slowly, deliberately, sometimes seemingly as much sideways as forward, but always as fully as possible in step with community partners.  Chrissy Sherman ’14 has traveled to do research in the community eight times, as has Lester Chavez ’14.  Other experienced team members have traveled from three to seven times each and, through that dedication, have developed understandings, appreciations, and real friendships within the community.

We now know the residents of the households in Chaguite, which number about 50.  We have mapped the region, the households, the health problems and assets. We seem to be realizing the vision in our name—and we continue to worry about our presence, our role, our relationships, and our partnership. Through repeated interviews in all households in the community, we have come to know residents and we have learned about their health and healthcare concerns, needs, and priorities.  We learned about the leaders and about interpersonal networks – those groups of people who communicate with one another and collaborate on occasion.  In our earliest interviews, we were struck by the paucity of communications and collaboration even as residents were able to identify “leaders.”  Residents told us that they did not work with leaders and that leaders did not work with them or understand their concerns and needs.  Through Social Networks Analysis (SNA), we identified “organic” networks of communication, groups of residents who do talk together and we encouraged them to meet together and with us to help us to understand the health and healthcare priorities.  They were modest in number, scope, and inclusiveness.

The social networks analysis (SNA) techniques enabled us to calculate measures of “network density” (the proportion of interpersonal connections reported as a proportion of the total possible connections for the respondents).  It is an imperfect method and an imperfect indicator, but SNA measures of network density provide an empirical and quantitative way to gauge communications and collaboration within communities.  In general, there is inadequate research to allow us to estimate what levels of density are “normal” or “typical,” but at a minimum, we can take measures at different points in time and compare these to observe change.  Our first round of research provided a network density estimate of less than two percent – that is, of all the dyadic (two-person) relationships that might exist in the community, less than two percent were reported as existing.

We have been working with these organic groups (which we began calling “regional groups”) for several years now and through communications within and across these groups, have worked with residents to create and authorize a five-year plan to improve health and healthcare.  Through these groups, we have partnered with the community to advance a project with Engineers Without Borders (EWB). We strongly suspect that our next round of SNA research will reveal significant changes in the level of estimated network density.  We believe, further, that network density is crucial to the development of effective social infrastructure – the organizing of resources, activities, and tasks needed for communities to collaborate to build sustainable solutions to shared problems.  We won’t know until we do a second round of systematic research, but it appears that levels of communication and collaboration have increased markedly over the last four years as we have encouraged engagement through the organic networks and participation through these in regular community meetings.  (We’ll be sure to report our findings to Chrissy Sherman no matter where her FOMO efforts may take her next.)

This year, we undertook interviews in households that have not been represented regularly (or at all) in regional group meetings or community meetings.  We are trying to understand how we might make engagement in community-level efforts to improve health more inviting, more accessible.  We were accompanied by community members from the respective regional groups in our hope to engage residents more fully in our research efforts.  The residents were more inclined to chastise those we visited than we preferred and we encouraged a point of view that emphasizes the value for all in increasing participation—particularly in the developing project to provide access to water for everyone in the community.

In a final note:  Chrissy Sherman once drove for approximately 3 seconds in Nicaragua.

Persistence and Partnering. 2/27/14

March 21, 2014 by

The MANOS advance team (Johnathan Maza ’15; 5th project trip); Stephanie Wraith ’15, fourth project trip; Sarah Martin ’17, 1st project trip; and me, 8th project trip) met with Dr. Benito Blanco, Medical Director of the MINSA clinic in Totogalpa, Nicaragua.  We summarized our medical and community efforts over the past seven years in Cuje (micro-region) and the community of Chaguite.  Dr. Blanco expressed appreciation for these efforts—and some mild aggravation about the lack of coordination of our efforts with his office.  He noted that our clinic has been helpful but could be more effective through such coordination.  We agree—and we are encouraged by his perspective.  We’ve been urging that point of view since 2007.  There are several plausible explanations for and possibly contributing factors to the lack of effective partnering to date.  It is likely, for example, that for the first several years the local medical professionals saw no reason to believe that we would keep coming.  There was a different clinic director when we began.  He’s now the mayor of the municipality of Totogalpa.  And, when we began, the region was in a deep drought and even the most meager of resources had dried up.  At that time, we found the clinic woefully under-staffed and with the most minimal medicines and equipment.  There was a “siege” kind of feeling about the operation and the clinic staff seemed more than satisfied for us to do anything—without much consideration of strategic advantages.

The entire region has seen remarkable improvements over the last several years:  more rain, resurgence of flora and fauna following the transformation of the ecology through clear-cutting of the evergreen forests, a relatively stable government, and increased presence and investment of national and international NGOs.  Like the clinic, the mayor’s office, where we met with the Sub-mayor and the General Secretary of Community Cabinets, the facilities were in good repair and had an air of organizational efficiency that clearly was absent when we visited earlier.

