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Two independent methods for dating rock art: Age determination of paint and oxalate layers at Eagle Cave, TX
Abstract
This study demonstrates a novel approach to overcoming challenges associated with obtaining reliable radiocarbon dates for rock paintings. Using two independent methods, we obtained ages for Pecos River style paintings at Eagle Cave in Langtry, Texas. The first method employed plasma oxidation to isolate organic carbon directly from the paint layer for accelerator mass spectrometry C-14 measurement. The second method treated mineral accretion layers with phosphoric acid to isolate calcium oxalate for plasma oxidation cleaning, combustion, and C-14 measurement to obtain minimum and maximum ages for the paintings. Radiocarbon dates for the paintings are statistically indistinguishable, with a weighted average of 3280 ± 70 years BP calibrated to 1740-1420 cal BC (3690-3370 cal BP) at 2 sigma (95.4%) probability. Radiocarbon assays obtained for the overlying accretion layers are younger and underlying accretion layers are older. The chronological stratigraphy of the accretion and paint layers supports the validity of both dating methods. With accurate and reliable dating methods, rock paintings in the region can be studied alongside excavated cultural deposits to provide a more complete understanding of this hunter-gather society. These methods for dating rock paintings can be applied to many rock art provinces around the world.
... Looking Inward -Rock Art Sites on the Skiles Ranch There are currently nine known rock art sites on the Skiles family ranch, and only a handful of these sites have been included in publications. For instance, some of the sites in Eagle Nest Canyon (ENC) proper were recorded by early rock art researchers using watercolors or illustrations (e.g., Jackson 1938;Kirkland and Newcomb 1967), while more recent publications focused on chemical analyses of rock art such as portable x-ray fluorescence and radiocarbon dating (Koenig et al. 2014;Steelman, Boyd, et al. 2021;Steelman, DeYoung, et al. 2021). ...
... Located to the right of the largest anthropomorph are a set of five smaller anthropomorphic figures painted in a line (not shown, Figure 5 in Steelman, Boyd, et al. 2021). The furthest panel-right small, black anthropomorph was selected for radiocarbon sampling and returned a date of 3210±110 14 C years BP (CAMS 170031, 3850-3150 cal BP) and a replicate analysis date of 3310±90 14 C years BP (CAMS 170819, 3830-3360 cal BP). ...
... The furthest panel-right small, black anthropomorph was selected for radiocarbon sampling and returned a date of 3210±110 14 C years BP (CAMS 170031, 3850-3150 cal BP) and a replicate analysis date of 3310±90 14 C years BP (CAMS 170819, 3830-3360 cal BP). Additionally, a winged anthropomorph to the right of these five figures was also sampled for radiocarbon analysis, resulting in date of 3400±270 14 C years BP (CAMS 170820, 4450-2950 cal BP) ( Figure 6 in Steelman, Boyd, et al. 2021). The winged anthropomorph has a black body, red wings, and is wielding two powerbundles. ...
... Each layer has the potential to yield datable organic carbon. If there is an ordered sequence with the paint date sandwiched between older and younger oxalate layers, then confidence in the accuracy of the paint date is increased (Steelman, Boyd, et al. 2021; Figures 6 and 7). ...
... Radiocarbon dates for two of the three images are statistically indistinguishable based on a chi-squared test, with a weighted average of 3280±70 14 C years 358 BP, calibrated to 1740-1420 cal BC (3690-3370 cal BP) at 95.4% probability. The third image sampled did not contain enough carbon to date (Steelman, Boyd, et al. 2021). ...
... Attempts to date the oxalate layers associated with these images succeeded. For sample 1, they obtained ordered stratigraphic ages for an overlying oxalate accretion, the paint layer, and underlying accretion (Steelman, Boyd, et al. 2021). For the other two samples, radiocarbon assays obtained for the overlying accretion layers are younger and underlying accretion layers are older than the paint layers. ...
... In every instance, the Pecos River style was painted on top of Red Linear figures, relatively dating Red Linear to be older than or contemporaneous with Pecos River art. Pecos River style imagery dates between 3420±40 and 1465±40 RCYBP based on six direct radiocarbon assays containing contextual, compositional, and laboratory measurement data (Bates et al. 2015;Steelman et al. 2021b). Boyd et al.'s findings challenge earlier assumptions regarding the temporal placement of the Red Linear style. ...
... Pecos River style rock art currently dates between 3420±40 and 1425±40 RCYBP, or 3820 and 1295 cal BP, based on six accepted assays (Bates et al. 2015;Steelman et al. 2021b). These dates do not reflect unpublished dates or legacy dates considered missing contextual, compositional, or measurement data (Steelman et al. 2021b). ...
... Pecos River style rock art currently dates between 3420±40 and 1425±40 RCYBP, or 3820 and 1295 cal BP, based on six accepted assays (Bates et al. 2015;Steelman et al. 2021b). These dates do not reflect unpublished dates or legacy dates considered missing contextual, compositional, or measurement data (Steelman et al. 2021b). Although not considered reliable, legacy dates hint at PRS extending further into the past (Chaffee 1993;Pace et al. 2000;Rowe 2000;Russ et al. 1990 The Cibola Subperiod (3150-2300 RCYBP) is often characterized by the Frio Interlude, a mesic shift in the region that transitioned the desert scrubland toward a grassland (Bryant 1966). ...
This thesis aims to further define the characteristics of Red Linear style anthropomorphic figures, identify regional variations, and establish its temporal relationship with other regional rock art styles of the Lower Pecos Canyonlands of Texas and Coahuila, Mexico. In 2013, Boyd et al. presented a list of diagnostic attributes for the Red Linear style, shedding light on the styles unique features. Additionally, they identified 38 Red Linear figures under the Pecos River style, suggesting that the Red Linear style as either older than or contemporaneous with the Pecos River style. Building on Boyd et al.'s foundation, this thesis incorporates anthropomorphic attributes from 15 additional Red Linear sites documented during Shumla Archaeological Research and Education Center’s Alexandria Project, resulting in a comprehensive list of 614 Red Linear anthropomorphs across 25 sites. Statistical and geospatial analyses were employed to
discern patterns of regional variation within the Red Linear style. To pinpoint the chronological context of the Red Linear style, I selected seven anthropomorphs with clear diagnostic Red Linear attributes for radiocarbon dating. Results derived from these figures position the Red Linear style between 4830±35 and 4275±35 RCYBP. These findings bolster Boyd et al.'s conclusions, offering an enriched understanding through absolute dating methods, pivotal for subsequent research endeavors in the region.
... The rock substrate is a dolomitic limestone. Mineral identifications were determined using X-ray diffraction (Steelman et al., 2021(Steelman et al., ). 1982(Steelman et al., , 1990aBoyd, 2003Boyd, , 2016Harrison Macrae, 2018), Red Linear (Turpin, 1984(Turpin, , 1990b(Turpin, , 2005, Red Monochrome (Turpin, 1986a), Bold Line Geometric (Turpin, 1986b), and Historic (Turpin, 1989). ...
... In the Lower Pecos, Steelman has utilized this improved plasma oxidation methodology to obtain 11 radiocarbon assayssix dates for paintings of the Pecos River style, one date for a red zigzag painting in another rock art style, and four dates for associated oxalate accretions to obtain minimum/maximum ages for paintings and provide independent verification of results (Bates et al., 2015;Steelman et al., 2021) ( Table 2). Oxalate dating in the region was originally conducted by Russ et al. (1994Russ et al. ( , 1995Russ et al. ( , 1996Russ et al. ( , 1999Russ et al. ( , 2000 to support a paleoclimate reconstruction for southwest Texas. ...
... So, by radiocarbon dating calcium oxalate, we can determine when a coating formed. At 41VV129, an oxalate accretion covering a paint layer was previously dated to 3220 ± 60 14 C years BP (CAMS-15147), providing the only oxalate minimum age for a Pecos River style painting (Russ et al. 1996 prior to the Eagle Cave study discussed below (Steelman et al., 2021). ...
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.
