Oxide reduction during triggered-lightning fulgurite formation

Jones, Britta E.; Jones, K.; Rambo, K. J.; Rakov, Vladimir A.; Jerald, Jason; Uman, M. A.

doi:10.1016/j.jastp.2004.11.005

Cited by 25 publications

(24 citation statements)

References 7 publications

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“…Lightning can also heat and even melt the materials it strikes. Because of the ∼10 9 J energy released by a lightning strike, temperatures in the surrounding air have been reported to rise up to 30,000 K, while ground temperatures can rise up to 2000 K [ Appel et al , 2006; Carter et al , 2010; Essene and Fisher , 1986; Frenzel et al , 1989; Jones et al , 2005].…”

Section: Introductionmentioning

confidence: 99%

Lightning remagnetization of the Vredefort impact crater: No evidence for impact‐generated magnetic fields

et al. 2012

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[1] The Vredefort impact crater in South Africa is one of the oldest and largest craters on Earth, making it a unique analog for planetary basins. Intense and randomly oriented remanent magnetization observed in surface samples at Vredefort has been attributed to impact-generated magnetic fields. This possibility has major implications for extraterrestrial paleomagnetism since impact-generated fields have been proposed as a key alternative to the dynamo hypothesis for magnetization on the Moon and asteroids. Furthermore, the presence of single-domain magnetite found along shock-generated planar deformation features in Vredefort granites has been widely attributed to the 2.02 Ga impact event. An alternative hypothesis is that the unusual magnetization and/or rock magnetic properties of Vredefort rocks are the products of recent lightning strikes. Lightning and impact-generated fields can be distinguished by measuring samples collected from below the present surface. Here we present a paleomagnetic and rock magnetic study of samples from two 10 m deep vertical boreholes. We show that the magnetization at depth is consistent with a thermoremanent magnetization acquired in the local geomagnetic field following the impact, while random, intense magnetization and some of the unusual rock magnetic properties observed in surface rocks are superficial phenomena produced by lightning. Because Vredefort is the only terrestrial crater that has been proposed to contain records of impact-generated fields, this removes a key piece of evidence in support of the hypothesis that paleomagnetism of the Moon and other extraterrestrial bodies is the product of impacts rather than past core dynamos.

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Section: Introductionmentioning

confidence: 99%

Lightning remagnetization of the Vredefort impact crater: No evidence for impact‐generated magnetic fields

et al. 2012

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“…The first condensates are highly refractory, ultra-reduced native metals and alloys, commonly Fe-Si alloys because FeO and SiO 2 are major oxides in most lithologies and relatively easily ionised. Recombinations with oxygen do not seem to be important at least in the early stages of condensation (Jones et al, 2005) since oxides are less refractory than silicides and carbides. Our first and highest temperature condensates -W-Fe-Si metal beads -are oxygen free.…”

Section: Discussionmentioning

confidence: 99%

Ultra-high pressure and ultra-reduced minerals in ophiolites may form by lightning strikes

Ballhaus¹,

Wirth²,

Fonseca³

et al. 2017

Geochem. Persp. Let.

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Since ultra-high pressure (UHP) minerals have been discovered in ophiolites from Tibet and the Polar Urals, it is speculated that the mantle sections of ophiolites may originate deep within the mantle. The UHP minerals are frequently found together with ultra-reduced silicides, carbides, and nitrides. Consequently, it is argued that the deep mantle, or at least domains within it, must be highly reduced, so reduced that practically all transition elements at depth are present in the metallic state. We find it problematic to rewrite the history of ophiolite complexes based on these observations and suggest we should search for alternative and more realistic modes of origin. Electric discharge experiments at >6000 K reported here show that the UHP and highly reduced phase assemblages may precipitate from plasmas. We argue that the mineral assemblages may originate by lightning strikes. As such, they may not record the origin and emplacement history of the mantle lithologies within which they occur.

