First insight on the genesis of iron oxide-hydroxide biospeleothems in Rancho Chico Lava Tube, Mexico

• Published in: International journal of speleology Vol. 54; no. 2; pp. 1 - 14
• Main Authors: López-Martínez, Rafael, Solleiro-Rebolledo, Elizabeth, Alcántara-Hernández, Rocio, Pi Puig, Teresa, Sedov, Sergey, Valera Fernández, Daisy, Luis-Vargas, M. Nayeli, Lima Vera, Yasmany, Solé, Jesús, Espinasa-Pereña, Ramon
• Format: Journal Article
• Language: English
• Published: Bologna University of South Florida Board of Trustees, a public body corporate, having locations in Tampa, St. Petersburg, and Sarasota 01.06.2025
• Subjects: Chemical reduction; Colour; Concretions; Crusts; DNA sequences; DNA sequencing; Electron microscopy; Ferric hydroxide; Field study; Gene sequencing; Hydroxides; Iron oxides; Lava; Microorganisms; Mineral deposits; Mineralogy; Minerals; Oxidation; Oxidation-reduction potential; Oxidoreductions; Petrography; Petrology; Precipitation; Redox reactions; rRNA 16S; Scanning electron microscopy; Volcanic fields; Azores; Mexico
• ISSN: 0392-6672; 1827-806X
• DOI: 10.5038/1827-806X.ijs2541

Iron is a common element in lava tube systems, typically observed as thin crusts or inferred from the reddish coloration of secondary mineral deposits. In this study, we describe iron oxide-hydroxide biospeleothems discovered in the Rancho Chico Lava Tube, located within the Xalapa Monogenetic Volcanic Field in Mexico. We adopt an integrative approach combining petrography, soil micromorphology, scanning electron microscopy, mineralogy, and 16S rRNA gene metabarcoding. DNA sequencing reveals the presence of microorganisms such as Acidithiobacillus , Gallionella , and members of the Leptospirillaceae family, which may be involved in the oxidation of Fe²⁺ within the lava tube. The source of iron appears to originate from the overlying soil, where pedogenic processes, including oxidation-reduction reactions, facilitate its mobilization.