... The pictograph panel at one time spanned a large portion of the shelter's back wall, but today the rock art is only preserved on the downstream end of the site. Some figures are over six feet in height, and many anthropomorphs (human-like figures) display the iconic "rabbit ear headdress" Macrae 2018;Steelman, Boyd, and Allen 2021). Subsequent rock art recording was conducted by A.T. Jackson (1938:196-198) and Forrest Kirkland (Kirkland and Newcomb 1967:39;Figures 4b and 4c). ...
... During the field school the pictographs were intensively documented following Shumla methods using photography, illustrations, digital microscopy, and portable X-ray fluorescence (pXRF) spectroscopy (Koenig et al. 2014), as well as collecting paint samples for radiocarbon dating. Radiocarbon dates on the pictographs were recently published (Steelman, Boyd, and Allen 2021), and are currently the earliest published dates on Pecos River style in the region (ca. 3450 cal BP; Steelman, Boyd, and Bates 2021). ...
Summary of 2014-2017 excavations at Eagle Cave, Texas, by the Ancient Southwest Texas Project.
... Another major focus around Eagle Cave, and the Lower Pecos Canyonlands in general, is the study of ancient rock art on the rock shelter walls. This has been examined throughout the Lower Pecos Canyonlands, though recently, this study has expanded into the art found at Eagle Cave (Dering 2021;Koenig et al. 2021;Steelman et al. 2021). In Eagle Cave specifically, exploration has been undertaken to date the rock art using novel radiocarbon dating methods of plasma oxidation and mineral accretion (Steelman et al. 2021 (Boyd and Dering 1996). ...
... This has been examined throughout the Lower Pecos Canyonlands, though recently, this study has expanded into the art found at Eagle Cave (Dering 2021;Koenig et al. 2021;Steelman et al. 2021). In Eagle Cave specifically, exploration has been undertaken to date the rock art using novel radiocarbon dating methods of plasma oxidation and mineral accretion (Steelman et al. 2021 (Boyd and Dering 1996). With specimens of mescal bean having been recorded at Eagle ...
Eagle Cave (41VV167) is an archaeologically significant dry rock shelter located in the Lower Pecos Canyonlands in Val Verde County, Texas. Prior excavations by the Ancient Southwest Texas Project of Texas State University sampled Late Pleistocene and Archaic period earth-ovens and earth-oven-adjacent features from Eagle Cave. Using 10 sediment samples from the project, I determined how people’s relationship with plants changed according to certain variables: feature type, environmental zone, plant seasonality, plant-use categories, and time. The hypotheses that macrobotanical and wood charcoal counts and weights changed with the variables were supported, with the exception of the hypotheses made about plant-use categories and time. This research contributes to knowledge regarding past diets by providing a comprehensive paleoethnobotanical study of plant-use at Eagle Cave. Results provide new data regarding the breadth of botanical consumption and fuel components at Eagle Cave, with implications throughout the Chihuahuan desert and south-central North America.
... In such a way it is established whether the formation of calcium oxalate at a given locality is related to environmental features (Livingston, Robinson, Armitage, 2009). If it can be proven that the calcium oxalate in the dye is a product of the decomposition of organic binders intentionally added by humans, the pigment can be successfully dated by the AMS-method (Brook et al., 2018;Pecchioni et al., 2019;Steelman, Boyd, Allen, 2021). Spanish researchers used a rather peculiar approach to the dating of calcium oxalates of painted images on the walls of the rock shelters of Sierra de las Cuerdas and Cueva del Tío Modesto (Hernanz, Gavira-Vallejo, Ruiz-López, 2007). ...
... To check this possibility, the chemical composition of both the pigment and the rock's surface without images and deposits closest to them should be analyzed. This will exclude accidental admixture of organic substances from the environment into the pigment, and prove that the dated calcium oxalate is a product of decomposition of an organic binder deliberately added by an ancient artist (see, e.g., (Pecchioni et al., 2019;Steelman, Boyd, Allen, 2021)) if it is the case. On exposed surfaces, the likelihood of organic contamination is high, and calcium oxalate could have formed in the pigmented area both before and after the image's creation (Sauvet, 2015: 214). ...
The study addresses modern methods of absolute dating of rock art. We review prospective approaches to dating petroglyphs under various conditions: AMS, OSL, uranium-thorium, and cosmogenic isotope. Not so much methods per se are discussed as principles of their application to certain reliably dated rock art sites of various periods in Europe, Asia, America, and Australia. Examples of satisfactory outcomes in international practice are cited alongside our assessment of prospects and limitations to be considered with regard to the method of dating the earliest petroglyphs and rock paintings in the Khakass-Minusinsk Basin. The review suggests that the basic conditions for the use of the uranium-thorium method are not met, the AMS method requires a preliminary analysis of the context, whereas OSL and cosmogenic isotope method are the most prospective.
... These investigations helped ensure enough organic carbon from the paint source while ABA pre-treatment removed contaminating calcium oxalates before combustion and graphitization for radiocarbon dating. Steelman et al. (2021) [129] used a different approach at Eagle Cave in Langtry, Texas, with plasma oxidation to isolate organic carbon directly from the paint layer, and avoided loss of dating material during an acid pre-treatment. An alternative to dating pigments is to date oxalate accretions over and beneath the painting. ...
... These investigations helped ensure enough organic carbon from the paint source while ABA pre-treatment removed contaminating calcium oxalates before combustion and graphitization for radiocarbon dating. Steelman et al. (2021) [129] used a different approach at Eagle Cave in Langtry, Texas, with plasma oxidation to isolate organic carbon directly from the paint layer, and avoided loss of dating material during an acid pre-treatment. An alternative to dating pigments is to date oxalate accretions over and beneath the painting. ...
Rock art is a widespread cultural heritage, representing an immovable element of the material culture created on natural rocky supports. Paintings and petroglyphs can be found within caves and rock shelters or in open-air contexts and for that reason they are not isolated from the processes acting at the Earth surface. Consequently, rock art represents a sort of ecosystem because it is part of the complex and multidirectional interplay between the host rock, pigments, environmental parameters, and microbial communities. Such complexity results in several processes affecting rock art; some of them contribute to its destruction, others to its preservation. To understand the effects of such processes an interdisciplinary scientific approach is needed. In this contribution, we discuss the many processes acting at the rock interface—where rock art is present—and the multifaceted possibilities of scientific investigations—non-invasive or invasive—offered by the STEM disciplines. Finally, we suggest a sustainable approach to investigating rock art allowing to understand its production as well as its preservation and eventually suggest strategies to mitigate the risks threatening its stability.
... Hunter-gatherer artists living in the Lower Pecos Canyonlands of southwest Texas and northern Mexico used similar visual stimuli to transform the ephemeral and intangible qualities of hearing and smell into something enduring and palpable. Radiocarbon assays obtained for Pecos River style (PRS) paintings place production of the art to at least 1700 cal BC (Steelman, Boyd, and Allen 2021), centuries before the earliest known graphic representation of speechbreath in Mesoamerica. In this article, we examine a recurring motif in PRS rock paintings: dots and lines exiting or entering the mouth of anthropomorphic and zoomorphic figures (Figure 2a-h and Figure 3). 1 We propose that Lower Pecos artists used these graphic devices not only to denote speech and breath but to transmit vital forces heavenward through images infused with life. ...
... South of the river in Coahuila, Mexico, 35 murals have been identified, but there are likely far more in the secluded canyons of the Serranías del Burro (Turpin 2010:41). Direct dates obtained for four PRS figures exhibiting speech-breath range from 1700 BC to AD 600, placing production of the speech-breath motif within the Middle to Late Archaic periods (Steelman, Boyd, and Allen 2021;Steelman, Boyd, and Bates 2021). ...
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.
... Steelman et al. (2021a) favor option (1), suggesting that Rowe's dates are "problematic and should not be used to draw archaeological conclusions." However, they used the plasma oxidation technique and another method (dating of overlying and underlying calcium oxalate) to date two Pecos River Style paintings at Eagle Cave, and these dates came out as statistically identical and within the expected range (3280 ± 70 rcbp, 3690-3370 cal BP, at 2 sigma) (Steelman et al. 2021b). ...
Stylized depictions of spearthrowers (atlatls) are present in several locations among the petroglyphs in Grapevine Canyon in southern Nevada. These have not previously been recognized in any published descriptions. They imply that some of the images within the canyon were created before ca. cal AD 600, and that the people who made them were connected to contemporaneous groups who made similar art in the Coso region of southern California.
