#256045 Geophysical Exploration of Tyuonyi Pueblo in Bandelier National Monument, New Mexico, USA Chelsea Sica1, David Graham1, Conrad Suen2, Emily Peacock2, Christopher Carchedi3, Andrea Creighton4, Danny Feucht5 , Jordan Jarrett6, Jamie Civitello6 , Chris Martin7, John Ferguson1, Darcy McPhee8, Louise Pellerin9 1 The University of Texas at Dallas, 2 The University of Texas at Austin, 3 Brown University, 4 University of Wyoming, 5 University of Colorado, Boulder, 6 National Park Service, 7 Sensors and Software 8 United States Geological Survey, 9 Green Geophysics

Introduction Objectives Archaeological History GPR Fence Diagram, Seismic Refraction Model, and Magnetic Sources Conclusions • Holocene alluvial terrace deposits overlie the The Summer of Applied Geophysical • To determine if re-routing the Main Loop Line y29 was surveyed over an area Qbt surface, and the Tyuonyi Pueblo was Experience (SAGE) class of 2017 carried out Trail is possible as well as to identify constructed on top of the highest terrace. near-surface geophysical investigations of archaeological features of interest. where two braided channels merge and have migrated over time. A small • On the north side of the Pueblo, coarse the Tyuonyi Pueblo of Bandelier National • Interpret GPR, seismic refraction, and Monument, New Mexico in order to aid trail portion of the proposed Main Loop colluvium from the steep canyon walls inter- magnetic profiles to determine shallow planning and identification of archeological Trail will overlap part of this drainage fingers with the alluvial terraces. geologic structure and possibly identify features that could potentially be impacted. network. • Alluvial fan lobes or boulders may be causing Tyuonyi is located in Frijoles Canyon, carved anthropogenic features. strong GPR reflections on the north end of Line by the Rito de los Frijoles, between the SE y5, followed by alluvial fan deposits. flank of the Jemez Mountains and the Rio N • The seismic model indicates a number of Grande, and contains pueblo room blocks, narrow, shallow channels incised into the tuff. kivas and cavates that were occupied by The magnetic data corroborate this model. ancestral Puebloans between 1250 and 1550 Fig. 3 • Shallow magnetic anomalies (Fig. 6) are CE. SAGE collected seismic refraction, Construction began ~1325 AD and was believed to reflect homogeneities in magnetic magnetic, and GPR data along targeted occupied until ~1550 (Keller, 2015). The Pueblo susceptibility within the Bandelier Tuff. profiles and grids north and east of Tyuonyi structure is ~40 m in diameter containing ~250 Pueblo. ground rooms ranging ~2.2 – 6.0 m in width and • The geophysical data show no identifiable length, with wall heights averaging ~1-1.5 m. archeological structures beneath the proposed new trail. Tyuonyi Pueblo Site N N Fig. 5 References

• Keller, L.K., (2015). Bandelier National Proposed Main Loop Trail reroute. Fig. 2 Monument: Geologic resources inventory report. Natural Resource Report. National Park Service, U.S. Department of the Interior. • Reneau, S.L., 2000, Stream Incision and N Terrace Development in Frijoles Canyon, Bandelier National Monument, New Mexico, Methods and the Influence of Lithology and Climate:Geomorphology, v. 32, p. 171–193, doi: • Two 30 X 30 m grids of GPR data were 10.1016/s0169-555x(99)00094-x. recorded along 1-m spaced lines using the N • Nisengard, J.E., Isaacson, J.S., Ferguson, J.F., 250 MHz Sensors and Software NOGGIN® Hinz, E., and Gauthier, R., 2008, Seismic 250 Smart Tow and processed using the Refraction at Ancestral Puebloan Sites on the EKKO Project V5 program. • Qal - Quaternary Alluvium Fig. 4 Pajarito Plateau, New Mexico: Journal of Field • Seismic refraction data were collected using The residual anomaly results Archaeology, v. 33, p. 85–100, doi: • Qbt - Bandelier Tuff a 48-channel Geometrics Strataview recorder from subtracting estimated 10.1179/009346908791071349. and a hammer source. There are seven dipole sources deeper than overlapping spreads with 0.5 m geophone 30 m from the total magnetic spacing and 28 shot points with a 6 m Results field. Vertical and horizontal Acknowledgements and Contact interval. Shot point offsets between 0.25 and gradients were computed. 47.75 m provided overlapping subsurface A velocity model was created through forward Magnetic depth was We would like to thank the National Park Service coverage. Seismic data from SAGE 2016 modeling to fit the seismic travel times estimated by means of dipole for allowing SAGE to work at Bandelier National and 2017 were merged into a 168 m long (Nisengard et al., 2008). The GPR images and source half-width rules. Monument, Sensors and Software, Geonics, profile. seismic model can be used to interpret the Source depths agree well Geosoft, the National Science Foundation, SEG Foundation (Endowment – founding donor • Magnetic data were collected along 1-m Quaternary geology of the site. These data trace with the Bandelier surface Geophysical Pursuit), American Geophysical spaced N-S lines in two 30 X 30 m grids and incision of the Rito de los Frijoles into the determined by seismic Union Riecker Fund, SAGE affiliates and industry along the seismic line using a Geometrics Bandelier Tuff over several stages of the canyon refraction. sponsors for their ongoing support. 858 cesium vapor magnetometer. development (Reneau, 2000).

Further Information: [email protected] Figure 1 Fig. 6