Fieldwork! Day 1

It seems my grand vision of immediately writing up each day's fieldwork experiences immediately after returning to BRASS Base was derailed after our very first working trip to El Pilar. In retrospect, that was probably a pipe dream all along - I'm usually tired coming out of the field on a normal day, and last Thursday (27 April) was a particularly hot one. I've already written about what we did in fairly broad strokes over at Experiment, and I'm trying to avoid overlap between these two platforms as much as possible, so I'll concentrate on some of the peculiarities of our first day in this post.

Bright-eyed, bushy-tailed, and ready to survey in the morning. I wish we looked this chipper at the end of the day.

The day started out like many others last year, albeit with a different set of objectives. Instead of our usual goal of surveying and mapping settlement remains in unexplored areas, we would be checking on a series of problematic structures identified by Anabel's students at UC Santa Barbara. Our project has mapped hundreds of mounds, plazas, platforms, quarries, terraces, chultunob' (storage pits), and other cultural features within the Reserve boundaries, and it's almost inevitable that certain bits of information will get lost in the process. Lucky for us, Anabel has built in a system of data checks that makes resolving these kinds of problems easier.

Today was also a chance for us to test a new extension for ArcGIS - the software I use to make all the fancy maps in here - that would allow us to load GPS points directly into the handheld units without using an intermediary program. This seemed like a good idea that would cut down the number of steps in transferring data and potentially prevent some transcription errors. GPS waypoints help us navigate to features on our LiDAR maps, and we record waypoints when mapping structures to guide their placement in real space. GPS is an integral component of our survey methodology, and we're always looking for more efficient ways to use these data. The results of this particular experiment, alas, were disastrous. The extension would only load 1000 waypoints at a time and returned an error message if you attempted to move to "page 2" of the waypoint list, which doesn't sound too bad, unless you have 1098 waypoints you want to load. Perhaps more ominously, attempts to download any waypoints through the extension crashed the entire program. But we decided to deal with this later.

They look so innocent nestled in their little crate...

An even bigger problem arose from the amount of waypoints we attempted to load into our handheld units, which was entirely my fault. As you can see above, we have four GPS units. They all look the same, but one of them is different. Three are Garmin 62s, and one is a Garmin 64s, which is a newer model with more capacity to handle GPS data. We loaded around 2500 waypoints into these little machines - certainly an excessive number that we would probably never need - but we didn't realize that the 62s models could only handle 2000 waypoints at a time. I checked that the waypoints we needed were loaded (they were) and that each unit had memory to spare (they did - about 3 GB each), but I didn't think to take any test points before heading to El Pilar the next morning. This led to some rather frightening error messages and a frantic scramble to delete unneeded waypoints when we reached the field. Not exactly how you'd want your first day in the field to begin, but we persevered and came up with a contingency plan that worked well enough.

It was not our intention to replicate Dr. Emmett Brown's Flux Capacitor schematic with our GPS tracks

Once we figured out a workaround, we were off to the races. I use that turn of phrase despite knowing of no races through thick tropical undergrowth in 100-degree weather at the time of writing. We estimated our walking distance at between 9 and 10 kilometers, and we covered a pretty good-sized chunk of the El Pilar core area. We did some of this walking on previously cut brechas and trails - whenever we could, in fact - but most of the groups we needed to check were a little off the beaten paths. Here's a look at what we did.

James is standing halfway up the mound.

Now James is on the mound's summit.

Some of the checks were fairly straightforward: locate the problematic mound, record whatever data happened to be missing, and move on to the next target. This wasn't too hard when working with larger mounds, such as the one James is standing on in these photos. If something looked fishy in our GIS drawings, we'd take a quick look around and make a decision before checking that structure off our list.


Other problems were not so easy to deal with, especially when our structure maps didn't accurately represent what we saw on the ground. When this happened, we had to decide what we were actually looking at, quickly measure and re-sketch the feature(s) in question, and take more GPS points to help redraw these features in our GIS back at the lab. Below is an example of what that looks like.

Nothing to see here, just your average mother-and-child mound pair

We thought this map looked very suspicious. You often see mounds of various sizes in close proximity to one another, but a tiny mound abutting a larger one at such an angle could not be taken seriously by any self-respecting Maya archaeologist. We had to see this for ourselves, and decided we were looking at a single, L-shaped mound instead. This could represent two structures that merged together after both had collasped, but there was no way of discerning this from the evidence on the ground, so we re-sketched the map and took more GPS points. As you'll see below, the error in the GPS measurements makes them far from perfect indicators of a structure's outline or position, but they do help guide final map drawing when combined with field sketches.

