El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province

A complete, clastic, continental, 300 meters-thick succession outcrops close to the border crossing of the Mayer River, in the Cordillera Patagónica Austral, unconformably lying on the pre-Jurassic basement (Río Lácteo Formation); it is succeeded transitionally by the Middle Jurassic-Early Cretaceou...

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Autores principales: Escosteguy, L., Geuna, S., Etcheverría, M., Franchi, M.
Formato: JOUR
Materias:
El Bello Formation
Extension
Mesozoic
Patagonia
conglomerate
Cretaceous
Jurassic
lithostratigraphy
outcrop
sandstone
volcanism
Argentina
Santa Cruz [Argentina]
Nica
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00044822_v71_n4_p_Escosteguy
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00044822_v71_n4_p_Escosteguy
record_format dspace
spelling todo:paper_00044822_v71_n4_p_Escosteguy2023-10-03T13:59:07Z El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province Escosteguy, L. Geuna, S. Etcheverría, M. Franchi, M. El Bello Formation Extension Mesozoic Patagonia conglomerate Cretaceous Jurassic lithostratigraphy Mesozoic outcrop sandstone volcanism Argentina Patagonia Santa Cruz [Argentina] Nica A complete, clastic, continental, 300 meters-thick succession outcrops close to the border crossing of the Mayer River, in the Cordillera Patagónica Austral, unconformably lying on the pre-Jurassic basement (Río Lácteo Formation); it is succeeded transitionally by the Middle Jurassic-Early Cretaceous El Quemado Complex. The importance of this finding resides in the magnitude of the recognized sequence, with clear base and top. We propose to reunite these clastic deposits in a new lithostratigraphic unit, El Bello Formation. The type-section is located in the Argentina-Chile border, next to the Mayer River and close to Puesto El Bello. The sedimentites are constituted by polymictic conglomerates and fine- to medium-grained sandstones, with subordinate volcaniclastic sandstones. The beds are coarsening-upward, and they compose a thinning-upward sequence. The conglomerate fraction shows crude, planar and parallel stratification, while sandstones are well laminated. This unit was formed in a fluvial environment, where alluvial fans prevailed. They were the first infill in a hemigraben basin, and they would have been deposited in the first stages of the extension that would later lead to the widespread Jurassic regional volcanism. Its age has not been precisely determined, but on-going palaeomagnetic studies point to an Early Jurassic age for the magnetic remanence. We propose to include into this unit several comparable deposits, described by other authors in the cordilleran region of Santa Cruz province. © 2014, Asociacion Geologica Argentina. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00044822_v71_n4_p_Escosteguy
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic El Bello Formation
Extension
Mesozoic
Patagonia
conglomerate
Cretaceous
Jurassic
lithostratigraphy
Mesozoic
outcrop
sandstone
volcanism
Argentina
Patagonia
Santa Cruz [Argentina]
Nica
spellingShingle El Bello Formation
Extension
Mesozoic
Patagonia
conglomerate
Cretaceous
Jurassic
lithostratigraphy
Mesozoic
outcrop
sandstone
volcanism
Argentina
Patagonia
Santa Cruz [Argentina]
Nica
Escosteguy, L.
Geuna, S.
Etcheverría, M.
Franchi, M.
El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
topic_facet El Bello Formation
Extension
Mesozoic
Patagonia
conglomerate
Cretaceous
Jurassic
lithostratigraphy
Mesozoic
outcrop
sandstone
volcanism
Argentina
Patagonia
Santa Cruz [Argentina]
Nica
description A complete, clastic, continental, 300 meters-thick succession outcrops close to the border crossing of the Mayer River, in the Cordillera Patagónica Austral, unconformably lying on the pre-Jurassic basement (Río Lácteo Formation); it is succeeded transitionally by the Middle Jurassic-Early Cretaceous El Quemado Complex. The importance of this finding resides in the magnitude of the recognized sequence, with clear base and top. We propose to reunite these clastic deposits in a new lithostratigraphic unit, El Bello Formation. The type-section is located in the Argentina-Chile border, next to the Mayer River and close to Puesto El Bello. The sedimentites are constituted by polymictic conglomerates and fine- to medium-grained sandstones, with subordinate volcaniclastic sandstones. The beds are coarsening-upward, and they compose a thinning-upward sequence. The conglomerate fraction shows crude, planar and parallel stratification, while sandstones are well laminated. This unit was formed in a fluvial environment, where alluvial fans prevailed. They were the first infill in a hemigraben basin, and they would have been deposited in the first stages of the extension that would later lead to the widespread Jurassic regional volcanism. Its age has not been precisely determined, but on-going palaeomagnetic studies point to an Early Jurassic age for the magnetic remanence. We propose to include into this unit several comparable deposits, described by other authors in the cordilleran region of Santa Cruz province. © 2014, Asociacion Geologica Argentina. All rights reserved.
format JOUR
author Escosteguy, L.
Geuna, S.
Etcheverría, M.
Franchi, M.
author_facet Escosteguy, L.
Geuna, S.
Etcheverría, M.
Franchi, M.
author_sort Escosteguy, L.
title El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
title_short El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
title_full El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
title_fullStr El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
title_full_unstemmed El Bello Formation (nom. nov.), early Jurassic from cordillera patagónica Austral, Santa Cruz province
title_sort el bello formation (nom. nov.), early jurassic from cordillera patagónica austral, santa cruz province
url http://hdl.handle.net/20.500.12110/paper_00044822_v71_n4_p_Escosteguy
work_keys_str_mv AT escosteguyl elbelloformationnomnovearlyjurassicfromcordillerapatagonicaaustralsantacruzprovince
AT geunas elbelloformationnomnovearlyjurassicfromcordillerapatagonicaaustralsantacruzprovince
AT etcheverriam elbelloformationnomnovearlyjurassicfromcordillerapatagonicaaustralsantacruzprovince
AT franchim elbelloformationnomnovearlyjurassicfromcordillerapatagonicaaustralsantacruzprovince
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