Ronald I Dorn
Datos Biográficos
| ID | 362816 |
|---|---|
| NOMBRE | Ronald I Dorn |
| NOMBRES | Ronald I |
| APELLIDO | Dorn |
| FIRMA | DORN R I |
| AFILIACIONES | Arizona State University |
| ORCID | 0000-0003-1343-4556 |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 36 |
| TOTAL DE CITAS | 210 |
| TOTAL COMO AUTOR | 36 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1983 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2026 |
| ÍNDICE H | 8 |
Problems of Dating Petroglyphs Using Measurements of Manganese Accumulation in Rock Varnish
Recent attempts at petroglyph dating have focused on measuring the manganese accumulation in the rock varnish coating that develops in a motif groove after it was engraved, under the assumption that this amount is systematically related to age. These efforts reflect the basic need for chronological control for both heritage management and research purposes. Despite the wide availability of portable X-ray fluorescence devices and their ability to …
Rock Varnish Dating, Surface Features and Archaeological Controversies in the North American Desert West
Archaeological surface features on desert pavements, including geoglyphs, are notoriously difficult to assess. Lacking temporally diagnostic artifacts, they may be impossible to place chronologically, limiting their inferential utility. Not surprisingly, controversies have developed in the North American desert west over certain of these features. We describe methods for chronometrically constraining the ages of desert pavement features using thr…
Threshold of Weathering Needed for Fire to Erode Rock Art
A Sonoran Desert petroglyph panel experienced an intense wildfire event in July 2021 that eroded the entire surface, removing the Hohokam-style rock art. Field observations during sampling in 1995 indicated that the panel: (1) was coated with a heavy rock varnish, (2) had a ‘fresh’ visual appearance, and (3) had some granite-derived sand (angular grus) at the panel’s base. Micron-scale back-scatter and nanoscale transmission electron microscopy o…
Protecting Stone Heritage in the Painted Desert
Located in northeastern Arizona (USA), Petrified Forest National Park (PEFO) presents a unique story of both geologic and human history. Though perhaps most well-known for its abundant petrified wood and being part of the Painted Desert, visitors are often surprised when they discover PEFO hosts many ancient petroglyph sites. Over the years, many attempts have been made to record the petroglyph sites, but nothing has been done to assess their geo…
Radiometric Dating/Techniques
Earth's natural surface formed from a mosaic of different geomorphic events over time. Thus, documenting the timing of different processes is a critical part of geomorphology. Accordingly, the last 60 years have seen a revolution in techniques used to date landforms. Geographers and other scientists have developed and refined dozens of different dating techniques. This entry presents some of the most common dating methods used by geographers and …
Weathering Processes and Landforms
Rock‐decay processes operating at the nanoscale and micron scale generate spectacular landforms that spike the curiosity of the general public and scholars alike. Tafoni holes in rock faces, meter‐thick slabs of granite from the release of pressure, tors consisting of granitic boulders that pile up as decayed granite sand erodes away, limestone tower remnants left behind as thick carbonate deposits dissolve in the humid tropics, and many other ba…
How Rivers Get Across Mountains
Although mountains represent a barrier to the flow of liquid water across our planet and an Earth of impenetrable mountains would have produced a very different geography, many rivers do cross mountain ranges. These transverse drainages cross mountains through one of four general mechanisms: antecedence—the river maintains its course during mountain building (orogeny); superimposition—a river erodes across buried bedrock atop erodible sediment or…
Advances in rapid condition assessments of rock art sites
Pace of Landscape Change and Pediment Development in the Northeastern Sonoran Desert, United States
Pediments of the Sonoran Desert in the United States have intrigued physical geographers and geomorphologists for nearly a century. These gently sloping bedrock landforms are a staple of the desert landscape that millions visit each year. Despite the long-lived scientific curiosity, an understanding of the processes operating on the pediment has remained elusive. In this study we revisit the extensive history of pediment research. We then apply g…
