... Oerald F. Wieczorek1 , William M. Brown 1112 , Robert K.Mark2 Pat Rice2 and Christopher S. Al... more ... Oerald F. Wieczorek1 , William M. Brown 1112 , Robert K.Mark2 Pat Rice2 and Christopher S. Alge.-3 ... Brabb, EE, 1980, Preliminary geologic map of the La Honda and San Gregorio quadrangles, San Mateo County, California: US Geological Survey Open-File Report 80-245 ...
Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced local... more Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1·9-6·2 ppm) and
Eos, Transactions American Geophysical Union, 1986
A colored slope map (scale 1:80,000,000) was generated from digital land and sea floor elevations... more A colored slope map (scale 1:80,000,000) was generated from digital land and sea floor elevations at 5‐min spacings from data tapes from the National Geophysical Data Center. Slope analysis is facilitated by examining the average slope in 250‐m altitude‐depth intervals both globally and in each of eight tectonic plates. The most striking feature of the map is the multiple parallel bands of steep slope at subduction zones. Submarine volcanic chains produce zones of steep slope that show little degradation at the scale of the map since the Cretaceous. The average slope, or roughness, of spreading ridges decreases exponentially with increasing spreading rate. The passive continental margins generate a steep zone at 1–2 km depth. The lowest average global slope (0.2°) occurs at sea level and reflects the base level that the sea provides for subaerial erosion and the upper limit for marine sedimentation. Slope minima also are caused by the abyssal plains at 4–6 km depth and by glacial ice caps at 3 km elevation.
Page 1. A fan dam for Tulare Lake, California, and implications for the Wisconsin glacial history... more Page 1. A fan dam for Tulare Lake, California, and implications for the Wisconsin glacial history of the Sierra Nevada BRIAN F. ATWATER US Geological Survey at Department of Geological Sciences, University of Washington ...
Stoev and Stoytchev (1992) identify circular rock carvings near Bailovo, Bulgaria as lunar calend... more Stoev and Stoytchev (1992) identify circular rock carvings near Bailovo, Bulgaria as lunar calendars or observatories. Based on their photographs, we observe that strikingly similar sites in California and elsewhere have been identified as known or probably soft-stone quarry sites (Schumacher, 1879; Heizer, 1954; Meighan and Johnson, 1957; Wlodarski, 1979; Mark, Newman & Rogers, 1990). The materials quarried include steatite (soapstone), chlorite-glaucophane blueschist, and greenstone, all relatively soft rock and capable of being worked with flint or other hard stone tools. The best-known sites, in ethnographic Chumcash territory on Santa Catalina Island, California (Figures 1 and 2), were still being used to quarry bowls or jars, and other utilitarian and ritual objects when the Spanish arrived. CA-SBn-12, a petroglyph site in San Benito County, California, is also thought to have been used as a quarry site (Mark et al., 1990) (Figure 3). Meighan and Johnson (1957) report that “St...
A method for mapping hazard posed by debris flows has been developed and applied to an area near ... more A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree of hazard over the area.
... Oerald F. Wieczorek1 , William M. Brown 1112 , Robert K.Mark2 Pat Rice2 and Christopher S. Al... more ... Oerald F. Wieczorek1 , William M. Brown 1112 , Robert K.Mark2 Pat Rice2 and Christopher S. Alge.-3 ... Brabb, EE, 1980, Preliminary geologic map of the La Honda and San Gregorio quadrangles, San Mateo County, California: US Geological Survey Open-File Report 80-245 ...
Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced local... more Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1·9-6·2 ppm) and
Eos, Transactions American Geophysical Union, 1986
A colored slope map (scale 1:80,000,000) was generated from digital land and sea floor elevations... more A colored slope map (scale 1:80,000,000) was generated from digital land and sea floor elevations at 5‐min spacings from data tapes from the National Geophysical Data Center. Slope analysis is facilitated by examining the average slope in 250‐m altitude‐depth intervals both globally and in each of eight tectonic plates. The most striking feature of the map is the multiple parallel bands of steep slope at subduction zones. Submarine volcanic chains produce zones of steep slope that show little degradation at the scale of the map since the Cretaceous. The average slope, or roughness, of spreading ridges decreases exponentially with increasing spreading rate. The passive continental margins generate a steep zone at 1–2 km depth. The lowest average global slope (0.2°) occurs at sea level and reflects the base level that the sea provides for subaerial erosion and the upper limit for marine sedimentation. Slope minima also are caused by the abyssal plains at 4–6 km depth and by glacial ice caps at 3 km elevation.
