Radiocarbon Dating of Ancient Rock Paintings
Texas A&M University College Station and Qatar A technique based on cold argon and oxygen plasmas permits radiocarbon dates to be obtained on paintings that contain
- contact@marvinrowe.xyz
The chemical environment of barium in Portland cement which is doped with barium nitrate was investigated using x‐ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FTIR). The barium doped cement showed tremendous increases in carbonate content over the undoped cement. An XPS sulfate signal was observed in the cement doped with 20% w/w Ba(NO3)2 but not in the 0 and 10% w/w doped cement. FTIR and XPS results lead us to believe that the barium exists as both BaSO4 and BaCO3 in the cement matrix.
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 wastewater generated during sheep wool processing poses serious environmental and economic concerns, as effective treatment is required to remove impurities prior to the discharge or recycling of water (Holkar et al., 2016;Poole and Cord-Ruwisch, 2004). Due to the detrimental impact of existing sheep wool processing techniques, the annual production of wool in the textile industry has reduced to 75% in European sheep farms . Therefore, scientists and environmentalists are seeking alternatives for conventional water-based treatment technologies in sheep wool processing.
The date C14, 9 th millenium BP, for the level that covers the Levantine figures described by Pericot in Cueva de la Cocina, Valencia (García Puchol et al. 2018: 265), may be added to what was obtained from the crust associated with a goat in motion in Ermites I rock-shelter, Tarragona, in the 10 th millenium BP (Viñas-Vallverdú et al. 2016) (Fig. 15). The preceding dates of the crust on the rock-shelter of Henarejos, Cuenca, and the archaeological context of the rock-shelter of l’Esplugón in Huesca, ensure that in the 7 th millennium BP, these naturalistic representations in progress continue to have effect Utrilla-Miranda et al. 2016). Keeping in mind the chronologies between the 13 th and 12 th BP of the levels of Dalmeri, that contain painted representations in motion, a period between the 13 th and the 8 th BP for Levantine art is acceptable
The team employed a combination of plasma oxidation and accelerator mass spectrometry, which has been used to date rock paintings worldwide (e.g., Russ et al., 1990; Steelman et al., 2005; Rowe, 2009). In contrast to traditional combustion methods, plasma oxidation occurs below the decomposition temperature of carbon-containing minerals such as carbonates and oxalates; therefore, their inclusion in the measured AMS graphite target is avoided for samples with a high mineral content (Russ et al., 1990 Thus, extensive acid washes used in conjunction with combustion are not necessary and can be avoided , minimizing the loss of organic material during wet chemical pre-treatment steps.
Dating rock art is one of the major challenges faced by archaeologists, and it is absolutely necessary to place the art in the cultural context (Steelman and Rowe 2012;Ochoa et al. 2021). Not without technical difficulties and strict protocols to be followed in order to minimize damaging the paintings, in Western European Palaeolithic caves, both French and Spanish researchers have focused on determining the age of spectacular rock paintings by dating charcoal pigments, obtaining more than a hundred dates so farOchoa et al. 2021). Standard procedures have been adopted for dating archaeological charcoal, using acid to remove carbonates and combustion to collect carbon for AMS 14 C dating. …
The chemical environment of barium in Portland cement which is doped with barium nitrate was investigated using x‐ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FTIR). The barium doped cement showed tremendous increases in carbonate content over the undoped cement. An XPS sulfate signal was observed in the cement doped with 20% w/w Ba(NO3)2 but not in the 0 and 10% w/w doped cement. FTIR and XPS results lead us to believe that the barium exists as both BaSO4 and BaCO3 in the cement matrix.
We extracted carbon from a sample removed from a small, non-descript, solid monochrome pictograph at Painted Indian Cave site on the Pedernales River, Blanco County, Texas (41BC1). It contains red iron oxide pigment and is approximately 10-20 cm in size. The sample was taken with a surgical scalpel with a new blade. Plasma-chemistry was utilized to extract the organic carbon, without getting contamination from inorganic carbon-bearing minerals, calcite and calcium oxalate. Because the background of organic carbon in nearby unpainted rock (limestone) was negligible, the age should be reliable. Further, it is supported by archaeological inference. However, as always with only a single radiocarbon date, especially with minimal carbon extracted, caution is advised pending further study. Radiocarbon analysis at the Center for Accelerator Mass Spectrometry of the Lawrence Livermore National Laboratory indicated an age of 770 ± 50 years BP. The age is consistent with the image of a bison within the small cave. The depiction of the bison probably corresponds with the earliest Late Prehistoric sightings of bison as they re-entered the south Plains of Texas in larger numbers.
