Environmental Archaeology

Day of Archaeology: Camping in Mongolia

Day of Archaeology: Camping in Mongolia

So on the actual Day of Archaeology I was in my archaeological office job daydreaming about my recent fieldwork in Mongolia. Here is the story of my Mongolia summertime excavation amid wildflowers and beautiful mountain passes in pictures …

The roads were fairly rough; this is the main road between the Soyo site and the tiny mountain village of Ulaan-uul. Tiny ground squirrels bounded around among the trackways, and often yaks or herds of other animals including camels, goats, sheep or horses, would cross the road in front of us.

The vans that took us were built to a 1950s Russian design. They were made for Siberian winters, with an engine inside so it could be fixed in relative warmth even if it was snowing outside. They forded many rivers remarkably well, but in the instance above, we did get stuck. Our driver changed to four-wheel drive but on several occasions we had to get out and push the car.

We camped beside beautiful clear streams in meadows filled with wildflowers. Mongolia is great for camping! Our site office in the field was a ger, which took a remarkably short time to set up and was very weatherproof! We drank from the local clear streams as well; I used a water-filter to purify the water before drinking.

The food at the dig was typically Mongolian – lots of meat, and very freshly cooked! The head is considered one of the best bits; a special portable blow-torch is used to remove the hair from the skin so that the skin can also be eaten. I really enjoyed the breakfast porridge or khosh; there was a delicious breakfast donut that was quickly became one of my favourite foods!

 

We surveyed and sampled and excavated different parts of the Soyo landscape; I was hoping to find out more about the environmental changes that happened when pastoralism increased and large herds of animals began roaming the central Asian steppes. It will take some time to process the samples I collected in the laboratory and answer the question of how much things changed under a mobile, pastoral economy. Thanks to Dr. Julia Clark at the American Center for Mongolian Studies for a really great archaeological research opportunity!

Core blimey! Jason Stewart and the Sediment Core Samples

The best thing about working as a geoarchaeologist at MOLA is the variety; one day I could be watching a machine ripping through the odorous remains of a 19th century gas works, the next day could find me wrestling with the implications of a newly returned set of radiocarbon dates.

Today however finds me in the lab examining sediment cores retrieved from an evaluation. The site is in Dartford within the Thames estuary and has early prehistoric peat forming on top of the cold climate landsurface with various phases of being mudflat, marshland or flooded.

The cores are carefully laid out with the top of the borehole at one end of the lab and the base at the other. As there is 16m of sequence and the cores are 1.5m long and filled with heavy sediment this can take longer than you would think.  The cores are then methodically cleaned and the colour texture, inclusions and nature of the boundaries are recorded.  This detailed cleaning and logging allows me to think about the depositional environment of the site and the nature and rate of the changes that occur.

The next task is to select the locations from which to take samples, we take samples for radiocarbon dating, this enables us to places the changes in environment in some kind of chronological framework allowing us to compare the developments onsite with other work we have done in the surrounding area.  We also sample for things which will tell us about the environment in the past (usually pollen, diatoms, ostracods and plant remains).  These are carefully sliced from the core and sealed in labelled bags to be sent off to the various specialists.  The cores are then re-wrapped and returned to their climate controlled environment, the lab surfaces cleaned and the results typed up.

Jason Stewart

Moving a site on Sanday – Bronze Age buildings, a well with steps, and much, much more.

Never assume you know what you’re going to find – sites always throw up surprises. SCAPE’s project with the Sanday Archaeology Group in Orkney is a perfect example… who thought we’d find a Bronze Age well during a reconstruction project!

Steps down into the well, with water at the bottom. ©Tom Dawson/SCAPE

Steps down into the well ©Tom Dawson/SCAPE

Our Day of Archaeology 2014 was very eventful, and to get an idea of the hive of activity, see a time lapse film of the first two hours on site. The Day came half way through our project on Sanday, where we were working with the local group to relocate a previously excavated Bronze Age site. Local residents had reported structures revealed on a beach after a storm, leading to an emergency evaluation (it was thought that there might be a burial within the stone tank). The excavation had showed the site to be one of only a handful of burnt mounds with surviving structures within them. After the excavation, the sea continued to attack the stone tank, orthostats and a corbelled cell, and the local group wanted to preserve something of the site by moving some of the stones to their newly opened Heritage Centre, away from the sea. The group contacted SCAPE’s Scotland’s Coastal Heritage at Risk Project – and a plan to relocate the stonework was devised as a ShoreDig project.

