scholarly journals The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland)

2020 ◽  
Vol 8 (3) ◽  
pp. 637-659
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Temperature Changes ◽  
Rock Face ◽  
Temperature Conditions ◽  
Denudation Rates ◽  
Reconstructed Temperature ◽  
Cryogenic Processes

Abstract. Denudation of steep rockwalls is driven by rock fall processes of various sizes and magnitudes. Rockwalls are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, which can precondition the occurrence of rock fall. However, it is still unclear how the fracturing of rock together with cryogenic processes impacts the denudation processes operating on steep rockwalls. In this study, we link data on long-term rockwall denudation rates at the Eiger (Central Swiss Alps) with the local bedrock fabric and the reconstructed temperature conditions at these sites, which depend on the insolation pattern. We then estimate the probability of bedrock for failure through the employment of a theoretical frost cracking model. The results show that the denudation rates are low in the upper part of the NW rockwall, but they are high both in the lower part of the NW rockwall and on the SE face, despite similar bedrock fabric conditions. The frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper part of the NW rockwall but relatively large on the lower section of the NW wall and on the SE rock face of the Eiger. We explain this pattern by the differences in insolation and temperature conditions at these sites. Throughout the last millennium, temperatures in bedrock have been very similar to the present. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation. We use these contrasts to explain the relatively low denudation rates in the upper part of the NW rockwall and the rapid denudation in the SW face and in the lower part of the NW rock face where frost cracking is more efficient.

scholarly journals The role of frost cracking in local denudation of steep Alpine headwalls over millennia (Mt. Eiger, Switzerland)

2019 ◽  
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Rate Data ◽  
Temperature Changes ◽  
Temperature Conditions ◽  
Denudation Rates ◽  
Reconstructed Temperature ◽  
Cryogenic Processes

Abstract. Denudation of steep headwalls is driven by rock fall processes of various size and magnitude. They are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, thus pre-conditioning rock fall. However, these controls and conditions thereof on the denudation processes operating on steep headwalls have remained debated. In this study, we link new and published long-term headwall denudation rate data for the Eiger Mountain in the Central Swiss Alps with the local bedrock fabric and the temperature conditions at these sites, which depend on the insolation pattern. We then estimate the tendency of bedrock for failure through the employment of a theoretical frost cracking model, which bases on the reconstructed temperature conditions. The results show that the denudation rates are low in the upper NW headwall compared to the high rates both on the NW footwall and on the SE face, despite similar bedrock fabric conditions. For these sites, the frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper NW headwall, but relatively large on the lower footwall of the NW wall and on the SE flank of the Eiger. We explain this pattern by the differences in insolation and local temperature conditions. These contrasts might be enhanced by permafrost occurrence in the upper NW wall, which would further reduce cracking efficiency. Throughout the last millennium, conditions have been very similar to the present temperatures in bedrock. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation, which explain the relatively low denudation rates in the upper NW headwall of the Eiger, but the rapid denudation in the SW side and NW footwall of the Eiger where frost cracking is more efficient.

High alpine rock-wall retreat rates over millennia through thermo-cryogenic pre-conditioned rock fall (Mt. Eiger, Switzerland)

2021 ◽  
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Rock Wall ◽  
Rock Face ◽  
Depth Profiles ◽  
Weathering Processes ◽  
Temperature Conditions ◽  
Low Efficiency ◽  
Cryogenic Processes

<p>Rock fall processes of various size and magnitude control retreat rates of high alpine rock-walls. For millennial time scales, these retreat rates can be quantified in-situ from concentrations of cosmogenic nuclides along bedrock depth profiles (Mair et al., 2019). We measured cosmogenic <sup>36</sup>Cl and <sup>10</sup>Be along several such profiles at Mt Eiger in the Central Swiss Alps to study the local rock-wall retreat on this time scale (Mair et al., 2019; 2020). The resulting spatial pattern shows that rock-wall retreat rates are low (0.5 to 0.6 ± 0.1 mm/yr) in the higher region of the NW rock-wall, in contrast to both the lower part of the NW rock-wall and the SE face, where rates are high (1.7 ± 0.4 to 3.5 ± 1.4 mm/yr). We link these retreat rates to differences in local temperature conditions, because the patterns of faults and fractures and the lithology of the bedrock are similar at all sites, and thermo-cryogenic processes are known to weaken the bedrock through fracturing, thereby preconditioning the occurrence of rock fall (e.g., Draebing and Krautblatter, 2019). However, it is still unclear how effective and at which rate individual thermo-cryogenic processes contribute to the preconditioning through fracturing. Therefore, we investigate several processes and estimate the probability of bedrock fracturing through the employment of a theoretical frost-cracking model, which predicts cracking intensity from ice segregation. The model results infer a low efficiency in the higher region of the NW rock-wall, but a relatively high one in the lower section of the NW wall and on the SE rock face of Mt. Eiger. Although the model is rather generic, the results disclose a significant control of temperature conditions on the erosional processes and rates. Furthermore, temperature conditions for the last millennia have been similar to present day conditions, as our reconstructions disclose, therefore the cosmogenic-nuclide-based long-term differences in rock-wall retreat rates predominantly stem from large contrasts in the microclimate between the NW and SE walls of Mt. Eiger. Accordingly, the site-specific differences in microclimate conditions could explain the lower retreat rates in the upper part of the NW rock-wall and the rapid retreat in the SW face and in the lower part of the NW rock face.</p><p>References</p><p>Draebing, D. and Krautblatter, M.: The Efficacy of Frost Weathering Processes in Alpine Rockwalls, Geophys. Res. Lett., 46, 6516–6524, doi:10.1029/2019GL081981, 2019.</p><p>Mair, D., Lechmann, A., Yesilyurt, S., Tikhomirov, D., Delunel, R., Vockenhuber, C., Akçar, N. and Schlunegger, F.: Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles, Sci. Rep., 9, 11023, doi:10.1038/s41598-019-46969-0, 2019.</p><p>Mair, D., Lechmann, A., Delunel, R., Yeşilyurt, S., Tikhomirov, D., Vockenhuber, C., Christl, M., Akçar, N. and Schlunegger, F.: The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland), Earth Surf. Dyn., 8, 637–659, doi:10.5194/esurf-8-637-2020, 2020.</p>

