Extraterrestrial microspherules from Bajada del Diablo,Chubut,Argentina
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摘要
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 handpicked specimens are single,but some of them exhibit compound forms.The single specimens are spherical with a mean size of 137 nm,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,Fe~0 with subordinate wiistite.Following consideration of possible anthropogenic and volcanic origins,these spherulites are ascribed to an extraterrestrial input.An accumulation rate of 47 microspherules per m~2/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.
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 handpicked specimens are single,but some of them exhibit compound forms.The single specimens are spherical with a mean size of 137 nm,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,Fe~0 with subordinate wiistite.Following consideration of possible anthropogenic and volcanic origins,these spherulites are ascribed to an extraterrestrial input.An accumulation rate of 47 microspherules per m~2/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.
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 handpicked specimens are single,but some of them exhibit compound forms.The single specimens are spherical with a mean size of 137 nm,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,Fe~0 with subordinate wiistite.Following consideration of possible anthropogenic and volcanic origins,these spherulites are ascribed to an extraterrestrial input.An accumulation rate of 47 microspherules per m~2/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.
引文
Acevedo,R.D.,Ponce,J.F..Rocca.M..Rabassa,J.,Corbella,H.,2009.Bajada del Diablo impact crater-strewn field:the largest crater field in the Southern Hemisphere.Geomorphology 110(3-4),58-67.
Acevedo,R.D.,Rabassa.J.,Ponce,J.F.,Martinez,O.,Orgeira,M.J.,Prezzi,C,Corbella,H..GonzaTez-Guillot,M..Rocca.M..Subias.I.,Vasquez,C,2012.The Bajada del Diablo astrobleme-strewn field,central Patagonia Argentina:extending the exploration to surrounding areas.Geomorphology 169,151-164.
Alonso-Zarza,A.M.,Wright,V.P.,2010.Calcretes.In:Alonzo-Zarza.A.M.,Tanner,LH.(Eds.).Carbonates in Continental Settings:Facies,Environments,and Processes.Developments in Sedimentology,vol.61,pp.225-268.
Ardolino,A.A.,1981.El vulcanismo cenozoico del borde suroccidental de la meseta de Somun Cura.provincia del Chubut.In:Proc.7 Congreso Geologico Argentine vol.3,pp.7-23.Buenos Aires,(in Spanish).
Ardolino,A.A.,1987.Descripcion Geologica de la Hoja 42f.Sierra de Apas,Provincia de Chubut.Servicio Geologico Nacional.Direccion Nacional de Mineria y Geologia,Buenos Aires,91 pp(in Spanish).
Ardolino,A.A.,Franchi,M.,1996.Hoja Geologica 4366-1.Telsen.Direccion Nacional del Servicio Geologico,Subsecretarfa de Mineria de la Nacion,Buenos Aires.Boletin 215.110 pp(in Spanish).
Bi,D.,Morton,R.D.,Wang,K.,1993.Cosmic nickel-iron alloy spherules from Pleistocene sediments,Alberta,Canada.Ceochimica et Cosmochimica Acta 5716,4129-4136.
Blanchard,M.B.,Brownlee,D.E.,Bunch,T.E.,Hodge,P.W.,Kyte,F.T.,1978.Meteor ablation spheres from deep-sea sediments.NASA Technical Memorandum78510,41 pp.
Bouza,P.J.,2012.Genesis de las acumulaciones de carbonates en Aridisoles nordpatagonicos:su significado paleopedologico.Revista de la Asociacion Geologica Argentina 69(2),300-315(in Spanish with English abstract).
Carracedo Sanchez,M.,Sarrionandia,F.,Arostegui.J..Gil IbarguchiJ.I.,2015.Silicate glass micro and nanospherules generated in explosive eruptions of ultrabasic magmas:implications for the origin of pelletal lapilli.Journal of Volcanology and Ceothermal Research 293,13-24.
Collins,G.S.,Melosh,H.J.,Marcus,R.A.,2005.Earth impact effects program:a webbased computer program for calculating the regional environmental consequences of a meteoroid impact on Earth.Meteoritics&Planetary Science406,817-840.
Dunlop,D.J.,(O|¨)zdemir,O.,1997.Rock Magnetism:Fundamentals and Frontiers.Cambridge University Press,Cambridge,U.K.,565 pp.