Page 1. A fan dam for Tulare Lake, California, and implications for the Wisconsin glacial history... more Page 1. A fan dam for Tulare Lake, California, and implications for the Wisconsin glacial history of the Sierra Nevada BRIAN F. ATWATER US Geological Survey at Department of Geological Sciences, University of Washington ...
Stoev and Stoytchev (1992) identify circular rock carvings near Bailovo, Bulgaria as lunar calend... more Stoev and Stoytchev (1992) identify circular rock carvings near Bailovo, Bulgaria as lunar calendars or observatories. Based on their photographs, we observe that strikingly similar sites in California and elsewhere have been identified as known or probably soft-stone quarry sites (Schumacher, 1879; Heizer, 1954; Meighan and Johnson, 1957; Wlodarski, 1979; Mark, Newman & Rogers, 1990). The materials quarried include steatite (soapstone), chlorite-glaucophane blueschist, and greenstone, all relatively soft rock and capable of being worked with flint or other hard stone tools. The best-known sites, in ethnographic Chumcash territory on Santa Catalina Island, California (Figures 1 and 2), were still being used to quarry bowls or jars, and other utilitarian and ritual objects when the Spanish arrived. CA-SBn-12, a petroglyph site in San Benito County, California, is also thought to have been used as a quarry site (Mark et al., 1990) (Figure 3). Meighan and Johnson (1957) report that “St...
A method for mapping hazard posed by debris flows has been developed and applied to an area near ... more A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree of hazard over the area.
Issue editor Aaron M. Wright, renowned rock art scholar Polly Schaafsma, and authors on the cutti... more Issue editor Aaron M. Wright, renowned rock art scholar Polly Schaafsma, and authors on the cutting edge of rock art research consider rock art within the physical and social contexts of its makers’ lives.
Volunteers and federal agencies are combining their efforts to locate and investigate rock art si... more Volunteers and federal agencies are combining their efforts to locate and investigate rock art sites, mainly pictographs, found in the southern portion of the Guadalupe Ranger District, Lincoln National Forest, and upon lands administered by the Bureau of Land Management, Carlsbad Field Office. Abstract symbols from low elevation sites on the east side of the Guadalupe range are similar to those found in mountain sites while representative fineline hunting scenes appear to be mainly confined to the Guadalupe Mountains themselves. Comparable fine line rock art appears in canyon settings in southwest Texas. Dating the fine line rock art is difficult because of the absence of associated artifacts and archaeological deposits and because of a general Archaic lifeway that continued into the historic period. Direct absolute dating of the rock art sites will greatly strengthen arguments that identify and separate pictographs into age-related components or styles. In mixed component rock art sites, x-ray fluorescence (XRF) may assist in separating and confirming element assignment. Digital enhancement photography of a panel from the BLM's Richard Brown Shelter (A.D. 1000-1250) has allowed preliminary comparison of that panel to undated Site LA 71921. One terminal Archaic rock art style (the Red Linear Style, defined in the lower Pecos River in Texas) has been identified as similar to elements at several sites in the Guadalupe Mountains (Mark and Billo, 2010, in press). Other styles proposed by Bilbo and Bilbo (1991) can possibly be resolved through absolute dating. Finally, pictographs are providing richer detail of prehistoric hunting techniques than was previously available.
San Diego Rock Art Research Association Symposium, 2020
Hueco Tanks State Park and Historic Site 28 (Figure 1) was “discovered” in 1969 and since then vi... more Hueco Tanks State Park and Historic Site 28 (Figure 1) was “discovered” in 1969 and since then visitors and researchers have photographed and described this site numerous times. The large goggle-eyed figure has long been described as wearing “clouds” as a headdress. Using dStretch, 3D modeling and other photo enhancement techniques, new details have been revealed. Known for the large “cloud headed” goggle-eye, there are other goggle-eyes in this shelter. Tracing photos that use the new techniques clarifies detail for this panel. While showing enhanced imagery from site 28, we will also show examples of similar images from other Hueco Tanks sites. These suggest similar details might be revealed at other sites.
Early rock art research indicated that there were few “horizontal bedrock” rock art sites in Sout... more Early rock art research indicated that there were few “horizontal bedrock” rock art sites in Southern New Mexico and far West Texas. These sites are often difficult to see and are easily missed in survey work. Recent research and survey work has documented a growing number of these sites on the etched limestone and sandstone of the desert slopes and basins. The use of photogrammetry makes it easier to document these sites and provide good images for analysis. Like the remnants of subtle agricultural features and puddled adobe ruins these subtle rock art sites give us insight into the culture of the Archaic and Jornada Cultures in Southern New Mexico and West Texas. This presentation will document a few of these and list some research possibilities.