The role of human-induced fire and sweet chestnut (Castanea sativaMill.) cultivation on the long-term landscape dynamics of the southern Swiss Alps

The Holocene ◽  
2014 ◽  
Vol 25 (3) ◽  
pp. 482-494 ◽  
Author(s):  
César Morales-Molino ◽  
Elisa Vescovi ◽  
Patrik Krebs ◽  
Eva Carlevaro ◽  
Petra Kaltenrieder ◽  
...  
Keyword(s):  
Landscape Dynamics ◽  
Swiss Alps ◽  
Sweet Chestnut

scholarly journals Temperature conditions at the mountain study site of Bílý Kříž (the Beskids Mts.) during the past 20 years

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 113-122
Author(s):  
Irena Marková ◽  
Dalibor Janouš ◽  
Ondřej Nezval
Keyword(s):  
Air Temperature ◽  
Global Climate Change ◽  
Global Climate ◽  
Growth Season ◽  
Temperature Changes ◽  
Temperature Characteristics ◽  
The Past ◽  
Temperature Conditions ◽  
Mean Annual Air Temperature

Global climate change (including temperature changes) had already observable effects on the environment and humanity. Air temperature characteristics have been observed at the mountain study site of Bílý Kříž (the Beskids Mts., Czech Republic) since 1989. This paper presents an analysis of long-term (1997–2016) air temperature conditions at this study. Comparison is made of selected long-term mean air temperature characteristics with mean air temperature characteristics for the period 1997–2016. The results show slightly increasing air temperature, as indicated not only by values for mean annual air temperature but also by changes in number of extreme days (summer, tropical, ice, etc.) and occurrence of hot period. Moreover, the length of the growth season has increase slightly.

Abusive head trauma (AHT) outcome at long-term follow-up and the role of elective neurosurgical approach: A report of 22 cases

2013 ◽  
Author(s):  
Francesca Menegazzo ◽  
Melissa Rosa Rizzotto ◽  
Martina Bua ◽  
Luisa Pinello ◽  
Elisabetta Tono ◽  
...  
Keyword(s):  
Head Trauma ◽  
Abusive Head Trauma ◽  
Long Term Follow Up

The Second Start of Transformation in Ukraine?

2014 ◽  
pp. 30-52 ◽  
Author(s):  
L. Grigoryev ◽  
E. Buryak ◽  
A. Golyashev
Keyword(s):  
Economic Growth ◽  
Armed Conflict ◽  
Political Crisis ◽  
Investment Climate ◽  
Institutional Reforms ◽  
Personal Consumption ◽  
Governance Quality ◽  
Political Turmoil

The Ukrainian socio-economic crisis has been developing for years and resulted in the open socio-political turmoil and armed conflict. The Ukrainian population didn’t meet objectives of the post-Soviet transformation, and people were disillusioned for years, losing trust in the state and the Future. The role of workers’ remittances in the Ukrainian economy is underestimated, since the personal consumption and stability depend strongly on them. Social inequality, oligarchic control of key national assets contributed to instability as well as regional disparity, aggravated by identity differences. Economic growth is slow due to a long-term underinvestment, and prospects of improvement are dependent on some difficult institutional reforms, macro stability, open external markets and the elites’ consensus. Recovering after socio-economic and political crisis will need not merely time, but also governance quality improvement, institutions reform, the investment climate revival - that can be attributed as the second transformation in Ukraine.

Thoughts on the Long-Term Strategy, Science and Democracy

2006 ◽  
pp. 4-19 ◽  
Author(s):  
L. Abalkin
Keyword(s):  
Strategy Development ◽  
Russian Science ◽  
Global Trends ◽  
The World ◽  
World Development ◽  
Crucial Condition

The article covers unified issues of the long-term strategy development, the role of science as well as democracy development in present-day Russia. The problems of budget proficit, the Stabilization Fund issues, implementation of the adopted national projects, an increasing role of regions in strengthening the integrity and prosperity of the country are analyzed. The author reveals that the protection of businessmen and citizens from the all-embracing power of bureaucrats is the crucial condition of democratization of the society. Global trends of the world development and expert functions of the Russian science are presented as well.

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