Evans,M.,Heller,F.,2003.Environmental Magnetism:Principles and Applications of Environmagnetics.Academic Press.Chapter 10(86),299 pp.
Folco,L,D'Orazio,M.,Fazio,A.,Cordier,C,Zeoli,A.,Cinneken,M.,El-Barkooky,A.,2015.Microscopic impactor debris in the soil around Kamil crater(Egypt):inventory,distribution,total mass,and implications for the impact scenario.Meteoritics&Planetary Science 50(3),382-400.
Folco,L,Di Martino,M.,El Barkooky,A..D'Orazio,M.,Lethy,A.,Urbini,S.,Nicolosi,I.,Hafez,M.,Cordier,C,van Ginneken,M.,Zeoli,A.,Radwan,A.M.,El Khrepy,S.,El Gabry,M.,Gomaa,M.,Barakat,A.A.,Serra,R.,El Sharkawi,M.,2011.Kamil crater Egypt:ground truth for small-scale meteorite impacts on Earth.Geology 392,179-182.
French,B.M.,1998.Traces of Catastrophe:a Handbook of Shock-metamorphic Effects in Terrestrial Meteorite Impact Structures.LPI Contribution No.954.Lunar and Planetary Institute,Houston,120 pp.
French,B.M.,Koeberl,C,2010.The convincing identification of terrestrial meteorite impact structures:what works,what doesn't,and why.Earth-Science Reviews981,123-170.
Genge,M.J.,Grady,M.M.,1999.The fusion crusts of stony meteorites:implications for the atmospheric reprocessing of extraterrestrial materials.Meteoritics&Planetary Science 343,341-356.
Genge,M.J.,Engrand,C,Gounelle,M.,Taylor,S.,2008.The classification of micrometeorites.Meteoritics&Planetary Science 433,497-515.
Glass,B.P.,Simonson,B.M.,2012.Distal impact ejecta layers:spherules and more.Elements 81,43-48.
Gonzalez Diaz,E.,Malagnino,E.C.,1984.Geomorfologia.In:Relatorio IX Congreso Geologico Argentino.Buenos Aires,pp.347-364(in Spanish).
Grieve,R.A.F.,Pilkington,M.,1996.The signature of terrestrial impacts.AGSO Journal of Australian Geology and Geophysics 164,399-420.
Guaita,C,Martegani,R,2008.Cosmic microsphere:a SEM study.Memorie della Societa Astronomica Italiana Supplementi 12,110.
Gurov,E.P.,Gurova,E.P.,1998.The group of Macha craters in western Yakutia.Planetary and Space Science 462,323-328.
Hay,R.L.,Wiggins,B.,1980.Pellets,ooids,sepiolite and silica in three calcretes of de southwestern United States.Sedimentology 27,559-576.
Johnson,B.C.,Melosh.H.J.,2012.Formation of spherules in impact produced vapor plumes.Icarus 2171,416-430.
Johnson,B.C.,Melosh,H.J.,2014.Formation of melt droplets,melt fragments,and accretionary impact lapilli during a hypervelocity impact.Icarus 228,347-363.
Maher,B.A.,Thompson,R..Hounlow,M.W.,1999.In:Maher,B.A.,Thompson,R.(Eds.),Quaternary Climates,Environments and Magnetism,(Chapter 1).Cambridge University Press,390 pp.
Marini,E,Raukas,A.,Tiirmaa,R.,2004.Magnetic fines from the Kaali impact-site(Holocene,Estonia):Preliminary SEM investigation.Geochemical Journal 38(2),107-120.
Narayan,D.,Tandon,S..1981.Calcrete conglomerate,case-hardened conglomerate and cornstone,Siwalik Group,Punjab,India.Sedimentology 28,353-367.
Pike,R.J.,1980.Control of crater morphology by gravity and target type-Mars,Earth,Moon.In:Proc.Lunar and Planetary Science Conference,vol.11,pp.2159-2189.
Prezzi,C,Orgeira,M.J.,Acevedo,R.D.,Ponce,J.F.,Martinez,O.,Rabassa,J.,Corbella,H.,Vasquez,C,Gonzalez,M.,Subias,I.,2012.Geophysical characterization of two circular structures at Bajada del Diablo Patagonia.Argentina:indication of impact origin.Physics of the Earth and Planetary Interiors192-193,21-34.
