The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas

The Bajada del Diablo astrobleme-strewn field is a huge domain of enigmatic circular structures located in central Patagonia. Three more localities are herein described, adding to the first area studied so far. Taking into consideration the four areas, a single, blurred crater dispersion ellipse has...

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Autores principales: Acevedo, R.D., Rabassa, J., Ponce, J.F., Martínez, O., Orgeira, M.J., Prezzi, C., Corbella, H., González-Guillot, M., Rocca, M., Subías, I., Vásquez, C.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0169555X_v169-170_n_p151_Acevedo
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spelling todo:paper_0169555X_v169-170_n_p151_Acevedo2023-10-03T15:07:13Z The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas Acevedo, R.D. Rabassa, J. Ponce, J.F. Martínez, O. Orgeira, M.J. Prezzi, C. Corbella, H. González-Guillot, M. Rocca, M. Subías, I. Vásquez, C. Argentina Astrobleme-strewn field Bajada del Diablo Patagonia Pleistocene asteroid astrobleme comet crater geomorphology magnetic anomaly pediment Pleistocene remote sensing stratigraphy Argentina Patagonia Spherules The Bajada del Diablo astrobleme-strewn field is a huge domain of enigmatic circular structures located in central Patagonia. Three more localities are herein described, adding to the first area studied so far. Taking into consideration the four areas, a single, blurred crater dispersion ellipse has been identified. The four sectors now have been investigated, mapped, and georreferenced. Their circular structures, with a total of 185 (some of which are partially obliterated by erosion or sediment accumulation), were identified by remote sensing techniques, but many have been evaluated in situ and interpreted as impact craters. Moreover, two of the structures have been surveyed in detail in the field using a total station instrument. In addition to the previously known occurrence of circular structures on the Eruptive Complex Quiñelaf (Miocene basalts), the Pampa Sastre Fm. (Pliocene conglomerates), and of the Pleistocene pediment gravels and sands, and the geomorphological inferences that have suggested the extra-terrestrial origin of this event, we should now add that the recurrent absence of the cited Pliocene stratigraphic unit at the bottom of the craters is found in the pediment gravel and sands. Its removal has been interpreted as directly related to the impact, according to the magnetometric record of existing magnetic anomalies. Other preliminary observations on the collected samples (glass, breccias, and, most relevant, Fe-Ni-bearing spherules picked up within the impact zones) are herein discussed. Two hypotheses have been put forward about the nature of the possible impacting object that formed these astroblemes which, fragmented into hundreds of pieces, hit the surface of the Earth most likely in middle Pleistocene times. One of these hypotheses is related to the impact of a disintegrated asteroid of the rubble pile type, whereas a second hypothesis refers to the collision of a split comet with the Earth surface. The latter hypothesis is favoured since no meteorite fragments have been found so far. © 2012. Fil:Acevedo, R.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Orgeira, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Prezzi, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vásquez, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0169555X_v169-170_n_p151_Acevedo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Argentina
Astrobleme-strewn field
Bajada del Diablo
Patagonia
Pleistocene
asteroid
astrobleme
comet
crater
geomorphology
magnetic anomaly
pediment
Pleistocene
remote sensing
stratigraphy
Argentina
Patagonia
Spherules
spellingShingle Argentina
Astrobleme-strewn field
Bajada del Diablo
Patagonia
Pleistocene
asteroid
astrobleme
comet
crater
geomorphology
magnetic anomaly
pediment
Pleistocene
remote sensing
stratigraphy
Argentina
Patagonia
Spherules
Acevedo, R.D.
Rabassa, J.
Ponce, J.F.
Martínez, O.
Orgeira, M.J.
Prezzi, C.
Corbella, H.
González-Guillot, M.
Rocca, M.
Subías, I.
Vásquez, C.
The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
topic_facet Argentina
Astrobleme-strewn field
Bajada del Diablo
Patagonia
Pleistocene
asteroid
astrobleme
comet
crater
geomorphology
magnetic anomaly
pediment
Pleistocene
remote sensing
stratigraphy
Argentina
Patagonia
Spherules
description The Bajada del Diablo astrobleme-strewn field is a huge domain of enigmatic circular structures located in central Patagonia. Three more localities are herein described, adding to the first area studied so far. Taking into consideration the four areas, a single, blurred crater dispersion ellipse has been identified. The four sectors now have been investigated, mapped, and georreferenced. Their circular structures, with a total of 185 (some of which are partially obliterated by erosion or sediment accumulation), were identified by remote sensing techniques, but many have been evaluated in situ and interpreted as impact craters. Moreover, two of the structures have been surveyed in detail in the field using a total station instrument. In addition to the previously known occurrence of circular structures on the Eruptive Complex Quiñelaf (Miocene basalts), the Pampa Sastre Fm. (Pliocene conglomerates), and of the Pleistocene pediment gravels and sands, and the geomorphological inferences that have suggested the extra-terrestrial origin of this event, we should now add that the recurrent absence of the cited Pliocene stratigraphic unit at the bottom of the craters is found in the pediment gravel and sands. Its removal has been interpreted as directly related to the impact, according to the magnetometric record of existing magnetic anomalies. Other preliminary observations on the collected samples (glass, breccias, and, most relevant, Fe-Ni-bearing spherules picked up within the impact zones) are herein discussed. Two hypotheses have been put forward about the nature of the possible impacting object that formed these astroblemes which, fragmented into hundreds of pieces, hit the surface of the Earth most likely in middle Pleistocene times. One of these hypotheses is related to the impact of a disintegrated asteroid of the rubble pile type, whereas a second hypothesis refers to the collision of a split comet with the Earth surface. The latter hypothesis is favoured since no meteorite fragments have been found so far. © 2012.
format JOUR
author Acevedo, R.D.
Rabassa, J.
Ponce, J.F.
Martínez, O.
Orgeira, M.J.
Prezzi, C.
Corbella, H.
González-Guillot, M.
Rocca, M.
Subías, I.
Vásquez, C.
author_facet Acevedo, R.D.
Rabassa, J.
Ponce, J.F.
Martínez, O.
Orgeira, M.J.
Prezzi, C.
Corbella, H.
González-Guillot, M.
Rocca, M.
Subías, I.
Vásquez, C.
author_sort Acevedo, R.D.
title The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
title_short The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
title_full The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
title_fullStr The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
title_full_unstemmed The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas
title_sort bajada del diablo astrobleme-strewn field, central patagonia argentina: extending the exploration to surrounding areas
url http://hdl.handle.net/20.500.12110/paper_0169555X_v169-170_n_p151_Acevedo
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