Le plus vieil art rupestre dans l’extrême ouest de l’Amérique du nord
Nous avons une série de 67 gravures rupestres datées par chronologie absolue, basée sur 106 analyses indépendantes provenant de la région du désert de Mojave en Californie, États‐Unis, dont une série de la Coso Range de renommée mondiale. Ces dates ont été obtenues en utilisant les techniques de datation par microlamination des patines (MLP) et par proportion de cations (PC). Nous avons pu évaluer cette suite de dates par recoupement, tests à l’a…
The Earliest Rock Art in Far Western North America
We have developed a suite of 67 chronometrically-dated rock engravings, based on 106 independent assays, from the Mojave Desert region of California, USA. These ages have recently been crosschecked, blind-tested, re-sampled and evaluated by two analysts using the VML and CR techniques. The most conservative interpretation, based on independently verified chronometric ages, is that the engraving sequence extends from 11,100 to 250 YBP; that is, fr…
The Rock Varnish Revolution
Rock varnish is a coating composed of clay minerals cemented to rock surfaces by oxides of manganese and iron. Although this dark brown-to-black accretion is most noticeable in arid regions, it occurs in all terrestrial weathering environments. Scholarly varnish research started with Alexander von Humboldt, when he asked how this external accretion forms and why manganese concentrations in varnish are 101-102 greater than in potential source mate…
Learning Desert Geomorphology Virtually versus in the Field
Statistical analyses of pre-test and post-test results, as well as qualitative insight obtained by essays, compared introductory physical geography college students who learned desert geomorphology only virtually, in the field and both ways. With the exception of establishing geographic context, the virtual field trip was statistically indistinguishable from real field trips in establishing basic knowledge about desert geomorphology. However, qua…
The Rock Art Stability Index
Analysis of burnt schist outcrops in the alps
Identification of the exact route followed by Hannibal during his invasion of Italia in the Second Punic War is one of the major questions of antiquity and one that historians/archaeologists have long studied. One of the many clues in the ancient literature that can help answer this question is the mention of fired rock, the result of a conflagration Hannibal is reputed to have employed to reduce the size of boulders in a blocking rockslide some …
The Integration of Literacy and Geography
To provide the first interstate quasi-experimental assessment on the power of content integration in building reading skills, the authors studied the effects on reading comprehension of GeoLiteracy—a K-8 package of 85 lessons that teaches geography in the context of practicing reading and writing skills. Ninety-six third through eighth grade teachers in Arizona and Michigan divided up into intervention and comparison groups. Intervention teachers…
A new strategy for analyzing the chronometry of constructed rock features in deserts
The western Great Basin contains thousands of constructed rock features, including rock rings, cairns, and alignments. Unlike subtractive geoglyphs, such as the Nasca Lines of Peru, that remove desert pavement, these surface features alter the location and positioning of cobble‐ to bouldersized rocks. The chronology of surface rock features has remained unconstrained by numerical ages because no prior chronometric approach has been able to yield …
The Geomorphic Evolution of the Yosemite Valley and Sierra Nevada Landscapes
Key Words: Yosemite Valleygeomorphologylandscapeevolutionsociology of science Additional informationNotes on contributorsRonald DornReviewed by
Sally's Rockshelter and the Archaeology of the Vision Quest
Quartz, the most common mineral on earth, is almost universally associated with shamans. Why this ritual association occurred worldwide has remained unexplained scientifically, at least in part because western scientific thinking assumes that religious beliefs and practices are epiphenomenal and not worthy of study. This association is archaeologi-cally evident at Sally's Rocksheiter, a small rock engraving-vision quest site in the Mojave Desert,…
Uncertainties in 14C ages for petroglyphs from the Olary province, South Australia
This report explains why previously published 14C dates for the Olary petroglyphs cannot be relied upon
Constraining the age of the Côa valley (Portugal) engravings with radiocarbon dating
