Pajarito Plateau Research Articles

Combining Paleohydrology and Least-Cost Analyses to Assess the Vulnerabilities of Ancestral Pueblo Communities to Water Insecurity in the Jemez Mountains, New Mexico

AbstractWe developed a new approach to identify vulnerabilities to water insecurity across entire archaeological culture areas by combining a paleohydrological model of the sensitivites of hydrological systems to droughts with least-cost analyses of the costs to acquire domestic water. Using a custom Python script integrated into ArcGIS Pro software, we calculated the pairwise one-way cost in time for walking between 225 water sources and 5,446 Ancestral Pueblo cultural sites across the Jemez and Pajarito Plateaus of the Jemez Mountains, New Mexico. This allowed us to identify whether periodic hydrological droughts occurring between AD 1100 and 1700 increased water acquisition costs across these regions. We found that hydrological droughts increased travel times in both regions to durations exceeding modern standards for water insecurity. Beginning in the fourteenth century, greater underlying hydrogeological sensitivities to droughts and the decline of a dual-residence pattern caused by population losses made the remaining aggregated communities of the Pajarito Plateau much more vulnerable to water insecurity than those on the Jemez Plateau. This would have upended long-standing relationships between communities and water on the Pajarito Plateau during a time when socioeconomic integration across the northern Rio Grande Valley pulled people toward valley bottoms.

Characterization of ambient polychlorinated biphenyl background conditions in surface waters of the Pajarito Plateau, New Mexico.

This study presents the development of polychlorinated biphenyl (PCB) background threshold values (BTVs) that statistically characterize ambient background conditions for surface waters in undeveloped and developed landscapes of the Pajarito Plateau in the Rio Grande Basin of New Mexico. Between 2009 and 2018, surface water data were collected at 45 locations under a variety of flow conditions and regimes. A total of 163 samples were collected, with roughly 1/3 of samples and locations being in undeveloped areas (n = 53 from 17 locations), and the remainder being in developed areas (n = 110 from 28 locations). While there are areas on the Pajarito Plateau where PCB point sources are known or likely to have contributed to PCBs in soils, PCB BTVs calculated for undeveloped portions of watersheds (upstream of areas where PCB point sources are known or likely to have contributed to PCBs in soils, and therefore not affected by PCB sources within the watershed) are well above New Mexico's human health organism-only (HH-OO) water quality criterion (0.64 ng/L). Background threshold values are even higher in developed areas upstream of managed soil sites, suggesting that in developed areas, both diffuse ambient PCB sources (e.g., atmospheric deposition) and localized urban sources (e.g., building materials, paints, and electrical equipment) contribute to PCBs in those watersheds. These findings indicate that New Mexico's current HH-OO water quality criterion for PCBs cannot practicably be met due to ambient conditions. It is also impracticable to meet the US Environmental Protection Agency (EPA) criterion continuous concentration (CCC) of 14 ng/L in developed background areas, where the BTV is approximately 1.5 times the CCC. Integr Environ Assess Manag 2023;19:1307-1319. © 2022 SETAC.

Future water resource shifts in the high desert Southwest of Northern New Mexico, USA

Study RegionThis study focuses on the headwaters of the Upper Rio Grande basin, the Pajarito Plateau, northern New Mexico, USA. Study FocusOur work examines 2050s water balance changes using the INFIL hydrologic model run under different downscaled earth system model (ESM) projections to simulate impacts on runoff, infiltration, and overall water regime shifts. New Hydrological Insights for the RegionClimate change is shifting the water balance in the high desert of the US Southwest. Across the Pajarito Plateau, increases in temperature and changing precipitation form and delivery result in increased rain during winter, spring and fall, and decreased snow during winter (47 % less snow is projected to fall). ESM projections of summer rainfall vary, with increases and decreases possible. High elevation recharge zones exhibit increased runoff and infiltration, but across the region aridity also increases due to warmer temperatures. This dichotomy illustrates the complexities in regional responses that occur across time and space, and require a firm understanding to mitigate impacts on the region’s ability to sustainably manage water resources within the next 30 years.