The Scotland's Coastal Heritage at Risk logo  ©SCAPE

The Scotland’s Coastal Heritage at Risk logo ©SCAPE

Before we could transfer the large stone slabs to the Heritage Centre, we had to reveal the masonry from under the beach cobbles. The original excavation had located a corbelled cell buried in the coastal section, but health and safety concerns had prevented full excavation. By the time we started digging in early July, the sea had eroded back the coast edge, allowing access the cell. After getting our Shetland stonemasons, Jim Keddie and Rick Barton, to check the structure, we excavated demolition and backfill material to reveal six steps leading down to an underground chamber.

Excavating the Bronze Age well on Sanday ©SCAPE

Excavating the Bronze Age well on Sanday ©SCAPE

The prehistoric structure stood three metres high to the top of its corbelled roof. The lower chamber was full of water; and the silt at the bottom of the well was full of remarkably well-preserved organic material (I’ve never seen Bronze Age seaweed before). Part of our Day of Archaeology was spent sampling the organic silts, bagging 100% of the material for future analysis.

Bronze Age seaweed from the well excavated on a beach, Sanday, Orkney. ©Tom Dawson/SCAPE

Bronze Age seaweed from the well excavated on a beach, Sanday, Orkney. ©Tom Dawson/SCAPE

Burnt mounds often have a large trough or tank, and in Scotland, some of these tanks are made of large, flat slabs of stone. We excavated the cut for the stone tank, finding that the base was far larger than the size of the tank – and that the four side-stones had been placed on the flat slab at the bottom.

Preparing to move the base slab of the stone tank.©Tom Dawson/SCAPE

Preparing to move the base slab of the stone tank. ©Tom Dawson/SCAPE

Much of our Day of Archaeology was spent moving the last of the stones to the reconstruction site. We plotted the relative positions of the stones with an EDM; and photographed, numbered and drew all the stones before lifting them. Jo and Ellie from SCAPE worked with Sanday Archaeology Group members to prepare the site so that the stones could be lifted. A second team of local volunteers were ready with tractors, trailers, digger and slings to move the stones off site.

Moving stones from the site at Meur ©Tom Dawson/SCAPE

Moving stones from the site at Meur ©Tom Dawson/SCAPE

Once the base slab was lifted, we saw that it had been built over an earlier, possibly corbelled, structure, perhaps explaining why such a large stone was used. This was very unexpected, and we managed to capture the moment as part of the filming we were doing for possible inclusion in the next series of Digging for Britain.

Jo filming Tom while stones are moved in the background. ©Ellie Graham/SCAPE

Jo filming Tom on site. ©Ellie Graham/SCAPE

Our Day of Archaeology was a great success – to learn more about what we found, (and what was under the slab) visit our Facebook page; or follow us on Twitter.

Counting Phytoliths from Songo Mnara, Tanzania

Right now, I spend my life counting phytoliths – over 3500 phytoliths so far….What’s a phytolith and why does it get me out of bed and into the lab before 7am? How did you not realise this was such an exciting archaeological technique?

© Hayley McParland-Clarke

Phytoliths are a bit like plant negatives; essentially the plant absorbs monosilicic acid (H4O4Si) from its water supply and during transpiration as the water ‘leaves’ the plant, the monosilicic acid becomes solid opaline silica. It has to go somewhere, so it fills in gaps within the cell structure of the plant. These gaps are either within the cells, or surrounding the cells, making silica negatives of the internal cell structure. Not all plants make phytoliths though, just like not all plants preserve well as charred plant macrofossils, and not all pollen grains enter the local archaeological record or preserve well. Plants have to degrade in situ for the phytoliths to be included in the archaeological record, no technique is perfect. But the key is, that phytoliths are well preserved in a variety of contexts and can add to our understanding of plant use; not only on sites with poor preservation of plant macrofossils and pollen, but also in contexts where plant remains may not have entered the archaeological record following charring. For example, organic crafts such as grass or palm matting may not be preserved by charring and therefore might be invisible on archaeological sites without waterlogged preservation. These may be visible through phytolith analysis if they have degraded in situ. To help identify diagnostic phytoliths I collected lots of plant samples from the field and I’m now creating a phytolith reference collection in the lab. It’s not a magic bullet to help us understand plant use in the past, but it is pretty cool!