Radiocarbon ages for the Côa petroglyphs are very similar to those obtained by Watchman (1995). Fundamental problems in the use of radiocarbon dating at Côa include evidence for the addition of younger carbon in an open system, and evidence of contamination from older sources of carbon. Radiocarbon measurements, therefore, cannot be used to decide whether the engravcings are or are not of Palaeolithic age
Understanding the Spatial Variability of Environmental Change in Drylands with Rock Varnish Microlaminations
A fundamental problem in the analysis of landforms and surface artifacts is how to correlate the ages of non-contiguous surfaces. One solution to this problem may lie within the varnish coatings on desert rocks. When viewed with a light microscope in ultra-thin cross-sections, rock varnish reveals orange and black layers that record drier and wetter climates, respectively. Consistent patterns of alternating orange and black microlaminae are evide…
Comment on "Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable," by Paul R. Bierman and Alan R. Gillespie
Comment on "Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable," by Paul R. Bierman and Alan R. Gillespie - Volume 43 Issue 2
AMS 14 C age constraints on geoglyphs in the lower colorado river region, arizona and california
Giant ground figures are widespread in the lower Colorado River area of southwestern North America, yet their chronology has remained unconstrained by numerical ages. Thirteen AMS 14 C measurements reported here indicate that geoglyphs were made from before ̃A. D. 1200 to before ̃900 B. C. We account for potential contamination from prior organics in weathering rinds. All other potential errors point to 14 C dates being minimum‐limiting ages for …
New Chronometric Dates for the Puquios of Nasca, Peru
Numeric age assessments of organic material encapsulated by rock varnish present on stone lintels of two "puquios" in the Nasca region of the south coast of Peru indicate a Precolumbian age. Accelerator mass spectrometry radiocarbon analyses at the Isotrace Laboratory revealed ages of cal A. D. 560(620)650 and cal A. D. 600(640)660 (1 sigma). These calibrated measurements are considered to be appropriate in the context of the archaeological settl…
New Perspectives on the Clovis vs. Pre-Clovis Controversy
We consider the Clovis vs. pre-Clovis debate from three perspectives: migration models; petroglyph and surface-artifact ages; and scientific method. First, we test the hypothesis that a Clovis migration can account for the temporal and spatial distribution of South American Paleoindian sites 'accepted' by Clovis-first advocates. Using a Clovis-first model, site ages are underpredicted by approximately 1,500 years, suggesting that the Clovis hypot…
New surface exposure ages for petroglyphs from the Olary Province, South Australia
Exposed surfaces of rock engravings in the Olary Province of South Australia develop coatings of rock varnish, amorphous silica, and oxalate‐rich crusts. Instead of relying on any single approach, we use three experimental approaches to assign minimum ages to the petroglyphs. Three methods involve dating manganiferous rock varnish formed over the petroglyphs: 14C measurements of organic matter at the varnish/weathering rind interface provides num…
New Approach to the Radiocarbon Dating of Rock Varnish, with Examples from Drylands
New electron microscope observations reveal that organic inclusions are often trapped in pockets under rock varnish. Accelerator radiocarbon dating of subvarnish organic detritus provides a new method of constraining when a rock was exposed by cultural or geomorphic processes. Applications are exemplified for human artifacts and landforms found in drylands. Three radiocarbon dates from 30,000 to 36,000 yr B.P. indicate rock engravings in South Au…
Rock art chronology in eastern California
Cation‐ratio dating has allowed us to obtain chronometric ages for 13 rock engravings from the Cima region, and an additional date from the Coso Range, eastern California, North America. These fourteen new dates, in combination with five previous dates from the Cosos and other lines of evidence, enable us to reassess the rock engraving chronology for eastern California. Rock engraving is indicated as beginning in the Late Pleistocene and continui…
Chronometric and Relative Age Determination of Petroglyphs in the Western United States