Using plasma chemistry, carbon was extracted from charcoal paint samples collected from megalithic monuments in north-west Iberia. Nine accelerator mass spectrometric radiocarbon dates on these paints establish their age to be within 1000 14 C years of each other, centred at approximately 5000 BP. These radiocarbon ages for megalithic paintings fal…
In 2002, eight pigment samples were collected from three rock art sites in the Big Belt Mountains of west central Montana. Samples from Hellgate Gulch (24BW9), Avalanche Mouth (24BW19), and the Gates of the Mountains (24LC27) were dated using plasma-chemical extraction and accelerator mass spectrometry. The dates were statistically indistinguishable with ages of 1170 ± 45, 1225 ± 50, and 1280 ± 50 B.P. When calibrated, these ages range from 650 to 990 cal A.D. This corresponds to the early Late Prehistoric period on the Northwestern Plains. An oxalate accretion sample overlying a painted area at another site, Big Log Gulch (24LC1707), provided a minimum age of 1440 ± 45 B.P. for the rock art present at this site. The dated images at the four sites fit within the Foothills Abstract and Eastern Columbia Plateau rock art traditions.
Plasma oxidation was used to obtain radiocarbon dates on six different materials from a naturally mummified baby bundle from the Lower Pecos River region of southwest Texas. This bundle was selected because it was thought to represent a single event and would illustrate the accuracy and precision of the plasma oxidation method. Five of the material…
J Archaeol Sci 30 (2003) 351 reported extremely interesting dates on a calcite layer covering a pictograph at the Toca da Bastiana rock shelter within the Serra da Capivara National Park, Piaui, Brazil. Thermoluminescence and electron paramagnetic resonance ages indicate that humans were present in Brazil prior to 35 ky ago.
A glossy, black deposit covers much of the ceiling and walls of Little Lost River Cave No. 1, Idaho. This site is of particular interest because of the red, orange, and yellow pictographs underlying the coating. Carbon and nitrogen stable isotope analysis has allowed us to better understand the nature and origin of the deposit. With a δ13C value of −20·1‰, δ15N value of +14‰, and a C/N ratio of 5·6 after removal of inorganic carbon from the sample matrix, the deposit appears to have been derived from animal tissue, not plant. Plasma chemical extraction of carbon from the organic material in another sample of the deposit, followed by accelerator mass spectrometric analysis, yielded a minimum uncalibrated radiocarbon age of 2990±50 bp for the paintings. This preliminary evidence suggests that the deposit may be a cooking residue.
The purpose of this semester-long study was to investigate the effect of replacing traditional lecture with cooperative group problem-solving sessions in a junior-level quantitative analysis course. The control and treatment groups had the same instructor, met on the same day, had the same reading assignments, and had common exams. The instructor worked sample problems for the control group. In the treatment group, students were assigned to heterogeneous cooperative groups of 4. The groups solved problems presented on an overhead that were the same or equivalent in content and number to those used in the control group. Students were responsible for making sure that all members of the group could work each problem. The students’ reasoning abilities were measured by the Test of Logical Thinking (TOLT). Groups were compared on quiz, exam, final, and course grades. Other data included attitudinal surveys, observations, field notes, interviews, and open-response evaluations. No significant differences were found in content measures. Differences were found in the number of students dropping the course and in the attitudes and perceptions of the two groups. Qualitative measures support a number of assertions concerning more positive attitudes and lower withdrawal rates in the treatment group, and a case for mixed delivery modes. Keywords (Audience): Upper-Division Undergraduate
The use of plasma-chemical extraction in radiocarbon dating of rock paintings is discussed. Radiocarbon dating of rock art allows an inventory of images to be studied along with other cultural remains of a given archaeological time period. Assigning painted images to a particular prehistoric culture allows archaeologists to gain information on artistic, cultural, and religious aspects of a people. Most dates on pictographs worldwide have been accomplished through measuring radiocarbon in either charcoal pigments or beeswax, the latter occurring only in a limited area of Australia.
