Past Events

Lucas R M Johnson, PhD, RPA, Far Western Anthropological Research Group, Inc.

Dr. Johnson's research at Caracol, Belize began in 2010 and initiated his training and application of ED-XRF on over 2,000 ancient Maya obsidian artifacts. Through this geochemical and technological analysis, he learned the basics of XRF physics, the importance of source reference material, and advanced statistical methods used to assign artifacts to known sources to assess ancient regional trade through time. Concurrent with this project, he worked with an international team to characterize obsidian artifacts from two project locations in Ethiopia. Through these projects, he established relationships with XRF specialists and developed a deeper knowledge of portable XRF instruments. Currently, as a practicing archaeologist in cultural resource management, he is expected to apply XRF analysis to obsidian, other volcanic rocks, and potentially other materials in conventional and in often creative ways. As a member of a laboratory team at Far Western Anthropological Research Group, Inc. and working toward advancing technical reports and research papers, he has stayed current with XRF literature describing analyses of various materials, taught other lab staff the fundamentals of XRF, and trained them to use an XRF instrument.

Marc Marino, MA, RPA, University of Arkansas

Marc Marino’s archaeological training with pXRF as an undergraduate student began with Dr. Lucas Johnson at the University of Central Florida Archaeology Laboratory in 2011. Subsequent training with Dr. Wesley D. Stoner, in both pXRF analysis and statistical analysis of data obtained with Neutron Activation Analysis (NAA), built on that foundation at the University of Arkansas, Fayetteville. His internship at the University of Missouri Research Reactor (MURR) with Dr. Brandi Lee MacDonald focused on the trade and exchange of decorated ceramics and obsidian in Aztec Period Mexico (specifically on the independent Tlaxcallan State). While his dissertation research was accomplished using NAA, XRF, and pXRF of obsidian, ceramics, clays, and sediments, Dr. MacDonald also introduced him to other applications of chemical analysis, including the analysis of ochres and pigments. Combined, these experiences have provided exposure to a wide range of projects across broad geographic areas.

Applications of XRF in archaeology have expanded beyond the analysis of homogenous materials, such as obsidian, to include more heterogenous materials used, created, formed, or associated with human practices. Applications therefore include characterizations of ceramics, metals, glasses, soils, sediments, plasters, pigments/ residues, cherts, and metavolcanic or metasedimentary rocks. While obsidian analysis is relatively straightforward, the other materials require additional procedures before formulating interpretations based on geochemical attributes. This online seminar presents two case studies, one using obsidian artifacts from the western Great Basin and one using both coarse and fine-paste ceramics from Mesoamerica. In this seminar, the instructors examine appropriate methods to prepare specimens, to assess the precision and accuracy of results obtained, and discuss the strengths and weaknesses of different sample preparation techniques. While it is recognized that a ‘one size fits all’ method does not exist for all pXRF applications, we discuss what factors should be given careful consideration if the goal is to share data across projects and emphasize that such results are of the greatest utility to clients and stakeholders alike.

1. Introduce the method of XRF to those who may or may not have access, but are interested in using XRF to answer anthropological questions relating to obsidian and ceramics.
2. Present case studies by which attendees may learn how to perform a specific analysis.
3. Outline what is required for XRF analysis of a given material and the limitations of XRF in analyzing certain materials.
4. Describe the fundamental physics of XRF and how software transforms XRF spectral to analytical units (i.e., calibrations).
5. Explain the basics of analyzing parts per million or weight percent versus untransformed photon peak counts (i.e., statistical procedures).

Mark Agostini, BA, MA, Brown University

Mark Agostini grew up in the town of Medfield, Massachusetts and from an early age became interested in archaeology and anthropology. He attended the University of Vermont, Burlington as an undergraduate majoring in Anthropology and Film. While there he became interested in archaeology of the American Southwest. Through the support of an NSF Research Experience for Undergraduates (REU) Fellowship, he completed an honors thesis exploring shifts in pottery traditions and communities of practice at sites in the Silver Creek region of East-Central Arizona. In 2016, he entered the Anthropological Archaeology PhD program at Brown University and since then has focused on methods of ceramic analysis like archaeometry and petrography while adopting new and less invasive approaches like LiDAR analysis, and surface artifact surveys of archaeological sites. His dissertation project is a collaborative archaeology partnership with the Pueblo de San Ildefonso in New Mexico, which aims to address questions concerning San Ildefonso Pueblo's archaeological and ethnographic ties to their earliest ancestral villages atop the Pajarito Plateau and in the Rio Grande Valley (1300 – 1600 CE).

Ancestors of the descendant Pueblo people living in the Tewa Basin of what is now the northern Rio Grande region of New Mexico experienced significant social, political, and economic transformations beginning in the late-thirteenth and early-fourteenth centuries. This talk summarizes the progress of a collaborative archaeological partnership with the Pueblo de San Ildefonso that investigates and builds on aspects of their historical connections to the Pajarito Plateau and their earliest ancestral village in the Rio Grande Valley called Perage (LA 41). Through LiDAR analysis, digital re-mapping, and artifact survey, this project evaluates how ancestral villages of San Ildefonso Pueblo on the Pajarito Plateau and Perage in the Rio Grande Valley contributed to the growth and development of the early Tewa cultural landscape and contemporary San Ildefonso Pueblo.

The Rising Scholars seminars are opportunities to learn from students and early career archaeologists as they share their current research or emerging methods and theories.