Lower Pecos Canyonlands Research Articles

Trace organic compounds in oxalate rock accretions from the Lower Pecos Canyonlands of southwestern Texas

AbstractCalcium oxalate‐rich rock coatings occur worldwide and commonly occur associated with prehistoric rock paintings. Radiocarbon dates of oxalates that cover or encapsulate rock paints have become the primary strategy for establishing chronologies of these artifacts. It is also apparent that oxalate films form episodically and are governed by particular climate conditions and thus could serve as a paleoclimate proxy. However, the mechanism(s) by which these coatings form remains unresolved. Here, we report on the trace organic composition of oxalate‐coating samples from the Lower Pecos Canyonlands in southwestern Texas. The samples contained a suite of dicarboxylic acids that are similar to the organic composition established for atmospheric aerosols. The predominant organic species in aerosols is oxalic acid, which reacts with calcium to form calcium oxalate. This suggests that aerosols could be a mechanism for the production of naturally occurring calcium oxalate on rock surfaces.

A Newly Identified Younger Dryas Component in Eagle Cave, Texas

Recent excavations by the Ancient Southwest Texas Project of Texas State University sampled a previously undocumented Younger Dryas component from Eagle Cave in the Lower Pecos Canyonlands of Texas. This stratified assemblage consists of bison (Bison antiquus) bones in association with lithic artifacts and a hearth. Bayesian modeling yields an age of 12,660–12,480 cal BP, and analyses indicate behaviors associated with the processing of a juvenile bison and the manufacture and maintenance of lithic tools. This article presents spatial, faunal, macrobotanical, chronometric, geoarchaeological, and lithic analyses relating to the Younger Dryas component within Eagle Cave. The identification of the Younger Dryas occupation in Eagle Cave should encourage archaeologists to revisit previously excavated rockshelter sites in the Lower Pecos and beyond to evaluate deposits for unrecognized, older occupations.

LATE PLEISTOCENE BIGHORN SHEEP DUNG FROM EAGLE CAVE, LOWER PECOS RIVER, TEXAS

We describe dung pellets identified as bighorn sheep (Ovis canadensis; Bovidae, Caprinae) radiocarbon dated to ∼12,500 cal BP, late Pleistocene. Pellets were excavated from a layer of trampled and butchered bison bones in Eagle Cave located in a box canyon tributary of the entrenched Rio Grande, southwestern Texas. Wild sheep are not known historically or from the Pleistocene from this region of the Lower Pecos Canyonlands. Phytolith analysis of the fossil dung revealed that the Ovis diet was predominantly a mixture of cool and warm season grasses, but dominated by warm season grasses. Morphology and content analysis imply that the dung represent a late-summer, or more likely, winter season accumulation.

Re-dating the Lower Pecos Canyonlands SMM (Skiles) mummy burial, dating a red-colored deerskin strap

An early 1980s University of Texas (UT) radiocarbon (14C) decay-based assay of colon contents from mummy SMM recovered from southwest Texas (41VV656) placed the death at 1150 ± 70 14C years ago. This mummy of a “relatively tall, gracile adult male” was discussed in some detail in a comprehensive paper on Late Archaic mortuary practices in the Lower Pecos River region. The megacolon of the mummy was described as a condition that is usually associated with Chagas disease, caused by Trypanosoma cruzi. A red colored deerskin strap had encircled the mummy, restraining the distended colon, and a portion of the strap was submitted for additional radiocarbon dating to test the reliability of the original UT date. Using low energy plasma radiocarbon sampling (LEPRS) at the Office of Archaeological Studies, Center for New Mexico Archaeology, we extracted CO2 by oxidation of organic material from four pieces of the strap and obtained eight 14C dates at the ETH-Zürich MICADAS AMS facility. Multiple samples were prepared to deal with the possibility of contamination from lacquer/shellac/varnish that was probably applied during the 1930s and of contamination from decades of handing. Our best estimate of the age of that burial is an average of four dates on a piece of the strap where all surfaces had been physically removed to avoid potential surface contamination. This average is 780 ± 30 14C years BP, 370 years more recent than the previous UT determination. It is likely that the original radiocarbon date is incorrect, and the difference is consistent with two other redatings of UT 14C dated contexts where more recent assays have been roughly 400 years younger when compared to the UT laboratory dates.