At the Toca do Serrote da Bastiana rock shelter in Brazil, a red, iron ochre pictograph of an anthropomorphic figure had become coated with a ‘calcite’ accretion over time. Using X-ray diffraction and Fourier transform infrared spectroscopy, we determined that the accretion also contains whewellite, the monohydrate of calcium oxalate, in addition
Early and recent work on Pu-Xe dating of achondrites (eucrites) is discussed here; the latter has focused on establishing the time of closure for Xe, not on the estimation of the time interval between the cessation of nucleosynthesis and the crystallization of solid bodies in our solar system. By using various Angra dos Reis dates as standard, the Xe closure of some eucrites were found to be early in the solar system, about 4.56 Gyr ago, synchronous within error with chondrites. The light cosmic ray produced Xe isotopes were found to be a good surrogate for the Nd content. Using the measured cosmic ray exposure age allows accurate closure times to be established. Combining this new information with data from CAIs and chondrules and chondrites suggests that the achondritic differentiation was accomplished within about 10 Myr or less. Pu-Xe dating in chondrites is not covered in this review.
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.
Indirect dating methods have previously been applied to the rock paintings of north Queensland, utilising patterns of superimposition, depictions of material items and animals of known antiquity, the use of fragile paints such as mud and white kaolinite, and in-situ pigment stratigraphies. These patterns suggest that the vast majority of Chillagoe rock paintings are relatively young, likely less than 3500 years old. We directly analysed radiocarbon in .the charcoal pigments in several of the Chillagoe rock paintings. Preliminary radiocarbon results at three sites confirm that these charcoal paintings are less than 3500 years old, as predicted. A change in the geographical distribution of rock art styles across north Queensland-from widespread non-figurative forms (as evident in surviving petroglyphs) to regionally distinctive motifs-suggests a regionalisation of artistic conventions starting around 3500 years B.P. Such a regionalisation implies that major cultural changes accompanied the changes in rock painting styles.
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.
This report presents four radiocarbon dates of charcoal pigments from Picture Cave, a site located in a remote wooded area in east-central Missouri. Carbon from charcoal pigments was extracted from three rock drawings on the wall of this cave. The four pigment samples contained sufficient carbon for accelerator mass spectrometric radiocarbon analysis. These black pigment samples (red and white paints are also present in the cave) yielded dates that place their affiliated motifs in a time-frame associated with Cahokia ca. 950 years ago. The dates are somewhat earlier than expected. We discuss the dates in connection with the iconography of the three motif panels tested.
A sample from a charcoal rock painting at the Arnold/Tainter Cave site (47Cr560) was radiocarbon dated, providing the first direct age determination for a pictograph in Wisconsin. The sample was pretreated with HCl and NaOH before organic carbon was extracted using an oxygen plasma. The painting, of a creature resembling a caribou because of the orientation of the tines on its antlers, is of interest because caribou have not been found in southwestern Wisconsin since the end of the Pleistocene. However, the accelerator mass spectrometry (AMS) radiocarbon age determination of 1260±60 BP is inconsistent with such a species identification. Another sample—from a painting of a deer—was also taken but did not yield enough carbon for radiocarbon measurement.
This article presents radiocarbon dates for painted motifs at Red Cliffs, west of Sedona in the northeastern corner of Yavapai County, Arizona. All rock painting shields at the Red Cliffs sites have usually been attributed to the Sinagua. Black pigment from one shield motif and an overlying white dot on another motif yielded uncalibrated radiocarbon dates of 1080 and 550 years B.P., respectively. The black pigment sample dates to a time when the region was extensively used. Assuming that the two shields were painted contemporaneously, the age of the white dot sample suggests that a later cultural group altered Sinagua paintings at Red Cliffs after the Sinagua abandoned the region. RESUMEN Este articulo presenta fechas del radiocarbon en adornos pintados en Red Cliffs, situadado al oeste del Sedona en la esquina del noreste del condado de Yavapai, Arizona. Todas los escudos pintados de la roca en sitios Red Cliffs se han asignados generalmente ai groupo cultural de Sinagua. Pigmento negro de un adorno de escudo, y un punto blanco sobre puesto en otro adorno, rendido las fechas sin calibrar del radiocarbon de 1080 y 550 años antepresente, respectivamente. La edad de la muestra de pigmento negra se conforma con una época en que había uso extenso de la región. La edad de la muestra del punto blanco sugiere que un groupo cultural altero a las pinturas de preexistencia en red cliffs despues del sinagua ahondaron la región, si se asume que los escudos fuero pintados contemporàneamente.
It has been 18 years since Andrée Rosenfeld suggested that the rock-art of north Queensland changed from non-figurative to mainly figurative forms some 5–4000 years ago. Her views were based on a small regional database and on indirect chronological evidence. This paper looks afresh at the antiquity of north Queensland’s rock-art by reviewing the existing evidence — much elaborated since Rosenfeld’s pioneering work — and by presenting new AMS radiocarbon results undertaken directly on rock-art. Her general chronological model is supported and refined by these new findings.
