Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina

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The Quaternary infilling of a circular structure located in Bajada del Diablo, Chubut Province, Argentina has been proposed as a crater strewn field in previous studies. Here we report the finding of about 65 microspherules collected in a trench excavated in the center of the structure. The majority...

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Autores principales:	Orgeira, María Julia, Castro, Liliana Norma, Prezzi, Claudia Beatriz, Sileo, Elsa Ester, Franzosi, Corina, Acevedo, Rogelio Daniel, Tofalo, Ofelia Rita de las Mercedes
Publicado:	2017
Materias:	Bajada del Diablo Chemistry Chubut Extraterrestrial microspherules Patagonia-Argentina asteroid chemical composition chemistry magnetite spherulite Antarctica Argentina Patagonia Transantarctic Mountains
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16749871_v8_n1_p137_Orgeira http://hdl.handle.net/20.500.12110/paper_16749871_v8_n1_p137_Orgeira
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_16749871_v8_n1_p137_Orgeira
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spelling	paper:paper_16749871_v8_n1_p137_Orgeira2023-06-08T16:26:26Z Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina Orgeira, María Julia Castro, Liliana Norma Prezzi, Claudia Beatriz Sileo, Elsa Ester Franzosi, Corina Acevedo, Rogelio Daniel Tofalo, Ofelia Rita de las Mercedes Bajada del Diablo Chemistry Chubut Extraterrestrial microspherules Patagonia-Argentina asteroid chemical composition chemistry magnetite spherulite Antarctica Argentina Chubut Patagonia Transantarctic Mountains The Quaternary infilling of a circular structure located in Bajada del Diablo, Chubut Province, Argentina has been proposed as a crater strewn field in previous studies. Here we report the finding of about 65 microspherules collected in a trench excavated in the center of the structure. The majority of hand-picked specimens are single, but some of them exhibit compound forms. The single specimens are spherical with a mean size of 137 μm, whereas the more complex samples show peduncles and drop shapes. Dendritic crystal growth is recognized in the internal structure of some broken microspherules. Preliminary chemical composition from the surface and center of microspherules was determined by energy dispersive spectrometry employing EDS. Quantitative EMPA and XRD analysis indicate that the microspherules are mainly composed of Fe and O with magnetite, Fe0 with subordinate wüstite. Following consideration of possible anthropogenic and volcanic origins, these spherulites are ascribed to an extraterrestrial input. An accumulation rate of 47 microspherules per m2/yr is estimated for the studied sediments. This value is two orders of magnitude higher than the reference flux for cosmic dust estimated for the last 1 Ma in the Transantarctic Mountains. The microspherules might have been generated as a byproduct of asteroid entry in the atmosphere. © 2016 China University of Geosciences (Beijing) and Peking University Fil:Orgeira, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Castro, L.N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Prezzi, C.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Sileo, E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Franzosi, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Acevedo, R.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Tófalo, O.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16749871_v8_n1_p137_Orgeira http://hdl.handle.net/20.500.12110/paper_16749871_v8_n1_p137_Orgeira
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Bajada del Diablo Chemistry Chubut Extraterrestrial microspherules Patagonia-Argentina asteroid chemical composition chemistry magnetite spherulite Antarctica Argentina Chubut Patagonia Transantarctic Mountains
spellingShingle	Bajada del Diablo Chemistry Chubut Extraterrestrial microspherules Patagonia-Argentina asteroid chemical composition chemistry magnetite spherulite Antarctica Argentina Chubut Patagonia Transantarctic Mountains Orgeira, María Julia Castro, Liliana Norma Prezzi, Claudia Beatriz Sileo, Elsa Ester Franzosi, Corina Acevedo, Rogelio Daniel Tofalo, Ofelia Rita de las Mercedes Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
topic_facet	Bajada del Diablo Chemistry Chubut Extraterrestrial microspherules Patagonia-Argentina asteroid chemical composition chemistry magnetite spherulite Antarctica Argentina Chubut Patagonia Transantarctic Mountains
description	The Quaternary infilling of a circular structure located in Bajada del Diablo, Chubut Province, Argentina has been proposed as a crater strewn field in previous studies. Here we report the finding of about 65 microspherules collected in a trench excavated in the center of the structure. The majority of hand-picked specimens are single, but some of them exhibit compound forms. The single specimens are spherical with a mean size of 137 μm, whereas the more complex samples show peduncles and drop shapes. Dendritic crystal growth is recognized in the internal structure of some broken microspherules. Preliminary chemical composition from the surface and center of microspherules was determined by energy dispersive spectrometry employing EDS. Quantitative EMPA and XRD analysis indicate that the microspherules are mainly composed of Fe and O with magnetite, Fe0 with subordinate wüstite. Following consideration of possible anthropogenic and volcanic origins, these spherulites are ascribed to an extraterrestrial input. An accumulation rate of 47 microspherules per m2/yr is estimated for the studied sediments. This value is two orders of magnitude higher than the reference flux for cosmic dust estimated for the last 1 Ma in the Transantarctic Mountains. The microspherules might have been generated as a byproduct of asteroid entry in the atmosphere. © 2016 China University of Geosciences (Beijing) and Peking University
author	Orgeira, María Julia Castro, Liliana Norma Prezzi, Claudia Beatriz Sileo, Elsa Ester Franzosi, Corina Acevedo, Rogelio Daniel Tofalo, Ofelia Rita de las Mercedes
author_facet	Orgeira, María Julia Castro, Liliana Norma Prezzi, Claudia Beatriz Sileo, Elsa Ester Franzosi, Corina Acevedo, Rogelio Daniel Tofalo, Ofelia Rita de las Mercedes
author_sort	Orgeira, María Julia
title	Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
title_short	Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
title_full	Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
title_fullStr	Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
title_full_unstemmed	Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina
title_sort	extraterrestrial microspherules from bajada del diablo, chubut, argentina
publishDate	2017
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_16749871_v8_n1_p137_Orgeira http://hdl.handle.net/20.500.12110/paper_16749871_v8_n1_p137_Orgeira
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Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina

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