I’m working on late 14th to early 16th Century samples from Songo Mnara, a Swahili stonetown in Tanzania, part of the  [1] and my PhD project at the University of York. Songo Mnara is part of the Kilwa Archipelago and it’s linked to other settlements and islands along the East African coast through the Indian Ocean Trade network. Songo Mnara has truly amazing preservation of stone buildings!! To get to the site you have to take a Dhow from Kilwa Masoko with a guide and once you arrive on the island you have to wade through a tidal Mangrove swamp, which can be anything between ankle deep and chest high! It’s off the beaten track, for sure.

Songo Mnara © Hayley McParland-Clarke 2013

During the 2013 excavation season, two types of structure were excavated; a stone house divided into rooms and a collapsed wattle and daub structure, which appeared open plan. Initially it was thought that the monumental stone architecture in the town was standing in an open area, but extensive test pitting by Dr Fleisher combined with Geophysical and Magnetometer survey[2] revealed the presence of concentrations of daub within this space. Excavation exposed two wattle and daub structures with comparable finds assemblages to that of the stone structures.

The phytoliths I’m looking at today come from Trench 32, one of the daub structures. Spot samples were taken across the entire packed sand floor surface of the structure on a 1m grid, in order to assess whether phytolith analysis can be used as a tool for spatial analysis and to understand the use of plant materials within the structure. Samples were also taken from the ‘outside’ of the structure in the open area to identify clear differences in the phytolith assemblage between ‘inside’ and ‘outside’ and to see if it was possible to recreate the environment immediately adjacent to and further away from the structure.

Sampling for Phytoliths at Songo Mnara © Hayley McParland-Clarke 2014

Sampling for Phytoliths at Songo Mnara © Hayley McParland-Clarke 2014

I’m really hoping that we’ll be able to see activity areas within the structure through the plant assemblage, for example food preparation areas or areas of matting. It may be possible to identify construction materials such as wood, or roofing materials such as palm thatch. I’m also hoping to see evidence of Indian Ocean Trade through phytoliths from imported edible plants within the assemblage, but as with all archaeology I can hope for lots of things, it doesn’t mean it’s there! We also sampled the stone house, which is really interesting, because it has clear rooms within it, whereas those divisions weren’t clear when excavating the daub structure. Phytolith analysis might enable us to see the limits of the daub structure by providing an ‘inside’ and an ‘outside’ botanical signature.

The process of counting involves using a high powered microscope at x400 magnification to identify phytoliths, photograph them, measure them and count them. I count around at least 250 per slide, which means that I’ve counted thousands from this site so far, and I’ve a lot more to do! Phytoliths are 3D objects, but when you’re looking down the microscope you only see the 2D image, which means that you have to remember that each phytolith type might look different depending on which angle you’re looking at it from! Phytoliths aren’t always round like pollen, in fact they’re frequently not round at all, they come in all shapes and various sizes!

Although lab work is often thought of as completely different to fieldwork, it’s sort of the same. I search through transects on the slide, much like layers of stratigraphy looking for microscopic evidence in the form of phytoliths rather than artefacts. It can take a long time, it’s systematic and sometimes I don’t find anything of interest. Recording stratigraphy on site tells you a lot about site formation processes and human actions, likewise recording information about the slide assemblage is useful. For instance, lots of phytoliths which are still articulated suggests that there was little bioturbation, or lots of microcharcoal might suggest burning episodes.

© Hayley McParland-Clarke 2014

I’m on my last few slides from this pilot study now, and I’ve started to get an idea of what’s happening in the structure which is really exciting. Each phytolith assemblage has a different character, which suggests that the spatial approach might be working!! I can clearly see a difference between the assemblages from the floor surface ‘inside’ the building and the outside; I can also see variations across the floor surface within the structure.

