TY  - JOUR
A1  - Panek, Tomas
A1  - Korup, Oliver
A1  - Lenart, Jan
A1  - Hradecky, Jan
A1  - Brezny, Michal
T1  - Giant landslides in the foreland of the Patagonian Ice Sheet
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Quaternary glaciations have repeatedly shaped large tracts of the Andean foreland. Its spectacular large glacial lakes, staircases of moraine ridges, and extensive outwash plains have inspired generations of scientists to reconstruct the processes, magnitude, and timing of ice build-up and decay at the mountain front. Surprisingly few of these studies noticed many dozens of giant (≥108 m3) mass-wasting deposits in the foreland. We report some of the world's largest terrestrial landslides in the eastern piedmont of the Patagonian Ice Sheet (PIS) along the traces of the former Lago Buenos Aires and Lago Puyerredón glacier lobes and lakes. More than 283 large rotational slides and lateral spreads followed by debris slides, earthflows, rotational and translational rockslides, complex slides and few large rock avalanches detached some 164 ± 56 km3 of material from the slopes of volcanic mesetas, lake-bounding moraines, and river-gorge walls. Many of these landslide deposits intersect with well-dated moraine ridges or former glacial-lake shorelines, and offer opportunities for relative dating of slope failure. We estimate that >60% of the landslide volume (∼96 km3) detached after the Last Glacial Maximum (LGM). Giant slope failures cross-cutting shorelines of a large Late Glacial to Early Holocene lake (“glacial lake PIS”) likely occurred during successive lake-level drop between ∼11.5 and 8 ka, and some of them are the largest hitherto documented landslides in moraines. We conclude that 1) large portions of terminal moraines can fail catastrophically several thousand years after emplacement; 2) slopes formed by weak bedrock or unconsolidated glacial deposits bordering glacial lakes can release extremely large landslides; and 3) landslides still occur in the piedmont, particularly along postglacial gorges cut in response to falling lake levels.
KW  - Quaternary
KW  - Landslide
KW  - Geomorphology
KW  - Relative dating
KW  - Glacier foreland
KW  - Glacial lake
KW  - Patagonian Ice Sheet
KW  - Paleogeography
KW  - South America
Y1  - 2018
U6  - https://doi.org/10.1016/j.quascirev.2018.06.028
SN  - 0277-3791
VL  - 194
SP  - 39
EP  - 54
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Zapata, Sebastian Henao
A1  - Cardona, A.
A1  - Jaramillo, J. S.
A1  - Patino, A.
A1  - Valencia, V.
A1  - Leon, S.
A1  - Mejia, D.
A1  - Pardo-Trujillo, A.
A1  - Castaneda, J. P.
T1  - Cretaceous extensional and compressional tectonics in the Northwestern Andes, prior to the collision with the Caribbean oceanic plateau
JF  - Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research
N2  - The Cretaceous units exposed in the northwestern segment of the Colombian Andes preserve the record of extensional and compressional tectonics prior to the collision with Caribbean oceanic terranes. We integrated field, stratigraphic, sedimentary provenance, whole rock geochemistry, Nd isotopes and U-Pb zircon data to understand the Cretaceous tectonostratigraphic and magmatic record of the Colombian Andes. The results suggest that several sedimentary successions including the Abejorral Fm. were deposited on top of the continental basement in an Early Cretaceous backarc basin (150-100 Ma). Between 120 and 100 Ma, the appearance of basaltic and andesitic magmatism (similar to 115-100 Ma), basin deepening, and seafloor spreading were the result of advanced stages of backarc extension. A change to compressional tectonics took place during the Late Cretaceous (100-80 Ma). During this compressional phase, the extended blocks were reincorporated into the margin, closing the former Early Cretaceous backarc basin. Subsequently, a Late Cretaceous volcanic arc was built on the continental margin: as a result, the volcanic rocks of the Quebradagrande Complex were unconformably deposited on top of the faulted and folded rocks of the Abejorral Fm. Between the Late Cretaceous and the Paleocene (80-60 Ma), an arc-continent collision between the Caribbean oceanic plateau and the South-American continental margin deformed the rocks of the Quebradagrande Complex and shut-down the active volcanic arc. Our results suggest an Early Cretaceous extensional event followed by compressional tectonics prior to the collision with the Caribbean oceanic plateau. (C) 2019 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
KW  - Northern Andes
KW  - Paleogeography
KW  - Cretaceous
KW  - Extension
KW  - Convergent margins
KW  - Provenance
Y1  - 2018
U6  - https://doi.org/10.1016/j.gr.2018.10.008
SN  - 1342-937X
SN  - 1878-0571
VL  - 66
SP  - 207
EP  - 226
PB  - Elsevier
CY  - Amsterdam
ER  -