This paper presents chronometric age determinations of petroglyphs from the Coso Range and Cima volcanic field and relative dating from other locations in the western United States using the new rock varnish technique of cation-ratio dating. Our results verify the proposed Great Basin relative stylistic chronology, which indicates that curvilinear abstract was followed by rectilinear abstract and representational. However, these styles have great…
Sally's Rockshelter and the Archaeology of the Vision Quest
Quartz, the most common mineral on earth, is almost universally associated with shamans. Why this ritual association occurred worldwide has remained unexplained scientifically, at least in part because western scientific thinking assumes that religious beliefs and practices are epiphenomenal and not worthy of study. This association is archaeologi-cally evident at Sally's Rocksheiter, a small rock engraving-vision quest site in the Mojave Desert,…
Cation-ratio dating of rock-engravings from the Olary Province of arid South Australia
Desert varnish, the distinctive coating on exposed rock surfaces in arid regions, can be dated by cation ratios, providing a rare means directly to date petroglyphs. A first application of the method, much used in north America, is here reported from Australia, where it indicates minimum ages up to 30,000 years old. And it also shows that the style of figures, so often taken as a measure of chronology, is in this instance largely independent of a…
Uncertainties in 14C ages for petroglyphs from the Olary province, South Australia
This report explains why previously published 14C dates for the Olary petroglyphs cannot be relied upon
Constraining the age of the Côa valley (Portugal) engravings with radiocarbon dating
Radiocarbon ages for the Côa petroglyphs are very similar to those obtained by Watchman (1995). Fundamental problems in the use of radiocarbon dating at Côa include evidence for the addition of younger carbon in an open system, and evidence of contamination from older sources of carbon. Radiocarbon measurements, therefore, cannot be used to decide whether the engravcings are or are not of Palaeolithic age
Understanding the Spatial Variability of Environmental Change in Drylands with Rock Varnish Microlaminations
A fundamental problem in the analysis of landforms and surface artifacts is how to correlate the ages of non-contiguous surfaces. One solution to this problem may lie within the varnish coatings on desert rocks. When viewed with a light microscope in ultra-thin cross-sections, rock varnish reveals orange and black layers that record drier and wetter climates, respectively. Consistent patterns of alternating orange and black microlaminae are evide…
AMS Radiocarbon and Cation-Ratio Dating of Rock Art in the Bighorn Basin of Wyoming and Montana
Samples of organic matter and rock varnish from seven rock-art sites in the Bighorn Basin of Wyoming and Montana were collected for dating purposes. Petroglyphs sampled include Dinwoody-style figures, shield-bearing warriors, and other well-known Plains rock-art motifs. Accelerator mass spectrometry (AMS) dating of 10 petroglyphs yielded dates from the Early Archaic to the Protohistoric periods. A strong numerical relation between varnish leachin…
Learning Desert Geomorphology Virtually versus in the Field
Statistical analyses of pre-test and post-test results, as well as qualitative insight obtained by essays, compared introductory physical geography college students who learned desert geomorphology only virtually, in the field and both ways. With the exception of establishing geographic context, the virtual field trip was statistically indistinguishable from real field trips in establishing basic knowledge about desert geomorphology. However, qua…
New Chronometric Dates for the Puquios of Nasca, Peru
Numeric age assessments of organic material encapsulated by rock varnish present on stone lintels of two "puquios" in the Nasca region of the south coast of Peru indicate a Precolumbian age. Accelerator mass spectrometry radiocarbon analyses at the Isotrace Laboratory revealed ages of cal A. D. 560(620)650 and cal A. D. 600(640)660 (1 sigma). These calibrated measurements are considered to be appropriate in the context of the archaeological settl…
Analysis of burnt schist outcrops in the alps
Identification of the exact route followed by Hannibal during his invasion of Italia in the Second Punic War is one of the major questions of antiquity and one that historians/archaeologists have long studied. One of the many clues in the ancient literature that can help answer this question is the mention of fired rock, the result of a conflagration Hannibal is reputed to have employed to reduce the size of boulders in a blocking rockslide some …
