While the fulgurite structure is predominantly amorphous silica glass (Supplementary Fig. The studied fulgurite was analysed using Raman spectroscopy, X-ray fluorescence and diffraction (XRF and XRD), electron dispersive spectroscopy (EDS), and electron backscatter diffraction analysis (EBSD see “Methods”). The core of the fulgurite is massive and glassy, whereas the rim is vesicular and frothy (Fig. 1), having formed in clay-rich soils in Glen Ellyn, Illinois, USA in 2016. The fulgurite used in this study is a dm-scale type II fulgurite 16 (Fig. Further, this presents a mechanism independent of meteorite flux for continually generating prebiotic reactive phosphorus on Earth-like planets, potentially facilitating the emergence of terrestrial life indefinitely. We propose that under the conditions on early Earth, phosphorus reduction via lightning strikes is a more significant process than previously appreciated, providing a widespread, quiescent source of reduced phosphorus. In this study, we identify abundant accessory schreibersite spherules in a fulgurite formed from clay-rich soil. Consequently, it has generally been assumed that other schreibersite sources are trivial 13. The Earth likely experienced a monotonic decline in impactors from the moon forming impact at ~4.5 Ga to present 17, 18, providing potentially 10 5–7 kg of reduced phosphorus annually throughout the Hadean and early Archean 11. Schreibersite is a common accessory mineral within some classes of meteorites 7 and is also found in some highly reduced glasses formed by lightning strikes called fulgurites 14, 15, 16. Thus, schreibersite is one commonly accepted source of phosphate for the terrestrial prebiotic synthesis of essential organic phosphate molecules 11, 12, 13. While such intermediate phosphorous species would hinder organic reactions, they may still play an important role in the origin of life by efficiently reacting with solar ultraviolet (UV) radiation and dissolved HS − to form orthophosphate (PO 4 3−) 11. When wetted, schreibersite forms hydrous, activated phosphate capable of forming key basic organic molecules, such as glycerol phosphate, nucleosides and phosphocholine 8, 9, and intermediate phosphorus species, such as hypophosphite (H 2PO 2 −) and phosphite (HPO 3 2−) 5, 10. In contrast, reduced phosphorus such as phosphide (P 0) in the form of the mineral schreibersite, (Fe,Ni) 3P, has been found to be highly reactive 5, 6, 7. While terrestrial abiotic phosphorus is essentially ubiquitous on Earth in the oxidised form of phosphate (PO 4 3−), it is bound in minerals such as apatite, which are effectively insoluble in water 4. Phosphorus is one of the key elements for life, involved in biomolecules such as DNA, RNA, phospholipids, and ATP. Life on Earth likely originated by 3.5 Ga 1 with carbon isotopic evidence suggesting as early as 3.8–4.1 Ga 2, 3.
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