Having been here a week now, those of us who’ve not been here before are beginning not to believe the horror stories about the horizontal rain, gale-force winds, bone freezing cold and biting insects. Today was another day of big blue skies with high diffuse clouds and endless sunshine. OK there were a few bugs on site for about an hour at the beginning of the day, but (on cue) the sea breeze picked up keeping them well at bay for the rest of the day. The site is beginning to come to life again – now fully opened up with new contexts, great new finds and screening of deposits beginning in earnest.
We trialled the new wet-screening frames today behind the village store where we have pressurised water linked to a long hose. Roy and Kisngalria modified some of our old on-site dry-screening frames, adding two lower drawers of finer mesh. – the smallest being 3mm. They also built some smaller frames (also with 3mm screens) that we could use for drying samples after wet-screening.
Screening protocols should ensure a systematic (and basic-quantitative) record of artefacts and ecofacts is made that can be compared across the site from all valid contexts. Screening is of course a time-consuming, process, with many logistical challenges and pitfalls in such a remote location. At Nunalleq there are huge logistical problems screening what is effectively organic peat – mesh becomes clogged very quickly with the wet waterlogged organic material that’s characteristic of all deposits from the site. Our morning trials today (where we started processing the sample backlog from last season) showed the large surface area of the new screening drawers (plus the high pressure hose) to be pretty efficient. Fine screening to 5 and 3mm revealed numerous fish bones and other small artefacts of wood, stone and ivory. Timing how long it took to process this rich organic material through the sieves, showed that samples of around 20 litres could be finished and transferred to the drying frames in around 20 mins, a good deal quicker than last year.
Trials of our new wet-screening system this morning show that we can efficiently process numerous sub-samples of these organic-rich sediments relatively efficiently. Whether they are bug and bear-proof – only the next few weeks will tell!
After work today, another great dinner was followed by the now obligatory trip to the Kanektuk river for an evening of salmon fishing. It’s the season for salmon runs and big fish can be seen leaping from the sandbar where we fish. A single pink salmon, plus another five large leopard trout, will provide a feast at dinner on our well-deserved day off tomorrow.
With the blog jam-packed with the daily updates, wonderful archaeology and (miraculously) blue skies of another field season, I thought I’d post a long-overdue update on all-things-isotope.
At Nunalleq, we’ve been using a method called stable isotope analysis to investigate the archaeological foodweb and subsistence patterns during the occupation of the site. This technique involves the chemical analysis of preserved animal and human biological materials, providing direct evidence of diet. As those of you reading this blog will have gathered, the preservation conditions at Nunalleq are incredible, with the site not only yielding animal bones, but also leather, animal fur, claw, and even cut strands of human hair. These materials are an invaluable archive of stable isotope data!
From 2010, I’ve been working on both human hair and animal remains at the site. Our first data from Nunalleq, focusing on some of the first phases of the site, revealed a very mixed terrestrial-marine diet – in interesting contrast to earlier sites in Western Alaska and the Alaska Peninsula. This year I’ve been focusing on the more recent phases of the site. Given the long period of site use, the large collections of human hair from Nunalleq will allow us to look at diet through time, and to see if and how the Little Ice Age influenced the foodweb and subsistence menu at the site.
Stable isotope analysis utilises mass spectrometry, an analytical chemistry technique. However, ahead of mass spectrometry, samples have to be prepared and cleaned – a very time consuming process, whether you are dealing with bone or hair/fur. Earlier this summer, I had some company in the lab – high school work experience student, Alice Jaspars. Alice, an aspiring archaeological scientist, helped prepare a batch of hair samples from the most recent phases of the site ready for analysis – a process that involves stripping the hair of debris and lipids (grease) using chemicals (chloroform and methanol) and an ultrasonic bath.