Temporal Variation in Obsidian Procurement in the Northern Rio Grande and Its Implications for Obsidian Movement into the San Juan Area

Arakawa and colleagues (2011) use temporal changes in obsidian source patterns to link the late thirteenth-century abandonment of the Mesa Verde region to Ortman's (2010, 2012) model of Tewa migration to the northern Rio Grande. They employ Anthony's (1990) concept of reverse migration, inferring that an increase in Mesa Verde–region obsidian from a specific Jemez Mountain source reflects the scouting of an eventual migration path. Weaknesses of this inference are that only obsidian data from the Mesa Verde region were used in its development and that the model does not consider the complexities of previously documented patterns of settlement and stone raw material use in the northern Rio Grande. By examining source data from parts of northwestern and north-central New Mexico, we find that the patterning seen in the Mesa Verde obsidian data is widespread both geographically and temporally. The patterns are more indicative of a change in acquisition within a down-the-line exchange system than a reverse migration stream. Population trends on the southern Pajarito Plateau, the probable source of the acquisition change, suggest ancestral Keres rather than Tewa involvement in thirteenth-century obsidian distribution.

Total Recoverable Aluminum: Not Totally Relevant for Water Quality Standards.

A large water quality data set, representing more than 100 surface-water locations sampled from 2007 to 2017 in the Los Alamos area of New Mexico, USA's Pajarito Plateau, was assembled to evaluate Al concentrations in unfiltered and filtered samples. Aluminum concentrations often exceeded United States Environmental Protection Agency (USEPA) and New Mexico ambient water quality criteria (AWQC), regardless of filter size and sample location. However, AWQC are based on laboratory toxicity studies using soluble Al salts and do not reflect natural conditions in Pajarito Plateau surface waters. The plateau is predominately covered by glassy and recrystallized volcanic ashes (e.g., Bandelier Tuff) containing colloidal to sand-sized aluminosilicates. Samples from natural background drainages and areas downstream of developed regions exhibited similar Al concentrations, suggesting that AWQC exceedances are caused by naturally elevated Al concentrations. Solubility calculations indicated that most samples were oversaturated with respect to amorphous Al(OH)3 (s). Therefore, AWQC exceedances are likely artifacts of the "total recoverable" sample preparation, which includes acidification and partial digestion, thereby liberating nonbioavailable Al from aluminosilicates. Accordingly, Al concentrations were strongly associated with suspended sediment concentrations (SSCs), implying that aluminosilicates in suspended sediment contributed to AWQC exceedances and Al oversaturation. Solid-phase particle characterization, using X-ray diffraction (XRD) and scanning electron microscopy with electron dispersive spectroscopy (SEM/EDS) did not identify potentially bioavailable amorphous Al(OH)3 (s) in any sample tested. Thus, current sample collection and analysis protocols should not be used to evaluate attainment of Al AWQC on the Pajarito Plateau or locations where aluminosilicates are substantial contributors to total recoverable Al. A sample preparation method (e.g., pH 4 extraction) capable of differentiating nonbioavailable and bioavailable forms of Al is recommended. Otherwise, current New Mexico and USEPA sample preparation approaches will continue to generate artifactual AWQC exceedances in surface waters that contain aluminosilicates. Integr Environ Assess Manag 2019;00:1-14. © 2019 SETAC.

