The Search for Tephra Continues… Updated August 2016: Next Steps Alpine Tephra

August, 2016
Quite a bit of progress been made in our search for and identification of Alpine tephra in the Colle Gnifetti ice core since my last post (below)!
Over the past year, after determining that the 1875 Askja eruption in Northeast Iceland was indeed our suspected tephra source, I spent quite a bit of time plotting our particles’ chemistry against numerous reported chemical compositions for Askja tephra. To our pleasure, the data matched exceedingly well with published Askja chemistry and was markedly different than the published values of the only other realistic candidate, the 1845 eruption of Hekla in Iceland.
Confident that we had found something worth reporting, I dove into the process of writing a scientific paper for the first time. Guided by Dr. Kurbatov, from University Maine, and Dr. Pascal Bohleber of the University of Heidelberg, I spent the better part of spring 2016 creating figures and writing the various parts of our paper. This endeavor was certainly a new experience for me, as a scientific paper is not particularly similar to the type of papers that we learned to write in Expository Writing freshman year at Harvard. It truly was a collaborative experience, as I received discrete input from all co-authors and cohesively incorporated it into the final form of the paper.

As of now, our small tephra paper has been submitted to Jökull—a journal that specializes in topics in earth science that pertain to Iceland—and is awaiting revisions. I am very thankful to the Initiative for Science of the Human Past at Harvard for providing me with this opportunity to really dive into an area of research that was wholly new to me and through hard work eventually end up as lead author on a scientific paper as an undergraduate.

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Matthew Luongo, ’17, presenting his findings at the SoHP public lecture “2,000 Years of European Climate,” Harvard University, November 11, 2015 (full video available here)
Moving forward, our paper will hopefully show other glaciologists that tephra has indeed made it to the Alps in the past, so that future work can proceed with the goal of saving ice for tephra searches. Identification of tephra and its originating eruption will go a long way in creating absolute dating for paleoclimate proxies, such as alpine ice cores, which should allow us to gain a better understanding of the deposition timelines. Particularly important to SoHP, a more accurate timeline can allow us to synchronize our scientific data with historical data and gain a better understanding through the comparison of the two disciplines. This is a topic I will be exploring in-depth in the next year in my senior thesis.

August, 2015

Since my first blog post in early July 2015, substantial progress has been made in analyzing the SEM ice core data that I gathered during my trip to University of Maine in mid-June. As a quick recap, earlier this summer (2015) I traveled to Orono on behalf of the Initiative for Science of the Human Past at Harvard, to work with Dr. Andrei Kurbatov and analyze the filtered contents from the Colle Gnifetti ice core using a Scanning Electron Microscope. The ultimate goal was to find volcanic tephra particles within the filters which could then be geochemically analyzed and tied to a specific source eruption, in order to provide a means of calibrating the dating of the ice core further. Dating is of the utmost importance, as the Colle Gnifetti ice core could become one of the most accurate records of Mediterranean climate.
When I returned to Cambridge, I spent several days writing an R script (R is a computer language designed for statistical computing and data visualization) to plot the tephra candidates on a geochemical chart. Seeing the geochemical composition of the candidate particles allowed us to immediately disregard certain data, determining they were decidedly not tephra, while also leading us to focus on the particles which held the most potential as tephra candidates. One filter in particular, roughly dated to the middle of the nineteenth century (1830s), had about ten particles with a similar composition that pointed toward potential tephra. Because we had several particles on this one filter, we were able to robustly look at the statistics of the tephra candidates and determine, much to our delight, that we most likely had the first definite tephra finding in an Alpine ice core.
Our efforts now focused in on this group of data, with the sole purpose of finding what volcanic eruption from which these tephra particles originated. After looking through the Smithsonian database of active volcanoes (freely available at http://www.volcano.si.edu) for nearby likely volcanic sources with eruptions in the mid-1800s, I created a list of possible source candidates and looked through published geochemical literature for data against which to compare our tephra composition. It was fairly easy to immediately disregard certain volcanic provinces; as an example, Italian volcanoes have a much lower silica content than our tephra candidates. We looked at volcanoes in the Mediterranean, Turkey, Azores, and Iceland.
Initially, our strongest source matches came from Greek volcanoes. In particular, the Nisyros and Santorini volcanic provinces were tantalizingly similar to our tephra. After discussion with Dr. Kurbatov, we determined that we could count out Nisyros because of differing geochemical signatures, and Santorini became our strongest candidate for a source match. However, there was a catch: the elemental composition of the Santorini tephra that matched our data so well was 3500 years old, and corresponded to a geochemical composition which had not been present in Santorini for several millennia. We obviously had a problem: how could tephra from 3500 years ago end up in an ice core layer which is only two centuries old? After brainstorming rather unlikely explanations such as tephra being blown away from tephra cliffs exposed on Santorini, we went back to the literature and focused our search for a source onto Iceland.
Thankfully, after only a short time searching through geochemical analyses on Icelandic eruptions, we discovered promising geochemical signatures from the 1875 Plinian eruption of Askja in Iceland. After a cursory glance through the elemental composition, I determined that Askja was a strong candidate indeed and plotted our tephra data against this possible source. On a geochemical chart, our data matched almost exactly with the tephra composition from 1875 Askja. Upon further research into this 1875 eruption, I learned that this event was the single largest volcanic eruption in recent Icelandic history and traces of this eruption have been uncovered many hundreds of kilometers away. Additionally, Dr. Kurbatov mentioned that atmospheric circulation patterns already established years ago by Dietmar Wagenbach make it quite possible that air from the Azores passed over Iceland and then looped back down over the Alps. This would provide a physical pathway for tephra deposition at our ice core site.
From here on out, we need to do more quality-checking and plotting of the data to ensure that 1875 Askja truly is our best candidate for the mid-nineteenth century tephra that we found. However, it seems quite likely that this is indeed our source and hopefully this will provide an impetus for future analysis of the Colle Gnifetti ice core and the search for any tephra contained within.
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My experience with SoHP

