Dating Iroquoia in American Antiquity

The team is excited to release our second project-related publication out into the wild!

AA title

While it’s mostly research that was conducted before the Dating Iroquoia project officially began, our latest publication in American Antiquity does present data about several sites in the Trent Valley sequence in Ontario, one of the village relocation sequences we’ve focused on for our Dating Iroquoia work as well. We present a revised timeline for the occupations of the Benson, Sopher, Ball, and Warminster sites. We wanted to know what order the sites were probably occupied in, especially for the Ball and Warminster sites. There’s been some debate about whether Ball or Warminster is the most likely candidate for the site of Cahiague, an Ancestral Huron-Wendat village that Samuel de Champlain spent some time in during AD 1615-1616.

Manning et al 2019 fig 2

Manning et al. 2019. Figure 2, pg. 691.

We got to use several different dating and Bayesian chronological modeling techniques to figure this out. From a well-preserved wall post at Warminster (a very rare find on an Iroquoian site) we were able to run a sequence of tree-ring dates and perform dendro wiggle-matching.

warminster post pic

Tree rings from a dated post at the Warminster site. From Manning et al 2018, Supplementary materials figure S4.

For each site, we split a few pieces of corn in half, and sent ½ to the Center for Applied Isotope Studies at the University of Georgia and the other ½ to the Centre for Isotope Research at the University of Groningen in the Netherlands. In our models, we combined the separate dates for each corn kernel, which resulted in single dates that were a little more precise.

Finally, we tried to assume as little as possible about the order the sites were occupied in. As one way to test possible sequences, or whether certain sites were likely to come before or after one another, we used the Order function in OxCal. This basically asks OxCal how likely it is that any radiocarbon date (single) or event (derived from several radiocarbon dates) came before any other. Our Order analysis made it clear that Benson was the earliest site, and that Warminster was the latest, which helped us build our models.

From our analysis, it became clear that the Ball site dated to a bit earlier than Warminster, and that people were probably not living there anymore by the time Champlain came through. Warminster, however, definitely was an active village in AD 1615-1616, and is the more likely candidate. This fits with a lot of the inferences that have been made based on ethnohistoric accounts and European trade goods.

The paper and supplementary materials are open access and free to download from CambridgeCore, so go check it out if you’re interested in learning more!


Manning, Sturt, Jennifer Birch, Megan Anne Conger, Michael W. Dee, Carol Griggs, and Carla S. Hadden. Contact-Era Chronology Building in Iroquoia: Age Estimates for Arendarhonon Sites and Implications for Identifying Champlain’s Cahiague. American Antiquity 84(4):684-707.

Manning, Sturt, Jennifer Birch, Megan Anne Conger, Michael W. Dee, Carol Griggs, Carla S. Hadden, Alan G. Hogg, Christopher Bronk Ramsey, Samantha Santf, Peter Steier, and Eva M. Wild. Radiocarbon re-dating of contact-era Iroquoian history in northeastern North America. Science Advances 4(12). DOI: 10.1126/sciadv.aav0280.


DI at the c14 and Archaeology Symposium

Last week, most of the Dating Iroquoia team got to participate in the 9th International Radiocarbon and Archaeology Symposium which was held in Athens, Georgia (home to the University of Georgia and 1/2 of the DI team!).



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One of our esteemed colleagues (paw-lleagues?) from CAIS

The symposium was organized by some of our friends and colleagues at the Center for Applied Isotope Studies at the University of Georgia.

Participants came from around the world to see four days of presentations, all of which involved using radiocarbon dating as a tool to learn more about archaeological sites and objects. There was also a mid-conference tour, where we all got to visit Ocmulgee Mounds National Historical Park.

Sturt Manning came down from Cornell to deliver the team’s presentation, where we described some of the solutions we’ve come up with for creating precise chronologies which cover a time period characterized by a “wiggle” in the radiocarbon calibration curve. After, we heard papers by colleagues who are dealing with the same kind of issues and have found their own creative solutions to handling it!