... In particular, the presence of pigment pieces of various sizes, pigment powders, and residues, and even paint drops in deposits, like seashells, stone and brick utensils, millstones, vessels of different kinds, and so forth, is well documented [9][10][11]. Moreover, the evidence of ochre processing laboratories (comprising raw materials, working tools, and/or holding vessels) in various time periods and locations reveals that the utilization of dyeing raw products was not random but a well-planned activity since prehistory, requiring a significant investment in time and effort in order to procure and process them [12][13][14]. ...
In this article, an investigation into the natural radioactivity content in natural inorganic pigments was carried out, together with the assessment of the radiological health risk for the public related to external exposure to ionizing radiations, via High-Purity Germanium (HPGe) γ-ray spectrometry measurements and the calculation of several indices like the absorbed γ-dose rate (D), the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin), and the activity concentration index (I). From the obtained results, it was possible to reasonably exclude radiological hazard effects. In addition, Pearson’s correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA) were carried out with the aim of determining correlations between natural radioactivity content and radiological indices and with the analyzed samples. As a result, five clusters of the investigated pigments were recognized at the highest level of detail based on their chemical composition and mineralogical nature.
... Foram observados dois factos muito interessantes: a detecção de gesso em algumas crostas da Ribeirinha, Lapas Cabreiras e Poço Torto e a existência de oxalato de cálcio em amostras de crosta das Lapas Cabreiras, Poço Torto e Ervideiro (Figura 4). A presença de oxalato de cálcio, confirmada por espectroscopia Raman e espectroscopia de infravermelho por transformada de Fourier (FTIR), abre um novo caminho à luz da ciência analítica, com grande interesse para a datação das crostas (e.g.Steelman, et al. 2021). Embora tenham sido verificados fenómenos específicos de dissolução nas camadas mais superficiais de algumas crostas, elas são, em geral, quimicamente muito estáveis. ...
No âmbito do projeto de investigação LandCRAFT, apresentamos as estratégias para a proteção e conservação de um conjunto de abrigos com pinturas rupestres pertencentes à tradição de Arte Esquemática no vale do Côa.
... In the case of a biogenic process, the oxalate carbon content originates from atmospheric carbon dioxide, with no carbon exchange from the substrate. In rock art painting, it is commonly accepted that oxalates correlate with microbial activity and the radiocarbon dating thereof can be used to constrain the age of rock pictographs, a terminus ante quem (Dumoulin et al. 2020;Russ et al. 2017;Steelman, Boyd, and Allen 2021 and references therein). For oxalates resulting from oxidative degradation mechanism, the carbon source relates to the degraded organic material (Otero et al. 2018). ...
Ancient panel paintings on wood are, with the exception of the mesmerising mummy portraits,extremely rare. However, a small corpus of other types of Romano-Egyptian panel paintings ispreserved in collections worldwide. The aim of this study is to explore the technical histories ofthese rare and intriguing artefacts. We present a comprehensive investigation of threeRomano-Egyptian panel paintings from the collections of the Ny Carlsberg Glyptotek,Denmark, including their construction, materials, pigments, binding media, and dating. Thepanels are examined by various methods of analysis to provide much deeper insights intothe materials and techniques used for their production, and to answer questions ofchronology and classification. In total, this work offers a more thorough understandingof their function, significance, and original appearance, as well as insights into the art ofpainting during the Roman period.
... Inferences are, however, not straightforward, since taphonomic limitations bias the record of ancient paintings. Bio-and physicochemical processes derived from the coupled effect of water, temperature, insolation, wind, and anthropogenic activities can alter or even destroy rock art paintings and rock substrates, hampering the interpretation of frequency, diversity, distribution, composition and chronology of this unique record (e.g., Bastian et al., 2010;Bednarik, 1994;Gallinaro & Zerboni, 2021;Huntley et al., 2021;Meiklejohn et al., 2009;Morillas et al., 2018;Saiz-Jimenez et al., 2011;Steelman et al., 2021). Thus, a taphonomic perspective in rock art studies provides not only tools for a better comprehension of the ancient rock art, but also gives conservation guidelines for heritage agendas (e.g., Franklin, 2014;Wright, 2018). ...
This work aims discussing the contribution of environmental and technological factors in rock art painting preservation, based on a 3-year experimental program and two archaeological cases from Patagonia (South America). Concerning technological factors, microscopic information of experimental and archaeological contexts indicate that fine-grained pigments have a better preservation potential than coarse-grained ones, likely related to the high binder adsorption capacity of silty and clay size particles, resulting in a strong pigment agglutination and substrate adherence. Mechanical entrapment/translocation of such small particles into the substrate further contributes to preservation. The experiment also evidences that blood-bearing paints present preservation advantages over fat/water-based ones, probably due to clotting and drying processes which agglutinate pigments and seal rock voids, avoiding binder migration. In contrast, experimental gypsum- and, to a lesser extent, charcoal-based paints show a rapid and significant deterioration, particularly in the temperate and humid context. The low archaeological expectancy derived from these results is supported by the scarce and/or ambiguous regional representation of these black pigments in ancient Patagonian paintings. Among natural factors, water-related processes (i.e., rainfall, snow, freezing and water infiltration) play a decisive role in the physicochemical paint degradation, also favoring bioactivity. Raman spectroscopy of neoformed white crystals in experimental paints may evidence, in a short term, a first stage of the profuse biomineralizations archaeologically observed, associated with lichens, fungus, and endolithic organisms. Finally, sheep rubbing and wind abrasion are proposed as the main agents affecting vertical frequencies and integrity of archaeological motifs at the cave and open-air contexts, respectively, whereas differences related to cardinal insolation likely impact in frequencies, motif color and weathering stages at the open-air site too.
... Applying this to Rowe's dates on the mural, Boyd (2016:26) calculated an average age of the White Shaman mural at 2000 + 400 years before present. Although this is as close as we can get with the available dates on the White Shaman mural, recently a more reliable date on the Lower Pecos River style has been obtained through the plasma oxidation technique, producing an assay of 3280 + 70 RCYBP, calibrated at 2-sigma to 1740-1420 B.C. (Steelman, Boyd, and Allen 2021). ...
Recent advances in the analysis and interpretation of the White Shaman mural, a Lower Pecos Style rock art panel in Val Verde County, Texas, has shown that it represents a graphic depiction of an ancient Mesoamerican myth involving the pre-Columbian peyote pilgrimage. In collaboration with the work of traditional religious practitioners of the Native American Church, an ideational landscape model is proposed that has the potential to enhance our understanding of the pre-contact communities of Central Texas spanning back ca. 3,500 years.
... It has the advantage of extracting minute quantities of carbon from the target pigment separately from carbonate and oxalate contamination because the plasma energy can be maintained below the energies (radiofrequency and temperatures) where those inorganic molecules dissociate. For examples of the experimental procedures used, see the recent publications from the three currently operating plasma oxidation laboratories (Armitage et al., 2020;Baker and Armitage, 2013;Loendorf et al., 2017;McDonald et al., 2014;Rowe et al., 2016Rowe et al., , 2021Russ et al., 2017;Steelman et al., 2019Steelman et al., , 2021. ...
We successfully measured four radiocarbon dates on two specimens of a black geometric rock painting with a fragment in jeopardy of naturally spalling off in the wall of a rock shelter in the Ẓufār region, in the south of the Sultanate of Oman. Extraction of carbon dioxide (CO 2 ) for radiocarbon dating of the binder in the black pigment of the rock painting specimen was conducted in the plasma oxidation laboratory at the Office of Archeological Studies in Santa Fe, NM. The radiocarbon content was measured on the Swiss ETH-Zürich accelerator mass spectrometer MICADAS. The dates obtained agreed with one another within the statistical uncertainty and the average date of the four samples was 1500 ± 35 radiocarbon years BP. The calendric equivalents of the average date results in calendric calibration date ranges that span the mid-fifth through mid-seventh centuries (440–453 CE, 478–496 CE, and 534–646 CE). This research demonstrates that it is possible to date the black paintings of the Jebel al-Qara’ area of Oman; this is the first pictogram that was dated using radiocarbon dating in the region.