by Santiago Pardo, Harvard College ’16 (History)

I first experienced the initiative for the Science of the Human Past at Harvard through the Digital Atlas of Roman and Medieval Civilization (DARMC). I joined the team through the invitation of, my then TF, Dr. Ece Turnator the summer before my sophomore year. I remember the first meeting feeling a bit out of place since everyone in the room seemed so much smarter and accomplished. My first DARMC project was a geodatabase of communications from 700 to 900 CE within Prof. McCormick’s Origins of the European Economy. This project taught me how to create an efficient database, but also, how historians use GIS for historical study.

My sophomore year I took my first class with Prof. McCormick, Fall of the Roman Empire. It was in this class where I found out about SoHP’s Harvard-Oxford Medieval Archaeology internship, a chance to learn how to excavate alongside Oxford undergraduate archaeology students in England. I ended up applying and that summer I left for England to excavate. I dug for eight hours each day, six days a week, in the blazing summer sun, but I loved every minute of it. I primarily excavated a late Roman ditch dating to the late fourth century. These were late Roman enclosure ditches that cut through the town and had some connection to the North-South Roman road that cut through the village. The ditch fill produced a lot of artifacts and so I got to excavate pounds of potsherds, mounds of animal bones, many iron nails, and the odd copper coin or two. The dig was an incredible experience. There is something incredible about doing archaeology that you will only understand once you leave the theory and do field work. I learned so much not only about Roman culture and archaeology, but also about myself and where I want to go intellectually and academically.

I continued to work for DARMC throughout my Sophomore year, but starting my Junior year, Prof. McCormick and I began a new project to geographically and temporally map the writings produced in Gaul during late antiquity. This was a great experience to plan and execute my own research projects under the mentorship of Prof. McCormick. After more than a year of work, the preliminary database and maps were presented at the “Quantifying Problems in Ancient History: Working with Numbers from the Distant Past” conference hosted by the Yale University Economic History Workshop (May 6, 2016). Attending this conference allowed me to interact with scholars on a professional level outside of the classroom. The highlight of the conference was meeting Prof. Kyle Harper, whose work inspired my senior thesis on extramarital sex in late antiquity.

My senior year, Prof. Christopher Loveluck taught in the History Department as a visiting professor of medieval archaeology. I took both of his classes: Anglo-Saxon and Viking Age Archaeology and Archaeology and History of Western and Mediterranean Europe. Prof. Loveluck’s classes were an incredible opportunity to learn how archaeologists use scientific approaches to understanding the past. He taught in a clear and insightful manner that not only demonstrated the depths of his knowledge and analysis, but also conveyed new concepts and taught them to the entire class regardless of prior experience. His remains one of the best courses I took at Harvard. I was blessed to have him be a part of SoHP during my undergraduate education.