It seems likely that these things have contributed most to the current moment for engagements:  (1) Success by Dr. Blanco and his colleagues and staff in gaining and using resources to achieve organizational and professional goals; (2) the increase in NGO presence in the area, leading to a sense of need and possibility for strategic arrangements; and (3) our persistence in returning to the area.

We do not quibble with Dr. Blanco’s view that more can be done through better collaboration. That, essentially, is our mantra.

We met also with officials in the mayor’s office.  We heard a similar message and we embraced that with equal enthusiasm.  We deserve and take no credit for their (seemingly) increased enthusiasm to partner—other than our persistent effort to learn from them how we can best work with them to partner with communities to improve health and health care.  Readiness to partner involves more than one potential participant.  And, in the current era of volunteering, service, service learning, engaged scholarship, action research, and participatory development, it seems necessary to establish proper creds in order to expect authentic discussions about the role that might be played by outsiders.

The Power of Teamwork: How I Know I’m Heading Down the Right Career Path

March 7, 2014 by

When I was in high school (and up to this point in college) all my school work had been rather lonely. In high school, group projects were only in class. In college a group meets just to delegate work for the individual members to do at home, and then meets up again to fit everything together. Most work is done silently and alone. The flow of knowledge is from teacher to student, and rarely do other students get involved in that relationship.

For most people, that works. I always thought it worked for me; it’s how I’ve been learning for the past 19 years. But this semester I started participating in more activities in the business school, and I found a totally new way of learning that makes more sense to me than anything before.

In late January, I participated in a conference called 3 Day Start-up, where teams literally build a company in 3 days. We started Friday night with everyone throwing around ideas for start-ups. New businesses do not need to be unique or revolutionary – you just need to do whatever it is better than anyone else. The 3DS participants with the best ideas pitched to the group, and we voted on 3 of our favorite ideas to execute during the weekend. We then split into groups and got to work. I ended up on a team that was trying to design a new hotel management system in which customers could check in on iPads and bypass the long check-in process. The traditional system costs about $30,000; we would sell ours for $4,000. Hotel clerks and clients would both have less hassle.

The guys who proposed this idea had been working on it for a while and already had a prototype set up. The team split into a group who worked on coding the system and a group who worked on marketing and business pitches. I was on the business side. My team spent Saturday doing market research – actually going from hotel to hotel to ask clerks what they thought about the product and what kind of suggestions they had for us. Learning about our market opened our eyes to a lot of nuances we would have never known about. Great Wolf Lodge, for example, we thought would love the idea because they get so busy at certain times. However, since they value customer interaction, they weren’t as enthusiastic about it as we thought. Other hotels, like the Hilton, thought it would be great during peak seasons or for business people who would rather avoid interaction.

On Sunday we worked on pitching the idea to investors and fitting the last pieces together. Watching everything come together was amazing! The prototype that the coders were working on all weekend looked like a professional app on an iPad. The business team had all the details of the pitch worked out. It was absolutely flawless, and I was so proud of the team.

The second instance of true teamwork happened for my Social Entrepreneurship class. The big project for the class is creating our own social venture in groups of 4. This is essentially like the 3 Day Start-up, except the start-ups are non-profits that help alleviate some sort of social problem. My group of four met up on a snowy night to figure out what in the world we were going to do for this project. What big social problem were we going to attempt to solve? We sat around pitching ideas, until someone said something that clicked for all of us: a website that crowd-sources local suggestions to fix local problems. We figured the best people to solve social problems are the ones actually there witnessing them.

With a big whiteboard and a rush of inspiration, we hashed out the business plan right there, challenging each others ideas and encouraging innovation. It was here that I had what I would call my first “flow” moment.

“Flow is the mental state of operation in which a person performing an activity is fully immersed in a feeling of energized focus, full involvement, and enjoyment in the process of the activity. In essence, flow is characterized by complete absorption in what one does.”

I felt invigorated and unstoppable, and this, I realized, is why I’m a business major. I learn from my peers, not myself. Sure, studying for an economics test is rewarding and challenging, but my own efforts are not nearly as spectacular as the ending product through teamwork. Both these experiences showed me that the combined knowledge of multiple people who are committed to a goal is far more powerful than the singular knowledge of one person. A team is the convergence of multiple experiences, viewpoints, and educations. A well-functioning team can increase productivity exponentially.

