Rock temperatures as an indicator of weathering processes affecting rock art
Archaeology ; Index ; Moisture ; Rock ; South Africa ; Temperature ; Thermal regime ; Weathering
To aid rock art conservation, rock temperatures have been monitored at different depths and acquisition rates in a painted rock shelter in the uKhahlamba-Drakensberg Park (South Africa). Preliminary results, records of winter temperatures
, in the study of rock temperature regimes are presented and briefly discussed with respect to rock weathering mechanisms.
Allison (1988, 1990) examined the intact strength properties of several types of carbonate rocks and considered that dynamic Young's modulus is a good indicator of rock material strength for geomorphic purposes, and cast doubts on the reliability.
This paper reports on rock temperature fluctuation in the north and south surfaces of a moraine boulder in Hunza Karakoram obtained over 2 years, and concludes that the rock surface weathering processes depend primarily on the differences
This second part of a review deals with the mechanisms of rock glacier formation and flow. The AA. first discuss terminological and classification problems associated with rock glaciers and dynamic nature of rock glaciers. The third part concludes
this series of papers by discussing the role and significance of rock glaciers in mountain geomorphology, glaciology and environmental reconstructions.
Degradation of talus-derived rock glaciers in the Upper Engadin, Swiss Alps
Alps (The) ; Classification ; Geophysics ; Mountain ; Periglacial features ; Permafrost ; Rock glacier ; Soil temperature ; Switzerland
This study aims at evaluating changes in the morphology and structure of rock glaciers with permafrost degradation. For this purpose, morphology, structure and thermal conditions are compared between active, inactive and relict rock glaciers
in the Upper Engadin, where the 3 types of rock glaciers co-exist within a small mountain area. On the basis of 109 rock glacier investigations (mapping, morphological parameters, temperature measurements and geophysical soundings), processes accompanying
permafrost degradation in rock glaciers are discussed.
Frost bursting : a violent expression of frost action in rock
The purpose of this paper is to substantiate an explosive origin for some rock breakdown by identifying the pertinent environmental conditions and mechanical properties of the rock in which it occurs.
Incipient motion conditions for single rock fragments in simulated rill flow
This paper examines incipient motion conditions for single rock fragments in simulated rill channels : threshold conditions for rock fragments in rill flow will be compared with existing theory (Shields) for channels and rivers.
Soil containing rock fragments: effects on infiltration
Rock fragments in soil: surface dynamics
Infiltration ; Model ; Rock ; Soil ; Soil properties
Procedures for quantifying soil and surface rock fragments are reviewed. Within the soil the physical properties and hydraulic properties that affect infiltration are shown to be influenced by rock fragments. Physical properties discussed are bulk
density, porosity and water content. Hydraulic properties that affect infiltration are water retention, saturated conductivity and unsaturated conductivity. Rock fragments on the soil surface have been reported to both increase or decrease infiltration
The effects of fire on rock weathering : some further considerations of laboratory experimental simulation
Cyprus ; Experimentation ; Fire ; Geotechnics ; Rainfall simulation ; Rock ; Temperature ; Temperature gradient ; Weathering
rock material properties, which can then be related to weathering susceptibility. A range of rock types were collected from the island of Cyprus. The rate of rock disintegration and effects such as case-hardening appear to be a function of rock thermal
Physical deterioration of sedimentary rocks subjected to experimental freeze-thaw weathering
Building materials ; Experimentation ; Freeze-thaw cycle ; Geotechnics ; Lithology ; Sandstone ; Sedimentary ; Sedimentary rock ; Weathering
This paper addresses the influence of pre-existing flaws on the durability of ten sedimentary rocks under experimental freeze-thaw weathering. Results suggest that the presence or absence of rock flaws alone does not control deterioration mode
, but rather that it is the coupled relationship between these flaws, and rock strength and textural properties which exerts greatest influence. This work also has practical implications for the study of landform development due to weathering
, and for the selection of representative rock samples in durability testing for building stone.
Stacks and notches at Hopewell Rocks, New Brunswick, Canada
Spectacular rock formations have developed in coarse, poorly sorted conglomerates and arkosic sandstones at Hopewell Rocks in the Bay of Fundy, which has the largest tidal range in the world. The purpose of this study was to determine the effect
of a very large tidal range, and the role of rock structure and variations in rock hardness on the nature and development of a rock coast in the Bay of Fundy.
The relations between modulus of elasticity and temperature in the context of the experimental simulation of rock weathering by fire
Fire ; Lithology ; Rock ; Temperature ; Weathering
The purpose of this paper is to investigate the possible geomorphological significance of fire for rock weathering. The simulation of fire in the laboratory and the monitoring of changes in rock modulus of elasticity, reveal that different rocks
respond differently to heating. It is postulated that the degree of change in elasticity as a result of simulated fire is such that rock outcrops subjected to real fires are likely to be sufficiently modified as to increase their susceptibility to erosion
Rock surface roughness as an indicator of degree of rock surface weathering
The AA. propose a standard procedure for recording and quantifying the roughness of rock surfaces at scales that may reflect differences in rock surface weathering. The techniques are illustrated using artificial and real rock surface profiles
This paper analyzes the results of an inventory of rock glaciers and protalus lobes in the South Shetland Islands. The work is based on aerial photo-interpretation, field recognition and measurements, and estimations of volumes, debris transport
and talus production using Barch's methodology. Three groups of rock glaciers can be recognised : those immediate postdating the last major ice recession, rock glaciers younger than 2000 years BP but pre-dating the Little Ice Age (LIA), and rock glaciers
Cirque ; Classification ; Geomorphogenesis ; Glacier ; Mountain ; Periglacial features ; Permafrost ; Rock glacier
Several contentions issues have arisen from rock glacier nomenclature, for example whether the term rock glacier implies genesis from glacial ice or from permafrost. The situation is compounded since rock glacier classification may be based
on several different parameters, some of which are measured and quantified, others inferred. These include: gross morphology, dynamics, processes of formation, location, internal characteristics, thermal regime and age. The distinction is made between rock
Arctic Region ; Avalanche ; Model ; Periglacial features ; Permafrost ; Rock glacier ; Snow ; Spitsbergen ; Svalbard
Visual year-round observations have shown that snow avalanches are driving the formation of rock glaciers near the glacier Larsbreen in central Svalbard. This model appeas consistent with information on the origin and geometry of internal structures
previously derived by indirect geophysical means on this and other rock glaciers in Svalbard, and on rock glaciers elsewhere. Avalanche-nourished rock glaciers are expected to exhibit a regional downwind preferred orientation.
Rock glacier dynamics in a marginal periglacial high mountain environment : flow, movement (1991-2000) and structure of the Argualas rock glacier, the Pyrenees
Creep ; Geophysics ; Mountain ; Periglacial features ; Pyrénées ; Rock glacier ; Sedimentology ; Spain ; Years 1990-99
This paper presents the results of detailed studies on the dynamics of the Argualas rock glacier in the Pyrenees from 1991 to 2000. The aim is to provide a better understanding of the surface movement and dynamics of the tongue-shaped rock glacier
This paper presents 5 different techniques for obtaining rock moisture data. The results, obtained in study areas in the Bavarian Alps, make it clear that direct rainfall is the main source of rock moisture. The influence of snow is limited
to the immediate vicinity of the snow fields and is not equally pronounced at different times and positions. Rock moisture levels are higher in summer than they are in winter. The moisture content of the rock is considered to be one of the major controlling factors