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A Capstone to my Harvard education: Discovering the Buried Capital of Visigothic Spain without a Shovel in the Summer of 2015

By: Richard Rush, Eliot House, College ‘ 15.

Freshman fall when I stepped into a Sever Hall classroom during shopping period, I had no idea that in four years I would be helping create new historical data with that energetic Professor McCormick who was pacing the front of the room. I remember that over the course of the semester I was entranced not only with Romans and the Germanic 1“barbarians” he was introducing the class to, but also with the scientific methods with which he and his colleagues were able to learn so much about the past. The narratives provided by historical documents were beautifully supplemented and even explained by biology, chemistry, and geology. McCormick made it obvious that the sciences were welcome in his critical engagement with human history. I was not surprised when I learned that McCormick was heading the Initiative for the Science of the Human Past (SoHP).

 

Over the next four years McCormick involved me in the SoHP where I brainstormed with other students and professors at Harvard and helped build a digital database of of medieval travelers. However, the highlight of my involvement in the SoHP began when Professor McCormick invited me to join an international expedition that he was organizing. A few months later, in July, I found myself under the hot Spanish sun, surveying land to be measured with the magnetometer, and surrounded by a team of crack archeologists from Germany, Spain, and the United States. To say that it was a unique –amazing– learning opportunity would be an understatement. Our goal was to explore the area surrounding the small excavated area of Reccopolis. We were quite sure that most of our areas of interest were directly in or just adjacent to the city walls and thought that stone foundations could still be present despite 1400 years of conquest, erosion, and farming. Our tool of choice was not the trowel, but a magnetometer.

The geomagnetometer detected the very small differences that soil and stone generate in the Earth’s magnetic field. Therefore, if there was a line of stones just below ground level indicative of a building foundation, it would appear in the measurements taken by the magnetometer. However, before the magnetometer could be used, we had to carefully and precisely survey the area to be geomagnetically prospected. Using a laser transit, we were able to measure out our plots to within a handful of centimeters and make sure that all of our individual plots were perfectly square with fixed local coordinates so that the image produced by the magnetometer could be fixed absolutely to their respective areas and not get mixed up.

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While the expedition was filled with its challenges and charms, the best part was undoubtedly working with top notch archeologists from three different countries. Not only was everybody pleasant to work with, I learned so much from them. From using the surveying equipment and magnetometer to getting advice on how to proceed with my postgraduate education to Leovigild, the Visigothic king who built Reccopolis, there was always something new to learn. A unique experience was the odd mixture of English, German, and Spanish that our team spoke. Occasionally, simply speaking with the other team members was an adventure in and of itself. While confusing at times, this conglomeration of languages served to richen the overall experience.

Naturally, everyone was excited to learn more about Reccopolis and we did. The grayscale images that the magnetometer produced yielded wonderful results. It was amazing to see the outlines of buildings, streets, and larger avenues emerge from the old barley fields that we were working in. 2By the time we had completed our two weeks at Reccopolis we had at least quintupled our previous knowledge of the layout and street plan of the Visigothic city. While these results are very exciting and have contributed greatly to our understanding of Reccopolis, our results also serve as a stepping stone for the ongoing excavations at Reccopolis by providing a map of the buried city.

Overall, this expedition was a success in every way imaginable. Not only did we produce incredible results, we also made some wonderful friends, enjoyed ourselves in a beautiful location doing something everybody was passionate about, and proved what can be accomplished both when we cooperate with our colleagues and when are not afraid to let the sciences and humanities mix. Truly, our results were made possible largely through mixing technology, geology, and history into archeology, thus turning the study of the human past more and more into an interdisciplinary science.

To accompany this expedition and assist in the process of creating new archaeological and historical knowledge served as a most fitting capstone to my undergraduate education. For four years I studied the data that past historians, archeologists, and scientists had produced. Finally, I was able to complete the circle and contribute my muscle and brain power to the discovery of something new that will be studied by future generations.

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Searching for Tephra

I first joined the Science of the Human Past initiative at Harvard because of the “S” in “SoHP.” As an earth science major, I was drawn to the possibility of being able to use the skills and lessons that I learned in my classes in order to gain a better understanding of historical events. It seemed like a great way to truly fulfill the liberal arts education that I was receiving: using science to dissect and understand records from the past.

