MA Student Kristen Welch is at Olduvai Gorge, the cradle of humanity. Read about what she’s doing, and what it’s like in one of the most important archaeological sites in the study of human evolution.
July 5, 2014
Greetings from the field! This summer I am working with Olduvai Geochronology and Archaeology Project (OGAP) at Olduvai Gorge. Explored since the 1930s by Louis and Mary Leakey, the sites at Olduvai Gorge, Tanzania have received worldwide attention with the discovery of early stone tools and hominin fossils. Our team is composed of international and multidisciplinary folks that all come together to study what our ancestors were doing in the past. My participation on the project is to assist in the analysis of the animal bones that are excavated from the site under the supervision of Dr. Michael Pante, my graduate advisor at Colorado State University.
So what can these old bones tell us?! One of my undergraduate mentors once said that there is a common misconception about what archaeologists do: Most people think that archaeologists study the past. Unfortunately, he said, this is impossible until we can travel back in time and actually observe what is going on. What archaeologists actually do is study traces of what happened in the past. It is from these traces that we can try and reconstruct what our ancestors were doing. The analysis of animal bones, then, tells us what animals lived in the environment, but also what animals our ancestors were subsisting on by looking at butchery marks left on the surfaces of fossils. The study of these traces, among others, fall under the field of Taphonomy.
Taphonomy is from the Greek word ‘taphos’ and ‘nomos’ meaning the laws of burial. Basically Taphonomy is the study of what happens from the death of an animal until its discovery. Some of these processes include rounding from water, trampling from ungulates, carnivore gnawing, and even trowel damage (Yes! Sometimes even the most careful archaeologists damage the bones during excavation!). The human traces on bones include cut marks from flesh removal and percussion marks from marrow extraction. Archaeologists can look at the marks and interpret what behaviors would have caused them. The best way to understand these marks is by comparing the them with those that have been made through experimentation. If we want to know what it looks like to break open bones for the yummy marrow, for example, we should try it ourselves to see what happens. If we see these same surface marks on fossils, we can know that our ancestors probably were behaving in this same way.
For partial fulfillment of my Masters degree I am working on a thesis project that seeks to understand the potential for these marks to identify certain behaviors that would have allowed our ancestors to survive millions of years ago through experimental archaeology. The field students, who arrive this week, will have the opportunity to participate in some of these experimental butcheries. Using local stone to produce simple stone knives, they will learn first hand what types of decisions our ancestors must have made when butchering a carcass. Luckily, they will not be vulnerable to scavengers on the savannah, so they wont have to fight off any salivating carnivores waiting to steal the goods.
Everyone at camp, the researchers, the Maasai, the students, all have made me feel very welcome. We are going to have a great season.
July 7, 2014
I SPY CHUI!!
Just another walk through the Gorge at sunset looking at the beautiful landscape and… Can you see what’s hanging up in that tree?! Look there! If you look a bit closer you’ll see what’s left of a chui’s (Swahili for leopard) dinner dangling from the branches! Leopards are one of what is called the big five in east Africa that occupy the Serengeti ecosystem. (The other four animals include the buffalo, elephant, lion, and rhinoceros). Leopards are solitary cats that don’t like to share. They will carry an entire carcass up into the trees so the scavengers, like hyenas, don’t get their paws on it and then continue to consume it bit by bit. If you ever see one of these kills while on a safari, take care- Chui don’t wander far from their kills!
July 11, 2014
For anyone who ever wondered what we excavate here at Olduvai, this blog is for you! To the left, you can see a picture of a profile of one of OGAP’s units this season. Like a cake, the earth deposits sediments in layers. The layer on the bottom is older than the layers above it. In this photo you can see a variety of different sediment types creating four different layers. The bottom most layer is clay. Above that is sandy conglomerate, then sandstone, and finally, the youngest layer, an erosion slope.
The sediments in this profile can give us a look into what the environment was like in this particular area. The main tip off is the layer of potatoes you can see sitting within the layer of sandy conglomerate. Yup! I said it! We excavate potatoes! In reality these are cobbles that have been rounded by fast moving water. Because of this profile, we know that when these sediments were deposited there was a water channel running through what we are currently excavating!
Another thing to note about Olduvai’s stratigraphy is the lower layer in the photo, the layer of clay. In Mary Leakey’s monographs of the Olduvai excavations, she makes a particular point to mention that the found her artifacts ‘in the clays.’ Clay signals for what archaeologists call in situ soils, which means it is the original soil context. If we have artifacts deposited in these clay soils, then we know that we also have in situ artifacts. Just like Mary did, we make a special point to document the soils and the context in which we make our discoveries!