Speech-Breath: Mapping the Multisensory Experience in Pecos River Style Pictography

Archaic period hunter-gatherers of the Lower Pecos Canyonlands of southwest Texas and Coahuila, Mexico, created complex rock art murals containing elaborately painted anthropomorphic and zoomorphic figures. These figures are frequently portrayed with dots or lines emanating out of or into their open mouths. In this article, we discuss patterns in shape, color, and arrangement of this pictographic element and propose that artists used this graphic device to denote speech, breath, and the soul. They communicated meaning through the image-making process, alternating brushstroke direction to indicate inhalation versus exhalation or using different paint application techniques to reflect measured versus forceful speech. The choices made by artists in the production of the imagery reflect their cosmology and the framework of ideas and beliefs through which they interpreted and interacted with the world. Bridging the iconographic data with ethnohistoric and ethnographic texts from Mesoamerica, we suggest that speech and breath expressed in the rock art of the Lower Pecos was tied to concepts of the soul, creation, and human origins.

Implications for rock art dating from the Lower Pecos Canyonlands, TX: A review

The Lower Pecos Canyonlands was the first study area where the method of plasma oxidation was employed to extract organic material from prehistoric rock paintings for accelerator mass spectrometry radiocarbon dating. During the developmental phase of this method, Rowe's laboratory at Texas A&M University obtained 32 radiocarbon measurements for Lower Pecos rock art: 29 dates for 16 paintings of the Pecos River style, and 3 additional dates for paintings of other styles found within the region. We evaluate these legacy dates based on contextual, compositional, and measurement elements, concluding that these experimental results are problematic and should not be used to draw archaeological conclusions. Building on knowledge gained during the development of the technique, Rowe established field and laboratory methods to address issues impacting the reliability and precision of radiocarbon results. Steelman's laboratory at Shumla Archaeological Research & Education Center has implemented these and additional protocols, including: (1) proper documentation of sampling locations so that the provenience of the sample is known (contextual); (2) analysis of unpainted control background samples to identify the presence or lack of contaminants in the rock substrate (compositional); (3) chemical pretreatment with base to remove any potential humic acid contamination (compositional); and (4) improved laboratory procedures to ensure that laboratory contamination is avoided (measurement). Using this methodology, Steelman's laboratory has obtained eleven radiocarbon results for four rock art sites in the region: 6 dates for Pecos River style paintings; 1 date for a red zigzag painting of another style; and 4 oxalate minimum/maximum ages. Three of these AMS measurements are from a single composition and pass a χ2-test consistent with being coeval. To our knowledge, this data also presents the first minimum, direct, and maximum age for a single pictograph. This review suggests that future dating research in the region will produce a refined chronology for age comparisons between different rock art sites, painting styles, and even sub-styles – adding to our knowledge of the hunter-gatherers who lived in this painted landscape.

Cave art reveals human nature

Summary Prehistoric artworks have been discovered on numerous cave walls around the world. They tell us about the minds and lives of ancient humans as well as about their relationship with the now extinct megafauna that surrounded them. Michael Gross reports.

Portable X-ray fluorescence of Lower Pecos painted pebbles: New insights regarding pigment choice and chronology

Painted pebbles are the primary mobiliary art found in the Lower Pecos Canyonlands of southwest Texas and northern Mexico. Previous studies of these artifacts have focused on stylistic variation of the imagery and interpretation of the role these artifacts played within Lower Pecos societies. The focus of this study is the use of portable X-ray fluorescence on Lower Pecos painted pebbles to conduct elemental analyses to identify the pigment used by ancient artists in the paint recipe for painted pebble production. Using a sample of recently excavated painted pebbles, as well as a sample from a private collection, a total of 254 pXRF measurements were collected on 70 pebbles. We determined that charcoal was used as a pigment for black paintings and that iron-based mineral pigments were used for red paintings. The newly excavated pebbles range in age from 6500 to 700 RCYBP, and the stratigraphic and chronologic context of these pebbles provides a dataset for analyzing not only pigment selection, but allows us to also address changes in painted pebble production through time. This paper summarizes the results from the pXRF analysis, and discusses the larger archaeological implications for Lower Pecos painted pebbles.

The Skiles Mummy: Care of a debilitated hunter-gatherer evidenced by coprolite studies and stable isotopic analysis of hair

The Skiles Mummy (SMM), a naturally mummified adult male from the late archaic period of Lower Pecos Canyonlands of South Texas, represents a unique case of care. SMM is an exceptional mummy within this region due to both the retention of a full head of hair, and having a diagnosed case of megacolon, a complication commonly associated with Chagas disease caused by Trypanosoma cruzi. Stable isotopic analysis of his hair is consistent with a diet incorporating of C4/CAM plants with some C3 plants, freshwater resources, and higher trophic level animals. However, the segments of hair most proximal to the scalp exhibited elevated δ15N values. Data from previous research indicate starvation and malnutrition can cause δ15N values to rise. The presence of large fecal boluses in the digestive tract suggest peristalsis ceased in the last four to five months of life, and this, together with results from coprolite analysis, indicate he would not have been able to adequately absorb protein and nutrients during this time. His condition would have rendered him immobile. Following Tilley’s index of care, someone would have had to bring him food resources, as well as attending to his daily needs.

