Sunday, July 17, 2016

Week Five

Santa Susana 2016 has come to a close. When I first began writing this post I had just completed database entry in lab and with it my final work day as a crew member, and now I finish it sitting in my room back in Pennsylvania after flying back from Lisbon yesterday. I already greatly miss Portugal, but I am excited about all we have accomplished this season and the experiences I’ve had.

Though this was the final week the tasks I completed varied greatly. On Monday I returned to the tesserae pit from last week and finished working there with my partner. The completion of the layer raised many questions regarding our bath complex and I am eager to see what we will be able to find in the coming seasons. I also helped clean a section of our most fragile mosaic with a scalpel. The mosaic was damaged over the winter, and while only a few parts of the last season’s finds remain, more of the mosaic was uncovered this season. It is also very fragile since it is disrupted by roots, leaving portions wobbly and unstable. Nevertheless, these portions needed to be cleaned, so medical scalpels were used to scrape the dirt off of individual tesserae faces and define their edges for a 1:1 drawing.

 On Tuesday I tried something entirely different and went out on high-intensive survey for the first time in the field near the site. Working across transects of five meters by twenty meters myself and three others collected and weighed every piece of building material after sorting them by brick, tile, or pan tile. This survey will help us determine what structures may lay beneath the surface of the field. It was exciting to experience an entirely different type of fieldwork from excavating. 

The field where high intensive survey was conducted

Wednesday was a lab day for me. I learned how to use Filemaker Pro and worked to enter the spreadsheet information amassed in lab into the database, the same task I completed later in the week. The database is now up to date with four seasons’ worth of information about finds at Santa Susana. On Thursday I worked to make a detailed drawing of a significant portion of the bath complex, as well as the older part of the site. In the midst of the drawings the whole crew worked to cover the mosaics for the off season. A new technique was used this year. We built retaining walls using building material that had been excavated around the mosaics at a height of about fifteen centimeters. The mosaics were then covered with roughly ten centimeters of sand and a layer of excavation dirt on top. This is an alternate method to covering the mosaics with tarps and excavation dirt, which traps moisture and can lead to water damaging the mosaics in the off season. Hopefully this method will be the most effective and keep our mosaics pristine until 2017.

A retaining wall around the mosaic I helped consolidate in week three

Friday night we journeyed back to Monsaraz for one final dinner together. The view from the castle walls to Spain on one side and Portugal on the other as the sun dipped low in the sky was one of the most beautiful things I’ve ever seen. It was an early wakeup call Saturday morning to go to the airport, but a late night at the castle was worth being tired the next day.

The crew at Monsaraz on the last night

This concludes my first field experience, but most assuredly not my last. I am intensely grateful that I have been able to have this experience, and would like to take this opportunity to thank my parents, project directors and supervisors, professors at Hopkins, and American Archaeology Abroad for all of their support and guidance in this process. Field work has been an event like no other, and being in the field has only deepened my interest and passion for archaeology and material culture. Before coming to site my only knowledge of archaeology was from museums and textbooks. Now, I have dug under the hot sun and uncovered objects that had not been seen for hundreds, if not thousands, of years. I have recorded and analyzed and surveyed and lived with people whose interest in the archaeology of the region is infectious. This has been a profoundly important experience to me, and I can’t wait until I can continue my work in the field. For now, tchau!

Sunday, July 10, 2016

Week Four

Week four is now coming to a close and I’m beginning to realize that I only have a week left on this project. The thought is slightly overwhelming since there is still so much happening on site! This week was full of activity.

One of my (self-assigned) activities this week was ordering the pottery washing toothbrushes by color

Monday, July 4th, was a lab day for me, and I worked through a large part of the ceramics that still needed labels. After lunch the Fourth of July celebrations commenced! While our crew has members from Sweden, Canada, Australia, Portugal, and Mexico, we all got into the spirit for the 4th. Everyone pitched in to make a delicious dinner of burritos and dessert of various chocolate cakes and pies, and two members of the crew went to the local Chinese store and purchased a kiddie pool. It was a really fun experience with a great group of people.

On site this week destruction, both modern and ancient, was a dominant theme. The area I began working in on Tuesday and continued into during the rest of the week holds thousands of tesserae that had been removed from earlier floors and dumped into a pit to make room for a new floor during antiquity. To me, the concept of destroying something as unique and intricate as a mosaic is mind-boggling, yet when I consider the constant remodeling efforts most Americans undertake on a regular basis I don’t bat an eye. It leads me to wonder whether one day someone will look at my house and shake their head at the waste we created when we ripped out our linoleum kitchen floors and replaced them with bamboo. I highly doubt the impact will be so great, or this event will even happen, but seeing the remodeling efforts of the ancients made them seem a little more human to me in that moment.

On the modern front I had my first experience with removing pavement. It was necessary to see the next layer, but as we were about to remove pieces with little deterioration my Portuguese director expressed his discontent with having to destroy one part of the occupation to access another. Even though our photos and drawings of the layer were pristine, after removing it the physical, tangible evidence of that layer would be gone save for the pieces kept for lab. Excavation is an inherently destructive process, but I felt the impact of that concept at its fullest this week. I was eager to see what would be found in the next layer, but it came at the cost of removing what was already preserved above.

