Author Archives: Manuel Will

Diary of an archaeologist part I: Recent excavations and research

Dear diary,

I have been awfully quiet the past 4 months regarding this blog. This is not due to sluggishness, dwindling enthusiasm or beef in the GAB-team (which, I can assure you, will never happen!). The simple answer is that the life of an archaeologist can be exhausting and time-consuming (and awesome!), finding topics and time to research and write them up as blog posts has been difficult. Then I realised that I don’t need new topics all the time, as I have the honour of being able to work on the things I want to discuss anyway. So, here is an insight into what I have been doing the last 4 months, how an archaeologists´ life goes and what kind of cutting-edge archaeology (pun alert!) we do.

Regarding these past activities, I have been part of the excavations at the archaeological site of Sibudu (South Africa, KwaZulu-Natal) from February to March. After the fieldwork, I moved for a 5-week study season to the KwaZulu-Natal Museum in Pietermaritzburg in order to analyze the stone artefact collections that form the basis of my doctoral thesis. So what is this all about?

 

What is Sibudu and what are we doing there?

View from the site of Sibudu

Fig. 1: Wouldn´t you like to have this view from your workplace? Enroll as an archaeologist, now! (Photo: M. Will)

In the middle of nowhere close to the very tip of the African continent – surrounded only by dense vegetation and a few people of the local Ndwedwe tribe – lies a vast rock shelter that overlooks a wild river. Standing there, looking into the hauntingly beautiful landscape (Fig. 1), one would never guess that this natural landmark, which we call Sibudu today, holds an astonishing three meter deep repository of our cultural history from ~80,000-40,000 years ago, the so-called Middle Stone Age (MSA, Fig. 2).

The archaeological site of SIbudu during excavations in 2012.

Fig. 2: Busy archaeologists at Sibudu during excavations in 2011. This picture also captures the rare sight of two field teams (Wadley´s  and Conard´s) peacefully working at the same time (Photo: M. Will)

In 1998 archaeologist Lyn Wadley from the University of Witwatersrand, Johannesburg, started the first large-scale excavations here, a project that was handed over in 2011 to Nicholas Conard from Tübingen University (Germany), the institution where I pursue my PhD. Today, excavations continue, digging both deeper, pushing further back in time, while also spreading out over other areas. The deepest hole, aptly named “Deep Sounding” is so deep that it wouldn’t end well if it collapsed upon you. There are strict safety measures to prevent this but I was still pretty happy to be working in the Eastern Excavation, one of the newer (and hence shallower) pits (Fig. 3).

View on the Eastern excavation (bottom) and Deep Sounding (top right). At this time, I was actually excavating in the deep hole...

Fig: 3: View on the Eastern excavation (bottom) and Deep Sounding (top right) – yes it is only a step away from each other! Also note the height differences! At this time, I was actually excavating in the the deep hole, still smiling… (Photo: University of Tübingen)

A pavement of old abandoned tools and the waste products of their manufacture, lying below the ground only waiting to be excavated by us after 60,000 years.

Fig. 4: A near pavement of tools and the waste products of their manufacture left by the inhabitants, lying below the ground only waiting to be excavated by us after 60,000 years. (Photo: University of Tübingen)

Our team excavates very carefully, often using the famous archaeologist brush – though these brushes are not used in archaeology as often as you’d think. The sediment colours change quickly and the number of lithic finds is so high that they often form a near pavement of historic tools (Fig. 4). Apart from that, our approximately 12-people strong crew lives in a beach house with a perfect view on the Indian Ocean and a garden fit for conducting soccer tournaments, explaining in part the awesomeness of being an archaeologist. On the weekends we even find time for coming close to indigenous game (giraffes!), not a bad life indeed…

… but back to science! The stratigraphic sequence (the succession of soil layers lain down over time, which are hopefully full of archaeological stuff) at Sibudu is extraordinary, mind-blowing! From my personal experience Sibudu’s stratigraphy is extremely rare: usually sediments that old in Africa and Europe look like one long boring brown wall! Yet, Sibudu has numerous thin and brightly-colourer layers (Fig. 5) that reflect a detailed record of multiple repeated occupations by people over a long time. Absolute dating suggests that some of these thin layers potentially encapsulate only one or a few generations, a chronological resolution rarely achieved in Stone Age times. These factors render the site ideal for studying trends and changes in the behavior of our ancestors over time at a very fine-scale. In addition to the presence of numerous stone artifacts and hearth features, you can find bone, ochre, charcoal, plants, bedding and even microscopic residues (e.g. blood!) on tools! In one of the next diary entries, I will discuss previous findings and the importance of Sibudu for the study of human evolution in more detail.