We also had a team meeting where we took stock of where we are with the project, discussed sampling for our last round of dates, and drew up a publication and presentation plan. We can’t say too much right now, but exciting things are on the horizon and we’re eager to publish some of the data we’ve been gathering over the next year.

The symposium was a great opportunity to share the work we’ve been doing with colleagues from around the world, and see how other people and other projects have handled the same problems that we deal with– messy parts of the calibration curve, short-lived sites, and traditional reliance on relative chronologies. Abstracts are available here, if you’d like to explore some of the research that was presented!

C14 and Archaeology group pic.jpg

Participants from the Radiocarbon and Archaeology Symposium gather for a group photo. Photo by Justin Cramb/Brandon Ritchison.

Dating Iroquoia at the Society for American Archaeology: Preview

The Dating Iroquoia team is excited to be hosting a symposium at the upcoming Society for American Archaeology meetings in Albuquerque, New Mexico, titled “Dating Iroquoia: Advancing Radiocarbon Chronologies in Northeastern North America”.

We’ll be presenting the results of our project so far—including newly-modeled dates and preliminary interpretations for five Haudenosaunee and Wendat community relocation sequences in Ontario and New York.


Iroquoian archaeological sites for which new dates will be presented during our symposium. Basemap: ESRI.

The session also gives us the chance to broadcast the innovative, exciting work of several of our colleagues, who are presenting the results of dating programs in Quebec, Eastern New York, Ontario, and the St Lawrence Valley.

DI session schedule

Titles, times, and authors for participants in the Dating Iroquoia session, Thursday April 11, 1-3:45 PM, Isleta Room 19 (from the SAA Meeting Final Program pg 72)

Our discussants, Dr. Kurt Jordan and Dr. Gary Warrick, will wrap up the session with some insightful syntheses about what all these new interpretations mean for current and future archaeological understandings of the Iroquoian world.

The session is on Thursday, April 11 2019, from 1:00 PM – 3:45 PM in Isleta Room 19, which is on the lower level of the Albuquerque Convention Center. It’s a smallish room, so get a quick lunch and arrive early to get a good seat!

Room Location

Our symposium is in the Isleta 19 Room, circled in red above. (From the SAA Meeting Final Program pg 15).

For more information about what to expect, you can view the symposium abstract here (we’re session #73), and the individual paper abstracts here.

We’ll see you in Albuquerque!

Dating Iroquoia in Science Advances

The first article reporting on results from the Dating Iroquoia project has been published!

Led by project co-PI Dr. Sturt Manning, the paper in Science Advances presents data from Draper, Spang,  Mantle, and Warminster, four sites in southern Ontario.


We used radiocarbon dating and Bayesian Chronological modeling to date the site relocation sequence of the Draper, Spang, and Mantle sites along the West Duffins Creek. Previously, based on a combination of ceramic seriation, settlement pattern chronology, and the presence/absence of European trade goods, we’d thought that these sites were occupied during the mid-fifteenth through mid-sixteenth centuries. The independent radiocarbon dates we analyzed, however, indicate that these sites were occupied as much as 50 to 100 years later, in the mid-sixteenth through early 17th centuries.

Photo 1. 2--Mantle-site

A human effigy on a ceramic rim from the Mantle site. Previously, the presence and absence of decorative attributes like the notches you see under the face were used to create relative chronologies to place the Mantle site in time. Photo: ASI

We also dated the Warminster site, believed to be the village of Cahiagué which Samuel de Champlain visited in AD 1615. Using radiocarbon dating, Bayesian Chronological modeling, and dendrochronology we confirmed that Warminster was occupied during the early 17th century, strengthening the case that it could be the village where Champlain stayed in the winter of 1615-1616.

Our new, absolute chronology for these two sites suggests that Mantle and Warminster, previously thought to have been occupied as much as a full century apart, were partially occupied at the same time. This was as much of a surprise to us as it might be to you, since these sites have very different material assemblages associated with them. Mantle was fully excavated in 2003-2005, and only three artifacts of European manufacture were identified from the entire site. Warminster was partially excavated throughout the 1940s through 1970s, with hundreds of European manufactured artifacts, including a very large collection of glass beads, identified from the site’s material assemblages.

