Painting Yosemite Valley : a Case study of rock coatings encountered at Half Dome
This paper identifies the types of rock coatings found on Half Dome, in Yosemite Valley, assesses the hypothesis that the rock coatings of Yosemite are consistent with the landscape geochemical model of rock coating formation, and considers
the relevance of equifinality. Eight types of rock coatings were identified: case-hardened surfaces, heavy metal skins, iron films, lithobiontic coatings, oxalate crusts, manganiferous rock varnish, silica glaze, and anthropogenic pigments. The landscape
geochemical model of rock coating formation and the concept of equifinality both proved useful in this investigation.
Formation of silica glaze rock coatings through water vapor interactions
Arid area ; Basalt ; Desert ; Geochemistry ; Hawaii ; Mars planet ; Moisture ; Rock coatings ; Rock varnish ; Silica ; Subtropical zone ; Volcano ; Water vapor ; Weathering
A two decade-long laboratory experiment tested importance of high water vapor content in silica glaze formation. Twenty years of exposing basalt rock chips to 80% and 90% levels of relative humidity revealed that water vapor alone can generate
silica glaze and may be an important factor in explaining why silica glaze is the dominant rock coating in humid warm drylands. In addition to adding a new dimension to the formation of terrestrial rock coatings, these findings may have importance
Field-scale estimation of the volume percentage of rock fragments in stony soils by electrical resistivity
Bassin parisien ; Beauce ; Electrical resistivity ; France ; Geophysics ; Model ; Quantitative analysis ; Rock fragment ; Soil ; Soil properties ; Soil water ; Stony soil
This paper presents a method that uses field spatial electrical resistivity measurements to determine the volume proportion of rock fragments. Based on the hypothesis that the electrical resistivity signal noise increases as the proportion of rock
fragments increases, a model was developed that uses the standard deviation of the apparent electrical resistivity measurements over a small area as an indicator of rock fragment contents. The model was tested on 3 study areas of several hectares containing
soil units with varying quantities of rock fragments in the Beauce region (Villamblain, France). The developed model strongly depends on the water content in the soil and the rock type and must be calibrated in each context. Nevertheless, estimations
of the rock fragment content in stony soils can be performed efficiently in the surface horizon as well as all along the soil profile.
Rock fall dynamics and deposition : an integrated analysis of the 2009 Ahwiyah Point rock fall, Yosemite National Park, USA
The AA. analyzed a combination of airborne and terrestrial LiDAR, high-resolution photography, seismic, and acoustic data in order to gain insights into the initiation, dynamics, and talus deposition of a complex rock fall in eastern Yosemite Valley
. The results suggest that accumulation of individual rock-fall boulders tends to steepen talus slopes, whereas large, energetic rock falls tend to flatten them. Detachment and impact signals were recorded by seismic and acoustic instruments and highlight
the potential use of this type of instrumentation for generalized rock fall monitoring, while LiDAR and photography data were able to quantify the cliff geometry, rock fall volume, source and impact locations, and geomorphological changes to the cliff and talus.
Inventory, distribution and topographic features of rock glaciers in the southern region of the Eastern Italian Alps (Trentino)
Alps (The) ; Bedrock ; Geographical information system ; Geological structure ; Glacier ; Italy ; Lithology ; Rock glacier ; Spatial distribution ; Topography ; Trentino-Alto Adige
A GIS-based rock glacier inventory was conducted in a region of about 6200 km2 located in the southern sector of the Eastern Italian Alps (Trentino). The five major mountain groups of the region were investigated and a total of 705 rock glaciers, 25
Progressive failure of sheeted rock slopes : the 2009–2010 Rhombus Wall rock falls in Yosemite Valley, California, USA
California ; Cliff ; Fracture ; Granite ; LiDAR ; Remote sensing ; Rock mechanics ; Rockfall ; Slope ; Slope dynamics ; United States of America
The AA. present high-resolution photography, video, and laser scanning data that document spatial and temporal patterns of a 15-month-long sequence of at least 14 rock falls from the Rhombus Wall, a sheeted granitic cliff in Yosemite Valley
behind cliff faces. They posit that as a region of failure spreads across a cliff face, stress concentrations along its margin will spread with it, promoting further crack propagation and rock falls.
Mining soil databases for landscape-scale patterns in the abundance and size distribution of hillslope rock fragments
California ; Grain size distribution ; Hawaii ; Mining activity ; Precipitation ; Regolith ; Rock fragment ; Sierra Nevada ; Slope ; Slope dynamics ; Soil properties ; Statistical distribution ; United States of America ; Washington State
The AA. explored the utility of soil survey databases for data mining, with the goals of identifying landscape-scale patterns in the abundance and size distribution of rock fragments (diameter D>2mm) and potential controls on grain size production
and transport, constructed depth-averaged grain size distributions and calculated the mass fraction of rock fragments and the median rock fragment grain size. They also categorized as bimodal, size distributions with a clear ‘breakpoint’ between fine and coarse
mechanistic hypotheses for rock fragment production on soil-mantled hillslopes.