Prezzi,C,Orgeira,M.J.,Acevedo,R.,Ponce,F.,Martinez,O.,Sarnataro,A.,Rabassa,J.,2013.Bajada del Diablo Circular Structures Chubut,Argentina:Ground Gravity,Magnetic and Electromagnetic Surveys.Latinmag 3 Reunion Bienal de la Asociacion Latinoamericana de Paleomagnetismo y Geomagnetismo,Montevideo,Uruguay.Latinmag Letters,3:3 2013,OA7,1-6(in Spanish with English abstract).
Prezzi,C,Orgeira,M.J.,Martinez,O.,Acevedo,R.D.,Ponce,F.,Goldmann,G..Magneres,I.,Rabassa,J.,2016.Circular structures of Bajada del Diablo Argentina:geophysical signature compatible with an impact origin.Geophysical Journal International 205(2),876-899.
Raukas,A.,2004.Distribution and composition of impact and extraterrestrial spherules in the Kaali area Island of Saaremaa,Estonia.Geochemical Journal382,101-106.
Rochette,P.,Folco,L,Suavet,C,Van Ginneken,M.,Gattacceca,J.,Perchiazzi,N.,Braucher,R.,Harvey,R.P.,2008.Micrometeorites from the transantarctic mountains.Proceedings of the National Academy of Sciences of the United States of America 10547,18206-18211.
Stankowski,W.T.J.,Katrusiak,A.,Budzianowski,A.,2006.Crystallographic variety of magnetic spherules from Pleistocene and Holocene sediments in the Northern foreland of Morasko-Meteorite Reserve.Planetary and Space Science 541,60-70.
Taylor,S.,Lever,J.H.,Harvey,R.P.,2000.Numbers,types,and compositions of an unbiased collection of cosmic spherules.Meteoritics&Planetary Science 55,651-666.
Valencio,D.A.,Orgeira,M.J.,Bobbio,M.L.,1987.Magnetoestratigraphy and magnetic susceptibility data of the late Cenozoic Ensenadense and Bonaerense of the cities of Buenos Aires and La Plata,central-eastern Argentina.Quaternary of South America and Antartic Peninsula 5,5-32.
Voldman,G.G.,Genge,M.J.,Albanesi,G.L.,Barnes,C.R.,Ortega,G.,2013.Cosmic spherules from the Ordovician of Argentina.Geological Journal 482(3),222-235.
Wright,V.,1983.A rendzina from de Lower Carboniferous of South Wales.Sedimentology 30,159-179.
Yada,T.,Nakamura,T.,Sekiya,M.,Takaoka,N.,1996.Formation processes of magnetic spherules collected from deep-sea sediments-observations and numerical simulations of the orbital evolution.Antarctic Meteorite Research 9,218.
Acevedo,R.D.,Rabassa.J.,Ponce,J.F.,Martinez,O.,Orgeira,M.J.,Prezzi,C,Corbella,H..GonzaTez-Guillot,M..Rocca.M..Subias.I.,Vasquez,C,2012.The Bajada del Diablo astrobleme-strewn field,central Patagonia Argentina:extending the exploration to surrounding areas.Geomorphology 169,151-164.
Alonso-Zarza,A.M.,Wright,V.P.,2010.Calcretes.In:Alonzo-Zarza.A.M.,Tanner,LH.(Eds.).Carbonates in Continental Settings:Facies,Environments,and Processes.Developments in Sedimentology,vol.61,pp.225-268.
Ardolino,A.A.,1981.El vulcanismo cenozoico del borde suroccidental de la meseta de Somun Cura.provincia del Chubut.In:Proc.7 Congreso Geologico Argentine vol.3,pp.7-23.Buenos Aires,(in Spanish).
Ardolino,A.A.,1987.Descripcion Geologica de la Hoja 42f.Sierra de Apas,Provincia de Chubut.Servicio Geologico Nacional.Direccion Nacional de Mineria y Geologia,Buenos Aires,91 pp(in Spanish).
Ardolino,A.A.,Franchi,M.,1996.Hoja Geologica 4366-1.Telsen.Direccion Nacional del Servicio Geologico,Subsecretarfa de Mineria de la Nacion,Buenos Aires.Boletin 215.110 pp(in Spanish).
