Castles and Coprolites

Ben Chan discusses this week's progress on the site tour This week has gone by so quickly, but we have managed to collect some great sets of samples, more than we can get made into slides at the moment! The first lot have already been sent off to Earthslides to get made into thin sections. An important lesson from the field - if you get over enthusiastic about collecting blocks of soil that weigh >1kg each, they will not fit in your luggage and will incur hefty postage fees. And lesson 2, blocks of soil wrapped in tissue and tape look very odd on the airport X ray and your bags will likely be searched. I ended up taking about 20 block samples in all, and spent much of my last day in Orkney panicking about how to transport them back.  Friday was my last day on site, and the day started with a site tour with each supervisor summarising what has been going on in the building/trench that week. A week is just not long enough to get my head around everything going on at the Nes...

Planning sampling strategy with Jo After planning the sampling strategy, the next few days have been spent collecting samples. I decided to focus on two areas of nicely stratified midden for the main sampling, and have collected overlapping sample blocks to provide an overview of the entire sequence. Already it's possible to see some quite ashy areas, so hopefully we will be able to get some nice information on resource use, and hopefully what activities the fuels relate to. We decided on a further 4 areas as secondary sample sets with a smaller number of samples, testing specific hypotheses from the excavations. More on those later this week. As well as the Orkney students, we also have a team here from Willamette University, Oregon, led by Professor Scott Pike . Professor Pike has a background in geology and expertise in pXRF (portable X-ray fluorescence). In brief this involves using a piece of kit that looks like a ray gun to fire X rays at material, which then...

ORCA project officer Dan explains what's going on with middens Marvelous midden at the Ness of Brodgar - check out those ashy layers! Earlier this year I was fortunate enough to be awarded 2 small grants from the Society of Antiquaries of Scotland and the Orkney Archaeological Society , to carry out a pilot microarchaeology study at the Ness of Brodgar site in Orkney. The Ness of Brodgar is part of the Heart of Neolithic Orkney World Heritage Site , and excavations are directed by Nick Card of ORCA/UHI . The site is one of the finest examples of Neolithic archaeology in the UK (along with the rest of Orkney!), and the extent of preservation of the buildings and middens provides a rare opportunity to study the subsistence activities of the inhabitants. The architecture here is some of the most impressive I've ever seen. It's interesting to note that the dates for the Neolithic here go to around 2500BC - roughly the same date that the Great Pyramid of Giza was cons...

A: gypsum plaster (Tell Brak, building) B. microcrystalline gypsum (Catalhoyuk, midden) C. gypsum rosette (Kamiltepe, building) D. microcrystalline gypsum (Kamiltepe, external area) This month we have some micrographs showing examples of some different ways you might encounter gypsum in archaeological thin sections, part 1 as there are a few other forms that I don't have photos of yet but will aquire at some point. Gypsum (aka calcium sulphate) often occurs in Near Eastern samples as a post-depositional feature, where the calcium sulphate salt, dissolved in water, precipitates as the water evaporates. The growth of the crystals can often cause a lot of damage to intact deposits, as the growth of the crystals pushes apart the material. The crystals can have a widely variable morphology, as a result of different formation mechanisms. As well as precipitation from water evaporation, the salts can precipitate due to the solution becoming saturated (i.e. there is so much present no ...