Castles and Coprolites

We've spent the past couple of days doing burning experiments in the reconstructed mudbrick house at Catalhoyuk, as part of our Wellcome Trust project. The aim of the experiments is to collect some pilot data relating to smoke emissions when ovens and hearths are in use. We don't have time in the pilot study to conduct a detailed series of controlled experiments - there are a lot of different variables that could be adjusted to test different scenarios - but we do hope to get some basic comparisons of different fuel types and how emissions change over a few hours of burning. I think the most useful part of doing this pilot work has been the practical side of things, the experience of having to find the materials for fuel, finding out how much fuel works best (and at what point there's too much fuel and you get smoked out of the house), observing how different people react differently to smoke levels. We tried using animal dung but it smouldered really badly, which we reali...

Me looking thrilled to be presenting my poster I just got back at the beginning of the week from the Society for American Archaeology conference, held his year in Vancouver. Although it is 'American' archaeology, the geographic spread of attendees and research topics is very international, and I ended up catching up with friends and colleagues from all over the UK as well as the US. I ended up being incredibly busy as I foolishly agreed to do three different sessions. Many months ago I was asked to participate in two sessions as a discussant, as well as submitting a poster on my NERC project. I assumed this meant a role of leading the questions at the end of the session, but on arrival realized it is almost the equivalent of a keynote, and involved giving an actual 15 minute presentation summarizing the papers and state of the field! Luckily the sessions are both topics on which I am passionate, and I managed to put together two talks that went very well. The first was ...

Back in March I mentioned that I was involved in a sciart collaboration, where artists and scientists come together to work on collaborative art projects, inspired by scientific research. I love this idea. I was always really into both art and science growing up (and took Art as an A Level subject!), and although I choose to go down the 'science' route for my career, I have maintained a keen interest in art, and particularly how we can use artistic expression to communicate scientific research. The artist I have been working with is Molly McEwan , an Edinburgh based artist and graduate of Duncan of Jordanstone College of Art and talented ceramicist.  The photos to the left are a sneak preview from Molly's exhibition at Wednesday's Girl, a free exhibition showcasing the work of female artists from Scotland, held at Space Club and supported by Somewhere To , an organisation provides spaces and venues for young people across the UK. Molly's solo exhibition , ...

This month's microfossil is a 'jigsaw' phytolith, or rather phytoliths, as it is actually a tissue fragment consisting of multiple conjoined silicified cells. These jigsaw types are associated with the epidermis of woody dicotyledonous plants, though they are also found in herbaceous plants. The two images show the same phytolith in two different focal planes. The uppermost image being the upper epidermis, and the lowermost image showing the underlying layer of 'regular' shaped cells, or the palisade mesophyll layer. The sample this was extracted from is from Sheik e-Abad in Iran, an early pre-pottery Neolithic site, though in terms of food, the plant remains suggest the people were relying to a large extent on non-domestic resources. What makes this sample particularly interesting is the context, within a layer of dark grey calcitic ash, as identified through thin section micromorphology. Dicot phytoliths account for 10% of whole assemblage, which is a lot conside...

I was recently alerted to this interesting new paper (open access!) through Google Scholar citation alerts, which is a very useful service for finding out when your papers are cited by other authors (in this case my 2011 paper on faecal lipid residues at Catalhoyuk ). The authors studied a sequence of lake sediments from Lake Igaliku in SW Greenland, looking at changes in the quantity of DOC and fungal spores. DOC is a bile acid (deoxycholic acid), and is found in both human and ruminant faeces, but at a higher concentration in ruminants. Humans have higher amounts of LC (another bile acid, lithocholic acid). Interestingly no LC was found, suggesting that the DOC comes entirely from herbivores (and that the runoff 'polluting' the lake is largely agricultural, rather than coming from settlement sewage waste). The fungal spores that were found are from coprophilous fungi - i.e. fungi that grow on faeces! The amount of DOC present correlated with the number of fungal spores, wi...

Bulliform cells in modern Zea mays tissue (source: Visuals Unlimited, Inc) Fellow animal dung enthusiast Sarah Elliot at the University of Bournemouth shared this fab little article describing the use of 'Eco goats' to manage invasive plants in the US . It is especially interesting that they note the use of goats as a pesticide-free way to manage Phragmites reeds. These reeds have distinctive phytoliths which archaeologists call 'keystone' bulliforms, which are relatively large single cell phytoliths that are named as they are said to resemble a Roman keystone arch in cross section.  In transverse section they look a bit sausage shaped, and within a plant these cells are 'stacked' next to each other as part of the upper epidermis (the plant 'skin'), and are related to water storage. If you're a botanist you might also call these motor cells, because during times of water stress, they shrink and cause leaves to fold or curl up. Phragmites phytoli...

