Parc Safari Update

November 12, 2009

Wanted to update you all on the Parc Safari work that has been going on. The students have written a number of great posts that overview some key aspects of this year’s work. Check it out here.

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Day 4…Microscope Eyes

November 12, 2009

Today was much like the past few days. My approach to learning Soil Micromorphology has been working so I stuck with it. I did make one minor modification though. Rather than pair slides with their relevant publication and go over the identified characteristics, I pulled out one of the best guides to Archaeological Soil Micromorphology, Soil and Micromorphology in Archaeology by Courty et al. 1989, and went through the major concepts while trying to locate evidence for each one in a number of slides. It was a bit frustrating but overall it went well. Not really the best approach unless you have slides that have already been analyzed and are supposed to have these features but it worked for me today and I recommend it.

The best part of this course is the enormous reference collection of thin sections that is at our disposal. After each topic is introduced, remember the two lectures a day program followed by hours of examining slides, we are introduced to another set of thin sections relevant to the topic. That means every half of day the slides we can look at grows and grows. Now that I am feeling a bit more confident in my approach to soil micromorphology I have realized just how valuable this experience truly is. The only unfortunate part is I wish I had more time to look through all of these things and really thoroughly study each topic in detail. A week doesn’t really lend itself to that however.

Today we were introduced to two more topics. We shifted into more rural habitation and looked at occupation surfaces, such things as constructed living floors like plaster, mortar, daub. This was the morning. In the afternoon we were treated to a lecture on the vague term Dark Earth. This type of sediment dates to the post-Roman period and is related to urban deposits that have been the medium in which soil has formed. As per the name it is very dark and visually diagnostic, often producing an extremely homogenized deposit. I won’t go into to too much detail but take a look at Dr Richard Macphail’s work if you’re interested in learning more. It is an extremely ubiquitous sediment type in London in particular and is an amazing example of how soil micromorphology can be applied to archaeological questions.

In addition to all this my eyes have begun to revolt to excessive use of a microscope. It may have something to do with a lack of sleep but I don’t have that luxury for another day so I am going to pretend it doesn’t exist.

Back tomorrow with Day 5 update, the final day of the training week.


Day 3…Over the hump day

November 11, 2009

Today was another whirlwind adventure in Archaeological Soil Micromorphology. The morning was spent listening to a lecture on the evidence for non-intensive cultivation and the afternoon built on this with a discussion of the evidence for slightly more intensive agricultural practices, particularly heavy manuring, burning, and ploughing. The topics are fascinating but the microscopic evidence in thin sections is extremely complex.

In attempt to ease the complexity added by time and post-depositional forces we discussed numerous experimental examples first, specifically the Butser farm site and the Umeå site (see Goldberg and Macphail 2006). The Butser farm experiment is a reconstruction of an Iron Age village that was thoroughly tested for many things before, during, and after occupation. The researchers also burned some of the dwellings and studied the resultant impacts on the subsurface. The Umeå site is similar but specifically tested the impact of slash and burn agriculture and ploughing (plus some other things). These examples are invaluable. The reason being that all the evidence for human modification to the landscape during occupation is masked by everything that has happened since abandonment; the pesky post-depositional process like pedogenesis, bioturbation, erosion, re-occupation, etc, etc. Therefore, these experimental projects were the first step, allowing us to understand the immediate impacts before moving into numerous examples of manured, burned, ploughed, and trampled soils and sediments that have been buried for a couple thousand years. It all makes sense when you think about it but the tough part is recreating the history of a sediment or soil after I identify numerous features in the thin sections.

Yes, that’s right, the features I can now identify. By no means am I an expert or even an intermediate. I am still 100% a beginner, well maybe 99%. Nevertheless, I feel as though this Wednesday was the day when I overcame some imaginary hurdle (perhaps a hump) toward proficiency in soil micromorphology. I am able to compartmentalize the sample into the coarse and fine fraction, identify the primary mineral components like quartz, glauconite, feldspar, mica, etc., say something about the structure (the porosity, the sorting, the shape, and abundance, etc.). I learned how to identified shell, egg shell, bone, phytoliths, calcium oxalate spherulites, phosphate enriched soils, charcoal, and organic matter. I also saw a fungal spore but didn’t locate it myself, although I feel I could now.

Most of this learning is thanks to my great classmates. There are about 12 of us (give or take a couple) and today everyone opened up a bit, the atmosphere was a little more collegiate and it made a huge difference. Maybe it was the group outing to the pub yesterday….either way, everyone had something to offer, except for me now that i think about…let’s say I added the enthusiasm. We even had a short presentation on phytolith morphology. I now know what a banana phytolith looks like and know way more about the domestication of bananas than I ever imagined I would. Sorry, that isn’t true. I’ve never even thought of banana domestication until today. It has a very interesting and complex history goes back to Papua New Guinea about 6000 years ago. I don’t have a reference but this seems to line up generally with what was said today if you want some more general information.