... We used the plasma oxidation technique which is particularly amenable to dating paintings with a high mineral content, such as these mural fragments of painted plaster, as it extracts only the organic fraction and leaves the inorganic matrix unaffected (Rowe 2001(Rowe , 2009Russ et al. 1990;Steelman et al. 2021aSteelman et al. , 2021bSteelman and Rowe 2012). The active species in the plasma allow reactions that normally occur only at high temperatures or very slowly to proceed rapidly at low temperatures. ...
At Lowry Pueblo, small fragments of painted plaster are all that remain of a bold white step pattern mural that once decorated Kivas A and B. We used the following analytical techniques to study these fragments: visual microscopic analysis, portable X-ray fluorescence, scanning electron microscopy with an energy dispersive X-ray spectrometer, powder X-ray diffraction, and radiocarbon dating. We identified zinc oxide and lead sulfate pigment minerals in the glossy white paint, whereas calcium carbonate was identified as the pigment for the matte white paint. Radiocarbon dating of a lead layer places mural production at 1030–1210 cal A.D., consistent with occupation at Lowry Pueblo Great House. Stratigraphic analyses of the painted plaster layers reveals that underlying glossy white paint was applied before the ultimate matte white layer. The change in pigment source and paint recipes demonstrate a design-modifying choice made by the kiva painters.
... Developed by Rowe, the method of plasma oxidation has been used to successfully AMS radiocarbon date over 300 rock paintings around the world (Russ et al., 1990(Russ et al., , 2017Rowe, 2012;Rowe et al., 2016;Armitage et al., 2020;Steelman et al., 2021). The plasma oxidation technique is particularly useful for dating rock paintings and other samples with abundant minerals. ...
At Serpentine Bends Site #1, we employed plasma oxidation followed by accelerator mass spectrometry to radiocarbon date two prehistoric rock paintings as well as soot on the shelter ceiling. Pictograph results are 2325 ± 30 ¹⁴C years BP for a black line and 1315 ± 40 ¹⁴C years BP for a red outline of a circle motif. We also utilized X-ray diffraction to chemically identify pyrolyzed carbon in the black stain on the shelter ceiling, confirming that it is from fire smoke. Four radiocarbon ages for the soot represent a weighted average of multiple fires, instead of a single event. The oldest result of 2740 ± 70 ¹⁴C years BP is from the underlying black soot closest to the rock substrate and, as a weighted average of multiple layers, represents a minimum age for human activity at the site. Dating both pictographs and prehistoric soot provide novel methods for dating human activity within rockshelters around the world, especially when there is a lack of excavated materials for study.
The remains of earth ovens are ubiquitous features in the Holocene archaeological record of North America and continue to be integral components of Indigenous lifeways. However, on a continental scale we lack a broad understanding of earth oven timing, chronology, morphological variation, and the role(s) these features played within Indigenous cultures—especially during the early Holocene. This dissertation focuses on three aspects of early Holocene earth ovens: 1) earth ovens in Eagle Cave, Texas; 2) experimental study of Agave lechuguilla processing; and 3), early Holocene thermal features from Wyoming. Eagle Cave contains a stratified record of early Holocene earth oven processing, and I evaluate whether Indigenous peoples were intensifying earth oven construction to cope with regional population growth or hosting social aggregations. Data analyses indicate earth oven use is likely related to both scenarios. To supplement the Eagle Cave analysis, I describe earth oven experiments for Agave lechuguilla evaluating how varying construction costs can shift our perception of earth oven cooking. This experimental study indicates that foragers can maximize caloric return rates by sharing construction costs, and Agave lechuguilla ovens likely generated considerably more food than previously recognized. To place the Eagle Cave data into a broader context, I compile the record of early Holocene thermal features in Wyoming. This analysis indicates earth ovens became a critical technology for Indigenous peoples in Wyoming soon after the Pleistocene, and variation in oven technology demonstrates that Indigenous people used different oven configurations to cook different foods during the early Holocene.
At the Painted Coulee site (24JT86), pictographs depicting both atlatl and bow technology are present. We utilized plasma oxidation followed by accelerator mass spectrometry to directly radiocarbon date the organic material in two paint samples. A red painting of an anthropomorph with a shield and a possible atlatl in conflict with a fleeing person holding a bow was dated to 1790 ± 50 RCYBP (cal AD 120–390). Another red anthropomorph wearing snowshoes and holding a bow was dated to 1710 ± 45 RCYBP (cal AD 240–425). Radiocarbon dates for underlying oxalate minerals provided maximum ages for the paintings that are consistent with the direct ages. This early example of Plains Biographic rock art is significant because it illustrates a scene between a Late Archaic shield-bearing warrior with a possible atlatl and an anthropomorph with a bow and arrow at a time when bows first came into use on the Northwestern Plains.
Calcium 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.
The study of painted artworks using scientific methods is fundamental for understanding the techniques used in their creation and their appropriate conservation. The ethical constraints involved in the handling of, and sampling from, these objects has steered recent developments in the field of Heritage science towards a range of new non-invasive/non-destructive spectroscopic techniques capable of providing important insights into their elemental or bulk chemical compositions. Due to the inherent complexities of heritage artefacts, however, their organic components are especially difficult to study in this way and their identification and degradation pathways are thus often best investigated using mass spectrometric (MS) techniques. The versatility, sensitivity and specificity of MS techniques are constantly increasing, with technological advances pushing the boundaries of their use in this field. The progress in the past ten years in the use of MS techniques for the analysis of paint media are described in the present review. While some historical context is included, the body of the review is structured around five most widely used or emerging capabilities offered by MS. The first pertains to the use of spatially resolved MS to obtain chemical maps of components in cross-sections, which may yield information on both inorganic and organic materials, while the second area describes the development of novel sample preparation approaches for gas chromatography (GC)-MS to allow simultaneous analysis of a variety of components. The third focuses on thermally assisted analysis (either with direct MS or coupled with GC-MS), a powerful tool for studying macromolecules requiring zero (or minimal) sample pre-treatment. Subsequently the use of soft ionisation techniques often combined with high-resolution MS for the study of peptides (proteomics) and other macromolecules (such as oligosaccharides and triglycerides) is outlined. The fifth area covers the advances of radiocarbon dating painting components with accelerator MS (AMS). Lastly, future application of other MS techniques to the study of paintings are mentioned; such as direct analysis in real time MS (DART-MS) and stable isotope ratio MS (IRMS). The latter, having proven its efficiency for the study of lipids in archaeological artifacts, is envisioned to become a useful tool for this area, whereas DART-MS is already being utilised to study the surface composition of various museum objects. Rapid technological advances, resulting in increased sensitivity and selectivity of MS techniques, are opening up new approaches for painting analysis, overcoming the fundamental hurdle of sample size available for destructive analysis. Importantly, while the last decade has seen proteomics applications come to the fore, this review aims to emphasise the wider potential of advanced MS techniques for the study of painting materials and their conservation.
This book examines the scholarly work of Terence Grieder, an early pre-Columbian art historian of wide-ranging interests and often provocative stances. Through a series of topical essays focused a variety of Pre-Columbian art historical topics, former students, professional colleagues, and other intellectual descendants discuss his major ideas through examples drawn from their own work. The work of those he mentored and interacted with is, in the end, the most important testament to his continuing influence in the field.
Fourteen different types of coatings cover rock surfaces in every terrestrial weathering environment, altering the appearance of the underlying landform. Some accretions interdigitate, while others blend together, creating a great number of variations. Rock coatings are important in geomorphology because coatings: alter weathering rates; play a role in case hardening surfaces; offer clues to understanding environmental change; and can provide chronometric insight into the exposure of the underlying rock surface. Following a landscape geochemistry paradigm, five general hierarchies of control explain the occurrence of different types of rock coatings: 1st order—geomorphic processes control the stability of bedrock surfaces on which coatings form; 2nd order—coatings originating in rock fissures are found on subaerial surfaces when erosion of the overlying rock occurs; 3rd order—the habitability of surfaces for fast-growing lithobionts such as lichens determines whether slowly accreting coatings occur; 4th order—the raw ingredients must have a transport pathway to the rock surface, and of course, they must be present; 5th order—physical, geochemical or biological barriers to transport then result in the accretion of the coating.