I just got my acceptance letter to the business school a few weeks ago, and I’m already ecstatic by the possibilities ahead. In the first semester, called “the block”, administration puts together groups of 4 or 5 students that take all classes together and work on homework and projects together. I’m so excited to integrate teamwork into my everyday education. For the first time in college, I can really visualize transferring my classroom setting to a work environment. It’s thrilling and satisfying to know the path I’m choosing is leading to a career that I’m going to love.

What I want to be when I grow up.

March 5, 2014 by

There are three questions every college senior gets asked.

  1. You’re a senior?! How does it feel?
  2. Do you know what you’re doing in May?
  3. What do you want to be when you grow up?

#3 is my personal favorite, because it instigates a sense of inescapable panic while simultaneously making me feel like a six year old. Typically I fire a generic response (“I’d like to pursue a career in marine science blah blah blah”). But Spring Break is here, meaning graduation is closer than I’d like to admit, and I can’t rely on generic responses forever. What do I want to be when I grow up?

The last time I knew exactly what I wanted to be, I was 8 years old. I wanted to be a country music star. I grew up listening to greats like Martina McBride, Jo Dee Messina, Sara Evans, and Reba McEntire (let me clarify: this was pre-Taylor Swift), and I was convinced I would get discovered, move to Nashville, and pursue a lifelong career in country music. My friend Katie and I would camp out in my basement, taping “demos” on her sister’s cassette recorder and speculating what we would do once we made it big. The closest I got to Nashville was my 4th grade talent show, where I sang a Dixie Chicks song while decked out in a cowboy hat and boots.

In many ways I envy 8-year-old me. I have never been so certain of my life plan as I was in that basement. But I grew up and my plans changed, especially after I learned it took more than the ability to hold a tune to make it big in the country music business (plus, my parents refused to move from Baltimore to Nashville).

In college, I made a great breakthrough when I decided I wanted to study marine science. Although I’m unsure where my studies will take me, limiting job options to a single discipline is a big feat. I’m fortunate that I’ve been able to experiment with many fields within marine science, and have subsequently narrowed down what I don’t want to do (I loved marine ecology, but marine geology was the absolute bane of my existence). But that still leaves me with a generic answer to question #3.

But I came a little closer to answering the question last week. Over winter break, I decided to apply for a fellowship that would take me abroad for nine months next year. It was up to the applicant to design a proposal—the only restrictions were that the research had to employ a method of digital storytelling and apply to a wide audience. The rest was up to the applicant. Inspired by my work with The Lionfish Project, I chose to study community-based invasive species management on islands.

I worked on the proposal for six weeks. I spent many late nights researching topics, often pushing aside piles of homework I’d have to scramble to make up later. There were even a few nights I chose my research over going out with friends, opting instead to stay huddled at my desk, reviewing research papers and writing hurriedly in my notebook. Piece by piece, my proposal came together. I spent the week before the due date meeting with professors and analyzing every line of my proposal, writing and rewriting until it was perfect. The night before it was due, I was up until almost 5am reviewing every tiny detail (no typos, all margins 1”, 12 pt Times New Roman font, all biographical data correct, etc).

I submitted the document at 11:17 on Friday morning, February 28th. As soon as I clicked the “Submit” button, I was flooded with a mix of pride, panic, and relief. But there was another feeling too.


I hadn’t been so excited about something since I wrote the proposal for The Lionfish Project in 2012. Never once did I mind the research—I looked forward to crafting, writing, and editing the proposal, and I was truly passionate about the topic. As I stared at the submission confirmation screen, I realized it didn’t even matter if I got the grant (although let’s be real, it would be awesome if I did). What mattered was that I had pursued a topic that made me truly happy.

So maybe I haven’t figured out exactly what I want to be when I grow up (although a marine biologist studying invasive species is definitely on the list). But that’s ok. This experience has shown me that no matter what I do, I want to be so passionate about it that it keeps me up at night. That might be a stretch, but maybe not. I have the rest of my life to find exactly what it is that makes me that excited.

For now, at least I know how to answer Question #3.

When I grow up, I want to be happy.


Working in a Winter Wonderland: The Gravity of the Situation (Part 2)

February 27, 2014 by

Last summer I reported on our field research in the High Plateaus of Utah. Erika Wenrich’s senior thesis project involves a gravity survey aimed at estimating the amount of sediment beneath Fish Lake, a large alpine lake developed in a high-elevation graben. In June we measured gravity at a network of stations around Fish Lake, but to complete the gravity survey, and model the sediment’s thickness in the basin, we needed gravity data on the lake itself. It’s now February and Fish Lake is covered by ice—time to return and complete the survey on the lake’s frozen surface.

Overview map of Fish Lake, Utah with 2014 gravity stations and core site.

Overview map of Fish Lake, Utah with 2014 gravity stations and core site.