Avian communities are decreasing with piñon pine mortality in the southwest

An increase in tree mortality is expected to occur worldwide due to climate-induced drought and increasing temperatures. The 2000–2002 drought in the southwestern United States was one of the most severe in the last 50 years. It led to a severe outbreak of bark beetles that resulted in high mortality of piñon pine (Pinus edulis) trees on the Pajarito Plateau in Northern New Mexico beginning in 2002. Many areas in piñon-juniper habitat had entire stands of piñon die leaving only juniper (Juniperus spp.). Point count surveys were used to determine avian responses to tree mortality from 2003 to 2013. We also tested whether birds responded differently in sites that were mechanically thinned in 2002 and 2003 on Los Alamos National Laboratory property compared to sites not thinned. Junipers and dead piñon pines due to bark beetles and drought were removed on thinned sites. Richness, diversity, and abundance steadily declined after 2003. There was a 73% decrease in abundance and a 45% decrease in richness from 2003 to 2013. There was no difference in community composition between thinned and unthinned sites. Bird abundance and species richness declined faster in thinned sites than unthinned sites, but diversity decreased similarly in both treatments. Several species disappeared over time and some declined substantially. Our results suggest a delay in bird responses to tree mortality on the Pajarito Plateau. Piñon mortality may be a significant threat to bird communities in the southwestern U.S., and tree thinning to control fire may be an added risk.

Shards in sherds: Identifying production locations and exchange patterns using electron microprobe analysis of volcanic ash temper in northern Rio Grande Biscuit ware

The research presented here focuses on the composition of Biscuit ware ceramics produced during the Classic period (1325–1650 CE) in the northern Rio Grande region of New Mexico. Data from sites in the southern part of the Pajarito Plateau are compared with those from the Chama area to the north to identify production sites. We employ petrographic analysis to determine the composition of lithic inclusions in clay plus electron microprobe chemical analysis of the glass shards in the characteristic volcanic ash temper to identify production location. We combine analysis of temper and paste composition with analysis of mechanical characteristics and design to identify production specialization in specific parts of the region. Examination of Biscuit ware distribution indicates that a specific set of ritual practices in the production area was expressed using a characteristic set of designs and icons. The limited circulation of only larger sizes of Biscuit ware serving bowls to more southerly sites, outside of the production area, likely represents an increase in inter-area communal feasting and the intentional production of goods for use in communal rituals.

Overstory Tree Mortality in Ponderosa Pine and Spruce-Fir Ecosystems Following a Drought in Northern New Mexico

Drought-caused tree dieback is an issue around the world as climates change and many areas become dryer and hotter. A drought from 1998–2004 resulted in a significant tree dieback event in many of the wooded areas in portions of the Jemez Mountains and the adjacent Pajarito Plateau in northern New Mexico. The objectives of this study were to evaluate and quantify the differences in tree mortality before and after a recent drought in ponderosa pine and spruce-fir ecosystems, and to assess the effect of mechanical thinning on ponderosa pine mortality. Significant increases in mortality were observed in the unthinned ponderosa pine ecosystem. Mortality varied significantly between species and within size classes. Mechanical thinning of ponderosa pines reduced overstory mortality to non-significant levels. A lack of rainfall, snowfall, and increases in daily minimum temperature contributed most to the mortality. Adaptive management, including the use of thinning activities, appear to moderate the impact of climate change on ponderosa pine forests in this region, increasing the long-term health of the ecosystem. The impact of climate change on the spruce-fir ecosystems may accelerate successional changes.

Volcanism and sedimentation along the western margin of the Rio Grande rift between caldera-forming eruptions of the Jemez Mountains volcanic field, north-central New Mexico, USA