Ethnohistoric Records of Hunter-Gatherer Diet of the Texas/Mexico Borderlands: Implications for Staple Foods of the Lower Pecos Canyonlands During the Holocene

Hinds Cave (41VV456) and other rockshelters excavated in the Lower Pecos Canyonlands have yielded thousands of coprolites spanning the Holocene. To date, several hundred specimens have been analyzed, providing a detailed record of meals consumed by hunter-gatherers who called this landscape home. This article compares the paleodietary records derived from these specimens with the foodways documented in the ethnohistoric records available for the Lower Pecos Canyonlands and adjacent landscapes. This comparison confirms the deep temporal roots of the foodways recorded in the earliest written records of the Texas/Mexico borderlands. Coprolite data corroborate the strong dependence on the seasonal staples of lechuguilla (Agave lechuguilla), nopales (Opuntia sp.), and tunas (Opuntia sp.) observed in the ethnohistoric literature. The temporal endurance of this subsistence strategy suggests that there may be some components of this dietary pattern that could inform on many of the diet-related health issues observed among modern Native American and other populations.

Characterizing ground stone bedrock feature variation in the Lower Pecos Canyonlands

Characterizing ground stone bedrock feature variation in the Lower Pecos Canyonlands

Beyond the Square Hole

ABSTRACTThe accurate and precise collection of three-dimensional (3D) context and provenience data is of critical importance for archaeologists. Traditional square-hole methods are being augmented by new digital techniques to increase the accuracy and precision with which 3D data are collected. Structure from Motion (SfM) photogrammetry is an emerging digital technique that is becoming more widespread for collecting 3D data of archaeological sites and features. We are using handheld digital cameras and ground-based SfM to record accurate and precise 3D context and provenience data at the scale of the excavation unit and profile during rockshelter excavations in the Lower Pecos Canyonlands of Texas. By combining SfM with traditional excavation methods, we collect 3D data on excavation units, layers, features, and profiles without excavating in grid-bound square units. SfM provides a straightforward and flexible method to excavate based on the stratigraphy and logistical pragmatics, which further aids in assigning precise context and provenience to recovered artifacts and samples. This article describes how ground-based SfM serves as a basic recording tool during excavation and shows that, by applying ground-based SfM methods to excavation, archaeologists can collect more, and more accurate, data than with traditional square-hole methods.

Response to Comments by Harrison

AbstractIn our article “A Reexamination of Red Linear Style in the Lower Pecos Canyonlands of Texas,” we presented the results of an analysis of 444 Red Linear style pictographs from 12 sites in the region. Using this greatly expanded data set, we produced a list of diagnostic attributes for the style and documented stratigraphie relationships among pictographs through macro- and microscopic field analysis. We identified 38 examples of Red Linear under Pecos River style, a style previously assumed to be older than Red Linear. No Red Linear figures were identified superimposing Pecos River style. These results were verified by an independent group of archaeologists and chemists engaged in the analysis of Lower Pecos rock art. We concluded that Red Linear style is either older than or contemporaneous with Pecos River style. In Harrison’s comments, he argues that our methods were faulty and the data inadequate to support our conclusions. We address a few of Harrison’s critiques in our response; however, a more careful reading of the original article and supplemental materials is advised.

A Black Deer at Black Cave: New Pictograph Radiocarbon Date for the Lower Pecos, Texas

A Pecos River style painting of a black deer from Black Cave Annex (41VV76a) in southwest Texas was radiocarbon dated. Using plasma oxidation and accelerator mass spectrometry, we obtained an age of 1465 ± 40 RCYBP (2 sigma calibrated age range of A.D. 470-660). This age is younger than the accepted age range for Pecos River style paintings, which is approximately 4000-3000 years B.P. This new measurement in association with other younger dates prompts us to question whether the Pecos River style endured for a longer time period than previously thought. More radiocarbon research is needed in order to understand how this anomalous result might fit within the Lower Pecos Canyonlands rock art chronology.

A Comment On “A Reassessment of Red Linear Pictographs in the Lower Pecos Canyonlands of Texas”

AbstractBoyd, Castañeda, and Koenig (2013) recently published a hypothesis in American Antiquity that Red Linear style rock art predates, or is contemporaneous with, the Pecos River style. While the authors present intriguing examples of over-painting at 41VV83 and 41VV612, their definition of the Red Linear style should be questioned based on its lack of diagnostic characteristics relative to the Pecos River style. The Boyd et al. report is preliminary in its findings and falls short of overturning the existing regional chronology; thus, further stylistic studies of Red Linear art are recommended.

