El Intercambio de Arquelogía y Ecología

Sunrise at CADIC

Today I was lucky enough to visit el Parque Nacional Tierra del Fuego with Pancho and his graduate student Pili to learn a bit more about both the environment and the Yamana (the indigenous people in southern Tierra del Fuego) who have lived here for thousands of years. Pili is studying how the Yamana processed seals after catching them by looking closely at the cut marks and various other human produced scrapes and scratches, carefully noting changes in how the seals were butchered over time. Thus, she is an excellent companion to have around, and with Pancho, provided me much insight about some of the characteristics and practices of the Yamana. Despite the abundance of archaeological sites here, there is still quite a bit of unkown information about these people, especially their ancestors from several thousand years ago.

There are number of ethno-historical accounts describing the culture and lifestyle of the Yamana written by British missionaries from the 18th and 19th centuries, however it can be problematic to extrapolate this information into the deeper past, not only because these first European contacts tended to exaggerate stories about the cultures they encountered, but also due to the fact that culture is constantly evolving and changing. The Yamana of 18th century were certainly very different from the Yamana of 6000 years ago, even if many of their tools and physical patterns of settlement only show subtle differences. We are unable to identify most of those potential differences since we are left with a scant record of artifacts and other archaeological data since the Yamana had no written language.

Nothofagus trees, with lichen that guanacos love to eat in winter

Despite this, we know that the Yamana were extremely mobile marine resource intensive hunter-gatherers, moving in small familial groups from site to site every few weeks. They would fashioning harpoons tips made of whale bone scavenged from beached whales to 3-4 meter long wooden poles from Nothofagus trees (a relative of oaks, for those of you familiar with trees from the northern hemisphere.) The Yamana of the Beagle Channel would paddle out to sea in their canoes (made from Nothofagus bark) and launch their long harpoons into their preferred targets, Arctocephalus australis, the Southern Fur seal. They would follow their targets until they died from their wounds, unable to dive with the large poles keeping them afloat. The fur seals, unlike other marine mammals, were small enough to fit in their canoes to bring to shore.

Once on shore, the Yamana would butcher the seals with bone and rock tools. (Some early stone tools were made of obsidian only found far to the north, evidence that the early peoples may have been more mobile than the more recent Yamana.) After this work was finished, a few remains, broken tools, and various other bits of unneeded materials were thrown to the side. Typically, working and living sites are identified by a circular pattern with the refuse all around the sides, creating pits in the middle. The vast majority of artifacts used to study these cultures come from the sides of these pits.

Bahia de Lapataia, connected to the Beagle Channel in the background

Why am I telling you all this? Today's goal was to go see some of these pit sites in person. Originally we planned to go the Tunel I, where all my seal samples came from. But a snowstorm yesterday made the 40 minute walk to the site impassable. Instead, we went to the national park were there are a number of other sites and things to see. One very popular tourist attraction, the Bahia de Lapataia (Lapataia Bay) has a number of raised boardwalks that prevent people from disturbing the numerous shell middens and pits underneath. (Midden is the archaeological term for "trash pile"). This particular site is so extensive and has so many shells that the soil chemistry has been altered, resulting in grass that grows in a different color. Unfortunately, these sites were all buried in snow so I couldn't see anything underneath the boardwalk, but I should be able to during my next trip south.

El Rio Lapataia, connecting Lago Roca to Bahia Lapataia

Another very cool place with an exciting geological history is the freshwater lake Lago Roca, which feeds a short, shallow and wide river that dumps into Bahia Lapataia and the Beagle Channel. I should state that all of Tierra del Fuego has an extensive glacial history, almost the entirety of the landscape here was influenced by glaciers during the Last Glacial Maximum (often abbreviated LGM, occurring roughly 25,000 years ago.) Glaciers carved not only the valley in which Lago Roca lies, but also the entire Beagle Channel. The lake is only at an elevation of 2-3 meters above sea level, hinting at its history as a fjord connected to the ocean after the glaciers retreated. Geologists believe that the fjord was cut off from the ocean about 6,000 years ago, leading to the formation of the lake. Archaeologists, however, contest this date since they find sites with shell middens (marine shells, mind you) from 4,000 years ago along the lake shores. While early peoples could have transported these shells inland, that would be inconsistent with observations found in other parts of Tierra del Fuego. In any case, it's very pretty and is a popular spot among hikers, canoers and kayakers during the summer months.

Looking toward the north shoreline of Lago Roca, where many shell middens are found

Looking at the south shoreline of Lago Roca, which marks the boundary with Chile

I was planning to write a bit about how the chemistry side of seal analysis was going, but this post seems pretty long and full of info already, so I'll save that for a post later this week. Stay tuned!