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.

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.

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

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Resumen Las cañadas de la parte baja del Rio Pecos en el suroeste de Texas y el norte de Palabras Clave: ARTE RUPESTRE, LOWER PECOS, 3-D LIDAR Abstract The Lower Pecos Canyonlands of southwest Texas and northern Mexico house some of the most complex and compositionally intricate prehistoric rock art in the