Distribution and behaviour of rock glaciers in the Adamello-Presanella Massif (Italian Alps)
Alps (The) ; Geographical information system ; Holocene ; Inventory ; Italy ; Little ice age ; Mountain ; Palaeo-environment ; Palaeoclimate ; Rock glacier
An inventory of rock glaciers in the Adamello-Presanella Group is presented. The distribution, behaviour and morphological characteristics of rock glaciers are desribed and organized in a GIS. Furthermore, the AA. analyse the relationship between
rock glaciers and vegetation and tentatively discuss that between rock glacier distribution and climatic parameters. In conclusion, it is necessary to be cautious in using the regional mean annual air temperature (MAAT) for identifying active forms
and in utilizing the position of rock glacier fronts for reconstructing the regional MAAT.
Very high-resolution photogrammetric and geodetic measurements about the deformation of transverse ridges on Murtèl, Muragl and Suvretta rock glaciers in the Upper Engadine, Swiss Alps are discussed. The contribution terminates with the presentation
of 2 hypotheses about transverse ridge development on rock glaciers.
Dynamics of an active rock glacier (Ötztal Alps, Austria)
Alps (The) ; Austria ; Climatic warming ; Discharge ; Glacier dynamics ; Meltwater ; Mountain ; Periglacial features ; Rock glacier ; Thermal regime ; Tirol ; Water temperature
The aim of this paper is to document the dynamics of a well-known active rock glacier in the Austrian Alps by using an integrated approach including morphological investigations as well as grain size, thermal, hydrological, and flow velocity
measurements, and to present a better understanding of the genesis and dynamics of rock glaciers.
Unravelling the source rocks of Late Eocene-Miocene orogenic wedge and foredeep arenites of the northern Apennines and southern Alps
The late Eocene to Late Miocene successions deposited along the northern Apennines and southern Alps are re-examinated through integration of arenite petrography with fission-track dating on apatite and zircon. Key heavy minerals and rock fragments
, chosen as indicators of Austroalpine, Penninic, Southalpine and Ligurian rock associations, have been combined to match with cooling ages of potential source rocks. - (NF)
The thermal regime of the active layer at the Murtèl rock glacier based on data from 2002
Active layer ; Air mass ; Air temperature ; Alps (The) ; Glacier ; Micromorphology ; Mountain ; Rock glacier ; Snow cover ; Switzerland ; Temperature ; Thermal regime ; Winter
Active layer temperatures are presented from a rock glacier in the Swiss Alps. The data represent a full year (2002) covering parts of 2 very different winters. Winter/spring 2002 was very cold and dry; fall 2002 was characterized by an unusual
amount of snow. Active layer temperatures are examined together with climate data and are used to discuss the processes which control the thermal regime of an active layer on a slope of a bouldery rock glacier surface : snow cover, snow depth, non-linear
heating of the bouldery material with increasing air temperatures and the microtopography of the rock glacier surface.
Rock-wall temperatures in the Alps : modelling their topographic distribution and regional differences
Rock-face near-surface temperatures have been measured over one year at 14 locations between 2500 and 4500 m a.s.l. in the Alps. These data were used to further develop and verify an energy-balance model that simulates daily surface temperatures
over complex topography. Based on a 21-year (1982-2002) run of this model, spatial patterns of rock-face temperatures in the Swiss Alps are presented and discussed. This model provides a basis for the re-analysis of past rock-fall events with respect
to permafrost degradation as well as for the simulation of future trends of rock temperatures.
The effects of fire on rock art : microscopic evidence reveals the importance of weathering rinds
A wildfire damaged the Whoopup Canyon petroglyph site, Wyoming, in 2001. This paper presents results of pre-fire (1991) and post-fire (2003) samples collected from rock engravings and adjacent sandstone joint faces. Optical microscopy and electron
microscopy reveal that fires create some thermal fractures that enhance panel erosion, but most of the fire-induced erosion occurs along weathering rinds that form long before petroglyph manufacturing. In addition, rock varnish on top of petroglyphs
experiences spalling, and fire ash strongly adheres to rock varnish on petroglyphs and spalled sandstone. Therefore it is important to prevent wildfires from reaching rock art panels.