The visual manifestation of the recent Hale-Bopp comet reminds us how telling are those rare objects which suddenly flare in the sky. One can suppose ancient people living by natural light were more compellingly struck by the sight of comets and supernovae, and understandably researchers seek images of them in the shapes of rock-art motifs. An absolute dating contradicts that supposition in respect of a presumed image of the visible supernova of AD 1054.
We report here progress on our technique for 14C dating of pictographs. We use low-temperature oxygen plasmas coupled with high-vacuum technology to selectively remove carbon-containing material in the paints without contamination from inorganic carbon from rock substrates or accretions. Pictograph samples dated generally agree with ages expected on the basis of archaeological inference. We also used the technique on eight samples of known 14C activity. In each case our results agree with previously determined ages. Each of these determinations supports our conclusion that the technique has the potential of producing accurate and reliable ages. Four new 14C dates were obtained on a quartered Pecos River style pictograph sample (41VV75-37A-D). We used an idealized model to estimate a lower limit for the age of the pictograph 41VV75-37. The “age” itself should not be taken seriously as a meaningful limit as the measured age indicates that background organic material in the basal rocks and accretions can be a serious problem.
We report here progress on our technique for C-14 dating pictographs. We use low-temperature oxygen plasmas coupled with high-vacuum techniques to selectively remove carbon-containing material in the paints without contamination from rock substrates or accretions. We dated >16 pictograph samples that generally agree with ages expected on the basis of archaeological inference. We have shown that carbonate and calcium oxalate decomposition does not occur during our procedure; little mass fractionation is produced. We also used the technique on samples of known C-14 activity. in each case our results agree with previously determined ages of archaeological charcoal samples. Two samples of the standard Third International Radiocarbon Intercomparison wood yielded ages in near accord with the accepted value. We used C-14-free samples to establish that the method and apparatus do not have a significant live carbon background. Each of these determinations supports our conclusion that the technique has the potential of producing accurate and reliable ages. However, background organic material in the basal rocks and accretions can be troublesome, often completely negating the dates obtained.
Oxygen isotopic compositions have been determined for whole-rock and separated components from the CI chondrites Alais, Ivuna, and Orgueil, and from the atypical CM chondrites Bells and Essebi. The composition of CI matrix is in agreement with previous measurements and is systematically different from that of CM matrix, probably due to warmer and wetter conditions of aqueous alteration for CI matrix. Although Bells matrix is like that of other CM chondrites, the matrix of Essebi falls in the CI field. Essebi also contains abundant magnetite, like CIs and unlike other CMs. The isotopic compositions of magnetite in Alais, Ivuna, Orgueil and Essebi define a trend with Δ17O of +1.3 to +1.8, distinctly out of isotopic equilibrium with the phyllosilicates in each meteorite. The magnetite serves as an isotopic tracer for the fluid which brought about aqueous alteration and oxidation, and thus provides additional evidence for a gaseous reservoir in the solar nebula which was more 16O-depleted than the earth.
Controversy has surrounded the All American Man pictograph in southeast Utah since its discovery in the 1950s. Its coloration, similar to the flag of the United States of America, has led to questions regarding its authenticity. We have obtained two radiocarbon values on a single sample comprised of pigmented sandstone fragments from one small area of this pictograph. They suggest the pictograph dates to the fourteenth century and indicate that it is an authentic, prehistoric pictograph, probably Anasazi in origin.
DATING of prehistoric rock paintings (pictographs) has traditionally relied on indirect evidence. This includes inferences based on the archaeological context, such as superpositions of pictorial styles1 and the depiction of images that constrain their ages1,2, as well as dating of deposits that either cover the art in situ 3,4 or contain separated fragments of the painted surface5. Migration of ions between the bulk rock and the natural coatings that form on a newly exposed surface has also been exploited to date petroglyphs (rock carvings) in desert regions6–13. Until recently14–17, however, direct dating (by radiocarbon techniques) of pictographs has not been possible18,19, mainly because of the problem of separating inorganic carbon from the organic material in the pigments. Here we report on a new technique which allows this separation to be effected by using a low-temperature, low-pressure oxygen plasma to oxidize selectively the organic component; this may then be analysed using standard14C methods. We have applied this technique to a portion of a pictograph from the Lower Pecos region of southwest Texas (Fig. 1). The date obtained, 3,865±100 yr BP (before present) is consistent with that expected on the basis of archaeological inference20. As organic carbon is a ubiquitous component of pictograph paints, this technique should be applicable to rock paintings throughout the world.