The Cerro Toledo Formation (CTF), a series of intracaldera rhyolitic dome complexes and their associated extracaldera tephras and epiclastic sedimentary deposits, records the dynamic interplay between volcanic, tectonic, and geomorphic processes that were occurring along the western margin of the Rio Grande rift between major caldera-forming eruptions of the Bandelier Tuff 1.65–1.26Ma. The Alamo Canyon and Pueblo Canyon Members differ significantly despite deposition within a few kilometers of each other on the Pajarito Plateau. These differences highlight spatial distinctions in vent sources, eruptive styles, and depositional environments along the eastern side of the Jemez Mountains volcanic field during this ca. 400,000year interval. Intercalated pyroclastic fall deposits and sandstones of the Pueblo Canyon Member reflect deposition with a basin. Thick Alamo Canyon Member deposits of block-and-ash-flow tuff and pyroclastic fall deposits fill a paleovalley carved into coarse grained sedimentary units reflecting deposition along the mountain front. Chemistry and ages of glass from fall deposits together with clast lithologies of sedimentary units, allow correlation of outcrops, subsurface units, and sources. Dates on pyroclastic fall deposits from Alamo Canyon record deep incision into the underlying Otowi Member in the southern part of the Pajarito Plateau within 100k.y. of the Toledo caldera-forming eruption. Reconstruction of the CTF surface shows that this period of rapid incision was followed by aggradation where sediments largely filled pre-existing paleocanyons. Complex sequences within the upper portion of the Otowi Member in outcrop and in the subsurface record changes in the style of eruptive activity during the waning stages of the Toledo caldera-forming eruption.

Restoration of degraded transitional (piñon–juniper) woodland sites improves ecohydrologic condition and primes understory resilience to subsequent disturbance

AbstractAn overstory thinning and slash mulch treatment designed to improve ecohydrologic condition of degraded transitional (piñon–juniper) woodland sites was evaluated at four sites over a cumulative 16‐year period beginning in 1994. Study sites were located within Bandelier National Monument and Santa Fe National Forest on the east‐facing Pajarito Plateau of the Jemez Mountains in North‐Central New Mexico. Across all sites, total understory cover increased several‐fold at 3 to 5 years post‐treatment relative to both pre‐treatment condition and control, whereas measures of runoff and sediment production were reduced by an order of magnitude. During the course of post‐treatment monitoring, several coincident disturbances (multi‐year drought beginning in fall 1999, wildfire in spring 2000 and piñon ips beetle outbreak in 2002) caused widespread vegetation mortality and allowed differential recovery patterns to be documented across treatment and control areas. Response to these unplanned disturbances suggested prior restoration to improve ecohydrologic function of denuded intercanopy locations also primed understory resilience as measured by the relative capacity of restored areas to regain levels of effective cover. Treatment areas affected by drought‐beetle tree mortality exceeded pre‐drought levels of understory cover within two growing seasons while retaining improved hydrologic function; by contrast, control areas continued to exhibit accelerated runoff and erosion despite temporary improvements in understory cover post‐disturbance. Post‐fire outcomes suggest that prior restoration also enhanced levels of understory cover post‐burn relative to control, despite negative‐soil‐heating effects from consumed slash. Copyright © 2014 John Wiley & Sons, Ltd.

Fumarolic pipes in the Tshirege Member of the Bandelier Tuff on the Pajarito Plateau, Jemez Mountains, New Mexico

The objective of this study is to demonstrate the relationships among devitrification, vapor phase alteration, localization of gas emanations into fumarolic pipes, and initial deformation of the ash flow sheet during cooling and lithification. Utilizing a unique and temporary exposure of the Tshirege Member of the Bandelier Tuff near Los Alamos, New Mexico, we identify several zones of distinctly preserved fossil fumarolic activity. The fumarolic zones vary in width from a few centimeters to more than a meter. Almost ubiquitously, these zones demonstrate fines-depletion, induration of the margins, upward-flaring geometries, and intense fracturing of overlying geologic units. The fumaroles were preferentially located on post welding, early formed cooling joints that vented to the surface after the vapor phase alteration stage. The pipes were regularly spaced at distances of approximately 4.5 m (N–S) to 7 m (E–W). In turn the pipes were covered by a surge deposit and overlying tuff which rapidly lithified. The overlying tuff was then brecciated during continued fumarolic pipe emissions. Geochemical evaluations confirm the presence of high-temperature mineral (scapolite) indicative of transport of hot volcanic gases through these zones. The pipe centers and walls are depleted in SiO2, and enriched in Al2O3 and FeO. The overlying tuff breccia zones are enriched in Al2O3, FeO and MgO, and depleted in SiO2, NaO, and K2O. From comparison to other ignimbrite cooling histories, the fissures, fumaroles, and structures observed all likely formed in the first few decades after the deposition of the upper Tshirege subunits. This may have significant implications as to timing of initial cooling fractures and subsequent consolidation of gas emission pathways.

