Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina

A palaeomagnetic study of Upper Palaeozoic rocks was performed on Paganzo basin, central-western Argentina and its western extension, Río Blanco subbasin. The volcanic-volcaniclastic Rio del Peñón and marine sedimentary Punta del Agua formations were sampled in the Rincón Blanco syncline. Both units...

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Autores principales: Geuna, S.E., Escosteguy, L.D.
Formato: JOUR
Materias:
Block rotations
Orogeny
Palaeomagnetism
Remagnetization
South America
Upper Palaeozoic
Carboniferous
geophysics
paleomagnetism
Permian
Argentina
Paganzo Basin
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0956540X_v157_n3_p1071_Geuna
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_0956540X_v157_n3_p1071_Geuna2023-10-03T15:52:05Z Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina Geuna, S.E. Escosteguy, L.D. Block rotations Orogeny Palaeomagnetism Remagnetization South America Upper Palaeozoic Carboniferous geophysics paleomagnetism Permian Argentina Paganzo Basin South America A palaeomagnetic study of Upper Palaeozoic rocks was performed on Paganzo basin, central-western Argentina and its western extension, Río Blanco subbasin. The volcanic-volcaniclastic Rio del Peñón and marine sedimentary Punta del Agua formations were sampled in the Rincón Blanco syncline. Both units represent the Upper Carboniferous-Lower Permian transition according to palaeontological and geochronological evidence. The Chancani and Cerro Colorado-Caminiaga formations were sampled in their type localities, in the eastern Paganzo basin. All-reversed, pre-tectonic characteristic magnetizations were isolated in all three localities, spanning a wide lithological variation. Particularly in the Rincón Blanco syncline, the same reversed magnetization is observed in the entire 1500 m-thick sequence in volcanic and sedimentary rocks; at least part of the deformation there is thought to be Permian in age, related to the San Rafael orogenic phase (SROP). The palaeomagnetic poles are: Rincón Blanco (RB) Lat. 77°S, Long. 294°E, N = 19, A95 = 4.9, K = 47; Chancaní (CH) Lat. 85°S, Long. 359°E, N = 3, A95 = 8.8, K = 196; Cerro Colorado-Caminiaga (CC) Lat. 79°S, Long. 291°E, N = 6, A95 = 8.0, K = 71. Neither of the poles is coincident with expected Late Carboniferous-Early Permian directions according to accepted apparent polar-wander paths (APWPs) from South America and from other plates forming Pangaea in Late Palaeozoic times. This discrepancy could be the result of: (i) polar wander affecting the western Gondwana margin, probably related to SROP; (ii) tectonic rotations related to strike-slip faults active in the area since the Palaeozoic and controlling the position of the main depocentres; (iii) incorrect age assignment for the sedimentary sequences or for the remanence acquisition, i.e. local remagnetizations. Tectonic rotations and local remagnetization have both been proven in particular localities and further work needs to be done to establish the Late Palaeozoic APWP for South America, however, SROP seems to have played a major role controlling both processes, rotation and remagnetization. © 2004 RAS. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0956540X_v157_n3_p1071_Geuna
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Block rotations
Orogeny
Palaeomagnetism
Remagnetization
South America
Upper Palaeozoic
Carboniferous
geophysics
paleomagnetism
Permian
Argentina
Paganzo Basin
South America
spellingShingle Block rotations
Orogeny
Palaeomagnetism
Remagnetization
South America
Upper Palaeozoic
Carboniferous
geophysics
paleomagnetism
Permian
Argentina
Paganzo Basin
South America
Geuna, S.E.
Escosteguy, L.D.
Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
topic_facet Block rotations
Orogeny
Palaeomagnetism
Remagnetization
South America
Upper Palaeozoic
Carboniferous
geophysics
paleomagnetism
Permian
Argentina
Paganzo Basin
South America
description A palaeomagnetic study of Upper Palaeozoic rocks was performed on Paganzo basin, central-western Argentina and its western extension, Río Blanco subbasin. The volcanic-volcaniclastic Rio del Peñón and marine sedimentary Punta del Agua formations were sampled in the Rincón Blanco syncline. Both units represent the Upper Carboniferous-Lower Permian transition according to palaeontological and geochronological evidence. The Chancani and Cerro Colorado-Caminiaga formations were sampled in their type localities, in the eastern Paganzo basin. All-reversed, pre-tectonic characteristic magnetizations were isolated in all three localities, spanning a wide lithological variation. Particularly in the Rincón Blanco syncline, the same reversed magnetization is observed in the entire 1500 m-thick sequence in volcanic and sedimentary rocks; at least part of the deformation there is thought to be Permian in age, related to the San Rafael orogenic phase (SROP). The palaeomagnetic poles are: Rincón Blanco (RB) Lat. 77°S, Long. 294°E, N = 19, A95 = 4.9, K = 47; Chancaní (CH) Lat. 85°S, Long. 359°E, N = 3, A95 = 8.8, K = 196; Cerro Colorado-Caminiaga (CC) Lat. 79°S, Long. 291°E, N = 6, A95 = 8.0, K = 71. Neither of the poles is coincident with expected Late Carboniferous-Early Permian directions according to accepted apparent polar-wander paths (APWPs) from South America and from other plates forming Pangaea in Late Palaeozoic times. This discrepancy could be the result of: (i) polar wander affecting the western Gondwana margin, probably related to SROP; (ii) tectonic rotations related to strike-slip faults active in the area since the Palaeozoic and controlling the position of the main depocentres; (iii) incorrect age assignment for the sedimentary sequences or for the remanence acquisition, i.e. local remagnetizations. Tectonic rotations and local remagnetization have both been proven in particular localities and further work needs to be done to establish the Late Palaeozoic APWP for South America, however, SROP seems to have played a major role controlling both processes, rotation and remagnetization. © 2004 RAS.
format JOUR
author Geuna, S.E.
Escosteguy, L.D.
author_facet Geuna, S.E.
Escosteguy, L.D.
author_sort Geuna, S.E.
title Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
title_short Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
title_full Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
title_fullStr Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
title_full_unstemmed Palaeomagnetism of the Upper Carboniferous-Lower Permian transition from Paganzo basin, Argentina
title_sort palaeomagnetism of the upper carboniferous-lower permian transition from paganzo basin, argentina
url http://hdl.handle.net/20.500.12110/paper_0956540X_v157_n3_p1071_Geuna
work_keys_str_mv AT geunase palaeomagnetismoftheuppercarboniferouslowerpermiantransitionfrompaganzobasinargentina
AT escosteguyld palaeomagnetismoftheuppercarboniferouslowerpermiantransitionfrompaganzobasinargentina
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