Archaeological radiocarbon assays Lower Pecos were compiled (n=473), spanning the Paleoindian through Proto-historic periods, including one hundred newly reported Ancient Southwest Texas Project assays. The data set was then critically vetted to identify potentially unreliable or irrelevant dates. Using Bayesian methods, the radiocarbon data are used to investigate timing of plant baking and the manufacture of fiber goods from evergreen rosettes. Relative human population fluctuations are investigated using a summed probability distribution of radiocarbon dates. The results of these analyses are compared with environmental proxy data and radiocarbon assays dating the intermittent presence of bison in the region. Correlations in these data are preliminary yet promising and warrant further investigation with more sophisticated analyses and a larger sample size of well-reported radiocarbon data.
Radiocarbon (C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
The Kimberley region in Western Australia hosts one of the world's most substantial bodies of indigenous rock art thought to extend in a series of stylistic or iconographic phases from the present day back into the Pleistocene. As with other rock art worldwide, the older styles have proven notoriously difficult to date quantitatively, requiring new scientific approaches. Here, we present the radiocarbon ages of 24 mud wasp nests that were either over or under pigment from 21 anthropomorphic motifs of the Gwion style (previously referred to as "Bradshaws") from the middle of the relative stylistic sequence. We demonstrate that while one date suggests a minimum age of c. 17 ka for one motif, most of the dates support a hypothesis that these Gwion paintings were produced in a relatively narrow period around 12,000 years ago.
The Lower Pecos Canyonlands of southwest Texas and northern Coahuila, Mexico, is home to some of the world’s most complex prehistoric rock art (Boyd 2003, 2016; Shafer 2013; Turpin 2010). The majority of known Lower Pecos rock art sites north of the U.S.-Mexico border are in Val Verde County, Texas, where there are over 300 rock art sites recorded. However, many are being lost due to age and natural weathering, and few have received the detailed documentation and iconographic description crucial for studying and protecting these endangered sites. To digitally document and preserve the rock art of the Lower Pecos, Shumla Archaeological Research & Education
Center launched The Alexandria Project in 2017 with the goal of conducting baseline documentation at all of the known rock art sites within Val Verde County. Through a combination of low and high-tech methods, including Structure from Motion (SfM) 3D modeling and gigapanoramas, the Alexandria Project will result in an incredible spatial and visual inventory of Lower Pecos rock art. This paper describes Shumla’s documentation methods used during the Alexandria Project, and demonstrates how new technologies can
be utilized by rock art researchers during an intensive survey-level project.
While radiocarbon dating Red Linear Style figures is difficult due to their small size, it is crucial to understand their temporal and geographical range. In the Guadalupe Mountains, five Red Linear Style paintings have been dated to 4400 to 1520 B.P. These dates provide chronological context for specific communal hunting strategies, including use of nets, atlatls, antler snares, and rabbit sticks. Regionally, these chronometric results strengthen parallels between the Red Linear Style of the Guadalupe Mountains of New Mexico and the Lower Pecos Canyonlands in Texas. However, there is only one direct radiocarbon date for a red oval at Cueva Quebrada in the Lower Pecos, highlighting the need for more chronometric studies on rock paintings in both regions.
Neandertal cave art
It has been suggested that Neandertals, as well as modern humans, may have painted caves. Hoffmann et al. used uranium-thorium dating of carbonate crusts to show that cave paintings from three different sites in Spain must be older than 64,000 years. These paintings are the oldest dated cave paintings in the world. Importantly, they predate the arrival of modern humans in Europe by at least 20,000 years, which suggests that they must be of Neandertal origin. The cave art comprises mainly red and black paintings and includes representations of various animals, linear signs, geometric shapes, hand stencils, and handprints. Thus, Neandertals possessed a much richer symbolic behavior than previously assumed.
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Oxtotitlán Cave paintings have been considered among the earliest in Mesoamerica on stylistic grounds, but confirmation of this hypothesis through absolute dating has not been attempted until now. We describe the application of advanced radiocarbon strategies developed for situations such as caves with high carbon backgrounds. Using a low-temperature plasma oxidation system, we dated both the ancient paint and the biogenic rock coatings that cover the paint layers at Oxtotitlán. Our research has significantly expanded the time frame for the production of polychrome rock paintings encompassing the Early Formative and Late Formative/Early Classic periods, statistically spanning a long era from before ca. 1500 cal B.C. to cal A.D. 600.
At Cova Eirós, we discovered 13 panels with paintings and engravings that stylistically point to the final moments of the Upper Paleolithic. Scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier transform Raman spectroscopy were used to identify charcoal as black pigment. Although contamination from medieval fires inside the cave complicates the dating of these pictographs, analyses of unpainted rock backgrounds allowed calculation corrections for contaminated samples. We used plasma oxidation and accelerator mass spectrometry (AMS) to directly radiocarbon ( ¹⁴ C) date two charcoal paintings—confirming that the images are more than 9000 yr old. As these paintings superimpose engravings, these ¹⁴ C dates also provide a minimum age for an engraving at Cova Eirós that is stylistically Final Magdalenian/Epipaleolithic. This is the first known evidence of Paleolithic cave art in Galicia of NW Iberia.
The 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.
The dating of South African rock art using radiocarbon is a considerable challenge and only 1 direct date has so far been obtained, on black pigments from Sonia's Cave Upper, Boontjieskloof. The main problem with direct dating these paintings is the presence of calcium oxalates behind, on, and within the pigment layers. Calcium oxalates are formed through lichen and bacterial action on the rock face. These reactions can sometimes take place over long periods and can incorporate carbon of a younger age into the pigments. This study aims to date black pigments from a rockshelter, RSA TYN2 (Eastern Cape, South Africa), by removing the calcium oxalate contamination. Two different protocols were tried: density separation and acidification. The latter successfully removed calcium oxalates and was therefore applied to 3 black pigment samples from the rockshelter. After acid pretreatment, accelerator mass spectrometry (AMS) dating was undertaken on the remaining residues. Three results were obtained (2072 ± 28 BP, 2100 ± 40 BP, and 2083 ± 32 BP), which constitute the oldest results so far obtained for direct dates on South African rock art. The most likely calibrated date range for the painting at this site is between 2120 and 1890 cal BP. The ages are in close agreement with each other and this consistency suggests that our preparation protocol has successfully removed the majority of the carbon contaminants.
Mapping is a critical aspect of systematic documentation no matter where archaeologists work. From hand-drawn maps of excavation units to maps created with Total Data Stations or LiDAR scanning, today’s archaeologists have a suite of mapping techniques and technologies to choose from when documenting a site. Typically, spectacular sites often receive high resolution mapping, whereas everyday sites rarely do. Recently, however, a revolutionary technology and technique has been created that can produce highly accurate and precise three-dimensional maps and orthophotos of archaeological sites, features, and profiles at a fraction of the cost and time of LiDAR and intensive TDS mapping: Structure from Motion (SfM). SfM is a new digital photography processing technique for capturing highly detailed, three-dimensional (3D) data from almost any surface using digital cameras. This article introduces the various platforms SfM photographs can be collected from (UAV, kites, balloons, poles, and groundbased) and provides examples of different types of data SfM can provide. The Structure from Motion Revolution is unfolding across the globe at a rapid pace, and we encourage archaeologists to take advantage of this new recording method.
