A Preliminary Analysis of Radiocarbon from the East Texas Archaic Period (Selden)


This post presents a few preliminary findings of a temporal analysis of the East Texas Archaic based solely upon the examination of radiocarbon dates from sites that have deposits that date to the period. Text and figures are reprinted here with the permission of the Journal of Northeast Texas Archaeology, where these findings were published in 2013 (for a more exhaustive overview, see JNTA 42). All assays employed in this effort were collected from research and cultural resource management reports and publications, synthesized, then recalibrated in version 4.1.7 of OxCal  using IntCal09.

The date combination process is used herein to refine site-specific summed probability distributions, illustrating—for the first time—the temporal position of dated archaeological sites with radiocarbon assays. In all, 73 radiocarbon dates from 34 sites serve as the foundation for this analysis of the East Texas Archaic period (ca. 8000-500 B.C.). All dates used in this analysis come directly from the East Texas Radiocarbon Database (ETRD). Within the sample, there are 19 sites with a single radiocarbon sample, eight sites with two dated samples, one site with three dated samples, three sites with four dated samples, one site with five dated samples, and one site with 14 dated samples. Of the 73 radiocarbon dates from the ETRD used in this analysis, one dates to the Early Archaic period (ca. 8000-5000 B.C.), eight date to the Middle Archaic period (ca. 5000-3000 B.C.), and the remaining 64 date to the Late Archaic period (ca. 3000-500 B.C.).

Date Combination

Archaic sites with combined radiocarbon dates include: Shell Lens (41FN130), Winston (41HE245), Finley Fan (41HP159), J. Simms (41NA290), Herman Ballew (41RK222), Mockingbird (41TT550), and 41UR77. The number of dates garnered through research at each of these sites is biased by variable research designs, mitigation strategies, and access to funding.

ETX Archaic Figure10

 Example – All and combined summed probability distributions for Archaic period dates from 41UR77 with 1σ and 2σ ranges, median ages, and number of samples.
(Figure appears courtesy of the 
Journal of Northeast Texas Archaeology)


In every case where date combination was applied, the new combined age replaced the assays used to calculate it. Upon completion of the date combination process, the summed probability distributions for all East Texas sites with Archaic-era radiocarbon assays were plotted chronologically. This allows us—for the first time—to view all of the Archaic-era assays at the regional scale.

In the future, it would be useful to apply some manner of chronometric hygiene to the Archaic sample of dates, whether following a conventional method or by vetting each date to ensure that each assay represents an Archaic component associated with some manner of human occupation (i.e., artifact manufacture or feature use). At this point it is unknown how many of these dates can actually be attributed to the Archaic occupation of the East Texas landscape, but this preliminary analysis does illustrate a fairly remarkable increase in the number of dates during the Late Archaic (ca. 3000-500 B.C.) period following a sparse dated record for the Early and Middle Archaic. The fact that the number of assays from each period increase through time is a familiar trend, and one that is often attributed to an increase in population size (although there are some substantive challenges to this approach).

ETX Archaic Figure11

East Texas sites with Archaic-era radiocarbon assays in chronological order.
(Figure appears courtesy of the Journal of Northeast Texas Archaeology)

Concluding Remarks

Although biases likely exist in the radiocarbon sample from sites in the region, it is evident that the most extensive Archaic occupation (concentration of dates) of East Texas occurred during the Late Archaic period. Certainly more dates are needed from Early and Middle Archaic horizons, but given the often ill-formed stratigraphy in archaeological deposits that occur throughout East Texas, finding suitable samples can be a challenge. Also, some measure of chronometric hygiene needs to be applied to this sample of dates to increase their resolution and temporal accuracy, and should the focus be upon population-based studies, a taphonomic correction may also be warranted. While large steps have been taken to explore East Texas archaeology, the Archaic period remains very ill-defined with respect to our understanding of the material culture as well as the chronology. The fact that only 73 dates from the East Texas Radiocarbon Database—which is currently composed of 1248 radiocarbon dates from East Texas—speaks to the need for further research.

About the Author

Dr. Robert Z. Selden Jris a Research Associate in the Center for Regional Heritage Research at Stephen F. Austin State University.


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2 thoughts on “A Preliminary Analysis of Radiocarbon from the East Texas Archaic Period (Selden)

  1. Thanks Robert for posting this interesting bit of data. The paucity of dates for the Early Archaic may hint of a paucity of people at that time in east Texas; this is a time in central Texas and the Balcones Canyonlands when there is a noticeable site population suggesting folks are clustering in this region. I assume that Calf Creek horizon would fall late into this time period too, and from my experience I do know of a substantial Calf Creek presence in Walker and Houston counties so not all of east Texas had a low population at this time.


    1. No doubt that there are some substantive challenges associated with using radiocarbon as a proxy for population studies; particularly when dealing with mobile populations. Will be interesting to see what happens to the sample when we apply our current measure of chronometric hygiene – if it’s anything like the Caddo corn sample, we may lose anywhere between 2/3 – 3/4 of the sample – if not more. With the current struggle to identify intact stratified Archaic and Paleoindian sites in East Texas (although several examples do exist), I imagine that we’ll remain heavily reliant upon relative dates for some time to come. That said, it would be interesting to round up all of the examples of the various “typed” projectile points from different areas in East Texas (akin to what Tim and I are doing with the ceramics), to see what manner of spatial and temporal dynamics can be said to occur across the broader region – anyone willing to tackle that for a dissertation topic?. I have a sneaking suspicion that the nature of these trends are much more fluid in nature than our currently constructed (and arbitrary) temporal boundaries allow. Lots to learn yet.

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