Interpretation of Rock Varnish in Australia
Rock varnish has a long history of study in Australia. Although Australian varnishes have biological, chemical and morphological similarities to varnishes in other continents, rock varnishes in arid Australia tend to be less stable than in other drylands. Still, with careful sampling, radiocarbon and cation‐ratio dating of rock varnish has been used to constrain the age of Henbury Meteor Craters, Northern Territory, and rock engravings in South A…
Advances in rapid condition assessments of rock art sites
The Rock Art Stability Index
Pace of Landscape Change and Pediment Development in the Northeastern Sonoran Desert, United States
Pediments of the Sonoran Desert in the United States have intrigued physical geographers and geomorphologists for nearly a century. These gently sloping bedrock landforms are a staple of the desert landscape that millions visit each year. Despite the long-lived scientific curiosity, an understanding of the processes operating on the pediment has remained elusive. In this study we revisit the extensive history of pediment research. We then apply g…
The Rock Varnish Revolution
Rock varnish is a coating composed of clay minerals cemented to rock surfaces by oxides of manganese and iron. Although this dark brown-to-black accretion is most noticeable in arid regions, it occurs in all terrestrial weathering environments. Scholarly varnish research started with Alexander von Humboldt, when he asked how this external accretion forms and why manganese concentrations in varnish are 101-102 greater than in potential source mate…
A new strategy for analyzing the chronometry of constructed rock features in deserts
The western Great Basin contains thousands of constructed rock features, including rock rings, cairns, and alignments. Unlike subtractive geoglyphs, such as the Nasca Lines of Peru, that remove desert pavement, these surface features alter the location and positioning of cobble‐ to bouldersized rocks. The chronology of surface rock features has remained unconstrained by numerical ages because no prior chronometric approach has been able to yield …
AMS 14 C age constraints on geoglyphs in the lower colorado river region, arizona and california
Giant ground figures are widespread in the lower Colorado River area of southwestern North America, yet their chronology has remained unconstrained by numerical ages. Thirteen AMS 14 C measurements reported here indicate that geoglyphs were made from before ̃A. D. 1200 to before ̃900 B. C. We account for potential contamination from prior organics in weathering rinds. All other potential errors point to 14 C dates being minimum‐limiting ages for …
Cation-Ratio Dating
Rock varnish coats many surfaces of geomorphic and archaeologic interest in arid lands. All varnish dating techniques are limited by the time lag between the exposure of a surface to subaerial processes and the onset of varnishing. They are valid only where manganese is not remobilized after deposition, for example, in most arid environments. The premise of a new age-determination method, cation-ratio dating, is that the ratio of the more mobile …
Chronometric and Relative Age Determination of Petroglyphs in the Western United States
This paper presents chronometric age determinations of petroglyphs from the Coso Range and Cima volcanic field and relative dating from other locations in the western United States using the new rock varnish technique of cation-ratio dating. Our results verify the proposed Great Basin relative stylistic chronology, which indicates that curvilinear abstract was followed by rectilinear abstract and representational. However, these styles have great…
Radiocarbon and Cation-Radio Ages for Rock Varnish on Tioga and Tahoe Marainal Boulders of Pine Creek, Eastern Sierra Nevada, California, and their Paleoclimatic Implications
Accelerator mass spectrometry 14 C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecol…
Rock art chronology in eastern California
Cation‐ratio dating has allowed us to obtain chronometric ages for 13 rock engravings from the Cima region, and an additional date from the Coso Range, eastern California, North America. These fourteen new dates, in combination with five previous dates from the Cosos and other lines of evidence, enable us to reassess the rock engraving chronology for eastern California. Rock engraving is indicated as beginning in the Late Pleistocene and continui…
Cation-ratio dating of rock-engravings from the Olary Province of arid South Australia