Our whirlwind outbound journey included an unexpected drive to Dulles airport to catch a long flight into Las Vegas followed by an even longer drive from Nevada to Fish Lake. We arrived at the lake weary from travel, but excited to get started. The lake was crusted over with ~30 cm of ice (12”) and a layer of snow from a recent storm. The temperatures were well below freezing and accompanied by a stiff breeze from the southwest—it was brisk.

View to the east of Fish Lake's frozen surface and Mytoge Mountain which rises steeply from the southeastern edge of the lake.

View to the east of Fish Lake’s frozen surface and Mytoge Mountain which rises steeply from the southeastern shore of the lake.

Erika Wenrich makes a gravity measurement.

Erika Wenrich makes a gravity measurement.

As expected measuring gravity on the lake’s icy surface during the day proved to be nearly impossible. The gravimeter is a delicate instrument that needs to be carefully leveled and works via the stretching of a spring balance with a constant mass. During sunny daylight hours the lake receives copious solar insolation that heats the ice, and as the ice expands fractures develop (not big through-going cracks, but rather small cracks here and there). When cracks propagate, seismic energy courses through the ice causing the delicate spring in the gravimeter to oscillate such that obtaining a reliable and reproducible measurement is not possible.

At night the ice is far more stable and consequentially we became nocturnal creatures wandering about on the dark icy surface making our gravity measurements. The lake was profoundly quiet during the wee hours and the veil of stars put on quite a show overhead. Working the night shift took its toll; after two consecutive evenings into the early mornings spent out on the ice we were wiped out. However, we completed three new gravity traverses across the ice and Erika is in a good position going forward with her research.

After a Hard Day's Night. W&M geologists Erika Wenrich and Peter Steele in the early morning after their nighttime gravity survey.

After a hard day’s night. W&M geologists Erika Wenrich and Peter Steele in the early morning light after their nighttime gravity survey.


The coring team at work on Fish Lake's icy surface.

The coring team hard at work on Fish Lake’s icy surface.

Our trip was timed to coincide with a visit by a team of collaborating geoscientists who were obtaining the first sediment core from Fish Lake. Once again the ice was critical, as the team’s coring rig was set upon the firm surface—for four days they lowered and raised the coring apparatus through 30 meters (100’) of water and into the muddy sediment at the lake’s bottom. They were rewarded with about 11 meters (35’) of core, which was safely transported to Oregon State University’s core repository to await detailed study by the team.

William & Mary alum and all-around good guy, Dr. Scott Harris from the College of Charleston used a transient electromagnetic (TEM) geophysical system to learn about the subsurface. He had quite a setup with a long (400 m) wire transmitter placed around multiple receiver loops out on the ice. The system induces an electric field and then measures the decay of that field through time, providing what is essentially a column of the conductivity in the subsurface. The lake’s fresh-water has a very low conductivity, while the infilling mud in the lake basin and underlying bedrock have much higher conductivities. His initial tests yielded subsurface information to depths of over 300 m, hopefully imaging the contact between the lake sediments and bedrock.


Dr. Scott Harris (W&M class of ’88), kneeling on the ice, runs the TEM geophysical system on a breezy day at Fish Lake.

Our gravity data indicate that the lake is underlain by upwards of 100 meters of sediment (>300’), so the coring operation sampled just the uppermost layers of the graben fill. In the future we hope to core though the entire sediment package to fully understand the geologic history of graben development, lake formation, and glaciation.

Erika is one of 33 William & Mary geology majors in the class of 2014 and they are all working on senior research (thesis) projects. These studies range from gaging rock erodibility along the banks of the Potomac River, to understanding the complexities of agricultural runoff in the Coastal Plain, and even searching for water ice on Mercury. As college seniors, W&M geology students are contributing new knowledge about how the Earth operates (and other worlds as well). It’s cool stuff and part of what makes majoring in geology at William & Mary distinctive.

Glimpses of the Past: the Catoctin Formation – Virginia is for Lavas

February 17, 2014 by

In 1969 Virginia embraced the travel slogan Virginia is for Lovers and at various times during the last 45 years William & Mary geology students have emblazoned departmental t-shirts with Virginia is for Lavas and turned the iconic heart into a volcano.


In that spirit, Geology Fellow Alex Johnson and I wrote a piece on the ancient lavas that once covered a large swath of what would become Virginia.  What follows is an abbreviated version.  Read the full version.