Future research will focus on the comparison of the stone house and the daub structure to see if there’s a difference between the uses of each structure. I also hope to look at some of the open area samples to try to understand how the urban landscape impacted on the local environment. Follow my progress and find out more about phytolith analysis, archaeobotany and archaeology on my blog, or follow me on twitter @Hayley_McP.

[1] Managed by Dr Stephanie Wynne-Jones and Dr Jeff Fleisher, funded by the NSF and AHRC.

[2] Welham, K., J. Fleisher, P. Cheetham, H. Manley, C. Steele, and S. Wynne-Jones. 2014. Geophysical Survey in Sub-Saharan Africa: Magnetic and Electromagnetic Investigation of the UNESCO World Heritage Site of Songo Mnara, Tanzania. Archaeological Prospection.

#ArchiveLottery – Part 3: Environmental

Still with us? Time for some small stuff

The environmental finds brought up lots of lovely tubes with a mixture of seeds & insects like these from Apothecaries Hall (thanks to @MyLifeIsHistory & 1886Guy for picking shelf 6!)

Seeds & insects

Seeds & insects

 

There was also a tub of parasites from Billingsgate for MOLA’s enviro archaeologist @KarenStewart

Billingsgate parasites

Billingsgate parasites

 

Wouldn’t be environmental archaeology without a coprolite or two like this one for @andyfev

poo

poo

 

And there was a nice few small fish bones from Bull Wharf for @ellie__miles

fishy

fishy

Next it’s our Metal artefacts – these objects are stored separately. A dehumidified store, sealed boxes and silica gel help us maintain these objects to a high degree of preservation as they’d slowly degrade in normal room conditions. Tweet @MuseumOfLondon or @AdamCorsini using #dayofarch or #ArchiveLottery or message us below, a number between 241 and 492 to discover, completely at random, what that shelf holds…

Multi-tasking archaeology! Teaching, fieldwork and medieval poop

I am pleased to be taking part in my third Day of Archaeology – see here for  my previous posts on work for the Feeding Stonehenge and Paisley Caves projects in 2012 and 2013. This year I am working on a whole range of things simultaneously, illustrated nicely in the cluttered picture of my desk below. I am starting my third year working at the University of Edinburgh, and have a lot more teaching responsibilities that I have ever had before. I am in the middle of preparing undergraduate lectures for the second year course, Scotland Before History, which covers Scottish archaeology from early prehistory right up to the medieval period, and making sure all the lab facilities are in place for my third/fourth year option course in Environmental Archaeology, where students get to do a lot of hands on work with environmental remains under the microscope. Alongside teaching prep, I am also putting together my schedule for a brief fieldwork session up at the Ness of BrodgarI started working there last year, and have been applying analytical chemistry and microscopy to midden deposits to investigate fuel resource use and the types of activities that people were carrying out in different parts of the site. Under the microscope you can see the micromorphology slides I am currently working on for the Ecology of Crusading conference in Riga in September – I’ve been blogging about these slides for the past year if anyone would like to know more about them! And finally, I am getting all my samples and paperwork together for a visit to the Organic Geochemistry Unit at the University of Bristol at the end of this month. I have collaborated with Bristol since my PhD, as they have the best facilities in the UK for archaeological chemistry. During this visit I will be working on a wide range of samples from my own research and in my role as research associate for the Ecology of Crusading project – identifying the species and dietary signals of medieval poo!

my desk today

The Archaeology of Food!

I’ve been a commercial archaeologist for 13 years and have worked in Ireland, Greece and Australia. My days once consisted of jumping into a muddy hole in the depths of winter to shovel out the sticky and waterlogged fills within and then trudge to the spoil-heap with heavy boots. My days also consisted of excavating beautiful wooden troughs in fulachta fiadh (burnt mounds) or excavating postholes of Bronze Age structures in the balmy summer sun. However, the recession in Ireland has led to a decline in commercial archaeological work and the absence of muddy viz-vest clad hordes of trowel-grasping excavators is the most visible proof of this!

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