As such, I have been involved with SoHP in every capacity that I can fit into my schedule. I have acted as a scribe at conferences, I have worked as a translator of climate events for the Digital Atlas of Roman and Medieval Civilizations (DARMC), and most recently, I have worked as a research assistant with Dr. Andrei Kurbatov at the Climate Change Institute of the University of Maine Orono. Let me elaborate a little more upon this.

In early June I received an email from Professor Michael McCormick asking me to consider a weekend trip to Maine where I would work at the CCI with Dr. Kurbatov in a quest to look for volcanic tephra hidden in the layers of the Colle Gnifetti ice core drilled in 2013 in the Swiss Alps. The goal of the trip was simple: find volcanic glass that could be analyzed and tied to specific volcanic eruptions in order to provide possible means of absolute dating for the ice core. I jumped at this opportunity to finally help out SoHP in my capacity as a scientist, and I booked my bus ticket as soon as I could.

When I arrived in Maine, I was greeted by Professor Kurbatov and his two graduate students, Teye and Sarah. Together, they walked me through the lab work that I would be doing throughout the weekend and explained the big picture nature of the research. The Colle Gnifetti ice core, if dated accurately, could be the most accurate measure of Mediterranean climate that we have to date, potentially reaching as far back as two millennia. In order to provide as accurate a record as possible, we needed to find some way of finding out exactly what year each ice layer corresponded to. Volcanic tephra provides the perfect dating tool, as we can geochemically analyze the tephra to see the elemental composition and then tie it to a specific volcanic eruption with a known timing. The only issue was finding that tephra.

I spent a whirlwind three days working with a Scanning Electron Microscope (SEM) equipped with EDS detector, which shoots a beam of high-energy electrons at a solid object in order to make an image. Once we lock the SEM on the particle we are looking at, it spectroscopically determines the elemental make-up; for volcanic glass, we were looking for twelve major elements, specifically silica and aluminum content. We took ice chips that were made during drilling, melted them down, and filtered the liquid through a .4 micron polycarbonate membrane filter. The tephra that we were looking for would be about 5-10 microns and required a sharp eye to scan through the jam-packed filters. Much of my time was spent determining whether a small chip might be tephra. Often times, even pieces that had the characteristic glass-shard shape were just small flakes of feldspar dust blown to the glacier from nearby deserts. However, if we could find just one piece of tephra, we can be justified in taking the next step, which would be to use the laser to scan through the ice core and find tephra in situ.

Currently, I am analyzing the data collected during my weekend from back home in Cambridge. I have modified and written a script in R to scan through the data files we created from the SEM/EDS instrument, and then plot the particles on a mineralogical chart. I should know soon the extent and amount of tephra that we found on these filters. More to come in that regard!

I have really appreciated the opportunity to work with SoHP and be a research assistant. Not many students can claim the truly interdisciplinary nature of the work that I am doing, weaving together science and history in such a way to improve upon both fields. I find it a little funny that I got offered a position to do geochemistry from my history professor, but I think this is a perfect example of how academia is changing in the twenty-first century. We are truly entering a phase in research where historians can be informed by science, and scientists can be informed by history. The lines between disciplines are becoming much more fluid, and I count myself lucky to be in a research group that is at the forefront of this movement.

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My DARMC adventures

I first started working on DARMC at the end of my junior year at Harvard, just after taking one of Professor Michael McCormick’s research seminars on Carolingian history. Our seminar included several workshops on new scientific techniques being brought to bear on historical debates, and DARMC-generated figures were a frequent feature of both seminar lectures and my fellow-students’ research projects. At the end of the course, Prof. McCormick made a characteristically energetic pitch for all of us to come on board as DARMC contributors if we so desired. The prospect of making a little extra money while doing interesting historical research was very appealing to me. It became even more appealing when, just a couple weeks later, I was forced to give up my usual end-of-term employment—cleaning bathrooms for Dorm Crew—after a freak accident during which I broke both of my feet. The story of this accident isn’t relevant to DARMC, though I will happily tell it to you if we ever meet at a party. Suffice to say, it was very nice to have a summer job I could do from a seated posture.

