Last Friday's fieldwork was eventful. With just a few days left in the field, we are down into the nitty-gritty of the feature excavations intended to recover detailed data about the Late Archaic (ca. 4000-1000 BC) occupations at the site. Last year's work in the block revealed the presence of a significant Mack component (dating to around 1000 BC) and hinted at the existence of an earlier Savannah River component (dating to around 2000 BC) in close vertical proximity. Although we won't know which features go with which component until we excavate and analyze them, Friday's work gave us some important clues. Enjoy the video!
You can find all the videos from the 2018 season on the Broad River Archaeological Field School website.
We had an eventful day in the field last Friday, so this week's video is longer than usual. Every project like this reaches what feels like a "hinge point" where you can start accurately sizing up what you can and can't get accomplished. We won't be able to do everything I wanted to do at 38FA608 this semester, but we'll be able to do a lot of it. Fingers crossed the weather continues to cooperate.
We finally took the large rocks out of the floor of Unit 5. One of them turned out to be something unexpected (I won't spoil is so you can enjoy the moment with us on the video). The other turned out to be . . . well, watch the video for that also.
My arms and hands began blooming with poison ivy rash at about 2:00 on Saturday morning. Last week it took a couple of days before I started to feel the irritation. My folk theory is that the lack of rain allows the oils to build up and concentrate. Spring is aggressive and early here: plants and animals move into the excavation areas during our week-long absences from the site.
Enjoy the video!
Today is my last morning in Tulsa at SEAC 2017. I spent all day yesterday in the "Paleoindian and Early Archaic Southeast" symposium: 18 papers that included state-by-state updates of what we know and the data we have and treatments of topics such as megafauna in the Southeast, plant use by early foragers in the region, wet site archaeology in Florida, lithic technologies, etc. It was a marathon.
My presentation with David Anderson was last in the lineup. I was tasked with an effort at a "big picture" demography paper. It was a lot to talk about in a short time (20 minutes) -- a difficult balancing act to discuss the dense data from such a large area and be able to explain how I tried to integrate it all into a geographical/chronological model that can be evaluated on a region-by-region basis. Anyway . . . the detail will be there in the publications that result from the endeavor.
I uploaded a pdf of my presentation here. Some of the details will change as we work through the process of refining the analysis and dividing the content into multiple papers. But you should be able to get a decent idea of what we were going for.
I'm currently in Tulsa, OK, at the 2017 Southeastern Archaeological Conference. I took a break this afternoon from papers and talking to hole up in my hotel room and put the finishing touches on the presentation I'll be giving tomorrow. I'm honored to be senior author on a paper with David Anderson (University of Tennessee). Our paper will be last tomorrow in a marathon symposium organized by Shane Miller (Mississippi State University), Ashley Smallwood (University of West Georgia), and Jesse Tune (Fort Lewis College).
I'm really looking forward to the session, which will present summaries, updates, and syntheses of work from across the Southeast. It's intended to be a 20-year update to the work that culminated in the landmark Paleoindian and Early Archaic Southeast volume that was published in 1996. Congratulations are due to the organizers who conceived of the symposium and pulled it off.
I briefly discussed our paper back in September. Significant work has happened since then, and I'm pretty happy with the result. The point of doing a "big" paper like this, in my view, is to attempt to identify and describe patterns that require explanation. We used information from three large datasets -- PIDBA, DINAA, and an always "in progress" compilation of radiocarbon dates -- to investigate patterns of population stability/fluctuation during the Paleoindian period in the Eastern Woodlands.
As of now (rushing through this blog post so I can go out to dinner) I like the result: a six period chronological/geographical model identifying the time/space parameters of population stabilities and fluctuations. As I listen tomorrow to region-by-region updates on what we know about the Paleoindian period in the Southeast, I will almost certainly learn of many things that are wrong. But I will be listening to the results of others' work with a model in mind. That's useful. As the famous quote goes: "all models are wrong, but some are useful." To me, a useful model is a machine for thinking that makes predictions about the world that can be evaluated. So I'm looking forward to seeing what I got wrong. I wish I had a big piece of paper I could spread out on a table so I could take notes time period by time period, region by region.
After this updated photograph of Woody Guthrie, I'll post images of a few key slides from the presentation. I'll put the whole thing on my Academia page tomorrow after the dust settles. [Update 11/13/2017: the presentation is available here.]
I recently announced the return of the Broad River Archaeological Field School for the spring semester of 2018. Student registration begins in November, and the logistical and strategic wheels are in motion.
This week I received radiocarbon dating results from two samples I submitted to Beta Analytic. Radiocarbon dates are not cheap (about $600 for an AMS analysis that returns an age estimate from a very small sample), and I am grateful to a private donor who supplied funds to date one of the samples from 38FA608.