Pueblo Peoples on the Pajarito Plateau: Archaeology and Efficiency. David E. Stuart

Pueblo Peoples on the Pajarito Plateau: Archaeology and Efficiency. David E. Stuart

Pueblo peoples on the Pajarito Plateau: archaeology and efficiency

Pueblo peoples on the Pajarito Plateau: archaeology and efficiency

Obsidian Evidence of Interaction and Migration from the Mesa Verde Region, Southwest Colorado

A growing body of evidence demonstrates that ancestral Pueblo people living in the central Mesa Verde region of the U.S. Southwest maintained long-distance contacts with other Pueblo peoples. Questions of Pueblo interactions through time and across space have traditionally been addressed using ceramic sourcing data. This research uses obsidian source data to argue that, from A.D. 600 to 920, residents of the central Mesa Verde region obtained obsidian from throughout the U.S. northern Southwest, but that from A.D. 1060 to 1280 they acquired obsidian almost exclusively from the Jemez Mountains area of north-central New Mexico. In addition, importation of obsidian from the Pajarito Plateau increased during the period of population decline in the Mesa Verde region, and population expansion on the Pajarito. Characteristics of the obsidian assemblage from central Mesa Verde region sites also suggest that Jemez obsidian entered the region primarily in the form of finished arrows, arrow points, and arrow-point preforms. We argue that these patterns reflect return migration by early immigrants from the Mesa Verde region to the northern Rio Grande, an early stage in the development of a migration stream between the two regions.

Effects of Wildfire and Postfire Floods on Stonefly Detritivores of the Pajarito Plateau, New Mexico

Wildfires alter the quantity and quality of allochthonous detritus in streams by burning riparian vegetation and through flushing during postfire floods. As such, fire disturbance may negatively affect detritivorous insects that consume coarse organic matter. We assessed how 2 crown fires impacted stonefly detritivores in streams of the Pajarito Plateau, New Mexico. We documented stonefly populations before and after the fires and postfire floods, and compared recovery trajectories among unburned, lightly burned, and severely burned reaches. We also conducted experiments to assess burned detritus as a food resource for Pteronarcella badia Hagen. Specifically, we characterized microbial conditioning, nutrient content, and breakdown rates of burned and unburned deciduous leaves and pine needles. We compared colonization of P. badia in field-placed leaf packs and growth of P. badia in a microcosm experiment on burned and unburned treatments. Detritivorous stoneflies in Plateau streams survived wildfire, but were extirpated from burned reaches after severe postfire floods in both Capulin and Guaje canyon. In Guaje Canyon, Amphinemura banksi Baumann and Gaufin was more resilient to flood disturbance than P. badia and recolonized soon after floods abated, whereas recolonization of A. banksi was delayed in Capulin Canyon. Experiments revealed that detritus quality did not explain slow recovery; despite reduced microbial conditioning and decomposition rates, P. badia colonized and grew well on burned detritus. Instead, postfire floods removed shredder stoneflies and their detrital resources; and traits such as body size, voltinism, and dispersal likely interacted with the postfire landscape to shape recovery trajectories in burned streams.

