Rock-art image in Fern Cave, Lava Beds National Monument, California: Not the AD 1054 (Crab Nebula) supernova
Description: The visual manifestation of the recent Hale-Bopp comet reminds us how telling 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. […]
Radiocarbon Dating of Ancient Rock Paintings
Description: 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 the ages expected on the basis of archaeological inference. […]
Dating Pictographs with Radiocarbon
Description: 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 the ages expected on the basis of archaeological inference. We […]
Radiocarbon Dates on the All American Man Pictograph
Description: 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 […]
Radiocarbon date for a red linear style pictograph
Description: A single date for a painting should not be used to define a chronology or timeline for an entire rock art style. Two of the dated images are labeled as unclassified. but have previously been categorized as Red Linear and Red Monochrome styles (Ilger et al., 1994). At Cueva Quebrada (41VV162a), the one experimental […]
Release of uranium from granitic rocks during in situ weathering and initial erosion (central Texas)
Description: 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 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 […]
Effect of magnetic field on reduction of nickel oxide
Description: 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 […]
Algebraic-eikonal approach to the electron-molecule-collision process: Vibrational excitation and quadrupole interaction
The vibrational excitation mechanism has been included in the algebraic-eikonal approach to the electron-polar-molecule collision process. A dipole operator that can induce vibrational transitions has been used, and a technique for the evaluation of the matrix elements required for the calculation of the scattering amplitude in the Glauber approximation has been developed. In addition to […]