Paisley Caves became well known a few years ago for it's famous coprolites, or fossil faeces, which were found to contain human DNA, dated between 14,170 and 14,340 cal. BP. Although there have been questions over the identification of these as human (and work is still ongoing), this ancient DNA analysis currently provides some of the earliest evidence for human occupation of North America. The research at Paisley has been key in demonstrating the utility of coprolites as an archaeological ecofact that can contribute to the wider picture of the human past, rather than simply a 'novelty' area of study or one which is purely ecological . But human poop isn't the only kind we find at Paisley Caves, in fact it isn't even the most common, by far! In this month's micrographs we have pictures of the poop that occurs most frequently at the site, bat poop. This stuff is fascinating, and is a huge contributor to the sediment profile of the caves. In the upper left at the...

I've just been notified of the publication of this great new paper via Google Scholar citations, as it cites my paper on lipid analysis of coprolites . That's not the only reason I'm writing about it mind you - anything dung related gets my attention, and this is one of the first papers to come out of the Ce ntral Zagros Archaeological Project , which I was involved with a number of years ago. The CZAP project aims to understand the origin and process of animal domestication and agriculture in the Central Zagros region of Iran and Iraq, and the team have also conducted ethnographic studies in modern villages in the area, in order to help interpret the archaeology. This paper by Elliot et al reports on a mix of ethnographic studies and scientific analysis of modern dung and plants. The authors look at the dung spherulites in modern samples of sheep, goat and cows - those little spherical particles that form in the guts of animals . Despite being used frequently to support t...

This post follows on from the Manganese Micrograph Mystery I posted a while ago. Blog followers will remember I posted some images of layered ruminant dung which had a distinctive black 'speckled' appearance, a bit similar but not quite the same as Mn staining. Thanks to my readers the mystery was solved through the kind contributions of Hans Huisman. Huisman is a geoarchaeologist with expertise in degradation and preservation of archaeological materials. He suggests that manganese would produce more dendritic like patterns, and that instead this appears to be iron sulphide staining. Iron sulphides include minerals such as pyrite, which can oxidise to rust . This type of staining can be recognised in OIL as having a 'metallic' lustre, or smaller particles, such as we have here, can be examined using reflectance microscopy at a high magnification. So I'll be doing that asap. For now I wanted to share this image showing the possible impact this staining has had on ...

There's an exciting paper out today in PNAS on Aşıklı Höyük , an early sedentary pre-pottery Neolithic site in central Anatolia, occupied a millennia earlier than that site oft discussed on this blog, Çatalhöyük . This paper by Stiner et al. is a great example of research that brings together work from different archaeological specialists to produce a coherent story, supported by multiple lines of evidence. The argument is based around the zooarchaeological analysis of animal remains, which demonstrates a shift over the occupation of the site from a broad spectrum of wild species, to a dominance of sheep by 8200 cal BC. However it is the geoarchaeological analysis that arguably provides direct evidence of deliberate animal management, and as a micromorphologist with a special interest in all things coprolite and dung related , I am very happy to see that this technique is one of the highlights of the paper! (Phytoliths also get a mention!). The researchers identify accumulation...

What a treat for you this month, another set of micrographs and it's only the end of the first week of the month! Actually, I am posting this because I need a bit of help - here we have an image of dung deposits in plane (PPL) and cross polarised light (XPL). You can see in the upper image, the layered appearance associated with ruminant dung, but we also have a lot of black 'speckling'. This appears to be concentrated in bands throughout the deposit. When we look at the deposit under XPL it turns out that these speckles are 'stains' on the dung spherulites! The only thing I have seen like this before was called microbial/fungal or manganese staining, but I can't find the reference (or it may have been something that was mentioned to me in passing?). Anyone got any insights/references? It's probably not vital to the interpretation but it could help understand the post-depositional processes going on here, and it is quite fascinating in itself (well, maybe ju...

I never imagined I would end up being a specialist on the subject of archaeological poop, but there you go. Coprolites, animal dung, palaeofaeces you name it. So I was very intrigued by an article published in the Proceedings of the National Academy of Sciences last week, claiming evidence for the earliest use of manure by European farmers 8000 years ago . Firstly let's consider the different methods that we can use to identify dung in the archaeological record. These can be divided into direct and indirect methods. The former include definitive evidence for the presence of dung, that is actual dung pellets, or lipid biomarkers which are found exclusively in dung (i.e. faecal sterols and bile acids from the gut). The latter include evidence which is suggestive of dung, for example weed seed assemblages. Although indirect indicators are often the only thing available in archaeology, in my opinion one cannot make definitive statements based on indirect evidence. The best we can do...