The abundance, distribution and nature of occurrence of uranium in granitic rocks in central Texas, and that in soil profiles and local stream sediments derived from these rocks have been determined by fission-track mapping, delayed-neutron counting and gamma-ray spectrometry. Selected samples were also analyzed for Th and K. In the granites, U occurs primarily in weathering-resistant accessory minerals (here called resistate U) and along grain boundaries of major minerals, particularly biotite (here called intergranular U).During in situ weathering and initial erosion of the granite, changes in U concentration are controlled by the chemical mobility of intergranular U and dispersal of the resistate U. No distinct trend is detected in soil profiles except that, in general, a slight depletion of U is noted at the top of the profiles, which may be followed by a slightly enriched zone and another zone of depletion before approaching the original U content of the granite at depth. Neither organic matter nor clays (mostly kaolinite) appear to be effective fixing agents of U in this area. However, in briefly-transported granitic sediment, mostly sand and gravel, significant loss of both U and Th has occurred. In the 1-km distance studied, U abundance reflects almost entirely the concentration of resistate U. These results indicate that most, if not all, of the mobile, intergranular U is released from granites during in situ weathering and initial transport; in granitic sediments resistate U is likely the predominant form.The mineralogical occurrence of Th has not been determined, but the rate of Th loss in stream sediments is even greater than that of U. Th, leached from granite during weathering, may have become adsorbed on clays and dispersed with them.
Results of observations recorded during constant temperature reduction of NiO, a paramagnetic substance, to Ni, a ferromagnetic element, are presented. The application of a large magnetic field (4,200 oersted) does not result in an acceleration of the reduction rate. To explain earlier observations that 500- and 1,400-oersted magnetic fields increase the reduction rate of iron ore which contains hematite (Fe2O3), Peters (1973) had suggested that thermodynamics theory could predict the acceleration in reaction rate when product and reactant species differ widely in their magnetic properties.
Uranium-helium “ages” have been determined for a suite of 25 whole-rock basalts from Madeira and Porto Santo islands in the Madeira Archipelago. We include petrographic descriptions of these samples. Uranium measurements were by delayed-neutron activation analysis. Helium measurements were by isotopic dilution in an all-metal system characterized by very low argon and helium blanks. For 19 of the samples “preferred” KAr ages were also obtained. None of the rocks are concordant in these two ages; all have lost helium. The uranium-helium “ages” are best described, on the average, as equal to 74% of the KAr ages minus 0.2 m.y. Nevertheless in our suite of young, chemically similar lavas the correlation between the KAr age and the helium content is good enough to make the helium measurement worthwhile as a check on a possibly anomalous argon age, especially in a system where the additional labor required to make the helium is minimal. The Columbia River basalt from which standard samples BCR-1 and BCR-2 were prepared was also dated. Its uranium-thorium-helium “age”, 4.45 ± 0.24 m.y. shows that this rock has retained even less of its radiogenic helium (30%) than the island basalts.
Recientemente se obtuvo una fecha de radiocarbono de 3030 ± 45 14 C AP, de la pictografía roja conocida como Diablo Rojo, por medio de la utilización de extracción con plasma químico y espectrometría de aceleración de masas. Esta es la primera pictografía de las Tierras Altas que ha sido fechada directamente. En la actualidad, el Departamento de Química de la Universidad de Texas A&M está explorando otras aplicaciones de la química de plasma para la arqueología y la cronología de radiocarbono. Aquí se describe una técnica no destructiva para obtener fechas de radiocarbono en artefactos orgánicos perecederos. La oxidación con plasma es una alternativa muy atractiva para establecer la cronología de artefactos arqueológicos raros y preciosos, debido a que es un método no destructivo. Sin embargo, este método es ideal para muestras que poseen un alto contenido de oxalato de calcio. No se observa ningún cambio visible o alteración -aún en los materiales más frágiles -después de que estos han sido expuestos al plasma. Los resultados de la aplicación de la técnica de radiocarbono en artefactos previamente fechados y de algunos estándares, así como varios materiales de un evento particular inferido (un entierro naturalmente momificado de un infante, procedente de la cueva Hind en Texas), se emplearon para establecer la exactitud y precisión del método. Además, se emplearon diferentes pre-tratamientos, incluidos: 1) ningún tratamiento; 2) lavado con agua; 3) lavado con base, y 4) una secuencia de lavados ácido-base-ácido. En general, se determinó concordancia. Los resultados prometen demostrar que la oxidación con plasma podrá ser empleada para producir fechas de radiocarbono no destructivas, así como también hará posible establecer la cronología directa de ejemplares de pintura rupestre.
