scholarly journals Retrospective Modeling of a Large Paleo-Landslide Related to Deglaciation in the Sierra de Urbión, Cordillera Ibérica, Spain

2021 ◽  
Vol 11 (9) ◽  
pp. 4277
Author(s):  
Pablo Sanz de Ojeda ◽  
Eugenio Sanz Pérez ◽  
Rubén Galindo ◽  
Cesar Sanz Riaguas

Through a study of glacial geomorphology and retrospective modeling of the stability of the slopes, it has been possible to reconstruct and know the mechanism of the formation of a large landslide induced by the retreat of the glacier corresponding to the Picos de Urbión (Coordillera Ibérica, Spain) during the last glacial cycle. It is a rotational landslide of 150 Mm3 that involved a layer of lutites and clays of the Cameros Basin that outcropped on one of the slopes of the valley, and whose initial geometry was modified by the over-excavation of the glacier tongue, which reached 140 m in height. The breakage occurred when the support of the ice tongue was partially removed. The structural layout and high water table also contributed to the landslide. It is the first time that landslides associated with the deglaciations of the last glacial cycle have been retrospectively modeled, which may be of interest when applied to geomorphological sciences.

CATENA ◽  
2021 ◽  
Vol 206 ◽  
pp. 105252
Author(s):  
Miguel Bartolomé ◽  
Carlos Sancho ◽  
Gerardo Benito ◽  
Alicia Medialdea ◽  
Mikel Calle ◽  
...  

2021 ◽  
Vol 14 (2) ◽  
pp. 97-103
Author(s):  
Cécile L. Blanchet ◽  
Anne H. Osborne ◽  
Rik Tjallingii ◽  
Werner Ehrmann ◽  
Tobias Friedrich ◽  
...  

2018 ◽  
Vol 14 (11) ◽  
pp. 1819-1850 ◽  
Author(s):  
Olivier Cartapanis ◽  
Eric D. Galbraith ◽  
Daniele Bianchi ◽  
Samuel L. Jaccard

Abstract. Although it has long been assumed that the glacial–interglacial cycles of atmospheric CO2 occurred due to increased storage of CO2 in the ocean, with no change in the size of the “active” carbon inventory, there are signs that the geological CO2 supply rate to the active pool varied significantly. The resulting changes of the carbon inventory cannot be assessed without constraining the rate of carbon removal from the system, which largely occurs in marine sediments. The oceanic supply of alkalinity is also removed by the burial of calcium carbonate in marine sediments, which plays a major role in air–sea partitioning of the active carbon inventory. Here, we present the first global reconstruction of carbon and alkalinity burial in deep-sea sediments over the last glacial cycle. Although subject to large uncertainties, the reconstruction provides a first-order constraint on the effects of changes in deep-sea burial fluxes on global carbon and alkalinity inventories over the last glacial cycle. The results suggest that reduced burial of carbonate in the Atlantic Ocean was not entirely compensated by the increased burial in the Pacific basin during the last glacial period, which would have caused a gradual buildup of alkalinity in the ocean. We also consider the magnitude of possible changes in the larger but poorly constrained rates of burial on continental shelves, and show that these could have been significantly larger than the deep-sea burial changes. The burial-driven inventory variations are sufficiently large to have significantly altered the δ13C of the ocean–atmosphere carbon and changed the average dissolved inorganic carbon (DIC) and alkalinity concentrations of the ocean by more than 100 µM, confirming that carbon burial fluxes were a dynamic, interactive component of the glacial cycles that significantly modified the size of the active carbon pool. Our results also suggest that geological sources and sinks were significantly unbalanced during the late Holocene, leading to a slow net removal flux on the order of 0.1 PgC yr−1 prior to the rapid input of carbon during the industrial period.


2009 ◽  
Vol 5 (3) ◽  
pp. 329-345 ◽  
Author(s):  
S. Bonelli ◽  
S. Charbit ◽  
M. Kageyama ◽  
M.-N. Woillez ◽  
G. Ramstein ◽  
...  

Abstract. A 2.5-dimensional climate model of intermediate complexity, CLIMBER-2, fully coupled with the GREMLINS 3-D thermo-mechanical ice sheet model is used to simulate the evolution of major Northern Hemisphere ice sheets during the last glacial-interglacial cycle and to investigate the ice sheets responses to both insolation and atmospheric CO2 concentration. This model reproduces the main phases of advance and retreat of Northern Hemisphere ice sheets during the last glacial cycle, although the amplitude of these variations is less pronounced than those based on sea level reconstructions. At the last glacial maximum, the simulated ice volume is 52.5×1015 m3 and the spatial distribution of both the American and Eurasian ice complexes is in reasonable agreement with observations, with the exception of the marine parts of these former ice sheets. A set of sensitivity studies has also been performed to assess the sensitivity of the Northern Hemisphere ice sheets to both insolation and atmospheric CO2. Our results suggest that the decrease of summer insolation is the main factor responsible for the early build up of the North American ice sheet around 120 kyr BP, in agreement with benthic foraminifera δ18O signals. In contrast, low insolation and low atmospheric CO2 concentration are both necessary to trigger a long-lasting glaciation over Eurasia.


2004 ◽  
Vol 118-119 ◽  
pp. 23-53 ◽  
Author(s):  
J Shulmeister ◽  
I Goodwin ◽  
J Renwick ◽  
K Harle ◽  
L Armand ◽  
...  

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