Fig. 4: On overview of the excavation plan of the site (top left), the entire stratigraphy of the 58,000 year old stratrigaphic sequence (right). Note the fine and brightly colored laminations on a section of the stratigraphic sequence (bottom left).

Fig. 5: An overview of the excavation plan of the site (top left) and the entire stratigraphy of the 58,000 year old sequence (right). Note the fine and brightly colored laminations on a section of this stratigraphic sequence (bottom left). Will et al. 2014, Fig. 1.

 

My own work – constructing and conducting a PhD

Photographs and associated drawings of beautiful stone artefacts aptly named "unifacial points". Note the convergent triangular retouch on the top end of all tools.

Fig. 6. Photographs and associated drawings of beautiful stone artefacts aptly named “unifacial points”. Note the similar convergent triangular retouch on the top end of all tools. Will et al. 2014, Fig. 3.

Being a lithic analyst, my PhD at Sibudu focuses on the stone tools that people produced, used and left at the site. My daily work pretty much consists of observing the various traces of knapping on the artifacts, recording them in a database, and making sense out of it. For me, the stone artifacts themselves – while often being exciting and even beautiful (Fig. 6) – are merely a proxy for studying how people lived, behaved and changed (or adapted) through time, which is where the interesting bit lies. As I explained in a previous post stone artifacts are THE source of information on behavior in the Stone Age, making their study prime to anyone interested in the cultural evolution of humans. My goal at Sibudu is to study the many assemblages dated to about 58,000 years ago of the Eastern Excavations that we are currently unearthing (Fig. 5). I want to document the variation in technology throughout this sequence and try to come up with hypotheses/explanations for (potentially non-existing?) changes through time. These results are then compared to other sites and regions to analyze these issues on various scales. In essence, I hope that this work can inform on the mode and tempo of cultural evolution during the MSA, which is a critical period in becoming ”us”.

We recently published the first part of this process in PLOS ONE. I chose this journal on purpose to publicize our results as it follows an open-access policy, making the findings available to both scientists and the general public (and here it is). As Africa is the cradle of humankind, and the MSA archaeology studies the culture history and evolution of these source populations, the findings of its Stone Age archaeology should also be available for all its contemporary descendents.

 

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Ancient housekeeping

Look around the room you are sitting in right now. Regardless of whether it is your study, a library, or your bedroom, you will recognize a certain order and organization to it (even if it is a mess). Contemporary humans like to structure the places where they live, work and sleep. Even if you do not realize it, this omnipresent organization of living space is something special. Today, we as a species are unique among all animals in living most of the time in our own constructed cultural niche. In doing so, we constantly modify or even bar the natural world. The four built walls plus floor and roof that separate you from the outside are ample proof of this parallel universe we inhabit (“outdoors” is a vivid description for this observation). Although many animals show evidence for organizing their domestic space – such as the hives of bees or nests of termites  – humans are peculiar in the way and extent they do so.

While there are many things to pick up from this contemplation, I want to focus on the early evidence for this cultural organization of living space – ancient housekeeping. For starters, we need to clarify where our hominin ancestors actually lived. Up until fairly recently (considering the time scale of human evolution), housekeeping did not even involve having a house. The earliest constructed huts date to about 20.000 before present (bp)1. This should come as no surprise; until our forebears invented farming around 10.000 bp, all humans were living in groups as mobile hunter- and gatherers. These foragers frequently moved around the landscape and never dwelled in a single place for more than a few days or weeks. With such a restless lifestyle, owning and building a permanent structure like a massive house would be highly inconvenient.

There is abundant evidence that hominins, equipped with a very mobile lifestyle, settled at various different places in the landscapes including open-air localities, rockshelters and caves. While we usually do not find any housing facilities from these sites, it is very likely that people lived in tents made from skins or otherwise constructed shelters that have perished (keyword “taphonomy”). Although some of the evidence does not survive the ages, we have several different sources of information to reconstruct ancient (non-)households in the Old Stone Age. For one, the spatial distribution of stone tools or bones can provide indications of activity areas. Abundant waste of knapped rocks at one place (“workshops”) or the aggregated remains of defleshed carcasses (“butchering sites”) are just two examples. Ancient pyromantic activities such as open fires or hearths leave traces in the ground – with debated evidence as early as 1.8 million years ago – that can be discerned by careful excavation and consideration of sediment surfaces (“features”). These exemplary reconstructions have one thing in common: they are based on “macroscopic” observations, that is to say by the naked eye.

