Controls on continental strain partitioning above an oblique subduction zone, Northern Andes

Visa fullständig post



Permalänk

http://hdl.handle.net/10138/315674

Citation

Schütt , J M & Whipp , D M 2020 , ' Controls on continental strain partitioning above an oblique subduction zone, Northern Andes ' , Tectonics , vol. 39 , no. 4 , e2019TC005886 . https://doi.org/10.1029/2019TC005886

Titel: Controls on continental strain partitioning above an oblique subduction zone, Northern Andes
Författare: Schütt, Jorina Marlena; Whipp, David Michael
Upphovmannens organisation: Institute of Seismology
Department of Geosciences and Geography
Datum: 2020-04
Språk: eng
Sidantal: 21
Tillhör serie: Tectonics
ISSN: 0278-7407
DOI: https://doi.org/10.1029/2019TC005886
Permanenta länken (URI): http://hdl.handle.net/10138/315674
Abstrakt: Strain partitioning onto margin-parallel thrust and strike-slip faults is a common process at obliquely convergent plate margins, leading to the formation and migration of crustal slivers. The degree of strain partitioning and rate of sliver migration can be linked to several factors including the angle of convergence obliquity, the dip angle of subduction, frictional coupling between the plates and the strength of the upper plate, among others. Although these factors are known to be important, their relative influence on strain partitioning is unclear, particularly at natural margins where the factors often vary along strike. Here we use a 3-D mechanical finite-element model to investigate the relationship between continental crustal strength, the convergence obliquity angle, the subduction angle, and strain partitioning in the Northern Volcanic Zone (NVZ) of the Andes (5 degrees N-3 degrees S). In the NVZ the subduction dip and obliquity angles both vary along strike, weaknesses in the continental crust may be present in suture zones or regions of arc volcanism, and strain partitioning is only observed in some regions. Thus, it is an ideal location to gain insight in which of the factors have the largest influence on deformation and sliver formation in the upper plate. Our numerical experiments confirm that a moderately high obliquity angle is needed for partitioning and that a continental crustal weakness is also required for movement of a coherent continental sliver at rates similar to geodetic observations from the NVZ. In contrast, the subduction dip angle is only of secondary importance in controlling strain partitioning behavior. Key Points Factors influencing formation of continental slivers investigated using 3-D numerical models of finite-width oblique subduction systems Model results indicate that convergence obliquity and the presence of weak zones in the upper plate are key to formation of well-defined slivers Model predictions are in good agreement with geodetic observations of sliver motion in the Northern Volcanic Zone of the Andes
Subject: 1171 Geosciences
subduction
strain partitioning
Andes
numerical modeling
geodynamics
WESTERN CORDILLERA
PLATE CONVERGENCE
BASIN FORMATION
SOUTH-AMERICA
NANGA-PARBAT
ECUADOR
DEFORMATION
EVOLUTION
BLOCK
CONSTRAINTS
Referentgranskad: Ja
Licens: cc_by
Användningsbegränsning: openAccess
Parallelpublicerad version: publishedVersion


Filer under denna titel

Totalt antal nerladdningar: Laddar...

Filer Storlek Format Granska
2019TC005886.pdf 4.845Mb PDF Granska/Öppna

Detta dokument registreras i samling:

Visa fullständig post