The influence of rock resistance on coastal morphology around Lord Howe Island, Southwest Pacific
Cliff ; Coastal environment ; Coastal erosion ; Coastal geomorphology ; Differential erosion ; Island ; Lithology ; Pacific Region ; Shore platform ; South-West Pacific Ocean ; Volcanic rock
The geology of the island is varied, with hard and resistant basalt lavas, breccias and tuffs of intermediate resistance, and highly erodible eolianites. This variability provides an excellent opportunity to examine the influence of rock resistance
on the development of the spectacular rock coast landforms that occur around the island. Relative rock resistance was assessed through a combination of Schmidt hammer data, and statistical analysis was undertaken to remove outlying values. The paper considers
Dendrogeomorphological assessment of movement at Hilda rock glacier, Banff National Park, Canadian Rocky Mountains
Canada ; Climatic variation ; Dendrochronology ; Glacier advance ; Mountain ; Periglacial features ; Rock glacier ; Rocky Mountains ; Tree line
The results of this dendrogeomorphological study provide evidence of the active movement of Hilda rock glacier. The samples were crossdated using locally and regionally developed tree-ring chronologies, and were shown to have been killed between
1576 and 1999. The results show that Hilda rock glacier has advanced at an average rate of 1.6 cm/year since the late 1790s, with limited evidence of similar rates of activity extending back to the mid-1570s. This rock glacier activity is believed
Fracture ; Freezing ; Hokkaido ; Ice wedge ; Japan ; Mountain ; Rock mechanics ; Rockfall ; Temperature ; Thermal regime
Crack widths and rock temperatures were monitored on an andesitic bedrock cliff in the summit area of the Daisetsu Mountains, Hokkaido. Sequential data recorded the gradual widening of a crack to the point of critical crack extension, which resulted
in catastrophic rock breakage. Using these sequential data, the timing, magnitude, and dominant agent of crack movement are considered, with particular focus on the parameters related to rock fracture mechanics.
Throughout the world, large caves in rocks (tafoni) are found, which originate from salt weathering. The growth of tafoni has been studied with a model that describes how a rock surface, containing a small pit, disintegrates by salt crystallization
during wetting/drying cycles. In the model the rock is mapped on a grid. The migration and crystallization of salts are simulated explicitly in the drying phase of a cycle. At the end of each wetting/drying cycle the amount of salt deposits at the grid
nodes is evaluated and the shape of the rock surface is adjusted by removing nodes. Discussion of the results.
Rock strength and development of glacial valley morphology in the Scottish Highlands and northwest Iceland
Geomorphogenesis ; Glacial erosion ; Glacial valley ; Highland ; Ice sheet ; Iceland ; Lithology ; Model ; Rock mechanics ; Scotland ; United Kingdom ; Valley
of low rock mass strength, broad U-shaped valleys are developed, whilst steeper sided, narrower cross-profiles have been developed on igneous bedrock of high rock mass strength. Findings suggest it is the interplay of the mass strength of the subglacial
Carbonate rock ; Chemical erosion ; Climate ; Comparative study ; England ; Erosion ; Geomorphology ; Inverted relief ; Ireland ; Isostasy ; Somerset ; United Kingdom ; Weathering
Denudation mechanisms differ fundamentally between limestone and silicate rock types, which are subject to very different rate thresholds and enhancers/inhibitors. Denudation of limestone and of silicates cannot be encompassed by simple models
of differential mechanical erosion of hard and soft rocks. The mechanisms involved, and the factors which influence them, are so fundamentally different that the denudation of these 2 main lithologies must be considered separately before the results are combined
Evidence for freeze-thaw events and their implications for rock weathering in northern Canada
. Temperature data were collected at 1 min intervals for 1 year. These data provide unequivocal proof for the occurrence of the freezing and thawing of water on and within the rock (freeze-thaw events). It was found that the temperature at which freezing occured
Creep ; Experimentation ; Ice ; Impact ; Periglacial features ; Permafrost ; Research technique ; Rock glacier ; Shear stress
on artificially frozen soils samples may help in developing a better understanding of rock glacier and general permafrost dynamics at temperature close to the melting point of ice.