Micromorphology sample Sibudu SR

Geoarchaeology for beginners: wrap plaster around a nicely cut section from the archaeological stratigraphy and – Ta-Dah – you have a micromorphology sample (Picture by Sarah Rudolph)

Recently, there has been much advance in “microscopic” methods of analyses in archaeology. This methodological progress also had an impact on what we know about the cultural construction and organization of living space in modern humans. I will pick one example from the archaeological site of Sibudu in South Africa to illustrate this point, as much exciting research has been done here lately. Furthermore, it is also the locality that I study for my PhD (more on this in later posts). Populations of Homo sapiens occupied the large rockshelter of Sibudu for more than 40.000 years during the Middle Stone Age, leaving manifold traces of their stays in the ground. With the introduction of a method called “micromorphology”, (geo-)archaeologists zoomed in more closely at the inhabitants actual day-to-day lives. In short, micromorphology takes samples from archaeological sediments in the field, cuts these up into extremely thin slices in the laboratory (“thin sections”) and studies these slides under very high magnification through a microscope.

Sibudu MW

View of the archaeological site of Sibudu during excavations carried out by the University of Tübingen in March 2011. Indeed a beautiful work area (Image by Manuel Will)

So what did the “micromorphology people” find out? In 2011, they reported on centimeter-thick, compacted and laminated layers of plant material which constitute by far the earliest evidence for the construction of plant beddings worldwide3. While this may not sound so exciting at first, there is some importance to this finding. With their age of ~77.000-48.000 bp, the plant mats are more than twice as old as the next oldest evidence for floor preparations made from grasses. Furthermore, the findings show that people structured their living spaces by manufacturing areas for working or sleeping. The inhabitants sometimes even burnt the constructed bedding after use, presumably to get rid of smell or insects settling down, only to build new mats on top. Additionally, some of the mats contained plant species with insecticidal attributes to protect against noxious vermin, like mosquitoes, nesting in their beds. In a previous study involving micromorphology at the same site, Goldberg et al.4 also found evidence for the repeated use of living floors. The inhabitants constructed hearths, cleaned and raked their fireplaces afterwards and disposed of waste in dump areas. These findings suggest that modern humans at Sibudu maintained and organized their domestic space in a systematic manner way before built huts entered history.

Bedding micromorphology (Wadley et al. 2011, Fig. 1)

Micromorphology snapshots of selected bedding layers from Sibudu. A) Laminated, articulated phytoliths (p) on top of a sedge layer (c). B) Bedding of siliceous plants in close-up. C) Repeated construction and burning of bedding (taken from reference 2, Fig. 1)

Ultimately, the re-organization of living space evidenced at Sibudu and other sites might indicate a re-organization of the brains, social lives and settlement strategies of these people. It is thus important to study at which times different kinds of housekeeping behaviors originated, from sweeping floors and raking out waste, to building houses and separating rooms for washing, sleeping, and working. Starting from novel analytical methods, we now know that proper housekeeping extends far into our past. Presumably, even Stone Age children were yelled at by their parents to clean up their room (whatever that was). Not tidying your place at these times, however, might have had more severe consequences than nowadays: getting killed by hyenas that are attracted by the bony leftovers from supper or being infected with unpleasant diseases from insects drawn by the stench of waste is arguably a far worse deal than being grounded for a few days. Such consequences might even have been a selective pressure for such behaviors to evolve and be maintained.

1Maher, L.A., Richter, T., Macdonald, D., Jones, M.D. Martin, L., Stock, J.T., 2012. Twenty thousand-year-old huts at a hunter-hatherer settlement in Eastern Jordan. PLoS One e31447.

2Wadley, L., Sievers, C., Bamford, M., Goldberg, P., Berna, F., Miller, C., 2011. Middle Stone Age bedding construction and settlement patterns at Sibudu, South Africa. Science 334, 1388-1391.

3Goldberg, P., Miller, C.E., Schiegl, S., Ligouis, B., Berna, F., Conard, N.J., Wadley, L., 2009. Bedding, hearths and site maintenance in the Middle Stone Age of Sibudu Cave, KwaZulu-Natal, South Africa. Journal of Archaeological and Anthropological Science 1, 95-122.

Paleolithic archaeology: Why stone tools matter

Why would any sane human being devote his or her life to studying battered and smashed rocks? Most people would probably just throw these stones away, or use them to construct a pathway through their lawn. Most Paleolithic archaeologists study precisely these rocks, crazy as it may sound. Since I am one of this queer bunch, I would like to explain the reasons for pursuing such a profession.

