scholarly journals Constraining deformation phases in the Aar Massif and the Gotthard Nappe (Switzerland) using Th-Pb crystallization ages of fissure monazite-(Ce)

Lithos ◽  
2019 ◽  
Vol 342-343 ◽  
pp. 223-238 ◽  
Author(s):  
E. Ricchi ◽  
C.A. Bergemann ◽  
E. Gnos ◽  
A. Berger ◽  
D. Rubatto ◽  
...  
Keyword(s):  
Aar Massif

scholarly journals Deciphering tectonic, eustatic and surface controls on the 20 Ma-old Burdigalian transgression recorded in the Upper Marine Molasse in Switzerland

2019 ◽  
Author(s):  
Philippos Garefalakis ◽  
Fritz Schlunegger
Keyword(s):  
Sea Level ◽  
Depositional Environments ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Crustal Material ◽  
Molasse Basin ◽  
Shallow Marine ◽  
Depositional Settings ◽  
Stratigraphic Architecture ◽  
Aar Massif

Abstract. The stratigraphic architecture of the Swiss Molasse basin reveals crucial information about the basin’s geometry, its evolution and the processes leading to the deposition of the clastic material. Nevertheless, the formation of the Upper Marine Molasse (OMM) and the controls on the related Burdigalian transgression are not fully understood yet. During these times, from c. 20 to 17 Ma, the Swiss Molasse basin was partly flooded by a peripheral shallow marine sea, striking SW – NE. We proceeded through detailed sedimentological and stratigraphic examinations of several sites across the entire Swiss Molasse basin in order to deconvolve the stratigraphic signals related surface and tectonic controls. Surface-related signals include stratigraphic responses to changes in eustatic sea level and sediment fluxes, while the focus on crustal-scale processes lies on the uplift of the Aar-massif at c. 20 Ma. Field examinations show, that the evolution of the Burdigalian seaway was characterized by (i) shifts in the depositional settings, (ii) changes in discharge directions, a deepening and widening of the basin, and (iv) phases of erosion and non-deposition. We relate these changes in the stratigraphic records to a combination of surface and tectonic controls at various scales. In particular, roll-back subduction of the European mantle lithosphere, delamination of crustal material and the associated rise of the Aar-massif most likely explain the widening of the basin particular at distal sites. In addition, the uplift of the Aar-massif was likely to have shifted the patterns of surface loads. These mechanisms could have caused a flexural adjustment of the foreland plate underneath the Molasse basin, which we use as mechanism to explain the establishment of distinct depositional environments and particularly the formation of subtidal-shoals where a lateral bulge is expected. In the Alpine hinterland, these processes occurred simultaneously with a period of fast tectonic exhumation accomplished through slip along the Simplon detachment fault, with the consequence that sediment flux to the basin decreased. It is possible that this reduction in sediment supply contributed to the establishment of marine conditions in the Swiss Molasse basin and thus amplified the effect related to the tectonically controlled widening of the basin. Because of the formation of shallow marine conditions, subtle changes in the eustatic sea level contributed to the occurrence several hiatus that chronicle periods of erosion and non-sedimentation. While these mechanisms are capable of explaining the establishment of the Burdigalian seaway and the formation of distinct sedimentological niches in the Swiss Molasse basin, the drainage reversal during OMM-times possibly requires a change in the tectonic processes at the slab scale. We conclude that sedimentological records can be used to decipher surface controls and lithospheric-scale processes in orogens from the stratigraphic record, provided that a detailed sedimentological and chronological database is available.

Structural-permeability favorability in crystalline rocks and implications for groundwater flow paths: a case study from the Aar Massif (central Switzerland)

2018 ◽  
Vol 26 (8) ◽  
pp. 2725-2738 ◽  
Author(s):  
Raphael Schneeberger ◽  
Daniel Egli ◽  
Georg W. Lanyon ◽  
Urs K. Mäder ◽  
Alfons Berger ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Crystalline Rocks ◽  
Flow Paths ◽  
Massif Central ◽  
Central Switzerland ◽  
Aar Massif

scholarly journals Orogen‐parallel migration of exhumation in the eastern Aar Massif revealed by low‐T thermochronometry

2021 ◽  
Author(s):  
L. Nibourel ◽  
M. Rahn ◽  
I. Dunkl ◽  
A. Berger ◽  
F. Herman ◽  
...  
Keyword(s):  
Aar Massif

scholarly journals Microstructures, mineral chemistry and geochronology of white micas along a retrograde evolution: An example from the Aar massif (Central Alps, Switzerland)