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“…Son fases minerales tienen diferentes composiciones de Fe y de Si, que forman compuestos como: FeSi (ferrisilita), FeSi 2 (ferdisilicita) y Fe 2 Si (hapkeita), los cuales se generan en condiciones dominantemente reductoras por volatilización extrema y temperaturas muy altas > 1800 °C (Essene y Fisher, 1986, Wasserman et al, 2002, Wasserman y Melosh, 2001, Jones et al, 2005, Sheffer et al, 2003 Wasserman et al, (2002) y Gopon et al, (2014), entre otros, sugieren como otro mecanismo que contribuye a la reducción extrema el material carbonoso de los suelos y la liberación de oxígeno durante la ebullición suministrados por el flujo de electrones a través del fundido, como ocurre en la electrólisis para formar óxido nítrico a partir del nitrógeno en la atmósfera ambiental. Así explican que, cuando en el sistema hay SiO 2 , antes del impacto, el material en estado sólido después del impacto es un líquido donde coexisten SiO 2 y Si metálico en equilibrio con SiO y O 2 en forma de gases y donde puede incorporarse Fe en el sistema en estados de oxidación con diferentes proporciones.…”

Section: Los Siliciuros Y Su Formaciónunclassified

“…De ser así, se trataría más bien de una seudofulgurita o fulgurita híbrida o mixta con aporte natural para su formación por el relámpago. Podría reservarse el término de seudofulgurita únicamente a las formadas experimentalmente sin intervención de un evento natural (Jones et al, 2005). Podría suponerse que los siliciuros se forman cuando han tenido intervención de energías de alto voltaje además del aporte del relámpago como la fulgurita Farmington de Connecticut (Sheffer et al, 2003(Sheffer et al, , 2006 y la del Rosario, (Ramírez-Cardona et al, 2006); ambas presentan esferoides grandes de siliciuros a diferencia de la fulgurita Zacatecas con siliciuros micrométricos; posiblemente el tamaño de los siliciuros se deba a la duración e intensidad del evento debido al aporte externo de energía eléctrica.…”

Section: Proporción De Elementos (% En Peso)unclassified

Estudio petrográfico, geoquímico y mineralógico de la fulgurita San José de Lourdes, Zacatecas, México

et al. 2017

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Reyes-Salas, A.M., Macías-Romo, C., Ortega-Gutiérrez, F., Reyes-Salas, E.O., Flores-Gutiérrez, D., Alba-Aldave, L., Girón-García, P., Robles-Camacho, J., García-Martínez, J.L., Cervantes-de la Cruz, K.E., 2017, Estudio petrográfico, geoquímico y mineralógico de la fulgurita San José de Lourdes, Zacatecas, México: Revista Mexicana de Ciencias Geológicas, v. 34, núm. 3, p. 170-181. RESUMENEn este trabajo se presentan los resultados del estudio petrográfico, geoquímico y mineralógico de fulguritas originadas en suelo calcáreo ubicadas al noroeste de Fresnillo en las inmediaciones de San José de Lourdes, en el Estado de Zacatecas, México. Las fulguritas, principalmente tienen formas tubulares, y están constituidas por vidrio vesicular de composición heterogénea comparable, químicamente, con andesitas. Ellas contienen en su matriz formas diversas de crecimiento incipiente de cristales de wollastonita y un silicato de Fe, no determinado; destacan también fragmentos de cuarzo formando esferoides rodeados de vidrio, -similares a los llamados cuarzo ballen (ballen quartz), característicos de las rocas de impacto-, cristobalita y granos escasos de ilmenita, apatita, circón, plata y oro. También incluyen algunas aleaciones micrométricas de Si-Fe (siliciuros) en composiciones variables y compuestos de arsénico-calcio, estos últimos reportados por primera vez en fulguritas. Con base en la formación de microlitos dentro del vidrio y fusión del cuarzo, se estimaron temperaturas pico de cristalización superiores a 1,700 °C.Palabras clave: fulgurita; wollastonita; cristobalita; aleaciones de Si-Fe; As-Ca; cuarzo ballen; Zacatecas; México. ABSTRACT

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Oxide reduction during triggered-lightning fulgurite formation

Cited by 25 publications

References 7 publications

Lightning remagnetization of the Vredefort impact crater: No evidence for impact‐generated magnetic fields

Lightning remagnetization of the Vredefort impact crater: No evidence for impact‐generated magnetic fields

Ultra-high pressure and ultra-reduced minerals in ophiolites may form by lightning strikes

Estudio petrográfico, geoquímico y mineralógico de la fulgurita San José de Lourdes, Zacatecas, México

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