Soil and rock surfaces support microbial communities involved in mineral weathering processes. Using selective isolation, fungi were obtained from limestone surfaces of Mayan monuments in the semi-arid climate at Yucatan, Mexico. A total of 101 isolates representing 53 different taxa were studied. Common fungi such as Fusarium, Pestalotiopsis, Trichoderma, and Penicillium were associated with surfaces and were, probably derived from airborne spores. In contrast, unusual fungi such as Rosellinia, Annulohypoxylon, and Xylaria were predominantly identified from mycelium particles of biofilm biomass. Simulating oligotrophic conditions, agar amended with CaCO3 was inoculated with fungi to test for carbonate activity. A substantial proportion of fungi, in particular those isolated from mycelium (59%), were capable of solubilizing calcium by means of organic acid release, notably oxalic acid as evidenced by ion chromatography. Contrary to our hypothesis, nutrient level was not a variable influencing the CaCO3 solubilization ability among isolates. Particularly active fungi (Annulohypoxylon stygium, Penicillium oxalicum, and Rosellinia sp.) were selected as models for bioweathering experiments with limestone-containing mesocosms to identify if other mineral phases, in addition to oxalates, were linked to bioweathering processes. Fungal biofilms were seen heavily covering the stone surface, while a biomineralized front was also observed at the stone-biofilm interface, where network of hyphae and mycogenic crystals was observed. X-ray diffraction analysis (XRD) identified calcite as the main phase, along with whewellite and wedellite. In addition, lower levels of citrate were detected by Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Overall, our results suggest that a diverse fungal community is associated with limestone surfaces insemi-arid climates. A subset of this community is geochemically active, excreting organic acids under quasi-oligotrophic conditions, suggesting that the high metabolic cost of exuding organic acids beneficial under nutrient limitation. Oxalic acid release may deteriorate or stabilize limestone surfaces, depending on microclimatic dynamics.
The question of when the first humans arrived in the New World has been a bone of contention for several decades. Similarly, the age of rock paintings has been heatedly debated. Settlements in the Serra da Capivara National Park have been dated to between 5 kyr and >50 kyr, which is far older than the Clovis barrier. Moreover, calcite formation on a rock-wall painting in a rockshelter yielded thermoluminescence (TL) and electron paramagnetic resonance (EPR) ages older than 35 kyr BP (Watanabe et al. 2003). In an attempt to contribute to this ongoing debate, we have studied calcite deposits covering prehistoric paintings from several rockshelters (Toca da Bastiana, Toca do Serrote de Moendas, and Toca da Gameleirinha [Pedra pintada]). Coupled AMS (accelerator mass spectrometry) C-14 and MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) Th-230/U dating was performed in Toca da Gameleirinha. The ages obtained for these calcites are younger than 12 kyr and suggest that the paintings could be more recent than proposed by previous studies.
Here we report AMS radiocarbon ages associated with rock art in the Kimberley, north-west Australia, from beeswax motifs (26), charcoal pigments (7), a fragment of ochred baler shell used for mixing pigments, and mineral deposits from the base of a pecked cupule. With one exception, these ages are for motifs or paraphernalia associated with the Wandjina painting tradition, which appears to have included a number of contemporaneous art 'styles'. The radiocarbon determinations range from similar to 3800 BP, to modern, a distribution very similar to that previously obtained for wax figures in Northern Territory rock art.
The cultural trajectory of Lower Pecos prehistory originates in stereotypic Paleoindian big game hunters who apparently entered the region some twelve thousand to fourteen thousand years ago. Based on the two known sites of this age, the economy was oriented toward the procurement of megafauna such as elephants, camels, horses, and bison, although the earliest kills were probably individuals or pairs of animals that were trapped and slain (Bement 1986). The later Folsom and Plainview hunters had apparently perfected the jump technique of bison hunting, suggesting organizational skills consistent with group procurement strategies that centered upon migratory herd animals (Dibble 1970). The extinction of the large game herds and the onset of a trend toward aridity triggered a transition to Archaic lifeways about ninety-four hundred years ago. The people apparently exploited a broader resource base, developing a reliance on plant products, both as food and as raw material for the burgeoning fiber industry, while retaining established lithic traditions. The transition culminated in a robust adaptation that gives the outward but perhaps misleading impression of great stability for a period of some four thousand years. Rockshelters became the nucleus of the settlement pattern, showing differentiated activity areas of a domestic nature where fiber, wood, bone, and hide were worked, as was the everpresent stone. Mortuary customs included disposal of the dead in convenient vertical shaft caves regardless of age or gender. Then, about fifty-five hundred years ago, the cultural system began a series of internal adjustments, presumably in response to an increasingly arid environment. The end result was the consolidation of traits into the full-blown Archaic expression that defines the Lower Pecos as a distinct cultural entity. A model that parsimoniously explains this development was formulated by analogy to emerging complex societies documented ethnohistorically and archeologically in arid lands around the world. In this model, changes in the distribution of essential resources, most prominently potable water, triggered responses in the settlement pattern and procurement strategies leading to a disproportionate concentration of people along the major rivers. Aridity does not imply a shortage of food, especially if desert succulents increase at the expense of grasslands, but gathering and processing of thorny plant foods and small mammals requires specialized techniques and knowledge. The responsibility for food procurement, especially hunting and gathering in the uplands, would have been delegated to mobile task groups who operated from their bases on the rivers. Diversification broadened the diet to include labor-intensive processing of a wider range of foodstuffs, activities that took place in open camps and rockshelters as well. New methods of social control were mandated by the redistribution of human populations, who were in effect circumscribed by the availability of water. The inevitable tensions introduced by proximity elicited a restructuring of society that was accompanied by the intensification of ritual that was, in turn, manifested by the florescence of publicly produced mural art. A common belief system, rooted in the principles of shamanism and expressed in cave paintings, held sway over the area that is now defined as the Lower Pecos cultural region. This period of time is the apogee of the Lower Pecos cultural trajectory: the consolidation of an ethnic identity that trembled on the verge of societal complexity that was never achieved, possibly for lack of the ability to generate an adequate surplus- the necessary and sufficient condition for sedentism. Sometime around three thousand years ago, the insular Lower Pecos cultural persona relaxed, perhaps disrupted by the advent of new people with a different economic strategy and social structure. A mesic interlude permitted the grasslands of the Great Plains to expand to the Rio Grande, drawing herds of bison and their attendant hunters. Even episodic, perhaps seasonal, influxes of people bearing a fully developed cultural system of their own must have had a perceptible effect on the resident population; at present it can only be discerned in settlement patterns, tool types, and possibly art styles. The return to aridity and the retreat of the grasslands created a vacuum filled by desert-adapted people who came north across the Rio Grande from northern Mexico. Soon, the archeology of the Lower Pecos found affinities with that of central Texas, sharing in the generalized Late Archaic lithic assemblage while perfecting its fiber industry, retaining its characteristic burial customs, and keeping a balance between rockshelters and open camp site occupations. Measures of population density again rise, reaching and exceeding the heights achieved during the Middle Archaic peak, but the processes behind the increase are less clear. The Late Prehistoric period experienced a cultural upheaval, including changes in settlement patterns, site types, mortuary customs, art styles, and artifact types. Pictograph styles show affinities with northern Mexico and the Big Bend region of Texas, lithic tool types are shared with the rest of Texas, and mortuary customs appear to be introduced from the north and northwest. Clearly, people, rather than ideas, were on the move. Late in prehistory, one intrusive group is identified by a distinctive artifact assemblage, including small arrow points and ceramics, a preference for promontories with sweeping views, and residences that used paired stones as pole supports for a thatch or hide cover. The people of the Infierno phase may be precursors to ethnohistorically described bison hunters who again seasonally congregated at the mouth of the Pecos River during yet another mesic interlude. The Spanish found little of value in the Lower Pecos, isolating it as part of the great uninhabitable desert of their northern frontier, but native peoples found refuge in the rugged terrain. Indigenous groups were soon replaced by Apaches who, in turn, were driven south by the Comanches where they sometimes joined the Kickapoos, staunch allies of the Mexicans, in resisting their common enemy. Under American hegemony, a concerted effort to clear the way west resulted in the extirpation of native people by the time the second transcontinental railroad was completed in 1882.
Oxalate accretions of whewellite (CaC2O4.H 2O) and weddellite (CaC2O4.(2+x)H2O, x ≤ 0.5) have been found by Raman microscopy on Post-Palaeolithic rock paintings from open-air rock shelters of Triassic sandstone in the Sierra de las Cuerdas (Cuenca, Spain). Scanning electron microscopy (SEM) of these accretions suggests that they could have been produced by colonies of lichens that lived on the rock surface. Raman and petrologic microscopy of samples from a painting panel has revealed the nature and distribution of the components: α-quartz, haematite, whewellite, gypsum, muscovite, microcline, anatase and rutile. Energy-dispersive X-ray (EDX) spectroscopy confirms these results. The observed microstratigraphic oxalate layers are very helpful for archaeological studies. The pigment, haematite, is located between two of them and some superimposition of pictographs or repainting processes have been detected. The observed oxalate layers protect these works of art, prevent weathering and have been used for the first AMS 14C dating of Post-Palaeolithic rock art in Spain.