Getting closer to reality, but it's a good thing we have our sketches

We moved quickly through these assignments and accomplished in one day what we had budgeted for two. But later in the afternoon, as we were walking back out through the bush to the main road and our car, the heat began to take its toll, at least on me. I was mindful to drink lots of water that day, it being my first back in the field doing actual work, but the heat was stifling, and I drank the last drop from my second canteen before leaving our final target. There were no direct trails back to the road, and the trudge through the forest was grim. I began to lose sense of my surroundings in the battle to put one foot in front of the other until we made it out, and I stepped directly over a medium-sized snake - an event of which I would've remained oblivious, had not James and Narcisso, who were behind me, immediately shouted for my attention. This didn't even register until I had taken several steps forward, and at that time I couldn't have cared less. Apparently it was only a boa, but it could've been something far worse. I guess got lucky this time.

Mapping the Twin Towns whilst Running Errands

Archaeological projects are complex machines. They run only as well as their infrastructure permits, and only as long as they're continuously oiled by a steady stream of logistical tasks. Fortunately for us, Anabel has been maintaining a robust base of operations in Santa Elena for years (more on that here), with a house that is lived in and maintained even after the project closes for the season. I've had to open field houses down here that were closed down since the previous year, and the results can be less than pretty.

Opening a lab house in 2010. It took a pickax to loosen these insect mounds from the door jambs.

Few things compare to the bouquet of dried cat urine in a sweltering concrete house. FYI: We didn't have a cat.

James, ready (?) to go with the GPS.

Even with a stocked and well-maintained base, there are always many errands to run before getting started with fieldwork. You have to buy food, supplies for both lab and field, and any number of miscellany; do vehicle maintenance, including such exotic tasks as buying tires and renewing insurance; and drop in on friends from town whom you may not have seen for a year. Different errands can be tedious, fun, or somewhere in between, but they are always time-consuming, no matter how you swing it.

You also need well-trained personnel to carry out your fieldwork, because even the fanciest gear produces garbage data when your surveyor can't use it properly. Training also takes time, and that's something we never have enough of when setting up a project. In the spirit of efficiency and innovation, we decided to combine these two tasks, and teach our new assistant archaeologist James how to use the GPS whilst running errands around the Twin Towns. We would also get James up to speed on our procedures for downloading GPS data and visualizing them in our Geographic Information System (GIS). This would also save us the embarrassment of being a survey crew forced to buy a map of our surroundings. Here's what we've come up with thus far. It's a work in progress, but it's getting there.

A couple of days worth of errands, all in one map.

The red line in the map, just like in our tour of El Pilar, shows the GPS track of our journeys around the Twin Towns and beyond. The small circles are GPS waypoints that we took at markets, vendors, mechanics, friends' houses, and other places we thought were important. This map is scaled up a bit to show our epic journey to the Mennonite community Spanish Lookout in search of new rear tires for our vehicle. Perhaps epic is a strong word - and we did know the tires would be waiting for us when we arrived, so we weren't exactly searching - but that particular errand took us quite a long way away from our base. If you locate the BRASS BASE waypoint and follow the red line east, you'll trace our route to the ferry across the Belize River and up toward Spanish Lookout. Much to my chagrin, the GPS also recorded a wrong turn I took on the way out to Caribbean Tire. You can also see that we took a different route back, following the road that runs north of the river to the southwest before dipping south across the Mopan at Bullet Tree Falls and returning home. The points and tracks through Santa Elena and San Ignacio are a little too crowded to be of much use at this scale, so we'll zoom in for a closer look.

It all looks so organized from up here...

Here you can see more of the places we've visited over the past couple of days, although some are still clustered too close together to be clearly labeled at this scale. We'll probably have to split up the Twins into separate maps at some point, and we're still expanding our database by taking different streets to visit different places. In time, we'll have a nifty map of project hot spots and know the best ways to get there. James now has experience gathering and processing "survey" data with the same procedures we'll be using daily at El Pilar, and we managed to accomplish all the tasks on our list - Anabel is much better at making those than I am - in a remarkably short amount of time. I think we hit the trifecta with this one.

A Quick Visit to El Pilar

James, our new assistant archaeologist, and I arrived in Santa Elena on Saturday evening, April 15. Santa Elena is the less touristy twin of San Ignacio, and we stay there because, above all else, we need to keep it real. Or perhaps because Anabel has established an impressive project infrastructure here after years of working in the area - I'll have to get back to you on that, but I've written a bit about our base here, and you can see pics of James and some of our other staff there as well.