Desert varnish, the distinctive coating on exposed rock surfaces in arid regions, can be dated by cation ratios, providing a rare means directly to date petroglyphs. A first application of the method, much used in north America, is here reported from Australia, where it indicates minimum ages up to 30,000 years old. And it also shows that the style of figures, so often taken as a measure of chronology, is in this instance largely independent of a…
Interpretation of Rock Varnish in Australia
Rock varnish has a long history of study in Australia. Although Australian varnishes have biological, chemical and morphological similarities to varnishes in other continents, rock varnishes in arid Australia tend to be less stable than in other drylands. Still, with careful sampling, radiocarbon and cation‐ratio dating of rock varnish has been used to constrain the age of Henbury Meteor Craters, Northern Territory, and rock engravings in South A…
New Approach to the Radiocarbon Dating of Rock Varnish, with Examples from Drylands
New electron microscope observations reveal that organic inclusions are often trapped in pockets under rock varnish. Accelerator radiocarbon dating of subvarnish organic detritus provides a new method of constraining when a rock was exposed by cultural or geomorphic processes. Applications are exemplified for human artifacts and landforms found in drylands. Three radiocarbon dates from 30,000 to 36,000 yr B.P. indicate rock engravings in South Au…
Olivine Does Not Necessarily Weather First
New surface exposure ages for petroglyphs from the Olary Province, South Australia
Exposed surfaces of rock engravings in the Olary Province of South Australia develop coatings of rock varnish, amorphous silica, and oxalate‐rich crusts. Instead of relying on any single approach, we use three experimental approaches to assign minimum ages to the petroglyphs. Three methods involve dating manganiferous rock varnish formed over the petroglyphs: 14C measurements of organic matter at the varnish/weathering rind interface provides num…
AMS Radiocarbon and Cation-Ratio Dating of Rock Art in the Bighorn Basin of Wyoming and Montana
Samples of organic matter and rock varnish from seven rock-art sites in the Bighorn Basin of Wyoming and Montana were collected for dating purposes. Petroglyphs sampled include Dinwoody-style figures, shield-bearing warriors, and other well-known Plains rock-art motifs. Accelerator mass spectrometry (AMS) dating of 10 petroglyphs yielded dates from the Early Archaic to the Protohistoric periods. A strong numerical relation between varnish leachin…
New Perspectives on the Clovis vs. Pre-Clovis Controversy
We consider the Clovis vs. pre-Clovis debate from three perspectives: migration models; petroglyph and surface-artifact ages; and scientific method. First, we test the hypothesis that a Clovis migration can account for the temporal and spatial distribution of South American Paleoindian sites 'accepted' by Clovis-first advocates. Using a Clovis-first model, site ages are underpredicted by approximately 1,500 years, suggesting that the Clovis hypot…
Comment on "Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable," by Paul R. Bierman and Alan R. Gillespie
Comment on "Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable," by Paul R. Bierman and Alan R. Gillespie - Volume 43 Issue 2
AMS 14 C age constraints on geoglyphs in the lower colorado river region, arizona and california
Giant ground figures are widespread in the lower Colorado River area of southwestern North America, yet their chronology has remained unconstrained by numerical ages. Thirteen AMS 14 C measurements reported here indicate that geoglyphs were made from before ̃A. D. 1200 to before ̃900 B. C. We account for potential contamination from prior organics in weathering rinds. All other potential errors point to 14 C dates being minimum‐limiting ages for …
New Chronometric Dates for the Puquios of Nasca, Peru
Numeric age assessments of organic material encapsulated by rock varnish present on stone lintels of two "puquios" in the Nasca region of the south coast of Peru indicate a Precolumbian age. Accelerator mass spectrometry radiocarbon analyses at the Isotrace Laboratory revealed ages of cal A. D. 560(620)650 and cal A. D. 600(640)660 (1 sigma). These calibrated measurements are considered to be appropriate in the context of the archaeological settl…
Understanding the Spatial Variability of Environmental Change in Drylands with Rock Varnish Microlaminations