Photo 2. Palasaide_Southern-part

Archaeologists from ASI excavate a portion of the southern palisade at the Mantle site in 2002-2003. Photo: ASI.

The fact that these two sites could be occupied at the same time, but have such dramatically different material assemblages, suggests to us that the people who lived at Warminster and the people who lived at Mantle were interacting with Europeans in very different ways, independent of one another.

Developing a deeper and more precise understanding of the timing and tempo of initial trade and interaction with Europeans is one of the central goals of Dating Iroquoia, and the results of this first article are a promising start. We are currently getting ready to submit our second round of radiocarbon samples for dating, and are in the process of analyzing and modeling our data from five other Iroquoian communities to present in a session we’re organizing at this year’s Society for American Archaeology meetings (more on that in a future post!)

We’re excited to see how other site sequences, including the Trent Valley sequence (which is where the people who built Warminster used to live) compare to the West Duffins Creek sequence of Draper, Spang, and Mantle.


3D Scanning: Why and How?

As we moved into our second round of sample submission, we noticed that a lot of our faunal bone samples had cut marks on them. With help from our colleagues at the University of Georgia Laboratory of Archaeology, we decided to 3D scan these bones to preserve the information they contain before we send them off for radiocarbon dating.

cut marks on bone

Butchery marks on the distal end of a White-Tailed Deer humerus from the McNab site in New York

What is 3D scanning?

3D scanning is a non-destructive way to create a detailed digital copy of an artifact. This digital copy can easily be shared, studied, downloaded, and archived, and can even be used to 3D print replicas of an artifact.

Why bother 3D scanning?

We decided to 3D scan the bones in order to preserve as much information about our samples as we can. Cut marks on archaeological bone give us lots of information about how that bone (and the meat formerly on it) was used. We’re going to have to destroy parts of the bones in order to radiocarbon date them, but if we 3D scan the artifacts beforehand, we can preserve that information digitally so future researchers can still use it, even if we aren’t using it for our project right now.

This also makes it easy for us to share high-quality images and representations of our artifacts with colleagues and the public!

How does it work?

We created our 3D scans using a NextEngine Desktop 3D Scanner at the University of Georgia Laboratory of Archaeology. We also referred to this super-useful article by the good folks at the Virtual Curation Laboratory, whose blog you should follow if you’re interested in learning more about 3D scanning, digital curation, and public outreach.

3d scanner set up

The laboratory’s NextEngine Desktop 3D scanner set-up; The top arm with the rubber nubbin holds the bone in place as the pedestal itself turns during scanning.

There are actually not that many steps involved in creating a 3D scan of a bone, and once you get the hang of it, it’s a pretty fun process. First, we secure the artifact on this pedestal, so it doesn’t wobble around as the pedestal turns to get scans at different angles.

Then, we scan the artifact from a few different angles. This helps us make sure that we get good images of all the nooks and crannies of the bone, and ensures we get the most accurate pictures possible.

3d scanning happening

The 3D scanner takes photos of the artifact at different angles and also scans it (with the red light you see in the photo) to get all the fine surface details.

Then, we digitally remove all the parts of the scan that aren’t the bone, including the pedestal itself and the bar which held the artifact in place.

trimming scan

The scanner records everything the red light touches (see previous photo); so, we have to edit some of it out. Here, we’re highlighting the arm which held this bone on the pedestal to remove it from the final image.

Then, we fuse the cleaned-up images together, so that we end up with one complete image rather than three or four with “holes”. We do this by taking two of the scans side-by-side and identifying a number of points which exist on both. The software then fuses them together at these points.


Aligning two images of the same bone. The yellow and red dots are placed on the same spot in the two different scans. The computer uses this information to stitch the two images together!

At this point, we now have the finished product: a single 3D image of the bone which recreates all the details of the artifact itself, including cut marks, breaks, even color and surface patterning. This artifact is now ready to be submitted for dating!