Climate change and rock fall events in high mountain areas : numerous and extensive rock falls in 2007 at Mittlerer Burgstall, Central Austria
In 2007, a number of rock fall events occurred on the sharp SE-ridge of the mountain Mittlerer Burgstall completely changing the shape of the mountain. In this paper the AA. use geomorphological mapping, permafrost distribution modelling, glacier
reconstruction, surface and near-surface ground temperature data, air temperature data, and airborne laserscanning data to assess these multiple rock fall events. Permafrost modelling and ground temperature monitoring indicate that the area of detachment
. Furthermore, the generally highly fractured bedrock favoured slope instability. The triggering event for the rock falls were most likely the effects of the warm winter of 2006/07. A monitoring programme regarding future rock falls at Mittlerer Burgstall
Palaeomagnetic investigation of Cenozoic volcanic rocks bordering the North Anatolian Fault Zone, Reşadiye and Koyulhisar Districts, central-east Anatolia, Turkey
A palaeomagnetic study is reported from the lavas of Eocene, Miocene and Pliocene age cropping out immediately to the north of the North Anatolian Fault Zone (NAFZ) in the Reşadiye–Mesudiye region of central-eastern Anatolia. Rock magnetic
investigations identify a high percentage of multi-domained magnetite as the dominant ferromagnet in these rocks. Thirty of 37 units yielded acceptable groupings of characteristic magnetisation directions. An earlier study indicated small anticlockwise crustal
block rotation in this region since Upper Cretaceous times. This study indicates that this was overtaken by clockwise rotation in Eocene times. Results from later Miocene and Pliocene volcanic rocks indicate that no significant tectonic rotation has
Integrated geological-architectural pilot study of the Biet Gabriel-Rufael rock hewn church in Lalibela, northern Ethiopia
Architectural legacy ; Architecture ; Engineering geology ; Ethiopia ; Fault ; Geophysics ; Human impact ; Northern Ethiopia ; Patrimony ; Regional geology ; Rock mechanics ; Site preservation
This paper presents a geological and architectural integrated pilot study, aiming at the preservation of the Biet Gabriel-Rufael church, the worldwide known Ethiopian rock hewn monumental site protected by UNESCO since 1978. The main scoriaceous
The AA. identify research needs in 4 major areas and at the interfaces between them : rock temperature measurement and modelling; remote sensing of rock walls; process understanding of rock mass instability; and flow propagation models of rock-ice
and transient thermal behaviour, coupled thermo-hydro-mechanical understanding, enhanced remote inventorying of rock wall instability and integrated approaches for a better understanding and modelling of mixed avalanches.
Rock warming and drying under simulated intertidal conditions, part II : weathering and biological influences on evaporative cooling and near-surface micro-climatic conditions as an example of biogeomorphic ecosystem engineering
The AA. measured the warming and drying of blocks of rock (limestone and granite) and marine concrete during low-tide events simulated in the laboratory, before and after a period of exposure (8 months) on rock platforms in Cornwall, UK. Over longer
Geomorphological and geotechnical causes of anthropogenically induced rock-mass falls in the Wachau-Danube Valley (Bohemian Massif, Lower Austria)
impact on slope morphology. Interdependences between quarrying and construction caused unstable rock slopes and 4 rock-mass falls have occurred at 2 quarries near Spitz (1961, 1984, 2002) and Dürnstein (2009). Rock mechanical analysis at these quarries
Multidisciplinary investigations on three rock glaciers in the Swiss Alps : legacies and future perspectives
Conceptual model ; Geotechnics ; Mountain ; Periglacial features ; Permafrost ; Rock glacier ; Switzerland ; Thermal regime ; Thermokarst
The multidisciplinary investigations described in this paper have focused on 3 rock glaciers, Muragl, Murtèl-Corvatsch and Furggwanghorn in the Swiss Alps, all of which have been subject to a varying degree of prior study, and which are continuing
that aim to explain some aspects of rock glacier kinematics, are also introduced.
Rain splash soil erosion estimation in the presence of rock fragments
Agropedology ; Cultivated land ; Erosion rate ; Experimentation ; Infiltration ; Initial conditions ; Rainfall simulation ; Rock fragment ; Roughness ; Soil erosion ; Soil properties ; Splash ; Water erosion
Rain splash soil erosion in the presence of rock fragments and different initial conditions was tested in laboratory flume experiments under controlled conditions. The aim of the experiments was to ascertain whether cumulative soil erosion
Rock glacier activity in the Retezat Mountains, Southern Carpathians, Romania
Carpathian Mountains ; Erosion rate ; Mountain ; Periglacial features ; Permafrost ; Rock glacier ; Romania ; Soil temperature
Thermal conditions in seven rock glaciers (RGs) in the Retezat Mountains were examined using ground surface temperature, the bottom temperature of snow (BTS) and late-summer water temperature at springs. RG activity is suggested based on BTS values
in the massif for several decades, study of the permafrost has been under development for only a few years, especially in the rock walls. Many hazards are related to glacier dynamics. Outburst flood from englacial pockets, ice avalanche from warm-based and cold
-based glaciers, and rock slope failure due to debuttressing are generally increasing with the current decrease or even the vanishing of glaciers. Permafrost degradation is likely involved in rockfall and rock avalanche, contributing to the chains
The structural control of erosion of 2 small alpine catchments of distinctive rock types is evaluated by comparing the correspondences between the orientations of their gullies and rock couloirs with (1) the sliding orientations of potential slope
and field observations. The orientations of the maximum joint frequency are clearly associated with the gully network, suggesting that its development is governed by anisotropy in rock strength. These 2 catchments are typical of bedrock-dominated basins
Assessing early Spanish explorer routes through authentication of rock inscriptions
Arizona ; Discoveries ; Eighteenth Century ; Exploration ; Historical geography ; Petrography ; Rock ; Sixteenth Century ; Spanish people ; United States of America
The paper reports interdisciplinary research of weathering profile stages on gneiss with regard to tectonic and landscape evolutions of the western Sila Grande Massif (Southern Italy). The outcropping rocks consist of medium- to coarse-grained
and biotite during the most advanced weathering stage. Microfractures and morphological variations occur on the original rock and, thereby, affect the surrounding landscape processes. The weathering profile mineralogy and rock textures viewed in the context