Stone tools

Early stone tools (“choppers”) from Melka Kunture dating to 1.7 Myr. (Didier Descouens / Wikimedia Commons / CC-BY-SA 3.0)

Paleolithic archaeology is the branch of archaeology that studies old (=paleo) stones (=lithic). A more scientific definition would be: Paleolithic archaeologists study the period of human history known as the  “Old Stone Age”. This part of human history is characterized by the eponymous implements made from various kinds of rocks – stone artefacts. By definition, the Paleolithic era begins with the earliest known stone artefacts that our early ancestors (hominins) manufactured. Currently, the oldest stone tools worldwide that have been knapped by hominin hands come from the archaeological locality of Gona in Ethiopia1. With their age, approximately 2.5 million (!) years old, they not only mark the beginning of the Old Stone Age but also signify the advent of human history and culture. The end of the Paleolithic period at around 10,000 years before present is characterized by the invention of agriculture and the adoption of a sedentary lifestyle, gradually replacing nomadic societies based on hunting and gathering. In sum, the Old Stone Age covers a breathtaking time period of 2.59 million years, which is 99.7 % (!) of our species’ entire history. In the remaining 0.3% – the pathetic rest of our history, including among others, the classic era, the medieval times or the modern period – we invented farming, houses, the wheel, written language, science, space travel and the internet you´re using to read this blog.

Time scale old stone age

Time scale of the entire cultural history of humans. Important events are highlighted with dates. The red bars mark the beginning and end of the Old Stone Age respectively (copyright New Scientist).

Stone knapping

Hominins manufactured stone tools by knapping: striking a block of rock with a hammerstone (Holdaway & Stern 2004, Figure 1-1-1)

But why did hominins start to manufacture and use tools made from rocks at all? Rocks utilized for making stone artefacts – such as flint, chert or quartzite – are tough, brittle and elastic. These properties allow for chipping smaller fragments when they are hit with another stone. This action of knapping rocks creates so-called “flakes”. These have sharp and durable cutting edges that are rarely found in nature. It is these sharp edges that early hominins desired and used in various tasks of their daily lives, such as cutting plant and animal tissue or killing their prey. In short, the stone artefacts provided our early ancestors with a means to extract a livelihood from the environment. This explains, in part, why it is so important to study these lithic remains: they provide a window into the behavior and activities of our ancestors. These tools also show the technical, manipulative and even cognitive abilities of their makers who lived in the deep past. Furthermore, the mere presence of knapped stone tools in the ground or on the surface attests to the presence of hominins at that place during the Old Stone Age. Due to their variety of shape, stone artefacts can also serve as markers for different stages within the vast Paleolithic period.

But there is another reason why many Paleolithic archaeologists are so obsessed with stone artefacts. The cause bears the name “taphonomy”. Taphonomy studies how organic and inorganic remains change through time after they have been buried in the ground. Organic remains – such as animal or plant cells and tissues (e.g. wood) – slowly decay through time after they enter the soil. In contrast, inorganic remains – such as minerals or stones – normally survive in the ground unchanged and are thus preserved even after immense passages of time have elapsed.

Why does this matter for the study of the Old Stone Age? Throughout the tens or even hundred thousands of years a “taphonomic bias” (or “differential preservation”) will be established in the soil: most organic materials that hominins left behind decay and are lost forever, never to be recovered by archaeologists. On the other hand, inorganic materials such as tools made from stone survive even for very long periods in the ground and can be recovered by archaeologists even after millions of years. Hence, while stone artefacts will almost always remain where our ancestors dropped them, there is a very low chance that organic materials such as tools made from wood or plants enter the fossil record. While we do know that hominins used artefacts made from organic materials – such as the 300,000 year old Schöningen wooden spears2 – these finds are extremely rare as they are only preserved in particular environments (deserts, permafrost soils, bogs, airtight conditions). In a sense, the name “Stone Age” is thus an apt choice for this time period, although hominins presumably used tools from a wide range of more perishable materials throughout their entire history.

In conclusion, artefacts made from stone are the ultimate source of data to examine the behavior and cultural evolution of our human lineage through more than 2 million years. They survive the ages through their durable nature, providing manifold information on the activities and capabilities of their makers. Getting your daily bread from studying ancient bits of stone may still seem a bit odd but perhaps you now have an idea why some, myself included, do it.

1 Semaw, S., Renne, P., Harris, J. W. K., Feibel, C. S., Bernor, R. L., Fesseha, N. & Mowbray, K. (1997). 2.5-million-year-old stone tools from Gona, Ethiopia. Nature 385, 333–336.

2 Thieme H. 1997. Lower Paleolithic hunting spears from Germany. Nature 385, 769–771.