Bi,D.,Morton,R.D.,Wang,K.,1993.Cosmic nickel-iron alloy spherules from Pleistocene sediments,Alberta,Canada.Ceochimica et Cosmochimica Acta 5716,4129-4136.
Blanchard,M.B.,Brownlee,D.E.,Bunch,T.E.,Hodge,P.W.,Kyte,F.T.,1978.Meteor ablation spheres from deep-sea sediments.NASA Technical Memorandum78510,41 pp.
Bouza,P.J.,2012.Genesis de las acumulaciones de carbonates en Aridisoles nordpatagonicos:su significado paleopedologico.Revista de la Asociacion Geologica Argentina 69(2),300-315(in Spanish with English abstract).
Carracedo Sanchez,M.,Sarrionandia,F.,Arostegui.J..Gil IbarguchiJ.I.,2015.Silicate glass micro and nanospherules generated in explosive eruptions of ultrabasic magmas:implications for the origin of pelletal lapilli.Journal of Volcanology and Ceothermal Research 293,13-24.
Collins,G.S.,Melosh,H.J.,Marcus,R.A.,2005.Earth impact effects program:a webbased computer program for calculating the regional environmental consequences of a meteoroid impact on Earth.Meteoritics&Planetary Science406,817-840.
Dunlop,D.J.,(O|¨)zdemir,O.,1997.Rock Magnetism:Fundamentals and Frontiers.Cambridge University Press,Cambridge,U.K.,565 pp.
Evans,M.,Heller,F.,2003.Environmental Magnetism:Principles and Applications of Environmagnetics.Academic Press.Chapter 10(86),299 pp.
Folco,L,D'Orazio,M.,Fazio,A.,Cordier,C,Zeoli,A.,Cinneken,M.,El-Barkooky,A.,2015.Microscopic impactor debris in the soil around Kamil crater(Egypt):inventory,distribution,total mass,and implications for the impact scenario.Meteoritics&Planetary Science 50(3),382-400.
Folco,L,Di Martino,M.,El Barkooky,A..D'Orazio,M.,Lethy,A.,Urbini,S.,Nicolosi,I.,Hafez,M.,Cordier,C,van Ginneken,M.,Zeoli,A.,Radwan,A.M.,El Khrepy,S.,El Gabry,M.,Gomaa,M.,Barakat,A.A.,Serra,R.,El Sharkawi,M.,2011.Kamil crater Egypt:ground truth for small-scale meteorite impacts on Earth.Geology 392,179-182.
French,B.M.,1998.Traces of Catastrophe:a Handbook of Shock-metamorphic Effects in Terrestrial Meteorite Impact Structures.LPI Contribution No.954.Lunar and Planetary Institute,Houston,120 pp.
French,B.M.,Koeberl,C,2010.The convincing identification of terrestrial meteorite impact structures:what works,what doesn't,and why.Earth-Science Reviews981,123-170.
Genge,M.J.,Grady,M.M.,1999.The fusion crusts of stony meteorites:implications for the atmospheric reprocessing of extraterrestrial materials.Meteoritics&Planetary Science 343,341-356.
Genge,M.J.,Engrand,C,Gounelle,M.,Taylor,S.,2008.The classification of micrometeorites.Meteoritics&Planetary Science 433,497-515.
Glass,B.P.,Simonson,B.M.,2012.Distal impact ejecta layers:spherules and more.Elements 81,43-48.
Gonzalez Diaz,E.,Malagnino,E.C.,1984.Geomorfologia.In:Relatorio IX Congreso Geologico Argentino.Buenos Aires,pp.347-364(in Spanish).
Grieve,R.A.F.,Pilkington,M.,1996.The signature of terrestrial impacts.AGSO Journal of Australian Geology and Geophysics 164,399-420.
Guaita,C,Martegani,R,2008.Cosmic microsphere:a SEM study.Memorie della Societa Astronomica Italiana Supplementi 12,110.
Gurov,E.P.,Gurova,E.P.,1998.The group of Macha craters in western Yakutia.Planetary and Space Science 462,323-328.
Hay,R.L.,Wiggins,B.,1980.Pellets,ooids,sepiolite and silica in three calcretes of de southwestern United States.Sedimentology 27,559-576.
