Physico-chemical study of an exogenic fulgurite from a thunderstorm on 10th August 2013 in Dallas, TX

Abstract

Droplet-like exogenic fulgurites comprise a minor grouplet of natural glasses resulting from powerful lightning strikes. Reports on such type-V fulgurites are scarce in the literature. In this work, a fulgurite specimen from the thunderstorm that took place on 10 th August 2013, in Dallas, TX, USA, has been analyzed using X-ray powder diffraction, X-ray fluorescence, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and infrared and Raman spectroscopy techniques. X-ray diffraction revealed the amorphous nature of the exofulgurite, and X-ray fluorescence showed a high Si, Al and Ca content. Infrared and Raman spectroscopy were key in revealing clear SiO modes related signatures and a very significant presence of water (OH/H2O).A parallel with glassy silicate materials, but also with opal-A, was essential in the understanding of the fulgurite's characteristics. In particular, Raman data evidenced the exofulgurite to have a high degree of depolymerization.

A Raman Spectroscopic Study of Lightning‐Induced Glass Produced From Five Mineral Phases

“…Raman spectroscopy is a non‐destructive analytical tool used to obtain chemical and structural information on melts, glasses, and mineral crystals within the Earth and planetary sciences (e.g., Angel et al., 2012; Cicconi et al., 2022; McMillan & Wolf, 1995; Mysen, 1983; Nasdala et al., 2004; Neuville et al., 2014; Rossano & Mysen, 2012; Seifert et al., 1982); including natural glasses such as volcanic glass (Di Genova et al., 2015; Dingwell, 2003; Giordano, González‐García, et al., 2020; Giordano, Russell, et al., 2020), fulgurites (Alte da Veiga et al., 2021; Carter, Hargreaves, et al., 2010, Carter, Pasek, et al, 2010; Cicconi et al., 2022), and impactites (Gucsik et al., 2004; Ostroumov et al., 2002; White & Minser, 1984). Raman spectroscopy has also been used in more recent studies to estimate the iron oxidation state (Di Genova et al., 2016; Di Muro et al., 2009; Le Losq et al., 2019; Magnien et al., 2006; Roskosz et al., 2008), water abundance (Behrens et al., 2006; Le Losq et al., 2012; Mercier et al., 2009, 2010; Schiavi et al., 2018; Thomas et al., 2008), and carbon dioxide content (Morizet et al., 2009, 2013) within synthetic and natural glasses.…”

Experimental generation of fulgurite under realistic lightning discharge conditions

“…Natural fulgurites were rst described (in sandy sediments) by Herman in 1706 1 , and the oldest fulgurite found to date has been speculated, on the basis of the fossiliferous Carboniferous rocks overlying the host, to be of Permian age 2 . The fulgurites present on Earth form by cloud-to-ground lightning strikes (by either thunderstorms or volcanic eruptions) or as a result of accidents involving electric transmission lines 3,4,5 . Natural fulgurites have been explored in terms of their morphological and chemical states 6,7,8,9 , including the description of high-temperature mineralization 10 , reconstruction of paleoecology 11 , and evaluation of the availability of chemical sources for pre-biotic chemistry 12,13,14 Experimentally generated fulgurites have also been brie y described in some preliminary feasibility studies 15,16,17,18,19,20 .…”