This would be a great time to visit the Twin Towns if partying was your game: most people had a long weekend over Good Friday and Easter, and a small fair had come to town, featuring food, music, and rides. Who wouldn't want to jump on a Ferris wheel colloquially called the Wheel of Death? Unfortunately, I have no pics to share of that monstrosity, as my phone was exhausted from its long journey and I had no other camera handy. You'll have to conjure the image of a smallish rusty-looking wheel, driven by an old truck engine to dizzying speeds, on your own. The Easter holidays continued through Monday, which is great if you work down here or are on vacation, but not so great if you're trying to set up project logistics on a short timeline. After a morning filled with project planning, we decided to make the most of everyone else's day off by taking a quick trip up to El Pilar to get James acquainted with the monumental core. Through the magic of Global Positioning System technology - the full name sounds much more magical than its shorthand (GPS) - you, too, can join our tour! I promise it will be brief - El Pilar is far too big to write about in one quick post. Have a look at the map. I'll do a quick explainer and then we'll follow our path through this part of the site, which is marked by the numbers in black.

Yes, indeed, we have LiDAR.

You're looking at the largest complex of monumental architecture at El Pilar. Just out of view to the right (east) is another massive monumental group, the Citadel, which reminds me of a European Iron Age hillfort. We didn't visit the Citadel this time, but fear not: you can read more about it here, and I'm certain to spill more digital ink on it in the near future. If you followed the two gray parallel lines running to the left (west) of the image - which represent a 30-meter-wide causeway - you would arrive at Pilar Poniente, a separate monumental complex connected to the group shown here by an offset causeway and sunken plaza. I'll return to Poniente at a later time as well. The red line you see is the track recorded by our handheld GPS unit, which shows our progression through the site. I've marked some points of interest with numbers to make sure no one gets lost.

Parking - This is where we parked our vehicle and took a new GPS point. El Pilar is set up to receive tourists, and this is a cleared area meant for the point's eponymous purpose. Having a GPS point where you leave your vehicle can come in very handy when you venture out of the areas maintained for tourism, and that's exactly what we'll be doing when we begin work next week.

Along the path from the parking area to our first point, we passed through an example of a Maya forest garden. This area was seeded with different economically useful plants and trees through consultation with contemporary, practicing Forest Gardeners, and it gives a sense of what ancient Maya infield agricultural plots - or home gardens - may have been like.

Paths lead through the Forest Garden east of the monumental core.

Point 1 - We arrive at our first point of interest, a large, ancient household group named Tzunu'un ("hummingbird").

Sign at Tzunu'un showing an architectural reconstruction of the household group.

Tzunu'un consists of five structures - and possibly a sixth, later platform - that would have been used by a residential group for different purposes. Three of the five buildings were made of perishable materials - wood, wattle-and-daub, and thatch - and were set on stone-faced platforms. These buildings, located along the north and west edges of the central patio, were probably where the group slept, cooked food, and carried out any number of other domestic activities. Little of them remains aside from their stone foundations. The eastern structure (Structure 2), pictured below, was a small pyramidal shrine with a stone-walled and thatch-roofed building placed on top. Eastern shrines were common among higher status residential groups during the Classic period, and the Maya frequently buried important family members inside these platforms. The building on top has a curious niche inset in its northern wall.

Structure 2, the eastern shrine at Tzunu'un.

The largest building at Tzunu'un, Structure 1, sat on the patio's southern border. It was the only building with a vaulted stone roof and plaster benches in this group, and its perch atop a large stone platform elevated it above the patio and other structures. Five rooms separated by spine walls comprised its interior. This imposing building was probably used for receiving audiences, important visitors, and other formal affairs. You can read more about excavations at Tzunu'un by Anabel and her team here.

Structure 1, the only vaulted building at Tzunu'un.