Johnson,B.C.,Melosh.H.J.,2012.Formation of spherules in impact produced vapor plumes.Icarus 2171,416-430.
Johnson,B.C.,Melosh,H.J.,2014.Formation of melt droplets,melt fragments,and accretionary impact lapilli during a hypervelocity impact.Icarus 228,347-363.
Maher,B.A.,Thompson,R..Hounlow,M.W.,1999.In:Maher,B.A.,Thompson,R.(Eds.),Quaternary Climates,Environments and Magnetism,(Chapter 1).Cambridge University Press,390 pp.
Marini,E,Raukas,A.,Tiirmaa,R.,2004.Magnetic fines from the Kaali impact-site(Holocene,Estonia):Preliminary SEM investigation.Geochemical Journal 38(2),107-120.
Narayan,D.,Tandon,S..1981.Calcrete conglomerate,case-hardened conglomerate and cornstone,Siwalik Group,Punjab,India.Sedimentology 28,353-367.
Pike,R.J.,1980.Control of crater morphology by gravity and target type-Mars,Earth,Moon.In:Proc.Lunar and Planetary Science Conference,vol.11,pp.2159-2189.
Prezzi,C,Orgeira,M.J.,Acevedo,R.D.,Ponce,J.F.,Martinez,O.,Rabassa,J.,Corbella,H.,Vasquez,C,Gonzalez,M.,Subias,I.,2012.Geophysical characterization of two circular structures at Bajada del Diablo Patagonia.Argentina:indication of impact origin.Physics of the Earth and Planetary Interiors192-193,21-34.
Prezzi,C,Orgeira,M.J.,Acevedo,R.,Ponce,F.,Martinez,O.,Sarnataro,A.,Rabassa,J.,2013.Bajada del Diablo Circular Structures Chubut,Argentina:Ground Gravity,Magnetic and Electromagnetic Surveys.Latinmag 3 Reunion Bienal de la Asociacion Latinoamericana de Paleomagnetismo y Geomagnetismo,Montevideo,Uruguay.Latinmag Letters,3:3 2013,OA7,1-6(in Spanish with English abstract).
Prezzi,C,Orgeira,M.J.,Martinez,O.,Acevedo,R.D.,Ponce,F.,Goldmann,G..Magneres,I.,Rabassa,J.,2016.Circular structures of Bajada del Diablo Argentina:geophysical signature compatible with an impact origin.Geophysical Journal International 205(2),876-899.
Raukas,A.,2004.Distribution and composition of impact and extraterrestrial spherules in the Kaali area Island of Saaremaa,Estonia.Geochemical Journal382,101-106.
Rochette,P.,Folco,L,Suavet,C,Van Ginneken,M.,Gattacceca,J.,Perchiazzi,N.,Braucher,R.,Harvey,R.P.,2008.Micrometeorites from the transantarctic mountains.Proceedings of the National Academy of Sciences of the United States of America 10547,18206-18211.
Stankowski,W.T.J.,Katrusiak,A.,Budzianowski,A.,2006.Crystallographic variety of magnetic spherules from Pleistocene and Holocene sediments in the Northern foreland of Morasko-Meteorite Reserve.Planetary and Space Science 541,60-70.
Taylor,S.,Lever,J.H.,Harvey,R.P.,2000.Numbers,types,and compositions of an unbiased collection of cosmic spherules.Meteoritics&Planetary Science 55,651-666.
Valencio,D.A.,Orgeira,M.J.,Bobbio,M.L.,1987.Magnetoestratigraphy and magnetic susceptibility data of the late Cenozoic Ensenadense and Bonaerense of the cities of Buenos Aires and La Plata,central-eastern Argentina.Quaternary of South America and Antartic Peninsula 5,5-32.
Voldman,G.G.,Genge,M.J.,Albanesi,G.L.,Barnes,C.R.,Ortega,G.,2013.Cosmic spherules from the Ordovician of Argentina.Geological Journal 482(3),222-235.
Wright,V.,1983.A rendzina from de Lower Carboniferous of South Wales.Sedimentology 30,159-179.
Yada,T.,Nakamura,T.,Sekiya,M.,Takaoka,N.,1996.Formation processes of magnetic spherules collected from deep-sea sediments-observations and numerical simulations of the orbital evolution.Antarctic Meteorite Research 9,218.