Personally, I stuck to my same strategy as yesterday: pairing slides with their publications and reviewing basic identification concepts and locating the appropriate feature or component in a number of slides. I am almost finished with the major concepts so tomorrow afternoon I move onto systematic thin section description from start to finish. By tomorrow night I will know whether I did actually make it over the hump or am still teetering somewhere near the top…let’s just hope I fall forward if it’s the latter.

I ended the day with a tall dark Guinness and walked home with a some fish and chips wrapped in newsprint. Mmmm!

Back tomorrow with another update.

References:

Goldberg, P. and R. Macphail, 2006   Practical and Theoretical Geoarchaeology. Blackwell Publishing, Oxford.


And it Begins….Ever so Slowly

November 9, 2009

Hello to everyone from sunny old England. I arrived in London this past Saturday, the overnight flight from Ottawa of course, only to be treated to a quirky British tradition surrounding Guy Fawkes day. In a small, yet enormous by London’s standards, back yard I spent the evening watching people set off fireworks and stare into a bonfire in honour of the parliament not being blown up back in the day. There’s a lot of information out there on this so I won’t dwell on it.

Sunday might as well not have existed thanks to jet lag but I did catch up on sleep. This was a good thing because today was the first day of my Archaeological Soil Micromorphology course at the Institute of Archaeology at UCL. The course is focused on a technique that involves collecting intact sediment samples, embedding them in resin, slicing and dicing, sticking them to a glass slide, and finally grinding them down to 0.03mm thick before sticking them under a microscope for description and interpretation (includes both geological and archaeological sediments). I have been looking forward to this course for months, reading as much as I could and looking at as many images of thin sections as possible. I thought I was somewhat prepared…boy was I way off.

The course started with an introductory seminar, followed by 3 hours looking at reference thin sections under the microscope. Lunch break was great! I found a nice sandwich and bag of crisps (aka chips) for 3 pounds. Then the afternoon was a lecture on buried soils and the numerous taphonomic factors that act upon them. This included marine water fluctuations and the resulting cycle of pyrite formation and oxidation, as well as other things like the velocity of deposition in flash floods and the sorting patterns produced. This lecture was again followed by a few hours of browsing reference samples under the microscope.

Today’s class was not overly uplifting. The lectures were great, the concepts all make sense and the interpretation that follow are somewhat satisfying. Even the basic principles of deposition, soil formation, and post-depositional alterations all fit nicely into my head. My biggest stepping stone is understanding the identification process. How do I know which minerals are quartz, pyrite, tourmaline, muscovite, etc. from clay, shell, bone, flint, and ash fragments.  Coming from a purely archaeology side of things (specifically North American archaeology rooted in an Anthropology department) my optical mineralogy, and mineral crystallography are a little weak…if not non-existent. So, some pretty major hurdles and there was quite a bit of frustration today but at least I know what I need to learn. To me, that’s a pretty good first day. I already know what I need to get out of this 2-week course.

So after 6 hours with the microscope today and a couple more reading, the screen is starting to go a bit blurry. It’s time for me to stop and do some more reading on birefringence. I’ll be back tomorrow night with some updates on the course and my progress.

 

 


The Curse of the MA thesis

October 23, 2009

Hello to those few readers that still care to stop by my measly little blog, I thank you. The extreme lack of posting has been in large part due to my cursed MA thesis that is now officially done, graded, and formally accepted. The only thing left is the actual convocation which I am told is a formality, one of those necessary human ritual things that through a public display formalize things (we sure are a weird species).

So, now that I am deshackled from my thesis I have moved on head first into a PhD at McGill, and over the next little while there are some exciting things happening that will appear up here on the blog. I have switched gears for my PhD, embracing the geoarchaeological work I have done in Jordan and has been mentioned a few times on the blog. Nothing against the archaeology on the Northwest Coast, definitely still an interest of mine, but I really enjoy the geoarchaeology and working with the people I met in Jordan, a great crew! This switch means I need to brush up on some geography, geology and soil science and as a result am auditing a class on Soils and the Environment this term, which is going great. It is through Geography, meaning I get to play the fun game of trying to relate pedogenesis and nutrient cycling for temperate environment agriculture to 300,000 year old buried soils in the basalt desert of eastern Jordan. That being said the course is incredibly informative and I would recommend a contemporary soils class to anyone doing field archaeology.