A fundamental problem in the analysis of landforms and surface artifacts is how to correlate the ages of non-contiguous surfaces. One solution to this problem may lie within the varnish coatings on desert rocks. When viewed with a light microscope in ultra-thin cross-sections, rock varnish reveals orange and black layers that record drier and wetter climates, respectively. Consistent patterns of alternating orange and black microlaminae are evide…
Uncertainties in 14C ages for petroglyphs from the Olary province, South Australia
This report explains why previously published 14C dates for the Olary petroglyphs cannot be relied upon
Constraining the age of the Côa valley (Portugal) engravings with radiocarbon dating
Radiocarbon ages for the Côa petroglyphs are very similar to those obtained by Watchman (1995). Fundamental problems in the use of radiocarbon dating at Côa include evidence for the addition of younger carbon in an open system, and evidence of contamination from older sources of carbon. Radiocarbon measurements, therefore, cannot be used to decide whether the engravcings are or are not of Palaeolithic age
Sally's Rockshelter and the Archaeology of the Vision Quest
Quartz, the most common mineral on earth, is almost universally associated with shamans. Why this ritual association occurred worldwide has remained unexplained scientifically, at least in part because western scientific thinking assumes that religious beliefs and practices are epiphenomenal and not worthy of study. This association is archaeologi-cally evident at Sally's Rocksheiter, a small rock engraving-vision quest site in the Mojave Desert,…
The Geomorphic Evolution of the Yosemite Valley and Sierra Nevada Landscapes
Key Words: Yosemite Valleygeomorphologylandscapeevolutionsociology of science Additional informationNotes on contributorsRonald DornReviewed by
A new strategy for analyzing the chronometry of constructed rock features in deserts
The western Great Basin contains thousands of constructed rock features, including rock rings, cairns, and alignments. Unlike subtractive geoglyphs, such as the Nasca Lines of Peru, that remove desert pavement, these surface features alter the location and positioning of cobble‐ to bouldersized rocks. The chronology of surface rock features has remained unconstrained by numerical ages because no prior chronometric approach has been able to yield …
Analysis of burnt schist outcrops in the alps
Identification of the exact route followed by Hannibal during his invasion of Italia in the Second Punic War is one of the major questions of antiquity and one that historians/archaeologists have long studied. One of the many clues in the ancient literature that can help answer this question is the mention of fired rock, the result of a conflagration Hannibal is reputed to have employed to reduce the size of boulders in a blocking rockslide some …
The Integration of Literacy and Geography
To provide the first interstate quasi-experimental assessment on the power of content integration in building reading skills, the authors studied the effects on reading comprehension of GeoLiteracy—a K-8 package of 85 lessons that teaches geography in the context of practicing reading and writing skills. Ninety-six third through eighth grade teachers in Arizona and Michigan divided up into intervention and comparison groups. Intervention teachers…
Learning Desert Geomorphology Virtually versus in the Field
Statistical analyses of pre-test and post-test results, as well as qualitative insight obtained by essays, compared introductory physical geography college students who learned desert geomorphology only virtually, in the field and both ways. With the exception of establishing geographic context, the virtual field trip was statistically indistinguishable from real field trips in establishing basic knowledge about desert geomorphology. However, qua…
The Rock Art Stability Index
The Rock Varnish Revolution
Rock varnish is a coating composed of clay minerals cemented to rock surfaces by oxides of manganese and iron. Although this dark brown-to-black accretion is most noticeable in arid regions, it occurs in all terrestrial weathering environments. Scholarly varnish research started with Alexander von Humboldt, when he asked how this external accretion forms and why manganese concentrations in varnish are 101-102 greater than in potential source mate…
Archaeology (29 obras) · Geography (26 obras) · Geology (24 obras) · Pleistocene-Era Hominins and Archaeology (19 obras) · Geology and Paleoclimatology Research (18 obras) · Archaeology and ancient environmental studies (17 obras) · Geology (15 obras) · Paleontology (13 obras) · Rock art (13 obras) · Archaeology and Rock Art Studies (12 obras)