A Primer on Sample Pretreatment

Earlier this month, Dr. Carla Hadden, a Research Scientist at the University of Georgia’s Center for Applied Isotope Studies, gave us a primer in how samples are pretreated prior to dating. In this post we’ll discuss how samples are prepared for taking radiocarbon measurements. Our next post will discuss the actual steps involved in radiocarbon dating.

Pretreatment is an essential step in the dating process. The main purpose of pretreatment is to remove contaminants from the material to be dated. In the case of bone samples, pretreatment includes extracting collagen, the material that is ultimately dated. Archaeological materials almost always include contaminants introduced by the materials that they were buried in or with, such as humic or fulvic acids in soil. Other sources of contamination can be introduced during the collection, conservation, or packaging of samples. These extraneous sources of carbon need to be removed in order to get an accurate measurement of the carbon absorbed by an organism during its lifetime.

First, let’s discuss the steps involved in the pretreatment of bone. This sample is a portion of a deer long bone from the bone from the Orion site in Ontario.


First, a subsample of the bone is cut away using a Dremel tool. That subsample is then cleaned using a scalpel and wire brushes in order to remove any surface contamination such as dirt and root fragments. It’s then gently broken down into pieces approximately 3-5 mm in size. The sample is then placed in a solution of hydrogen chloride (HCl). The HCl works on the material to demineralize it and extract collagen — which is what ultimately gets dated. The HCl and bone solution is kept cold in order to control the pace of the chemical reaction.


Dr. Hadden has to work fast to ensure that the collagen in the sample remains intact during the sodium hydroxide treatment

The acid is then decanted and the demineralized bone fragments are rinsed multiple times in ultrapure water. The bone fragments are then treated with Sodium Hydroxide (NaOH) to dissolve and remove contaminants such as humic acids. It’s then washed again in ultrapure water three times. The demineralized bone fragments were then rinsed again in HCl to eliminate atmospheric carbon dioxide that might be absorbed during pretreatment. They are then rinsed again in ultrapure water to and placed in a slightly acidic solution and heated at 80ºC for 8 hours to reduce the solution.

2018-06-05 11.21.09

Dr. Hadden places samples onto a hot plate so that the liquid evaporates gently, concentrating the collagen in the solution

The resulting solution is then filtered through a glass fiber filter to isolate the collagen that has been extracted. The collagen is then freeze-dried. At the end of the process, this collagen looks fluffy and crystalline, somewhat like cotton candy.

2018-06-05 11.22.22

The end result of the pretreatment process. Freeze-dried collagen.

The majority of samples we have dated thus far during the Dating Iroquoia project have been maize. Plant material goes through a different set of steps during the pretreatment process.

As with bone, the sample is cleaned under a microscope to remove dirt particles and extraneous material.

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Dr. Hadden cleans a maize kernel to prepare it for pretreatment.

The sample is then carefully split with a scalpel. The remainder of the sample is retained by the lab in case we need or want to run additional measurements on the material in the future. Sometimes it is very useful to have multiple dates from the same sample. Only a very small amount of material is needed for AMS dating and Dr. Hadden tries to take less than half so that a robust amount remains for future analysis.

Plant material goes through an acid/alkali/acid pretreatment. The plant material is then treated with HCl to remove carbonates and acids that might be present due to contamination. Since these materials can be of a different age than the sample itself it’s important to remove them before dating. The samples are then rinsed, treated with NaOH at room temperature to remove humic substances, rinsed again and then treated with HCl a second time, rinsed repeatedly with ultrapure water, and dried.

That’s it for the pretreatment process! In our next post we will talk about the next steps that happen in the lab and the actual process of radiocarbon dating.

April Adventures in New York

April was a busy month for the Dating Iroquoia team!

Samantha Sanft visited the New York State Museum to collect samples from multiple Onondaga sites. Those samples are in the process of being prepared for submission to the Center for Applied Isotope Studies (CAIS) at the University of Georgia the Centre for Isotope Research (CIO) at the University of Groningen. This work brings us very close to having all of the samples identified in our proposal collected.