Chronology of colluvial apron deposition within Canada del Buey, Pajarito Plateau, New Mexico

Chronology of colluvial apron deposition within Canada del Buey, Pajarito Plateau, New Mexico

Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 2: The Chaco Halo, Mesa Verde, Pajarito Plateau/Bandelier, and Zuni Archaeological Regions

Chemical and nutrient analyses of 471 soil samples from 161 sites within four archaeological regions (Pajarito Plateau/Bandelier, Zuni, Mesa Verde, and the Chaco Halo) were combined with historical climate data in order to evaluate the agricultural productivity of each region. In addition, maize productivity and field-life calculations were performed using organic-nitrogen (N) values from the upper 50 cm of soil in each region and a range (1–3%/year) of N-mineralization rates. The end-member values of this range were assumed representative of dry and wet climate states. With respect to precipitation and heat, the Pajarito Plateau area has excellent agricultural potential; the agricultural potentials of the Zuni and Mesa Verde regions are good; and the agricultural potential of the Chaco Halo is poor. Calculations of N mineralization and field life indicate that Morfield Valley in Mesa Verde should be able to provide 10 bu/ac of maize for decades (without the addition of N) when organic N-mineralization rates exceed 2%. Productivity and field-life potential decrease in the following order: Zuni, Mesa Verde, Bandelier, Chaco Halo. The Chaco Halo is very unproductive; e.g., 10 bushels per acre can be achieved within the Halo only from soils having the highest organic N concentration (third quartile) and which undergo the highest rate (3%) of N mineralization.

Incisor microwear textures of five bioarcheological groups

AbstractDental microwear texture analysis has proven to be a valuable tool for inferring aspects of subsistence behaviour in human groups and diet in other mammals. Studies have to date been limited to molar teeth. Here we report on the first microwear texture analysis of incisors. Five bioarcheological groups were included in this analysis: Aleuts from various islands in the Bering Sea (n = 24), Arikara from the Mobridge site in South Dakota (n = 18), ethnic Chinese cannery workers from Kodiak Island (n = 16), a Late Woodland Bluff sample from Jersey County, Illinois (n = 18) and Puye Pueblo from Pajarito Plateau in New Mexico (n = 18). First, point clouds with 0.18 µm lateral spacing and 0.005 µm vertical resolution were obtained from maxillary central incisor labial surfaces using a white‐light confocal profiler. Four adjoining fields were sampled for a total area of 276 µm × 204 µm for each specimen. Surface data were then imported into scale‐sensitive fractal analysis software for texture characterisation. Results indicate significant variation among groups in anisotropy, fill volume and heterogeneity. These differences are likely related to differences in diet, degrees and types of non‐dietary incisor use, as well as exposure to abrasives. This study also suggests that texture variables most useful for characterising and comparing incisor microwear may differ from those most useful for distinguishing molar microwear patterns. Copyright © 2009 John Wiley & Sons, Ltd.

PAJARITO PLATEAU GLAZE PAINT WARE PRODUCTION

The Classic period (1325–1600) in the north and middle Rio Grande region (Cordell 1997) was a time of reorganization as historically diverse peoples aggregated into larger villages. Reorganization resulted in various changes including the production of glaze-painted pottery, which was widely exchanged throughout much of the pre-Hispanic Southwest. Previous research has focused on its production in the Albuquerque area and the Galisteo Basin. This article summarizes previous and recent work providing evidence of production of glaze-painted pottery on the Pajarito Plateau and presents new petrographic and stable lead isotopic studies that reveal that Pajarito potters produced glaze-painted pottery and were part of a larger network of potters who used lead from the Cerrillos Hills in the glaze paint.

Seismic Refraction at Ancestral Puebloan Sites on the Pajarito Plateau, New Mexico

Geophysical techniques can be used for non-invasive surveys at archaeological sites. One under-utilized technique, seismic refraction, has many potential applications. It is an inexpensive, efficient way to characterize subsurface deposits, especially at sites with shallow accumulations over bedrock. Archaeologists and geophysicists participating in the Summer of Applied Geophysics Experience from Los Alamos National Laboratory and Bandelier National Monument on the Pajarito Plateau in northern New Mexico characterized Ancestral Puebloan sites (A.D. 1200–1450) using this technique. We provide an overview of how seismic refraction works and demonstrate the applicability of seismic refraction for identifying buried archaeological features such as communal structures and walls.