As part of her work, she cleaned the long strand pictured here – one of around 6 or 7 strands we’ve found like this so far. When these long strands are found in the field, we geeks get especially excited! Human hair grows at a rate of ~1cm per month, which means a long section like this contains a dietary record that spans almost two years of an individual’s life. After Alice cleaned this particular sample, I was able to align the hairs and cut the lock into 5mm sections, which will provide bi-monthly isotope data. The tiny samples were then weighed out into small tin capsules, and are now waiting patiently to be analysed. I know the thrills of the lab cannot compare to those in the field, but when the Excel file with those data pings into my email inbox, I will be giddy!
As well as Alice, I’ve been lucky enough to be joined by two other wonderful isotope scientists on this project – PhD students Ellen McManus and Alex Jamieson. Ellen, a regular both on site and in the lab, has been primarily investigating isotopes in animal remains, in particular the dietary relationships between the inhabitants of Nunalleq and their canine companions. Uniquely, her work incorporates both zooarchaeological analysis and isotopes, and also promises to provide insights into the archaeological foodweb. Not only can this help us understand the subsistence menu at this site, but will also enable us to compare how animal ecology has changed in the area over the last few hundred years. Now in the dreaded final year of her PhD, Ellen is deeply ensconced in data analysis and writing, but I am really looking forward to seeing all her hard work come to fruition over the next months.
Alex is the newest member of our team, and making her way to Nunalleq as I write. Like Ellen, Alex will be focusing on animal remains to better understand the site, human subsistence choices and also animal ecology in deep time. Alex’s work, however, will focus on faunal mobility rather than diet – particularly the migratory behaviours of caribou, then and now. As tooth enamel grows incrementally, like the hair, we can sequentially-sample tooth enamel from animals we suspect may be migrants and analyse their strontium isotope ratios. These data correspond with the underlying geology the animal was living and feeding on at the time, allowing us to reconstruct the archaeological migration routes of this important subsistence species.
Well, I think that is more than enough isotopes for one day! I will check back in soon with updates on the DNA front too, but for now – back to the field season, incredible archaeology, and those hard-working diggers who make the isotopes possible!
Yesterday, we witnessed one of those breath-taking Alaskan midnight sunsets. The photos do not do justice to the immensity of the sky and the sense of space one has in this landscape: the flat tundra, the mountains in the background, the ever changing clouds all gained a new quality in the reds and purples of the late night sun. We woke up to a beautiful morning, sunny and windy enough for mosquitoes to keep away. Many fishing boats were casting their nets just off the beach, taking advantage of the high tide.
Despite the warm weather, the ground is still partly frozen is some areas of the 2013-2013 excavation, and Edouard removed two massive columns of ice from the bottom of a couple of squares – a reminder of the low temperatures sustained during the winter. Having dedicated part of the morning to the organisation of the tent, the site records and finds processing areas, most of the day was spent deturfing, but the dry weather and the occasional artefacts found just below the sod top layer (like the dog skull and almost complete clay lamp that Rick and Ziggy found) made for a very good day. We planned the looter’s holes in Area D (West) and started removing the fill of the deepest one, which held some treasures despite the looting, including carved ivory head very similar to the one from last year, which has become the logo for the project. This is a good omen! More on this artefact later.
By the end of tomorrow, we should be able to start excavating in Area C (East), where we have already found three large wood posts. But it feels like proper archaeological digging now that we are getting to cultural deposits: check out Edouard in action doing the first open-area photograph.
We returned home to another one of Cheryl’s divine dinners, Vero’s arrival and the news that a bathroom has been built in the main sleeping quarters. Oh joy!! No more running across the street in the middle of the night! The evening has continued as wonderfully summery as the rest of the day – a real treat, as you can see!
Continuing good weather is really helping the fieldwork. While James and I went off to clean and record another soil profile along the beach bank, the rest of the team set out to deturf as much area as possible. We are planning to open 17 new squares, which will add 68 square meters to our total excavation area. So far, we’ve been making excellent progress: after only two days, Rick, Jack, Ziggy, Edouard and Keith have already deturfed half of these squares. The northwest area of the excavation was affected by looters, who made holes through the archaeological deposits. Nonetheless, most of the site is very well preserved, and we have found a few artefacts and fauna remains just below the sod.
