Author(s):
Kullberg, M. C. 
; Kullberg, J. C. ; Ribeiro, A. ; Phipps, S.
Date: 1995
Persistent ID: http://hdl.handle.net/10362/2284
Origin: Repositório Institucional da UNL
Document details
Geodynamics of the eastern sector of the Arrábida chain (W Portugal)
Description
N.º4, p.263-267 The Arrábida chain - located in the southern segment of the Lusitanian basin - is a S-wards directed fold and thrust belt of Miocene age of deformation. ENE-WSW striking frontal ramps and associated folds are connected to sinistral NNE-SSW and N-S striking lateral ramps, that show left-lateral and SE-wards reverse movements. Both frontal and oblique ramps form imbricate duplexes. Constriction increases SE-wards due to the presence of a basin boundary fault (SetúbaI- Pinhal Novo fault) that acts as a buttress to the oblique thrust movement. Kilometre scale transpressive structures can be observed along the basin boundary fault. A map scale sheath fold like structure can be observed at the Viso anticline, which is a consequence of a strong anisotropy contrast of the Mesocenozoic strata.The Arrábida chain thrusts migrated backward, i.e. to the north, according to an overstep model. Detailed geometrical reconstruction and kinematic analysis of the structures of the eastern region of Arrábida (Formosinho, Vise and Serra de S. Luis anticlines) show that a thin-skinned tectonic model (Ribeiro, A. et aI., 1990) fits very well with the geometry of the structures of the Arrábida chain.
N.º4, p.263-267 The Arrábida chain - located in the southern segment of the Lusitanian basin - is a S-wards directed fold and thrust belt of Miocene age of deformation. ENE-WSW striking frontal ramps and associated folds are connected to sinistral NNE-SSW and N-S striking lateral ramps, that show left-lateral and SE-wards reverse movements. Both frontal and oblique ramps form imbricate duplexes. Constriction increases SE-wards due to the presence of a basin boundary fault (SetúbaI- Pinhal Novo fault) that acts as a buttress to the oblique thrust movement. Kilometre scale transpressive structures can be observed along the basin boundary fault. A map scale sheath fold like structure can be observed at the Viso anticline, which is a consequence of a strong anisotropy contrast of the Mesocenozoic strata.The Arrábida chain thrusts migrated backward, i.e. to the north, according to an overstep model. Detailed geometrical reconstruction and kinematic analysis of the structures of the eastern region of Arrábida (Formosinho, Vise and Serra de S. Luis anticlines) show that a thin-skinned tectonic model (Ribeiro, A. et aI., 1990) fits very well with the geometry of the structures of the Arrábida chain.
Document Type
Article
Language English
Language English
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