Here are the date results on a generalized figure of the stratigraphy at 38FA608 as I currently understand it (based on profiles of Units 1, 2, 9, 11, and the original machine cut):
The date for Zone 7 -- from a single piece of charcoal that Jim Legg picked out of the profile of Unit 9 -- came back right at the Middle/Late Archaic transition. It's a date that's consistent with Zone 7 being related to the Guilford point fragments that we've gotten from the site (only one of which has actually been found in situ). Thus my original suspicion of a Middle Archaic age for Zone 7 is supported.
The date for the Zone 19 sample, however . . . was a bit of a surprise. It also came back as Middle Archaic in age, about 700-800 calendar years older than Zone 7.
I only wrote briefly about Unit 11, which I and several volunteers put in after field school to get our first good look at what is beneath the deposits exposed by the original machine cut. There wasn't much material until we neared the boundary of a seasonal water table. Right above that, there were some large cobbles and a very light scattering of small, angular quartz fragments. As I wrote back in May, none of the cobbles appears to have been modified (at least based on a macro inspection), and none of the pieces of angular quartz is a slam dunk for a human-made stone tool. Other than human deposition, however, I can't think of a good explanation for how that material got there -- it is so unlike its sandy matrix in terms of size that it could not have been transported by the same mechanism.
I dated a single piece of charcoal plucked from the wall of Unit 11 (FS 1318) from a zone beneath the "cultural" material in an attempt to learn something about where those deposits might be in time. Given what seemed to be a fairly regular accumulation of the sand from the Middle Archaic though the Woodland period, I was expecting an Early Holocene rather than a Middle Holocene age -- I thought we might be looking at the edge of an Early Archaic deposit.
There are two main possibilities for the date: (1) it accurately dates the age of Zone 19; or (2) it doesn't.
It's possible that that piece of charcoal worked it's way down through the sand from a higher elevation, perhaps through bioturbation (movement by animals or roots). There's no obvious signs of intrusion from where the sample was taken, but that doesn't mean much in these old sands: we wouldn't necessarily expect that subtle signs of intrusion would be discernible in these kinds of sediments after 6000 years.
So the date could be "bad" in the sense that it isn't giving us the age of the deposit. I think it's entirely possible, however, that it is accurate. While the idea of a slow and steady accumulation of sand over the course of the Archaic is appealing, there's no reason to assume that that's how it went down. It's possible that rates of deposition varied. The levee could have aggraded more rapidly during the Middle Holocene, perhaps as a function of both Middle Holocene climate and the lower elevation of the existing surface at that time (making it easier for the landform to be over-topped by flood waters).
If Zone 19 really dates to around 4700 BC, the deposits in Zone 15 could be related to a deeply-buried Morrow Mountain occupation.
Investigating the deep deposits at 38FA608 is a top priority for excavations in the spring. Stay tuned!
We're now into the fourth week of the semester here at the University of South Carolina. As usual I've been writing for this blog less than I'd like (I have several unfinished draft posts and ideas for several more, and there's currently a backlog of Fake Hercules Swords). A good chunk of my time/energy is going into the Forbidden Archaeology class (you can follow along on the course website if you like -- I've been writing short synopses, and student-produced content will begin to appear a few weeks from now). Much of the remainder has gone into pushing forward the inter-locking components of my research agenda. This is a brief update about those pieces.
Small-Scale Archaeological Data
At the beginning of the summer I spent a little time in the field doing some preliminary excavation work at a site that contains (minimally) an intact Archaic component buried about 1.9 meters below the surface (see this quick summary). Based on the general pattern here in the Carolina Piedmont and a couple of projectile points recovered from the slump at the base of the profile, my guess is that buried cultural zone dates to the Middle Archaic period (i.e., about 8000-5000 years ago).
My daughter washed some of the artifacts from the site over the summer, and I've now got an undergraduate student working on finishing up the washing before moving on to cataloging and labeling. Once the lithics are labeled we'll be able to spread everything out and start fitting the quartz chipping debris back together. Because I piece-plotted the large majority of the lithic debris, fitting it back together will help us understand how the deposit was created. I'm hoping we can get some good insights into the very small-scale behaviors that created the lithic deposit (i.e.,perhaps the excavated portion of the deposit was created by just one or two people over the course of less than an hour).
Drawing of the deposits exposed in profile. The numbers in the image are too small to read, but the (presumably) Middle Archaic zone is the second from the bottom if you look at the left edge of the drawing. Woodland/Mississippian pit features are also exposed in the profile nearer the current ground surface.