Stony Man is a high peak in Virginia’s Blue Ridge Mountains that tops out at just over 1200 m (4,000’).  Drive south from Thornton Gap along the Skyline Drive and you’ll see the impressive cliffs of Stony Man’s northwestern face.  These are the cliffs that give the mountain its name, as the cliffs and slopes have a vague resemblance to a reclining man’s forehead, eye, nose, and beard.  Climb to the top and you’ll see peculiar bluish-green rocks exposed on the summit that are ancient lava flows, part of a geologic unit known as the Catoctin Formation.  From the presidential retreat at Camp David to Jefferson’s Monticello, from Harpers Ferry to Humpback Rocks, the Catoctin Formation underlies much of the Blue Ridge.  This distinctive geologic unit tells us much about the long geologic history of the Blue Ridge and central Appalachians.

Stony Man’s summit and northwestern slope, Shenandoah National Park, Virginia. Cliffs exposed metabasaltic greenstone of the Neoproterozoic Catoctin Formation.

Stony Man’s summit and northwestern slope, Shenandoah National Park, Virginia. Cliffs expose metabasaltic greenstone of the Neoproterozoic Catoctin Formation.


Geologic cross section of Stony Man summit area (modified from Badger, 1999).

Geologic cross section of Stony Man summit area (modified from Badger, 1999).

The Catoctin Formation was first named by Arthur Keith in 1894 and takes its name for exposures on Catoctin Mountain, a long ridge that stretches from Maryland into northern Virginia.  The word Catoctin is rooted in the old Algonquin term Kittockton.  The exact meaning of the term has become a point of contention; among historians the translation “speckled mountain” is preferred, however local tradition holds that that Catoctin means “place of many deer”.

Origin of the name aside, the Catoctin Formation is a geologic unit that crops out over a large tract in the Blue Ridge region of Virginia, eastern West Virginia, Maryland, and southern Pennsylvania.  Its current geographic extent does not, however, represent the original extent of the Catoctin Formation.  In southern Pennsylvania and Maryland, the Catoctin Formation crops out in one contiguous area, but in Virginia there is an eastern and western outcrop belt of the formation.  The Catoctin Formation is exposed on both limbs of the Blue Ridge anticlinorium, a complex regional-scale fold that has been breached by erosion thereby exposing older rocks in the center and younger rocks such as the Catoctin Formation along the flanks.  Originally, the eastern and western belts were contiguous, but erosion has removed the younger Catoctin Formation to expose older rocks in the central Blue Ridge.

Map illustrating the distribution of the Catoctin Formation in the central Appalachians.

Map illustrating the distribution of the Catoctin Formation in the central Appalachians.

Column joints in the Catoctin Formation exposed along the Skyline Drive in Shenandoah National Park.

Column joints in the Catoctin Formation exposed along the Skyline Drive in Shenandoah National Park.

The Catoctin Formation is composed primarily of metabasalt, commonly referred to as greenstone due to the rock’s greenish tint.  When the basalt was metamorphosed, igneous minerals such as pyroxene, plagioclase, and olivine were converted to new minerals (chlorite, actinolite, and epidote), which give the rock its distinctive color.  The Catoctin Formation also contains discontinuous layers of metasedimentary rock (including phyllite, quartzite, and even marble), as well as volcanic breccia and metarhyolite.

As the Catoctin lavas cooled, columnar joints developed in many flows.  Columns form as the rock volumetrically contracts during cooling.  As a lava flow cools, both from its top and bottom surface, these cooling cracks propagate inward, forming hexagonal columns. Columnar joints are best developed in lava flows that extrude onto a landscape.  These columns are common in the Catoctin Formation’s western outcrop belt and indicate the flows were extruded on land.  In contrast, at a number of outcrops in the eastern Blue Ridge, pillow lavas are preserved in the Catoctin metabasalts. Pillow lavas are bulbous to lobate masses formed as lava rapidly cools underwater, forming a glassy shell as the surrounding water quenches the lava.

Pillow structures in the Catoctin Formation exposed along the south bank of the Hardware River in southern Albemarle County, VA.

Pillow structures in the Catoctin Formation exposed along the south bank of the Hardware River in southern Albemarle County, VA.


How old are the ancient lavas of the Catoctin Formation?  When did a vast volcanic plain cover the terrain that would become central and northern Virginia?

Metabasalt dikes commonly intrude and cut older granitic rocks in the Blue Ridge, and in rare cases these feeder dikes can be traced upward into metabasalt flows that covered the granitic rocks.  Based on these cross cutting relations, the Catoctin Formation is clearly younger than the old Blue Ridge granites that crystallized between 1.2 and 1.0 billion years ago.  The Catoctin metabasalts are overlain by a sequence of sedimentary rocks that contain fossils including Skolithos, a distinctive trace fossil formed by burrowing creatures.  These fossils are characteristic of sediments deposited during the early Cambrian period some 520 to 540 million years ago.

Graph illustrating isotopic ages and their associated uncertainty for the Catoctin Formation.

Graph illustrating isotopic ages and their associated uncertainty for the Catoctin Formation.