A Pecos River style painting of a black deer at from Black Cave Annex (41VV76a) in southwest Texas was radiocarbon dated. Using plasma oxidation and accelerator mass spectrometry, we obtained an conventional age of 1465 ± 40 year B.P.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.
Rock art in an inland cave on the island of Lifou, New Caledonia, has been radiocarbon dated. A cluster of early paintings date to 2500 years ago, soon after the arrival of the first settlers, who must have quickly gone inland probably in pursuit of fresh water, available near the cave. They left their mark on the cave in the form of numerous hand stencils. During the first millennium AD, later generations of artists used the same cave, drawing birds and a circular sign for water still recognised by the present community.
The nature, origin and age of some thick multi-layered oxalate-rich crusts from quartz-rich rocks in Australia are presented, with a view to alerting restorers and conservators to their value in palaeo-environmental and rock art dating studies. Mineralogical and geochemical data, together with field observations and evidence from cross-section analysis, suggest that these deposits are formed naturally by chemical reaction of organic acids in rainwater acting on calcium-rich dust particles which have accreted on stable siliceous rock ledges and other sheltered surfaces. Carbon-14 dating of the oxalate mineral, whewellite, found in the surface crusts ranges from modern to 8800 years BP: evidence that the natural processes which form oxalate-rich surface deposits have been continuous for many thousands of years. Such dating of oxalate layers provides a means for establishing time-frames in which different prehistoric painting styles can be fixed; the method does not give a direct age for individual artistic motifs.
A whewellite-rich rock crust covers vast areas of limestone inside dry rock shelters and under rock overhangs throughout the Lower Pecos Region in southwestern Texas (USA). The natural rock crust, composed primarily of whewellite and gypsum with lesser amounts of quartz and silicates, encapsulates the paints of the extraordinary pictographs at more than 250 rock art sites in the region. The authors propose a model that describes the origin of each crust constituent and the evolution of these surfaces. Furthermore, they describe the relationship between the ancient paints and crust matrices, information that is necessary for the development of sound conservation strategies.
Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world.
Chemical analyses of prehistoric rock paints from the Lower Pecos Region of southwestern Texas were undertaken using laser ablation-inductively coupled plasma-mass spectrometry. This technique allowed us to measure the chemical composition of the paint pigments with minimal interference from a natural rock coating that completely covers the ancient paints. We also analyzed samples representing potential sources of paint pigments, including iron-rich sandstones and quartzite from the study area and ten ochre samples from Arizona. Cluster analysis, principle component analysis and bivariate plots were used to compare the chemical compositions of the paint and pigment sources. The results indicate that limonite extracted from the sandstone was the most likely source for some of the pigments, while ochre was probably used as well.
Oxalate is a key metabolite that plays a significant role in many metal and mineral transformations mediated by fungi. Metal and mineral transformations are central to geomycological processes including nutrient and element cycling, rock, mineral and metal transformations, bioweathering and mycogenic biomineral formation. Some fungal transformations have potential applications in environmental biotechnology, e.g. metal and radionuclide leaching, biorecovery, detoxification and bioremediation, and in the production or deposition of biominerals or metallic elements with catalytic or other properties. Metal and mineral transformations may also result in adverse effects when these processes result in biodeterioration of natural and synthetic materials, rock and mineral-based building materials (e.g. concrete), biocorrosion of metals, alloys and related substances, and adverse effects on radionuclide speciation, mobility and containment. Oxalate is ubiquitous in all these contexts. This paper seeks to draw together salient information from environmental and applied research to emphasize the importance of oxalate in geomycology, biodeterioration, environmental biotechnology and bioremediation.
Cueva la Conga, recorded in June 2006, is the first limestone cave in Nicaragua reported to contain prehistoric rock paintings, culturally modified natural formations called speleothems, and artifacts. Located in northcentral Nicaragua in the Department of Jinotega, Cueva la Conga is
the farthest south on the Mesoamerican periphery that a cave of this type has been reported, and it extends our knowledge of ritual cave use, including cave painting and speleothem modification, to include Nicaragua. Radiocarbon analysis of charcoal in five samples of the paint, the first
such dating of Nicaraguan rock art, yielded calibrated dates from cal A.D. 680-905 to cal A.D. 1403-1640. The baseline data provided by Cueva la Conga are of great importance for regional rock art analysis and for our growing understanding of regional and Nicaraguan prehistory. More archaeological
survey and excavations in the area will be key in establishing a firm cultural context for the rock art and ritual cave use found at Cueva la Conga.
Abstract. The Wadeye - Fitzmaurice region is in the northwest of the Top End of Australia’s Northern Territory. It lies between two major geographical and cultural regions of northern Australia, the Kimberley to the southwest and Arnhem Land to the northeast. Its location suggests that it has potential to address questions concerning relationships between the two, but it has been little researched archaeologically. In collaboration with Traditional Owners of the area, we undertook a survey of cultural places of much of the region, concentrating on areas in the centre and south and along the Fitzmaurice River. The initial results from the recording of rock paintings suggest presence of cultural ties with areas to the south and west. Results of direct dating of surface accretions allow identification of a sequence of painting styles changing over time from about five thousand years ago. The most recent representations were painted within the last century. The earliest images are distinctive mulberry-red representations of anthropomorphs with resonances to similar styles described for the Kimberley and Keep River. The similar antiquity of this style of painting in all three regions tends to confirm cultural connectedness over a wide area during that period.
[ Full text is available at: www.ifrao.com/wp-content/uploads/2014/08/27-2-WatchmanAgra.pdf
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.
The likely sources of iron-oxide pigments used in prehistoric rock paintings in the Lower Pecos Archaeological Region were identified on the basis of chemical fingerprinting using LA–ICP–MS. The chemical signatures of 13 red rock paint samples collected from two south-west Texas sites were compared with three potential source materials (ochre, siltstone and rhyolite), and two pigment cakes (crayons) that were excavated near the sampling sites. The significant chemical similarities between the paint and siltstones suggest that siltstone was used as the source of the colour. The overlapping chemical signatures for one of the pigment cakes and siltstone further suggests that some of the prehistoric people inhabiting the area 3000–4000 years ago had acquired the skills to extract iron oxide from siltstone and process it into paint pigments.
U/Th data obtained on CaCO3 layers covering rock art at Nerja Cave (Spain) evidence erroneous ages and an inverse relation between uranium concentration and apparent ages. This open system behavior could be due to a mechanism causing uranium mobility, resulting in apparent ages being too old with respect to their real age. This article also questions recently published U/Th data on samples from Ardales, Maltravieso and La Pasiega caves (Spain) where a few U/Th ages older than 40 ka BP, suggested that cave art could be attributed to Middle Palaeolithic population (Hoffmann et al., 2018). For these caves, U/Th data also display an inverse relation between U content and ages, indicating possible uranium mobility and erroneous ages.
This paper reports on the development of radiocarbon dating of mud wasp nests to provide age estimates for rock art and other anthropogenic modifications to the surfaces of open rock shelters.
Over 150 rock shelters in the remote Kimberley region of Western Australia were visited in five field seasons. Mud wasp nest samples were collected from 108 sites. Thirty newly constructed wasp nests were collected to understand their initial composition and to determine the major sources of carbon. Charcoal-rich fractions extracted from 9 modern nests were radiocarbon dated and, whilst most were of zero age, some were found to be up to 1000 years old with the mean age being 255 years.
Of the old wasp nest samples, 120 were utilised in the experiments reported here. A variety of different physical and chemical pretreatment methods were explored but small sample sizes and low carbon concentrations limit the range of techniques that can be used in practice. The radiocarbon ages measured on the 75 nest samples that contained sufficient carbon for analysis ranged from Modern to just over 20 cal ka BP. Half of these nests were older than 8 cal ka BP and 20% were older than 11 cal ka BP. Even allowing for the inherent uncertainties due to any inbuilt carbon age, the method is capable of producing useful age estimates for rock art and other features of archaeological interest, in relatively open rock shelters.