2017 ◽  
Vol 721 ◽  
pp. 179-195 ◽  
Author(s):  
Alfons Berger ◽  
Philip Wehrens ◽  
Pierre Lanari ◽  
Horst Zwingmann ◽  
Marco Herwegh
Keyword(s):  
Mineral Chemistry ◽  
Central Alps ◽  
Massif Central ◽  
Aar Massif

Multi-phase late-Neogene exhumation history of the Aar massif, Swiss central Alps

Terra Nova ◽  
2016 ◽  
Vol 28 (6) ◽  
pp. 383-393 ◽  
Author(s):  
Pierre G. Valla ◽  
Meinert Rahn ◽  
David L. Shuster ◽  
Peter A. van der Beek
Keyword(s):  
Central Alps ◽  
Late Neogene ◽  
History Of ◽  
Aar Massif ◽  
Multi Phase ◽  
Exhumation History

scholarly journals Magnetic fabric evolution in ductile shear zones: examples in metagranites of the Aar Massif (Swiss Central Alps)

Terra Nova ◽  
2015 ◽  
Vol 27 (3) ◽  
pp. 184-194 ◽  
Author(s):  
Jessica L. Till ◽  
Jean-Pascal Cogné ◽  
Didier Marquer ◽  
Jean-Charles Poilvet
Keyword(s):  
Shear Zones ◽  
Magnetic Fabric ◽  
Central Alps ◽  
Ductile Shear Zones ◽  
Fabric Evolution ◽  
Aar Massif ◽  
Ductile Shear

Granite genesis and migmatization in the western Aar Massif, Switzerland

2009 ◽  
Vol 186 (3) ◽  
pp. 309-320
Author(s):  
Kai Hettmann ◽  
Wolfgang Siebel ◽  
Cornelia Spiegel ◽  
John Reinecker
Keyword(s):  
Aar Massif

scholarly journals Earthquakes in Switzerland and surrounding regions during 2017 and 2018

2021 ◽  
Vol 114 (1) ◽  
Author(s):  
Tobias Diehl ◽  
John Clinton ◽  
Carlo Cauzzi ◽  
Toni Kraft ◽  
Philipp Kästli ◽  
...  
Keyword(s):  
Ground Motions ◽  
Structural Complexity ◽  
Normal Fault ◽  
Strike Slip ◽  
Crystalline Basement ◽  
Border Region ◽  
Thrust Faulting ◽  
Fold And Thrust Belt ◽  
Aar Massif ◽  
Alpine Foreland

AbstractThis report summarizes the seismicity in Switzerland and surrounding regions in the years 2017 and 2018. In 2017 and 2018, the Swiss Seismological Service detected and located 1227 and 955 earthquakes in the region under consideration, respectively. The strongest event in the analysed period was the ML 4.6 Urnerboden earthquake, which occurred in the border region of cantons Uri, Glarus and Schwyz on March 6, 2017. The event was the strongest earthquake within Switzerland since the ML 5.0 Vaz earthquake of 1991. Associated ground motions indicating intensity IV were reported in a radius up to about 50 km and locally approached intensity VI in the region close to the epicentre. Derived focal mechanisms and relative hypocentre relocations of the immediate aftershocks image a NNW–SSE striking sinistral strike-slip fault. Together with other past events in this region, the Urnerboden earthquake suggests the existence of a system of sub-parallel strike-slip faults, likely within in the uppermost crystalline basement of the eastern Aar Massif. A vigorous earthquake sequence occurred close to Château-d'Oex in the Préalpes-Romandes region in western Switzerland. With a magnitude of ML 4.3, the strongest earthquake of the sequence occurred on July 1, 2017. Focal mechanism and relative relocations of fore- and aftershocks image a NNE dipping normal fault in about 4 km depth. Two similarly oriented shallow normal-fault events occurred between subalpine Molasse and Préalpes units close to Châtel-St-Denis and St. Silvester in 2017/18. Together, these events indicate a domain of NE–SW oriented extensional to transtensional deformation along the Alpine Front between Lake Geneva in the west and the Fribourg Fault in the east. The structural complexity of the Fribourg Fault is revealed by an ML 2.9 earthquake near Tafers in 2018. The event images a NW–SE striking fault segment within the crystalline basement, which might be related to the Fribourg Fault Zone. Finally, the ML 2.8 Grenchen earthquake of 2017 provides a rare example of shallow thrust faulting along the Jura fold-and-thrust belt, indicating contraction in the northwestern Alpine foreland of Switzerland.

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