Before moving on, I'd like to make a quick note on residential unit interpretation and population estimates. Many of us working in the Maya Lowlands struggle with population estimation, which is one of the most basic pieces of data necessary to reconstruct aspects of past societies. How do you come up with a population estimate for people who cannot be counted? Archaeologists use different formulas, based on ethnographic observations and a number of assumptions (like structure contemporaneity and other esoterica best left alone here), to estimate ancient populations. We apply these formulas to what we think are domestic structures, because they are presumably the buildings that housed the populations we are trying to estimate. Problems arise when considering which buildings actually housed people and can be meaningfully used as proxies for those people. Some researchers use the total number of domestic structures in their population estimates, and that seems problematic. We don't think people were living in Structure 1, and we're certain they weren't living in Structure 2. One of the smaller, perishable buildings was likely a kitchen, so people probably didn't live in there, either. If we applied our population formula to all five structures at Tzunu'un we would have an artificially high estimate. Not such a big deal at this scale, perhaps, but when you consider the hundreds or thousands of domestic structures across an entire site, you can begin to see the scope of the problem. I'll come back to population estimates in a later post...we've tarried here long enough.

Point 2 - I don't have any pictures for this or the next point, so please bear with me, and I'll be brief. They are interesting features, and I'm sure I'll return to them again in later posts. We passed a large, peculiar range structure along our path north from Tzunu'un. This actually consists of three structures in a linear, roughly north-south arrangement, which measures about 60 meters long. The central structure - clearly not vaulted but possibly once topped by a perishable building - was higher than those that flanked it, but none were taller than three meters. This configuration is similar to the massive winged temple EP7 in Plaza Copal (more on that later), and the structure's location is also curious: it is almost due east of EP7 and closely matched to its alignment. This was probably a later construction, which raises the question of why the inhabitants would build what appears to be a cheap knockoff of an old and venerable temple? One more item on the to-do list, but probably not for this year.

Point 3 - We proceeded from the anomalous range structure up a small rise and arrived at a level surface that supported another patio group. The mounds here were large but configured differently from the nearby Tzunu'un group, and their proximity to the central monuments further suggested the high status of their occupants. Unlike Tzunu'un, however, no structures in this group have been excavated. The small hill is bordered on the east by a steep ravine, and the people living here could have seen the Citadel in that direction. We followed a small, raised causeway - we'll call it that for now, anyway - down from this group toward the monumental structures to the west.

Point 4 - After crossing the modern road that cuts through part of the central complex, we passed through Plaza Duende, a large open terrace with a solitary pyramid near its north end. We continued down a trail to the Chert Site, where masses of stone tool production debris were discarded. Large, general purpose bifacial axes were produced here from chert, aka flint if you come from across the Pond. Smaller pieces of debris were recovered in situ from the surface of a nearby cobble platform, and the larger, hazardous flakes were collected and deposited in a massive heap away from this work surface. The sheer volume of material deposited suggests specialized production of an important economic resource. Although not unique, large-scale production locales such as this are rare in Maya city centers (reference here, gated).

Thousands of chert flakes on the ground surface. Lens cap for scale.

Point 5 - Winding our way back from the Chert Site, we passed through the most open and accessible plaza in the site center and into the most restricted, inaccessible complex of buildings and courtyards to the north. This acropolis comprises a series of elevated buildings and smaller, sunken plazas, with access-ways offset to further restrict movement in and out. The architectural expression of centralized power and authority here is stunning. Already large buildings were scaled up and renovated throughout the Classic period, creating a complex and confusing architectural sequence that has only been partially unraveled. In this area Anabel discovered, excavated, and consolidated a standing vaulted passageway. Intact passageways are relatively rare in the Central Maya Lowlands due to the instability of corbel vaults over long periods of time. I suspect that the strange westward spike in our GPS track occurred when we entered this tunnel.

Corbel arch entryway to the vaulted Zotzna Tunnel.

Point 6 - After spending quite a bit of time climbing around the administrative center of El Pilar, we gradually made our way back south and into the public ceremonial precinct. Plaza Copal, where Point 6 is located, contains some of the oldest and largest temple pyramids in the city. The structures bounding Plaza Copal to the east and west are part of an E-Group, an ancient architectural configuration with roots in the Middle Preclassic (~ 900 B.C.) that became widespread across the lowlands. Middle Preclassic structures were discovered by tunneling excavations into EP7, the 17-meter-tall eastern winged temple, and a section of an early platform was revealed beneath EP10 across the plaza. This area contains the oldest architecture known from El Pilar, and it seems to have been an important area from the earliest days of the city's founding. Another important feature of Plaza Copal is the ballcourt in its southeast corner, through which we walked on our way back to our vehicle in the parking area.

Look east across Plaza Copal at EP7, the 17-meter-high winged temple.

I could spend several more hours discussing things like E-Groups, ballcourts, palaces/administrative centers, specialized production, population estimates, and so on, but I think this is a good place to end the tour, for now. There's a lot more to come, and we haven't even started the real work yet.