Petro-mineralogical, micro-chemical and isotopic (δ³⁴S-CaSO4 and ¹⁴C dating) analyses were carried out in selected samples from the rock paintings of Nyero (Upper Lake Victoria Region, Uganda) aiming to characterize for the first time both the composition of the red and white pigments of the drawings (mainly representing concentric circles, and shapes resembling vegetables, boats and other stylized forms) and determine their age. The rock panels were classified as metamorphic rocks (gneiss), containing quartz, plagioclase, orthoclase, microcline and muscovite. Such minerals were also found in the paints, though the red drawings also showed the presence of Fe-oxides, which were practically absent in the white ones where kaolinite was recognized. A consistent amount of Ca-oxalates was found to be well distributed through the white and red pigments, suggesting its origin in the organic binder used to properly spread the pigments onto the rock panels. Thus, the ¹⁴C ages on the Ca-oxalates are to be considered as the age of the paint. The 68% probability time intervals of calibrated ages for the white and red pigments were in cal 2880–2280 BCE and 1390–1010, respectively, demonstrating >1000 years time gap between them. This difference was also pronounced in motifs of complexity. The red drawings (attributable to settled or semi-settled societies) are richer in styles, forms and patterns than the white ones, the latter being likely related to a nomadic population as also suggested by the simpler drawing techniques. Our results have important implications for integrating semiotics and anthropologic studies, to delimit the boundaries of a homogeneous cultural area and shedding new light on human settlement dynamics and change from nomadic lifestyle to settling during the Late Stone Age in East Africa.
This study represents the first positive identification of plant gum binding media in pre-Columbian art, and the first dates from indigenous cave art in the Caribbean. Mona Island reveals an extensive and well-preserved pre-Columbian and early colonial subterranean cultural landscape with dense concentrations of newly-discovered cave art in up to 30 caves. A multi-method approach to the research of pigments and binding media, charcoal, and cave sediments was used to elucidate the technologies, chronologies and processes of indigenous art and artists. Analyses included on-site use of a portable X-ray fluorescence (P-XRF) device to inform sample selection, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) on paint and charcoal samples, polarized light microscopy (PLM) for material characterizations, and gas chromatography - mass spectrometry (GC-MS) and X-ray diffraction (XRD) for detailed chemical analysis of paint structures and composition. In addition direct dates of cave art using radiocarbon (C14) and Uranium-thorium (U-Th) dating methods are discussed. Results demonstrate multiple centuries of cave use during indigenous occupation and multiple phases and techniques of mark-making in dark zone locations within extensive cave systems. Visitors set out on pre-meditated journeys underground, making rock art using pigments from the cave floors, which they mixed into complex paints with the addition of plant gums from outside. This study is the first of its kind in the Caribbean providing insight into native paint recipes, material choices, and mark-making techniques. The methods have scope for widespread application and advance the integration of cave art research in archaeology.
A landmark in the study of rock art, this extensively illustrated volume reveals that prehistoric hunter-gatherers in southwest Texas painted one of the earliest known pictorial creation narratives in North America.
The Grotte Cosquer (southeastern France) is a Paleolithic painted cave only accessible by a deep-water dive. The cave has yielded numerous Paleolithic engravings and drawings, which were produced from wood charcoal. This article presents new radiocarbon dates obtained on samples collected in 2012 directly on 17 parietal representations and at the soil surface, and discusses the ¹⁴ C results obtained since the discovery of the cave in 1992. A total of 41 samples were dated with ages ranging from 33,000 to 20,000 cal BP. They show that the cave was intermittently decorated over about 10,000 yr.
If radiocarbon measurements are to be used at all for chronological purposes, we have to use statistical methods for calibration. The most widely used method of calibration can be seen as a simple application of Bayesian statistics, which uses both the information from the new measurement and information from the 14 C calibration curve. In most dating applications, however, we have larger numbers of 14 C measurements and we wish to relate those to events in the past. Bayesian statistics provides a coherent framework in which such analysis can be performed and is becoming a core element in many 14 C dating projects. This article gives an overview of the main model components used in chronological analysis, their mathematical formulation, and examples of how such analyses can be performed using the latest version of the OxCal software (v4). Many such models can be put together, in a modular fashion, from simple elements, with defined constraints and groupings. In other cases, the commonly used “uniform phase” models might not be appropriate, and ramped, exponential, or normal distributions of events might be more useful. When considering analyses of these kinds, it is useful to be able run simulations on synthetic data. Methods for performing such tests are discussed here along with other methods of diagnosing possible problems with statistical models of this kind.
U-series dating is a precise and accurate geochronological tool which is widely applied to date secondary CaCO3 formation, for example in speleothem based palaeoclimate research. It can also be employed to provide chronological constraints for archaeological sites which have a stratigraphic relationship with speleothem formations. We present in detail our methods to conduct precise and accurate U-Th dating of calcite crusts that formed on top of cave paintings. Our protocols allow the application of U-series measurements on small, thin calcite crusts covering cave art, which can be found in many sites, while taking care not to harm the art underneath. The method provides minimum ages for the covered art and, where possible, also maximum ages by dating the flowstone layer the art is painted on. We present dating results for crusts from two locality types in Spain, a typical cave environment (La Pasiega) and a more open, rock shelter type cave (Fuente del Trucho).
The rock-art of the Pecos River region, on the Texas-Mexico border, is deservedly celebrated for its very large and inspiring human depictions, convincingly interpreted as images of shamanism. Study of plant remains in associated middens gives a new aspect to understanding of the images.
The question of when the first humans arrived in the New World has been a bone of contention for several decades. Similarly, the age of rock paintings has been heatedly debated. Settlements in the Serra da Capivara National Park have been dated to between 5 kyr and >50 kyr, which is far older than the Clovis barrier. Moreover, calcite formation on a rock-wall painting in a rockshelter yielded thermoluminescence (TL) and electron paramagnetic resonance (EPR) ages older than 35 kyr BP (Watanabe et al. 2003). In an attempt to contribute to this ongoing debate, we have studied calcite deposits covering prehistoric paintings from several rockshelters (Toca da Bastiana, Toca do Serrote de Moendas, and Toca da Gameleirinha [Pedra pintada]). Coupled AMS (accelerator mass spectrometry) 14C and MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) 230Th/U dating was performed in Toca da Gameleirinha. The ages obtained for these calcites are younger than 12 kyr and suggest that the paintings could be more recent than proposed by previous studies.
DOI: 10.2458/azu_js_rc.55.16254
Oxalate films observed on stone monument surfaces deserve greater interest because of their possible role in protecting against deterioration. Their origin remains controversial. We present here the results of research conducted on production of oxalic acid and other organic acids by bacterial communities isolated from two monuments. Both communities were developed in vitro, and oxalate production was evaluated in a context of global metabolic activities that could eventually lead to protection or to degradation of the surface itself. HPLC analyses of organic acids production revealed that all mixed cultures produced oxalic acid but in different amounts. Besides oxalic acid, other organic acids are released that can solubilize stone calcium carbonate and have a deteriorating activity. Calcium carbonate solubilization, evaluated both by mixed cultures and isolated strains, was stronger with mixed cultures than with single strains. Our data show that oxalate production is promoted by the bacterial communities inhabiting the monument surface: Oxalate, being a minor representative among the organic acids released by the microbe cultures in a relatively short-term analysis, could form insoluble calcium salts that progressively accumulate.
Radiocarbon age determinations are presented on three hieroglyphic texts from Naj Tunich cave in Guatemala containing Maya calendar dates. The ages obtained are on average 110-140 years older than the calendar dates. Several possible reasons are discussed for this discrepancy: one that is applicable to all radiocarbon dates on charcoal, one that applies to rock paintings, and one that is specific for the tropics. Possible problems with the ages ascribed to the Maya calendar dates are also discussed. Even with the potential problems that may exist, these dates still fall within 110-140 years of the ascribed calendar dates. Caution is urged in the interpretation of dates on charcoal pigments from rock paintings; consideration of the "old wood" and "old charcoal" factors is important.
