.png){kind=icon}
.png){kind=icon}
Return
Climatic, lithologic and topographic control on alpine rock fracturing and talus evolution
.png){kind=icon}
OA
AI
D
S
S
T
S
DOI：10.1002/esp.70331.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Improved understanding of why rockfall rates differ across space and time will help to anticipate future rockfall activity. Rockfalls erode bedrock, producing accumulations of talus, which are characteristic landforms of alpine environments. Talus characteristics can be abductively used to reconstruct past rockfall activity and, when coupled with information on rockwall properties and climate, can be used to evaluate rockfall drivers. We systematically investigated three active Holocene rockwall–talus systems in a deglaciating valley in the Swiss Alps to assess rockfall rates and changes under different topographic, rock mass and climatic conditions. At the rockwalls, we measured rock mass strength, surface and sub-surface fracture densities and calculated past glacier stresses. At the taluses, we measured talus topography, clast size and shape and talus age. We combined our data with previously published site information on talus thickness, frost cracking processes and rockwall retreat rates. We found that rockwall fracture densities, when measured along transects immediately above each talus apex, were greater than those located at lower elevations in the catchment, which may relate to more recent glacier retreat and greater frost cracking intensities. For talus slopes that began accumulating earlier in the Holocene, a characteristic bi-segmented length profile was observed, with increasing clast size with distance from the rockwalls and with talus clast sizes typically much smaller than median rockwall fracture spacing. In contrast, the most recently formed talus lacks sorting and median clast sizes match the rockwall fracture spacing. Differences likely reflect rockwall-talus system maturity and rockwall size. Our study suggests that, at least in alpine environments, landscape and climate history can influence talus sedimentology and morphology. In summary, lithologic and topographic conditions in concert with climatic-driven stresses and time since deglaciation result in rockwall fracture patterns that control rockfall size, erosion rates and the characteristics and evolution of talus.
Keywords:
frost weathering
glacier retreat
paraglacial processes
rockfall
rockwall stability
talus
Journal
IF:
2.7
Papers:
324
Citations:
1.5W
Organization
Cited Papers