New York State Museum

The team also presented the preliminary results of the project at the New York State Archaeological Association meetings. The paper contained some preliminary modelling from site sequences in Ontario and New York. Thus far the latest results are articulating very well with our pilot study. However, until we are confident that new dates will not alter those preliminary results we are not going to post them here. Altogether, the paper was met with a good response. The NYSAA meetings also gave us a chance to confer with other researchers who are interested in chronology-building in the northeast. Jim Bradley, an expert on Onondaga archaeology, helpfully offered to seek out samples from collections we were unaware of!

NYSAA meeting program

NYSAA meeting program

After the meetings, Jennifer Birch visited the archaeology collections at Syracuse University. Here, she was able to access collections from sites that were the basis of James A. Tuck’s research on the Onondaga for the project. This visit provided the opportunity to collect samples for the project as well as to examine some excellent examples of the “archaeology of archaeology” — in particular, the kinds of expedient containers artifacts may be stored in. In this case, cigar boxes and seed bags.

Syracuse University

Syracuse University

Finally, team members met at Cornell University for a day of updates and project planning before we all head off for summer fieldwork, dissertation research, and writing.

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A windy day on Cayuga Lake in Ithaca, NY

The sample collection phase of our project is very nearly complete and we are looking forward to submitting the final set of samples for phase I of the project. Expect great things in fall 2018 as the first sets of formal modelling and interpretation come together!

Dating Iroquoia at the NYSAAs

Our team will be presenting preliminary results of our project at the NYSAA meetings in Syracuse, NY on Sunday April 29. If you will be at the meetings, drop by and say hello.

Sunday April 29, 8:40 am, Jennifer Birch, Sturt Manning, Samantha Sanft, and Megan Conger. High-Precision Radiocarbon Chronology of Iroquoian Occupations in New York and Ontario: Preliminary Results and Implications.


Sample Collection in New York, at RMSC


The Rochester Museum and Science Center (RMSC) is the repository for about half of the assemblages from the New York sites in our project. Thanks to the amazing staff at RMSC, who approved our request to conduct radiocarbon dating and consistently facilitated our research, we have finished collecting all of our samples from RMSC.

Samantha, a research assistant with our Cornell team, has been traveling to Rochester over the last few months to collect data for radiocarbon sample selection. After piecing together information from site maps, RMSC site files, primary artifact files, and field notes, Samantha selected samples that will provide the most amount of information for our project. During subsequent visits, she assessed the condition of the samples and made sure that enough organic material from these specific contexts would remain in RMSC collections for future archaeological projects. Lastly, Samantha made one last round of visits to Rochester in order to collect the samples and bring them back to Cornell for further analysis. After which point, the samples will be sent off to the lab for radiocarbon dating!


It was incredible seeing the massive amount of organics recovered from some of the sites (see the gallon-sized bag full of carbonized beans from the Alhart site, pictured below) and it was fascinating learning more about how past peoples lived. The Alhart beans were recovered from a rectangular underground storage pit. The pit housed two bark barrels full of beans surrounded by corn cobs and contained a wooden ladle sitting on top of one of the barrels of beans – how cool!


Next, Samantha will travel to Albany to visit the New York State Museum.

Sample Selection and Submission, Round One

We have been busy preparing the first round of samples for submission to the Center for Applied Isotope Studies at the University of Georgia. These samples primarily consist of carbonized maize kernels and cob fragments from 12 ancestral Huron-Wendat sites in southern Ontario.

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Megan Conger preparing samples for submission to CAIS

Our project includes a multi-laboratory strategy to control for and ensure no inter-laboratory offsets. This means that we will be aware of how any differences in sample processing between the labs may be affecting the results.

For each site, at least one sample is being divided and split between two laboratories. This means literally splitting some carbonized maize kernels in half and dating each half separately. Overall, a mix of pairings will be used across three laboratories to establish that comparable results are achieved independent of the individual laboratories.

These samples will be joined soon by others from New York State in the first round of submissions. Once we have a sense of how the results from the first round are coming together, a second round of samples will be dated in order to clarify any ambiguities in the data set.