Painters in prehistory: archaeology and art of the Lower Pecos Canyonlands

Painters in Prehistory is a revised update of the book Ancient Texans: Rock Art and Lifeways along the Lower Pecos, edited by Harry Shafer with photographs by Jim Zintgraff, and published by the Witte Museum, in conjunction with a permanent exhibition in 1986. The Witte Museum is known for its focus on natural history, science, and the history and culture of South Texas, and the scholarly and artistic pieces collected in the book are the result of years of research and dedication to the story of the ancient canyon dwellers along the Rio Grande. The remnants of prehistoric Lower Pecos people reveal lifeways unlike those anywhere else in the world. The people who inhabited the land in what is now Texas left a unique series of narratives in their shelters, including art on rock walls, pictographs, and organic residue and trash. These narratives are tantalizing in their novelty--they provide information about almost 12,000 years of existence, the last 7,000 of which are still astoundingly evident. This updated edition features significant research by new scholars who have deepened the understanding of rock art interpretation, scientific analysis of artifacts and coprolites, and the lifeways of prehistoric Lower Pecos people.

Portable X‐Ray Fluorescence Spectroscopy of Pictographs: A Case Study From the Lower Pecos Canyonlands, Texas

We evaluate the effectiveness of non‐destructive portable X‐ray fluorescence spectroscopy (pXRF) for elemental analysis of pictographs at 10 sites in the Lower Pecos Canyonlands of Texas. Considerations and limitations of pXRF analysis are discussed to inform future research. We found that manganese and iron minerals were the main constituents of black and red paints, respectively. However, 40 pXRF measurements from 31 images tested at 41VV75 and 41VV76 did not contain manganese, suggesting charcoal pigment—the first widespread documentation of charcoal figures in the area. The identification of charcoal‐based pigments is important for rock‐art and radiocarbon studies in the region.

A Reassessment of Red Linear Pictographs in the Lower Pecos Canyonlands of Texas

AbstractRed Linear is one of four presently defined prehistoric pictograph styles in the Lower Pecos Canyonlands of southwest Texas and Coahuila, Mexico. Based on interpretation of images and two experimental radiocarbon dates, the style was presumed to have been brought into the region by intrusive bison hunters around 1280 B.P. This would place production of Red Linear after the large, polychromatic Pecos River style paintings (4200–2750 B.P.). However, during a recent rock art recording project we identified Red Linear overlain by presumed older Pecos River style. This prompted our re-examination of Red Linear through analysis of 444 figures from 12 sites. We produced a list of diagnostic attributes for Red Linear and documented stratigraphie relationships through macro- and microscopic field analysis. We identified 38 examples of Red Linear under Pecos River figures, thus inverting the relative chronology for the two styles and forcing a reconsideration of previous assumptions regarding the culture that produced the art. This paper demonstrates the potential afforded by analysis of rock art assemblages to reveal inter- and intrasite patterning of attributes and provide insight into relative chronologies. Further, it cautions against the use of variation in artistic style as a marker for ethnicity.

Groove Marks in the Lower Pecos Canyonlands

Groove marks are an extremely enigmatic style of rock art. Incised groove marks are deep narrowly incised lines, usually in the shape of a "V" or "W" that rarely are more than six millimeters in depth and two to three millimeters wide. Several functional hypotheses have been introduced to explain the purpose of this rock art style. In 2010, the author designed an experimental study designed to test one long held hypothesis that suggests groove marks in limestone were formed by sharpening bone implements. The experiment conducted in the ethnoarchaeology lab at the University of Nevada, Las Vegas demonstrated that groove marks most likely were not used as a way to sharpen bone awls in limestone. Instead, the experiment suggests that archaeological groove marks in the Lower Pecos Canyonlands were created with chert flakes.

Digital Documentation and the Archaeology of the Lower Pecos Canyonlands

<p>The Lower Pecos Canyonlands of southwest Texas and northern Mexico house some of the most complex and compositionally intricate prehistoric rock art in the world. Because of the unique nature and the incomparable richness of this cultural legacy, it is imperative to create a permanent visual, auditory and textual archive for present and future generations and to promote preservation of this resource through education. SHUMLA’s Lower Pecos Rock Art Recording and Preservation Project is meeting this need through digital documentation of rock art sites, creation of a digital library to archive rock art data, establishment of a comprehensive, multi-disciplinary research program, and continuation of hands-on education programs that connect people of all ages to this unique cultural legacy.</p>