Geologists have attempted to date the Catoctin lavas with varying degrees of success.  In 1988, Badger and  Sinha reported a late Precambrian age of 570 ± 36 Ma for the Catoctin Formation based on the Rubidium/Strontium (Rb-Sr) dating technique, however this isotopic system can be readily disturbed by later metamorphism.  Zircon is a high temperature igneous mineral that is ideal for geochronological studies.  Zircon crystals invariably contain a small amount of uranium, a radioactive element that decays to lead at a constant and well-known rate.  By comparing the ratio of certain uranium and lead isotopes in a given crystal, it is possible to discern how long the uranium has been decaying, and thus the age of crystal and, by association, the rock in which it is situated.  However, silica-poor mafic igneous rocks, such as basalt, commonly lack zircons and thus cannot typically be dated with this technique.

Yet, all is not lost as the Catoctin Formation is composed of more than just metamorphosed basalt; in northern Virginia, western Maryland, and southern Pennsylvania, metarhyolite is interlayered with the metabasalt.  Rhyolites are felsic volcanic rocks that typically contain zircon and can be dated with the U-Pb method.  Based upon U-Pb ages from metarhyolites in the Catoctin Formation, the extrusion of this volcanic complex occurred around 570-550 million years ago (Aleinikoff et al., 1995; Southworth et al., 2009) during the Ediacaran Period at the end of the Neoproterozoic Era.

What is a sequence of volcanic rocks doing in the Blue Ridge?

The Catoctin Formation is likely a continental flood basalt associated with late stage rifting that broke apart the Rodinian supercontinent and created the Iapetus Ocean.  Flood basalts are large igneous provinces where low viscosity basaltic lava floods vast areas of the Earth’s surface.  Due to the lava’s low viscosity, flood basalts are generally extruded quite rapidly, geologically speaking.  In the case of the Catoctin Formation, more than 30,000 cubic kilometers of lava were extruded in a few million years.  The origin of flood basalts is widely debated, however the most common explanation involves a combination of decompressional melting due to both continental rifting and the rise of a hot and expansive mantle plume.  The origin of mantle plumes is also poorly understood, but likely involves a buoyant melt produced near the mantle-core boundary, which proceeds to rapidly rise through the mantle, melts other rocks, and drives extrusion of volcanic rocks at the surface.

Schematic diagram of a rising mantle plume 1) moving through the mesosphere 2) spreading in the asthenosphere 3) piercing thelithosphere and extruding onto the surface.

Schematic diagram of a rising mantle plume 1) moving through the mesosphere 2) spreading in the asthenosphere 3) piercing the
lithosphere and extruding onto the surface.

Throughout geologic time, the cycle of assembly and dispersal of so-called supercontinents has been one of the most dramatic examples of plate tectonics at work.  The supercontinent Rodinia is hypothesized to have been formed in the Late Mesoproterozoic and Early Neoproterozoic.  At its core was Laurentia, a large landmass composed of what is now modern day North America, Greenland, and northern Scotland.  As supercontinents are wont to do, Rodinia began rifting apart some 600-550 million years ago; the tectonic plates began to once again change direction and slowly drifted away from one another, forming new oceans and closing others.  One of these new oceans that was created (and later destroyed during the creation of the most recent supercontinent, Pangea) was the Iapetus. The Iapetus formed between the eastern edge of the Laurentian craton and almalgam of tectonic blocks that would eventually be formed into what is referred to as Gondwana. It was during this period of rifting that the volcanic rocks of the Catoctin Formation were extruded on Laurentia’s margin.

A key method by which geologists have discerned the cycle of supercontinent formation and dissolution has been through paleomagnetism, which is the study of the magnetic properties in certain minerals as means to reconstruct the past location of tectonic plates.  Although paleomagnetism has played an integral part in developing the theories of plate tectonics and continental drift, paleomagnetism in old rocks is complex.  Take for instance the plight of Rodinia, different researchers have constructed multiple iterations of the supercontinent’s configuration and location.  One study, focused on the Catoctin Formation in particular, place Laurentia near the South Pole at the end of the Neoproterozoic.

Paleogeographic reconstruction of Laurentia and surrounding continents at ~550 Ma. Note Laurentia was in the southern hemisphere (data from numerous sources).

Paleogeographic reconstruction of Laurentia and surrounding continents at ~550 Ma. Note Laurentia was in the southern hemisphere (data from numerous sources).

How did a vast plateau of volcanic rocks that were buried beneath kilometers of shallow marine sedimentary rocks become the foliated greenstones that undergird the Blue Ridge Mountains?  The answer to this question involves a complex history of deformation, metamorphism, and uplift.