Investigating Rock Art at Four Sites South of Winslow, AZ, 2020
NA 11,910 NA 11,911 NA 11,915 New Site Two photogrammetric models, each followed by a derivitive ... more NA 11,910 NA 11,911 NA 11,915 New Site Two photogrammetric models, each followed by a derivitive product. Photogrammetric Model and Enhancement We became aware of three MNA numbered sites in a canyon south of Winslow that contain rock art (two with pictographs, all three with petroglyphs). The site cards by Fred Briuer in 1972 have only a few details about the rock art, so we decided to update the records. In addition to relocating the sites, we found a new pictograph site near NA 11,911. This poster shows some of the work in progress such as completed 3D photogrammetric models and image enhancement results. Site NA 11,915 contains over 100 monochrome pictographs created with black, green, and five shades of red paint. Several fine-line red picto-graphs were drawn using dry pigment. Common petroglyphs include complex geometric designs, grooves, cupules, and some human and animal depictions. We are not aware of similar painted sites in the area.
In the shadow of Cooke's Peak there are numerous petroglyph sites. One that has always intrigued ... more In the shadow of Cooke's Peak there are numerous petroglyph sites. One that has always intrigued me is on an outcrop of bedrock along one of the intermittent arroyos in that area. The images flow over the bedrock outcrop and around the undulating surface of the rock. Still photos of the site do not do justice to this fluidity, nor do they show the relationships between the individual elements. Included in the rock art elements are four mortars and nine cupules. This is one of the poorly documented rock art sites in the Mimbres Region. After a few visits made to take photographs for documentation, I decided the best way to document the site. Using 222 of my photos, Robert Mark of Rupestrian Cyber Services created a 3-D SketchFab model of this outcrop.
The Fort Stanton Petroglyph Rock has been documented in the past using various photographic and d... more The Fort Stanton Petroglyph Rock has been documented in the past using various photographic and drawing techniques. Recently I used a Structure from Motion (SfM) 3-D model to help take the guesswork out of my sketch work to create a more complete and accurate drawing.
Many of the petroglyphs in the Tularosa Basin and the surrounding area are easy to see and photograph due to the contrast between the dark patina and the original color of the rocks revealed when the indigenous people pecked through the desert varnish. But occasional researchers are confronted by difficult panels that were placed on rocks with little to no patina. Furthermore these are often softer surfaces which rapidly deteriorate.
Use of Radiance Scaling to Enhance Visibility of Petroglyphs in 3D Models, 2020
High quality Structure from Motion (SfM) 3D models can be used to enhance the visibility of petro... more High quality Structure from Motion (SfM) 3D models can be used to enhance the visibility of petroglyphs that are otherwise almost or completely invisible. The model must accurately capture the geometry of the rock surface. A colored curvature map, that is generated from the model's mesh using Meshlab Render Radiance Scaling and then is manipulated in Photoshop, can produce surprising results. Photoshop is used to blend (overlay, soft light, or hard light) the red or blue channel from the color curvature map with the original image or a shaded image that can also be generated in Radiance Scaling. Many rock art locations contain petroglyphs that are difficult to discern, such as those covered with lichen and/or moss. Sometimes color-based enhancement of images can help, but too often there is no useful color contrast available for those techniques to work. The method that is described here is based upon curvature mapping of photogrammetric models. It has proved to be helpful in revealing hidden glyphs. Figure 1 shows the results of the radiance scaling from a model of one side of a petroglyph boulder in Oregon that helps to see patterns and additional cupules.
When documenting rock art sites Rupestrian CyberServices (RCS) often utilizes many digital images... more When documenting rock art sites Rupestrian CyberServices (RCS) often utilizes many digital images taken from various perspectives to create high-quality Structure from Motion (SfM) 3D models. When these models accurately capture the geometry of the rock surface, they can be further processed using Meshlab Render Radiance Scaling and then Adobe Photoshop. Photoshop is used to blend (overlay, soft light, or hard light) the red or blue channel from the color curvature map with the original image or a shaded one that can also be generated in Radiance Scaling. The results enhance the visibility of petroglyphs that are otherwise difficult to see.
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Papers by Robert K Mark
Many of the petroglyphs in the Tularosa Basin and the surrounding area are easy to see and photograph due to the contrast between the dark patina and the original color of the rocks revealed when the indigenous people pecked through the desert varnish. But occasional researchers are confronted by difficult panels that were placed on rocks with little to no patina. Furthermore these are often softer surfaces which rapidly deteriorate.