HR: 08:20h
AN: U51B-02 [Abstracts]
TI: Structural Style and Tectonic Evolution of the Domeyko Range, North Chilean Precordillera
AU: * Amilibia, A
EM: aamilibiac@ub.edu
AF: Departament de Geodinamica i Geofisica, Facultat de Geologia, Universitat de
Barcelona, Marti i Franques s/n, Barcelona, 08028, Spain
AU: Sabat, F
EM: sabat@ub.edu
AF: Departament de Geodinamica i Geofisica, Facultat de Geologia, Universitat de
Barcelona, Marti i Franques s/n, Barcelona, 08028, Spain
AU: McClay, K
EM: ken@gl.rhul.ac.uk
AF: Fault Dynamics Research Group, Geology Department, Royal Holloway University of
London, Egham
SURREY, Egham, TW20 0EX, United Kingdom
AU: Munoz, J
EM: jamuñoz@ub.edu
AF: Departament de Geodinamica i Geofisica, Facultat de Geologia, Universitat de
Barcelona, Marti i Franques s/n, Barcelona, 08028, Spain
AU: Roca, E
EM: eduardroca@ub.edu
AF: Departament de Geodinamica i Geofisica, Facultat de Geologia, Universitat de
Barcelona, Marti i Franques s/n, Barcelona, 08028, Spain
AU: Chong, G
EM: gchong@ucn.cl
AF: Departamento de Ciencias Geologicas, Facultad de Ingenieria y Ciencias
Geologicas, Universidad Catolica del Norte, Av. Angamos
0610, Antofagasta, Chile
AB:
The structure of the Domeyko Precordillera is dominated by a number of elongated N-S trending basement
ridges. These ridges were exhumed by steep reverse N-S faults that deformed the Mesozoic-Cenozoic cover. The
vergence of the fault system varies along the strike, conferring an apparent doubly-vergent pop-up geometry to the
axial zone. New structural data show that these geometries resulted from the reactivation and inversion of both
the Triassic and the Late Jurassic - Early Cretaceous extensional faults. Typical basement short-cut faults are
present. Basement faults uplifted the Paleozoic rocks of the hanging wall and transferred part of the shortening to
the Mesozoic - Cenozoic cover of the footwall. Both thick and thin-skinned fault systems have a common origin
and root in a rear basement fault. Fieldwork provided little evidence of strike-slip movement in these N-S
basement faults. Tertiary porphyry intrusion emplacement was strongly controlled by basement faults that
facilitated ascension of magma and its intrusion into the sedimentary cover as sills in the hanging wall anticlines.
The Late Eocene-Early Oligocene giant porphyry copper bodies (Chuquicamata, La Escondida, El Salvador)
located in the Domeyko Range show an adakitic affinity. This affinity together with structural evidence indicates
that porphyry emplacement occurred at the end of the basement-involved contractional stage and points to the
existence of a flat-slab subducting beneath the Central Andes (22°-26° SL). The eastward
migrating compressional regime in the upper plate from the Late Cretaceous onward could be attributed to the
shallowing of this slab.
DE: 8005 Folds and folding
DE: 8102 Continental contractional orogenic belts and inversion tectonics
DE: 8104 Continental margins: convergent
SC: Union [U]
MN: 2007 Joint Assembly