That course is great but the thing I am most  excited about this term is the course I have signed up for with Prof. Rich Macphail at the Institute of Archaeology at UCL. In a couple weeks I am heading over to London for an intense workshop/course on Archaeological Soil Micromorphology. While I am over there I will keep you all up to date on what the course is like and the trials and tribulations of learning micromorphology.

Have to run. Time to head out to the Parc Safari cemetery to finish digging up and mapping the remains of an enormous male watusi…yes I am going to leave that hanging at the end of the post…don’t worry I will fill you in shortly.

-Chris


Huge Weight off the Shoulders!

May 15, 2009

I’m still in Jordan but I finally got that pesky thesis finished and into the multiple revision process. I’ll have to say I am fairly happy how it turned out. There were a few times when I wasn’t too sure if it was going to come together. Now, I don’t mean get it finished on time because the submission deadline isn’t actually until June 15th. I was worried about how to effectively portray all the variables I needed on one graph. However, thanks to the great help of a friend in my lab, the Computational Archaeology Lab at McGill, I was able to figure it out.

Since it’s been a while, before I tell you about the graph I better review the thesis. The whole point is to test current descriptions of the prehistoric transition from chipped stone to ground stone technology on the southwest coast of British Columbia, Canada. Specifically, I am looking at whether or not the concept of phase (prehistoric periods of time for which all sites get grouped together) has an impact on interpreting archaeological change. So, I analyzed the above mentioned transition using prehistoric periods and then again without them, using strictly carbon-14 dates, to see if there was a difference in the temporal and spatial pattern of change. The tricky graph I mentioned was the final one, placing all the assemblages (75 of them) on one graph that had time and space (coordinates) represented as continuous axes as well as including the proportion of chipped stone, ground stone, and faunal tools for each assemblage. That makes 6 variables for one graph…and voila….kind of

composite_plot _2

What we came up with is this graph. It is a basic scatterplot with the Y-axis being time, the X-axis being space, and the assemblages coloured using an RGB composite where Red = ground stone proportions, Green = faunal tool proportion, and Blue = chipped stone proportion. This gives every assemblage a unique colour based on the combination of the three colour proportions. There were two tricky parts. First, the spatial axes is actually two variables, the latitude and longitude. Luckily our sites are positioned on a fairly east/west axis so we reclassified them as the distance from the mouth of the River. Zero kilometers is the river mouth and everything East is inland up the river while everything to the West is in the delta or coast islands. You can see the division between deltaic sites and coastal island sites clearly on the graph between 30 and 50km W. The other tricky part was the legend but thanks to some helpful colleagues we got it figured out properly. What the graph shows is a pattern that goes against the current descriptions of the transition and suggests that continuous axes of time and space are more appropriate than archaeological phases for understanding change through time. I’m sure more info is needed but that will have to come later.

For now, enough technical mumbo jumbo. I’ll get you up to speed on the work here in Jordan very soon!


Triangular Confusion

March 8, 2009

What a week! I am fully enjoying a very slow Sunday after an insanely frantic week. Thankfully the payoff was well worth every minute of stress.

Yesterday was the final day of the first (and hopefully annual) McGill Anthrograd Conference. Myself and two other friends put together a two day event at McGill that brought together the wide range of research that the grad students are conducting. It was a phenomenal success thanks to the many hours of hard work from all of the volunteers. We even had the local archaeology lab band Megalith end the evening last night with an hour and a half show. With so many wonderful volunteers the conference organization was only minimally responsible for the ferocity of this week on my nervous system. Most of the suffering was induced by me also presenting my MA thesis in the first session on Friday evening. But I managed to get my primary analysis done and the results proved to be much more thought provoking than I expected. The project is examining the transition from predominantly chipped stone tool technology to ground and polished antler, bone, and stone tool technology on southwest coast of British Columbia over roughly the past 9000 years. Now the end points of this transition are well established and my initial question was why did this transition happen. But before I could as why did things change I needed to understand the nature of this change through time and space. What I stumbled upon is that very little detailed work had been done on the broader temporal and spatial patterns of the transition and most people conclude/assume that there was a gradual or incremental increase in ground stone technology at the expense of chipped stone technology through time. The result of this observation is my thesis: Is the temporal and spatial distribution of the observed technological change on the southwest coast of British Columbia over the past 9000 years gradual and spatially uniform? Here’s my answer to the temporal component:

Ternary Plot

What you see here is a ternary  plot on which each point is an assemblage and its position represents the proportions of chipped, ground, and faunal tools. If the change through time is gradual or incremental we would expect the gray-scale (which represents the age of an assemblage) to get gradually lighter as it extends out from the bottom left corner. Clearly this is not the case. Once you get more than 10% ground stone there is no discernible pattern through time or by phase. I think we need to reconsider the dynamics between the two endpoints of this transition.


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