My involvement with DARMC also introduced me to fascinating areas of historical inquiry that I was perhaps unlikely to have pursued on my own initiative. My knowledge of science is, alas, dilettantish at best, and in my historical studies I’ve always gravitated much more towards texts and literature than archaeology or material culture. I like the intellectual intimacy of communing with vanished minds, and the warmth of individual personalities engages my interest more intensely than larger historical trends. Through DARMC, however, I became aware of the ways in which seemingly-mundane details extracted from a large number of texts can be used to create compelling visualizations of the larger world inhabited by the scribes and authors for whom I feel such affection. A data-driven approach can reveal the circumstances and assumptions that underlie historical writings, opening up new vistas for the imaginations of eager readers.

So far I’ve been a co-contributor on a variety of databases: I’ve filled out spreadsheets documenting weather events from monastic annals, and shipwreck coordinates from archaeological journals. My chief solo project was the construction of a database inspired by E.A. Lowe’s Codices Latini Antiquiores, a descriptive catalogue of all extant Latin manuscripts written before the ninth century. (I felt a profound empathetic connection with the monastic scribes of yore as I carefully populated several thousand spreadsheet cells with manuscript stats.) The database isn’t up on the website yet, but I’m excited to see what our GIS whizzes can do with it. Eventually, I hope, viewers will be able to track the movements of each manuscript, as it was transported, presented, purchased, and purloined across eleven or more centuries.

Even though the Codices Latini Antiquiores database is complete for the moment, I still find myself thinking about ways it could be improved or expanded. I never, for example, found a satisfactory way to treat palimpsests—texts written on top of other texts. In his catalogue, Lowe treats each script as a separate item; thus, a palimpsest with two scripts became two separate entries in the database. This format is probably ideal for most paleographers’ purposes, but I found myself intrigued not just by the scripts themselves, but by the fortunes of the individual pieces of paper on which they were written. I’d like to be able to track a piece of papyrus, parchment, or vellum across the globe—where was it first written on? When and where was it rewritten? When was it dismembered and put into book-bindings? Where did those books end up? All of this information is present in the database, but it isn’t linked up in a way that’s visualizable… yet. I’d also love to be able to track when and where particular works are being copied. At the moment, it isn’t really possible to search the database by work or author—each manuscript typically contained works by a number of different authors, which all had to be listed under a single field (for space reasons: if I had given each and every work its own entry or column, the database, already enormous, would have quickly ballooned out of control!) A purposeful database focusing on works rather than scripts would, however, be relatively easy to build using the information from the works column. A DARMC project for the future, perhaps.

My Codices Latini Antiquiores project also led me to contemplate the implications of digital tools for the future of academic research. From my own brief undergraduate foray into the study of insular paleography, I am aware that a number of scholars take issue with E.A. Lowe’s classifications of insular hands and manuscripts—and I’m sure that there must be plenty of debates raging in other areas of the field as well. I think it’s important to be very aware of the limitations of any data set: in this case, not only is the data determined by factors such as manuscript survival and discovery, it’s also circumscribed by Lowe’s individual scholarly judgments. A visualization based on a database inspired by the Codices Latini Antiquiores is thus, in some sense, a visualization of pre-C9 Latin manuscripts, but it’s also a visualization of Lowe’s paleographical theory. I don’t think this compromises the validity of the database in any way—converting a theory into a manipulable map opens up new and powerful avenues for critique. If one were to modify the existing database to reflect another scholar’s paleographical identifications, and then compare the two visualizations side by side, that could be an extremely illuminating and forceful supplement to debates hitherto conducted in articles and monographs. I think this is a pretty good example of the exciting (and perhaps slightly terrifying) ways that scholarly debate could evolve in the digital age. I’m thrilled to think that I might have contributed in some small way to the inception of a fascinating new era of paleographic inquiry, and I hope to continue making useful contributions to DARMC in years to come.

– Brianna Rennix

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Welcome!

Welcome to Scopes & Scrolls, the blog written by the community of undergraduate, graduate and professional archaeologists, classicists, historians, medievalists and scientists involved with the Initiative for the Science of the Human Past at Harvard.

Studies for the Libyan Sibyl and a small Sketch fo

Following on the success of our inaugural conference last year, we now come together from all corners of Harvard Yard, from our institutional homes in a wide spectrum of departments from computer science and biological anthropology to classics and history.  We are freshmen, seasoned professors and everything in-between, a group of curious minds with diverse experiences and backgrounds but united in the goal of better understanding the human past through collaboration and an increasingly deep and varied multidisciplinary toolkit. In this blog, we share with you the reports of our ongoing endeavors and projects, our discoveries and surprises. We hope you will join us!

– Jakub Kabala

 

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