Since excavation for this season will be coming to a close next week the work on site has been punctuated with drawing the site and taking elevations more so than usual. Our site does traditional hand drawings rather than using a total station, and since this may be unfamiliar to some I’ll take a moment to explain how the process works. The drawings are done in two dimensions, length and width, that are recorded onto graph paper. Using a set meter line and a measuring tape the perimeter of the unit is plotted to show the shape of the unit. Drawings can include the perimeter of the area as well as features within. 

Elevations are then taken by setting a level and viewing a measuring stick at relevant points in the unit. The value on the measuring stick is subtracted from an absolute value to determine the elevation above sea level. This task usually takes at least two people and gives an accurate view of the unit that can be used for reference as the project progresses. 

The measuring line and the tape

My partner Emily using a "Portuguese Plumb", a nail with twine, to determine the point. The benefit of "making the draws", as our supervisor calls them, is that they can be made at all units across the site at once, though this does sometimes means plumb bobs need to be improvised if they are all in use.

The level looking out onto the unit

Next week will be the final days of excavation for Santa Susana 2016. Though there will be more cleaning than excavating later in the week, anything can happen! I am excited to see what we will find before the season ends and how it will guide preparations for 2017.

Sunday, July 3, 2016

Week Three

This week the project worked on mosaic consolidation! I was lucky enough to be able to help out and experience on-site conservation firsthand. The mosaics on site are likely from Late Antiquity and are absolutely brilliant. They were uncovered during the first and second seasons of excavation, and the majority have held up surprisingly well given the disruption the site has faced.

A conservator is coming to assess the state of the mosaics later this season, but for now measures had to be taken to ensure that the mosaics would remain in good condition while in situ. This did not come without a series of challenges; for one, there is not a trained conservator on site, which limits the technicality that the consolidation measures can take. Another factor that must be considered is the reversibility of the process. The measures taken will need to be easily reversed by a conservator if another method of conservation is deemed necessary later in the project. Yet another factor is the availability of materials in rural Portugal. This greatly influences the types of conservation that can be attempted. After all these factors were taken into consideration, Dr. Sanchita Balachandran of the Johns Hopkins Archaeological Museum advised the project that a Gum Arabic solution would be most effective in holding the mosaics together in sections where tesserae had come apart or been lost entirely and least invasive overall. Gum Arabic is water soluble and would easily be able to be removed by a conservator. Additionally, cotton gauze could be applied around the edges to ensure that the tesserae would remain intact in the most sensitive areas.

The process for consolidating mosaics using Gum Arabic solution in situ was relatively simple, yet effective. It began with pure Gum Arabic, blocks of tree sap, that were crushed with a hammer into smaller bits. The Gum Arabic was then weighed on a scale. Once its weight in grams was recorded, the number was multiplied by four to determine how many grams of water would be needed to create a 1:4 solution of Gum Arabic to water. The two ingredients were then combined in a water bottle, shaken thoroughly, and dissolved in the sun. After sitting in the sun for about half an hour, the solution was mixed entirely and ready for application.

Pure Gum Arabic

Crushed Gum Arabic being weighed

Weighing the water for the solution

Dissolving the solution in the sun

Once the solution was prepared it was applied liberally to any cracks in the mosaic using a paintbrush. This step took us the better part of the morning before break as we checked repeatedly to make sure that each area where the mosaic was not fully mortared was covered. After the solution was applied directly to any cracks in the mosaic, the edges and holes needed to be addressed. The tesserae at the edge and in areas where large groups of tesserae had fallen away were most in danger of becoming separated from the rest of the mosaic and needed attention beyond Gum Arabic. The solution to this problem was to cut strips of cotton gauze and apply them to the edges using the solution. This gave the mosaic additional support and was equally reversible.

Solution and the paintbrush used for application

Cotton gauze strips

Me in the process of applying gauze to the edge of the mosaic using solution

The mosaics on site are now consolidated and will soon be packed away for the season. It seems that in situ consolidation is a series of difficult decisions to determine whether preservation efforts will ultimately help or hurt the object being consolidated. The site’s mosaics vary from excellent to poor preservation, leading to a variety of conservation techniques being applied. As we decided where to put the Gum Arabic on mosaics that were in better condition, the mentality of “less is more” was ever-present. If a mosaic was able to survive for nearly two millennia, it could potentially be less helpful to try and fix something that was not broken. Another challenge to consolidation was the presence of plaster near cracks in the mosaic. The goal of the consolidation effort was to only cover small parts of the mosaic and avoid other materials, such as plaster, entirely, to ensure their own preservation. While this made some parts of the consolidation effort difficult, it ultimately was preferable to keep all parts of the site in their best possible condition.

Along with mosaic consolidation we finished removing the sector I have been working in for the past two weeks. Excavation is moving quicker and quicker as the season progresses. Our dig has two sessions, and while I am staying for both, Session One is drawing to close on Sunday and many crew members will be leaving. I am excited to meet the new crew but will definitely miss the people who have made this session so great. Stay tuned next week for more news from Santa Susana!