Meantime, Roy and Kisngalria worked all day on creating these sophisticated sieves for screening the bulk soil samples for recovering animal bones, especially fish and small bird bones, Contrary to what happens with larger fauna remains, which are easy to recognise and collect during excavation, these bones are difficult to spot. They are, however, important for a better understanding of the subsistence strategies of the Nunalleq inhabitants and the environment in which they lived, something that Edouard is particularly interested in.
The morning stayed cool, grey and damp, so Ana and I bundled up in waterproofs to hike a couple of kilometres south to the north mouth of the Arolik. We were there to find and sample geological profiles the river had deposited and cut over the last several thousand years. Accompanied by the loyal site dog (Lokys, who soon got tired, started whining, and needed to be carried), we started at the river mouth and collected clay deposits for some experiments — the inhabitants of Nunalleq made considerable amounts of pottery, and Ana is building understanding of the range of variation in clay sources in the immediate area around the ancient village.
Following that we moved 500 m or so north to some older coastal sections that hadn’t been cut by the river and cleaned back a two-meter-deep section so we could sample and draw the sedimentary sequence and begin making sense of the formation processes that gave rise to the landscape. Our working interpretation is that the deeper grey-blue clays are sediments of the late Pleistocene, and following shoreline transgression are then cut into by braiding streams in the Arolik’s flood plain and filled by low energy organic-rich alluvium during the early Holocene, which are then overlain by the peat sediments.
Surprisingly this landscape wasn’t under ice even at the maximum extent of the last (Wisconsin) glaciation between about 25 and 20 thousand years ago, so what we’re able to view in these profiles is a near-continuous sequence of landscape evolution under various episodes of climate change. This helps us contextualize human history within the longer term ecological changes that occurred in these dynamic landscapes. We collected soil samples for compositional analysis that will provide some more precise data on formation processes as well as a bucket of good clay for some experimental pottery making later in the week!
The day ended with heavier rain, so by the time we wandered back up to the main excavation the whole crew was muddy, wet and tired — fortunately Cheryl had made a Mexican-inspired feast for us this evening so we were restored and ended the day (very) well fed and content.
We have woken up to a drizzly morning and are now getting ready to leave for another day on site. Yesterday, we managed to almost finish removing the backfill, except for a relatively thin layer of permafrost soil, which should have melted by now. With the help of our outstanding local crew, we have now moved around 50 cubic meters of dirt by hand. This means that the site will be ready for excavation before the end of the week, in advance of the main student crew! We will also be able to open new ground very soon – possibly as early as today we’ll start de-turfing the new area! Meantime, we’ve had visits from many local residents, welcoming us back to Quinhagak. John Smith, who carved some beautiful things for us last year, came in for a chat with Rick and they both poured over the photos of artefacts from last year – these are the artefacts we’ve spent the spring cleaning, cataloguing and conserving.
This is a very busy season for the local community, as it is berry picking season. Everyone is driving around in their ‘Hondas’, coming and going from their traditional patches of berries and greens. This year the crop of salmon berries is low due to lack of cold weather last winter. Annie has told me that this year there was a week of winter and then a week of summer during the cold season, and very little snow. Annie is a basket maker (among lots of other things) and has showed me the kinds of grasses she collects by the beach for basketry making. We have a huge collection of baskets and mats from Nunalleq, as well as evidence for vegetable material being added as temper to the pottery, so it is very interesting to learn more about these grasses.
Today John Hunter showed us his sealing harpoon, made with a toggling harpoon the same size and shape as prehistoric examples we have been finding at the Nunalleq site. John’s point was made from aluminum while the early harpoon points are made from antler. Both the old and new points are designed to toggle or turn sideways inside the seal to prevent it coming out. A line attached to the shaft unwinds as the seal struggles to escape, slowing him down as the shaft drags sideways behind him in the water. Then the seal is shot and brought into the skiff. In earlier times the seal would be towed behind a kayak.