When the archaeology faculty met to discuss the classes we'd be offering in the spring semester, I pitched the idea of running a one-day-per-week field school at the site. Assuming I can get sufficient enrollment numbers, that looks like it's going to happen. The site is within driving distance of Columbia, so we'll be commuting every Friday (leaving campus at 8:00 and returning by 4:00). The course will be listed as ANTH 322/722. It's sand, it's three dimensional, and it's pretty complicated -- it's going to be a fun excavation. I'll be looking to hire a graduate student to assist me on Fridays, and I'll be applying for grant monies to cover the costs of the field assistant's wages, transportation, and other costs associated with putting a crew in the field.
Large-Scale Archaeological Data
Some parts of my quest to assemble several different large-scale datasets are creeping along, some are moving forward nicely, and some are still on pause.
Complex Systems Theory and Computer Modeling
Complex systems theory is what will make it possible to bridge the small and large scales of data that I'm collecting. Last year, I invested some effort into transferring my latest computer model (FN3_D_V3) into Repast Simphony and getting it working. I also started building a brand new, simpler model to look at equifinality issues associated with interpreting patterns of lithic transport (specifically to address the question of whether or not we can differentiate patterns of transport produced via group mobility, personal mobility between groups, and exchange).
As it currently sits, the FN3_D_V3 model is mainly demographic, lacking a spatial component. Over the summer I used it to produce data relevant to understanding the minimum viable population (MVP) size of human groups. Those data, which I'm currently in the process of analyzing, suggest to me that the "magic number of 500" is probably much too large: I have yet to find evidence in my data that human populations limited to about 150 people are not demographically viable over spans of several hundred years even under constrained marriage rules. But I've just started the analysis, so we'll see. I submitted a paper on this topic years ago with a much cruder model and didn't have the stomach to attempt to use that model to address the reviewers' comments. I'm hoping to utilize much of the background and structure of that earlier paper and produce a new draft for submission quickly. I also plan to put the FN3_D_V3 code online here and at OpenABM.org once I get it cleaned up a bit. I also discuss this model in a paper in a new edited volume titled Uncertainty and Sensitivity Analysis in Archaeological Computational Modeling (edited by Marieka Brouwer Burg, Hans Peeters, and William Lovis).
How big does a human population have to be to remain demographically viable over a long span of time? Perhaps not as big as we think. The numbers along the bottom axis code for marriage rules (which will be explained in the paper). Generally, the rules get more strict from left to right within each category: 2-0-1 basically means there are no rules, while 2-3-8 means that you are prohibited from marrying people within a certain genetic distance and are compelled to choose marriage partners from within certain "divisions" of the population.
It will be a relatively simple thing to use the FN3_D_V3 model in its non-spatial configuration to produce new data relevant to the Middle Paleolithic mortality issue I discussed at the SAA meetings a couple of years ago. I'm also going to be working toward putting the guts of the demographic model into a spatial context. That's going to take some time.
As I mentioned briefly in a post yesterday, I've become interested in looking into the evidence for an abandonment of large portions of the Southeast at the end of the Early Archaic period.
This (2012) paper by Michael Faught and James Waggoner provides an example of how this could be done on a state-by-state basis. Faught and Waggoner use multiple lines of evidence to evaluate the idea of a population discontinuity between the Early Archaic and Middle Archaic periods in Florida. One of the things they discuss is the presence of a radiocarbon data gap between about 9000 and 8000 radiocarbon years before present (RCYBP). They are able to identify that gap (which is consistent with a significant drop in or lack of population at the end of the Early Archaic using a dataset of 221 pre-5000 RCYBP radiocarbon dates from Florida.
Assembly of radiocarbon datasets for states across the Eastern Woodlands would be really useful for seeing if there is a similar "gap" in other areas of the Southeast that correlates with technological and statigraphic discontinuities. It seems to me that small bifurcate points (e.g., LeCroy cluster) and/or larger lobed points (e.g., Rice Lobed cluster) are good candidates for marking a contraction or retreat of late Early Archaic hunter-gatherer populations. While common in the Midwest, such points are absent (?) from Florida and present in only parts of South Carolina, Georgia, Alabama.
I'm aware of the Kentucky, Ohio, West Virginia Radiocarbon Database published by Cultural Resource Analysts, Inc. I'm wondering if there are similar existing compilations (either print or electronic) for other eastern states, especially those south of the Ohio River. I've only spent a short amount of looking, but I haven't come across any yet. At the risk of being accused of being lazy, I thought I'd throw the question out there and see what turns up. I will be very surprised if radiocarbon compilations haven't been produced for many areas of the east, and it seems worthwhile to ask about existing resources (which may not yet be easily "discoverable" online) before I contemplate yet another large-scale data mining effort. Please let me know if you can help.
Update (3/27/2016): I've created this "Eastern Woodlands Radiocarbon Compilation" page to store links and references to radiocarbon compilations.
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