Recent geochronological studies indicate that the penetrative deformation and metamorphism, the tectonic event that produced the distinctive foliation in the Catoctin Formation, occurred between 320 and 350 million years ago during the Carboniferous Period. Some 20 to 30 million years later Blue Ridge rocks were thrust over sedimentary rocks of the Valley & Ridge province, during the collision that produced Pangea.  The mountains produced during this collision likely rivaled the size of today’s Himalayas.

In the million of years since their uplift, the Blue Ridge has slowly been beaten down with rounded ridges replacing rugged mountains.  As the processes of weathering and erosion continued their interplay, different rock types eroded at different rates resulting in the modern topography of the Blue Ridge.  Compared to the overlying stratified rocks and underlying granitic basement complex, the fine-grained metavolcanic rocks of the Catoctin Formation are particularly resistant to erosion.

The great American author Nathaniel Hawthorne once noted “mountains are earth’s undecaying monuments.”  Here in the central Appalachians much of that monument is shaped from the basaltic rocks of the Catoctin Formation, a unit birthed by fire during the breakup of ancient Laurentia and later changed to greenstone during the growth of the new Pangean supercontinent.

Oman’s Mega-Sheath Folds

January 30, 2014 by

Shaded relief map of the Muscat area, Oman with Wadi Mayh highlighted.

Shaded relief map of the Muscat area, Oman with Wadi Mayh highlighted. 30-m data from the Shuttle Radar Topography Mission.

Oman is a sunny place and cloudy days are rather uncommon.  On Friday, January 10th we awoke to cloudy skies over Muscat.  Today was the day to tackle “the exposure” at Wadi Mayh about 25 km (19 mi.) south of Muscat.  Wadi Mayh is a through-going drainage that offers tremendous exposures of bedrock in its channel and valley walls.

The exposure we wished to see (and photograph) is a steep north-northeast facing slope rising 170 meters (~560 ft.) above the wadi.  At this time of year the face is nearly always in shadow and the bright Omani sun backlights the scene making photography tough.  I thought the clouds would provide just enough cover to mellow the lighting and result in a better picture.


Google Earth image of the Wadi Mayh exposure, note its north-facing aspect.

Google Earth image of the Wadi Mayh exposure, note its north-facing aspect.

Alex Johnson and I climbed to a high perch across from the exposure and readied the equipment, but the sun refused to be muted behind the clouds.  We waited patiently.  There were moments of less sun, but we never got the lighting conditions we’d hoped for.  Nevertheless, we put the GigaPan to work, taking a set of 56 images of the rocky face that we later stitched together into a seamless high-resolution image.  What follows is the stitched image that spent some time getting ‘massaged’ in Photoshop to highlight this brilliant exposure and was then uploaded to the GigaPan website.  Try zooming in to the image to see fine-scale details such as fractures, veins, and fold hinges.

(View the Oman Sheath Folds GigaPan.)

These gray limestones lack much contrast, but the layering is readily evident.  It is difficult to appreciate the scale of the image.  Recall the height of the exposure exceeds 150 m (500’); the best scale markers are near the bottom of the image, they are ~7 meters tall (23’) power poles.  This is a huge exposure.

In the view below (of the central part of the face), the rock almost seems to be smiling at the camera.  Follow individual layers and you’ll find that they turn back on themselves and trace out a curious elliptical pattern.  Clearly, the rocks are folded, but these aren’t your everyday folds.  These are sheath folds, and mega-sheath folds at that.

Close up of the central part of the exposure at Wadi Mayh, Oman.  Lower image is a tracing of the layers wrapping around the sheath fold.

Close up of the central part of the exposure at Wadi Mayh, Oman, note bushes for scale.  Lower image is a tracing of the layers wrapping around the sheath fold.  Sheath fold axis trends into the cliff face, approximately normal to the photograph.

Sheath folds are distinctive curvilinear folds in which the hinge actually wraps around on itself.  In three-dimensions sheath folds look much like their name implies, a sheath that might holster a sword (or in Oman, the traditional khanjar!).  When eroded, the tubular-shape of a sheath fold displays a characteristic eye-shape in cross section—that’s what we see on the slopes above Wadi Mayh.

Sheath folds were first recognized in the late 1970s and early 1980s, but, in my opinion, not properly appreciated until the 1990s.  They form when layers are strongly sheared and early formed fold hinges are rotated into cone-like shapes; the long-axis of the sheath fold parallels the direction along which the rocks were most stretched.

Schematic model illustrating the development of a sheath fold.  Note distinctive eye-shape in cross section normal to sheath axis.

Schematic model illustrating the development of a sheath fold. Note distinctive eye-shape in cross section normal to sheath axis.