Examination of the isotopic composition of xenon from achondrites reveals that the124Xe, 126Xe, 128Xe and130Xe are all linearly correlated indicating only two principal components for these isotopes-trapped and cosmic ray produced xenon. No evidence is found for the reaction 127I(n, γβ)128Xe in the achondrites. We thus place approximate limits on the neutron flux relative to the flux in the Abee chondrite. A correlation in the plot of124Xe/130Xe versus129Xe/130Xe points to a129Xe/126Xe ratio of ≤ 0.84 in xenon from cosmic ray spallation and allows us to set a lower limit on the amount of radiogenic129Xe from the decay of extinct129I in the achondrites. The average value of ≳4.4 × 10−12 cm3/g excess129I for achondrites contrasts with typical values of ∼ 10−10 cm3/g for ordinary chondrites and ∼ 10−9 cm3/g for enstatite chondrites.
Rowe and Kuroda (1965) presented their measurement of the isotopic composition and abundance of xenon in a sample of the Pasa- monte meteorite in which fissiogenic xenon, pre- sumably from the spontaneous fission of ex- tinct Pu'”, was detected. The Pu’-Xedecay interval was found to be about 300 m.y. The data on a second sample of Pasamonte are re- ported here. The experimental procedure was essentially identical with that of Rowe and Kuroda and will not be discussed here. Table I compares the abundance and isotopic ratios of xenon from Pasamonte I (Rowe and Kuroda, 1965) with that from Pasamonte II (this paper). A, is defined here as
The distribution of rare earth elements was studied among component minerals in an ordinary chondrite, Bruderheim. For this purpose a wet fractional phase separation method was applied to a powdered sample of Bruderheim. Eleven members of this group of elements in the fractionated samples were determined mass-spectrometrically and by neutron activation, without individual chemical separation. Most of the elements were found to be concentrated in the phosphate fraction which was isolated mainly in EDTA solution. On the other hand, practically all of Eu and an important part of Yb were found in the HCl-insoluble silicate fraction. This result may indicate a lower oxidation level of the system in which the minerals were formed.
Texas A&M University College Station and Qatar A technique based on cold argon and oxygen plasmas permits radiocarbon dates to be obtained on paintings that contain
A sample from a charcoal rock painting at the Arnold/Tainter Cave site (47Cr560) was radiocarbon dated, providing the first direct age determination for a pictograph in
Archeological artifacts such as burial and embalmment materials are commonly dated by 14C labeling using accelerator mass spectrometry (AMS). The presence of contaminant organic matter can
Watanabe et al. [14] reported exciting thermoluminescence (TL) and electron paramagnetic resonance (EPR) dates on a calcite layer deposited over a red pictograph at the Toca
The chronology of open-air rock paintings in the Iberian Peninsula is still subject to scientific debate due to a paucity of direct radiocarbon dates. Rock paintings
The ceremonial and medicinal use of peyote (Lophophora Williams) by Native Americans in recent history has been described in numerous publications (e.g., [22,23]). We present new
THE TYPE 1 AND TYPE 2 carbonaceous chondrites (CI 1 and CM2) are among the most primitive meteorites, particularly in regard to their bulk chemical compositions,
The dating of rock art has been a major archaeological problem because, until recently, the art could not be directly dated, and clear associations with dateable
After completing the study of 134 rock art sites in the state, Diaz-Granados concluded that AMS radiocarbon dates were needed to place at least a selection
When an archaeological sample is radiocarbon dated, it typically undergoes three separate steps: (1) chemical pretreatment to remove contamination or isolation of sample-specific chemical compounds, (2)
Students often become disinterested in chemistry when the course involves only their passive note-taking (1). An increase in positive attitudes often results when there is a
The abundance, distribution, and nature of occurrence of uranium in granitic rocks in Central Texas and in soil profiles and local stream sediments derived from these
A glossy, black deposit covers much of the ceiling and walls of Little Lost River Cave No. 1, Idaho. This site is of particular interest because
It has been 18 years since Andrée Rosenfeld suggested that the rock art of north Queensland changed from non-figurative to mainly figurative form some 5-4000 years
Initial results from the analyses of geological and anthropological samples for amino acids were difficult to accept because of the high enantiomeric purities of the analytes
contact@marvinrowe.xyz
Copyright © 2023 marvinrowe.xyz