robert z selden jr, caddo, archaeology, biface, george c davis, caddo mounds state historic site, nagpra, museum studies, lithic, stone tool, archaeology, culture heritage, cultural heritage, history

Lithic morphological organisation: Gahagan bifaces from the Southern Caddo Area

New paper in-press at Digital Applications in Archaeology and Cultural Heritage with John Dockall and Harry Shafer on the morphological variability of Gahagan bifaces – https://doi.org/10.1016/j.daach.2018.e00080.

Abstract

This analysis of Gahagan biface morphology enlists the three largest samples of Gahagan bifaces, to include that of the type site (Gahagan Mound) as well as the Mounds Plantation and George C. Davis sites. Results indicate a significant difference in Gahagan biface morphology at the Mounds Plantation site when compared with Gahagan bifaces from the Gahagan Mound and George C. Davis sites. Tests for allometry and asymmetry were not significant. The test of morphological disparity indicates that Gahagan bifaces produced at the Mounds Plantation site occupy a more restricted range of morphospace than those produced at Gahagan Mound, providing evidence for standardisation and diversity in Caddo biface production. While the sample includes a wide range of variability, the test of morphological integration indicates that Gahagan bifaces are significantly integrated, meaning that those traits used to characterise their shape (blade and base) vary in a coordinated manner. These results articulate with a shift in Caddo bottle morphology over the same geography, potentially indicating two previously unrecognised and morphologically-distinct lithic and ceramic production areas.

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projectile point, dart point, clovis, gainey, 3d, 3d scan, 3d model, geomagic design x, geomagic control x, analysis, geometric morphometrics, 3d geometric morphometrics, archaeology, archeology

Paleoindian Archaeology and the Index of Texas Archaeology

New article published in PaleoAmerica discussing some of the Paleoindian resources available on the Index of Texas Archaeology (https://www.tandfonline.com/doi/abs/10.1080/20555563.2018.1467686?journalCode=ypal20#metrics-content).

(2018). Paleoindian Archaeology and the Index of Texas Archaeology. PaleoAmerica: Vol. 4, No. 2, pp. 95-98.

Paleoindian Archaeology and the Index of Texas Archaeology

Source: Paleoindian Archaeology and the Index of Texas Archaeology

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robert z selden jr, blackwater draw, clovis, agate basin, 3d, 3d scan, 3d model, projectile point, dart point, new mexico, culture, history, prehistory, heritage

3D Scan Data for Selected Artifacts from Blackwater Draw National Historic Landmark

Between February 8-11, 2016, selected artifacts from the Blackwater Draw National Historic Landmark (LA3324) were scanned in advance of a grant proposal to digitally aggregate the Clovis-era artifacts from the Clovis type site. These data were collected using a NextEngineHD running ScanStudioHD Pro, and post-processed in Geomagic Design X 2016.0.1. All data associated with this project are publicly available (open access) and accessible in Zenodo under a Creative Commons Attribution license, where they can be downloaded for use in additional projects and learning activities. These data have the capacity to augment a variety of research designs spanning the digital humanities, applications of geometric morphometrics, and many others. Additionally, these scans will augment a wide range of comparative research topics throughout the Americas and beyond. Reuse potential for these data is significant.

Unprocessed 3D data are included on the landing page, and links to the processed files are included in the data paper. Download the data paper here:: 3D Scan Data for Selected Artifacts from Blackwater Draw National Historic Landmark

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robert z selden jr, gault, clovis, 3d, 3d scan, 3d model, projectile point, dart point, texas, culture, history, prehistory, heritage

Preprint available on SocArXiv

Now available on SocArXiv – download here. The paper includes a 3D figure–preprint must be downloaded then opened in your PDF viewer to activate the 3D model. Learn more about how to interact with a 3D PDF here. Many thanks to the folks at the Open Science Framework, SocArXiv and Overleaf. This data paper is currently in review.

DOI 10.17605/OSF.IO/9YD7J | ARK c7605/osf.io/9yd7j

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3D Geometric Morphometrics of Projectile Points – Populating Splines

 

As we continue to think through the various spline configurations (see previous post here), I have been constructing a number of models based primarily on the efforts of previous analyses for both 2D and 3D geometric morphometrics. While this is representative merely of a (very) humble beginning, experimenting with the reconstruction of configurations used in other analyses could help us to better understand how we might begin to move toward a replicable consensus configuration (certainly some great examples out there).

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In this example, I am using the framework of two splines that were created as a 3D mesh sketch in Design X (above). I then added 10 equidistant sections (below) between the top and bottom of the projectile point. While those would most likely be cut where they intersect with the splines above prior to populating point data, I wanted to see where the–equidistant–points would populate along the various profiles.

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In this case, it may work best to cut each of the 10 sections where they intersect either the exterior or interior profiles (or both), prior to populating the LM/sLM data. I did not populate the 10th section (very near the point of the projectile) for this example, simply because it was almost impossible to view the location of Point 2 (which is defined by the confluence of the vector and the poly-vertices of the mesh at the tip of the projectile) when that particular section was populated.

ZSpline_2

Another question that we will need to ask ourselves sooner than later, is where do we reach a point of saturation or diminishing returns with regard to the number of LM/sLM data points? There is still much left to think about, and we will continue to move toward the definition of a replicable consensus configuration as we work through replicating (as closely as possible) the numerous configurations that have been used in the past.

Our tactics differ from many of our colleagues, due primarily to our efforts to devise a configuration aimed at performing an initial “sort” at the assemblage level–different configurations would then be used for each of the identified categories based on more specific attributes. In the coming months, I hope to share some of our minor successes, and–no doubt–numerous failures as we continue to work toward a suitable configuration.

As always, your comments and constructive criticisms are welcome. You can comment by clicking on Leave a Comment below, or you can email me directly at selden3d@gmail.com. 

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