In 2007 Mike Searle and Ian Alsop published an excellent article in the journal Geology on mega-sheath folds from the Wadi Mayh area.  The sheath folds are developed in shallow marine carbonate rocks of Permian and Triassic age that are in tectonic contact with underlying high-pressure metamorphic rocks formed when the Oman ophiolite was obducted onto the Arabian margin.  The folds in the photo are actually subsidiary folds of an even larger mega-sheath fold about 15 km in length!

For me, sheath folds, regardless of the scale, dramatically illustrate that solid rocks are capable of flow, often in complex, but enticingly beautiful ways.

Annotated and traced image of the sheath folds at Wadi Mayh, Oman

Annotated and traced image of the sheath folds at Wadi Mayh, Oman.

Dispatches from Oman: Juxtaposition

January 14, 2014 by

A new semester awaits 11,000 kilometers away in Williamsburg.  Time to depart Oman, but before heading west towards home there was one last mountain to climb.  I’ve had my eye on this ridge at the north end of Jebel Akhdar for months, as the view from its crest should provide an exceptional overview of the region’s geology.

Shaded relief map of a part of northern Oman.  30-m data from the Shuttle Radar Topography Mission.

Shaded relief map of a part of northern Oman. 30-m data from the Shuttle Radar Topography Mission.

The ridge stands ~800 m (~2600 ft.) above the small villages of Murri and Ash Shakdar.  We parked the saloon car in the morning shadows and set off—I headed for the ridge, and Alex bore on to the wadi that cuts dramatically through the ridge.  This is an anticlinal ridge and the wadi slices neatly across the anticline providing a spectacular cross section through folded strata.

I walked up the eastern dip slope of this geologic structure to the gently dipping strata along the ridgecrest; below Alex negotiated house-sized boulders in the wadi bottom.

View from the top of the Murri anticline, northern Oman (view to north-northwest). Annotated geology in lower image.  This will be posted as a Gigapan in the coming weeks.

View from the top of the Murri anticline, northern Oman (view to north-northwest). Annotated geology in lower image, note the ophiolite on either side of the Cretaceous strata. The wadi bottom is ~700 m below.  This image will be posted as a Gigapan in the coming weeks.

Rocks exposed along the ridge and in the gorge below are Cretaceous limestones deposited some 95 to 115 million years ago in reefs and shallow warm seas on the northeastern margin of Arabia.  These are the strata that underlie much of the alpine scenery in northern Oman.  Although these strata are folded in dramatic fashion, the rocks are essentially in the same location as where they were originally deposited.  This sequence of rocks is considered autochthonous, a tough-to-spell geologic term for rocks that are still located where the formed.  In contrast, allochthonous rocks are no longer where they originally formed, rather, they’ve been displaced along faults and, in many cases, are far traveled bits of wayward crust.

Look to the periphery of this photo and you’ll notice ragged brown terrain, both to the northeast and northwest of the anticlinal ridge.  This is the ophiolite underlain by peridotite, a dense dark rock that originally formed in the mantle 15 to 20 kilometers (9 to 12 mi.) below the ocean floor.  In some locations there are other allochthonous rocks including a complex sequence of deep-sea sedimentary rocks (known as the Hawasina sequence), exotic blocks of limestone, and mélange (which, just as the name implies is a tectonic swirly pie of many rocks) between the ophiolite and the limestones.  The contact between these geologic units is a thrust fault of the first order.

While standing on the ridge taking in the scene one word came to mind—juxtaposition.  I’ll use the word in a sentence:

The juxtaposition of rocks from the Earth’s mantle (highly allochthonous rocks) against the shallow marine rocks (autochthonous strata) is a profound geologic sight.

Geologic map and cross section of the Murri anticline and Oman ophiolite.  Ophiolite is juxtaposed against mélange and autochthonous limestones.

Geologic map and cross section of the Murri anticline and Oman ophiolite. Ophiolite is juxtaposed against mélange and autochthonous limestones.

The arched nature of the sequence makes it easy to visualize that the ophiolite was thrust long distances up and over the Cretaceous limestone.  Prior to erosion of the modern mountain range (the terrain we see today) the juxtaposed ophiolite from the Deep Earth would have overlain the autochthonous rocks.  Later deformed folded the rocks and then erosive surface processes removed the ophiolite sequence to expose the autochthonous strata below.  That is quite a story!

There are other compelling geologic stories to share about Oman.  In the coming weeks I’ll post more pieces on Oman’s geology and upload our Gigapans.  Alex and I are also working up a series of videos that illustrate both our travels through Oman and the geology of this wonderful country.  Music Professor Anne Rasmussen and I are moving forward with plans to take a field course/study abroad program to Oman in the future.  Much to do back in Williamsburg.