Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity

Abstract

Abstract:The caves of the Irazú volcano (Costa Rica), became accessible after the partial collapse of the NW sector of the Irazú volcano in 1994, offering the opportunity to investigate active minerogenetic processes in volcanic cave environments. We performed a detailed mineralogical and geochemical study of speleothems in the caves Cueva los Minerales and Cueva Los Mucolitos, both located in the northwest foothills of the main crater. Mineralogical analyses included X-ray diffraction (XRD) and Raman spectroscopy, while geochemical characterization used Energy Dispersive X-ray spectroscopy (EDX) coupled to Scanning Electron Microscopy (SEM). In addition, measurements of environmental parameters in the caves, cave drip water and compilation of geochemical analyses of the Irazú volcanic lake (~150 m above the cave level) and fumarole analyses were conducted between 1991 and 2014. We identified forty-eight different mineral phases, mostly rare hydrated sulfates of the alunite, halotrichite, copiapite, kieserite and rozenite groups, thirteen of which are described here as cave minerals for the first time. This includes the first occurrence in cave environments of aplowite, bieberite, boyleite, dietrichite, ferricopiapite, ferrinatrite, lausenite, lishizhenite, magnesiocopiapite, marinellite, pentahydrite, szomolnokite, and wupatkiite. The presence of other new cave minerals such as tolbachite, mercallite, rhomboclase, cyanochroite, and retgersite, is likely but could not be confirmed by various mineralogical techniques. Uplifting of sulfurous gases, water seepage from the Irazú volcanic lake and hydrothermal interactions with the volcanic host rock are responsible for such extreme mineralogical diversity. These findings make the caves of the Irazú volcano a world-type-reference locality for investigations on the formation and assemblage of sulfate minerals and the biogeochemical cycle of sulfur, with potential implications for Astrobiology and Planetary science.hydrated sulfates, sulfate speleothems, volcanic caves, crater lake, cave minerogenesis Ulloa A., Gázquez F., Sanz-Arranz A., Medina J., Rull F., Calaforra J.M., Alvarado G.E., Martínez M., Avard G., de Moor J.M. and De Waele J., 2018. Extremely high diversity of sulfate minerals in caves of the Irazú Volcano (Costa Rica) related to crater lake and fumarolic activity.

Distribution and Chemical Composition of Halotrichite in Geothermal Fields of Kamchatka

“…Также галотрихит образуется в низкотем-пературных вулканических обстановках, хотя описания таких находок единичны. В качестве примера приведем описание галотрихита среди солевых выцветов вулканических эксгаляций вулканов Поас и Ирасу в Коста-Рике (Rodríguez, Bergen, 2017;Ulloa et al, 2018) и Уайт-Айленд в Новой Зеландии (Cody, Grammer, 1979). В России известно шесть мест, где обнаружен галотрихит: из них в трех местах генезис минерала связан с зоной окисления рудных месторождений Cu, W и Hg (Eremin et al, 2014;Gongalsky, Krivolutskaya, 2019), а в трех других местах находок минерал образуется в результате вулканической деятельности.…”

New insights on secondary minerals from Italian sulfuric acid caves

“…Pickeringite and copiapite have been previously described in cave environments, and in association with tamarugite (Forti et al, 1995; (Mosch & Polyak, 1996). Pickeringite, metavoltine, and tamarugite have been seen in the volcanic-fumarole related environment of Grotta dello Zolfo (Naples, Italy) (Franco, 1961), and more recently, with a wide variety of sulfates in the Cuve de los Minerales on Irazù Volcano, Costa Rica (Ulloa et al, 2018). Pickeringite and tamarugite have also been encountered in thermal caves such as the case of Diana in Romania (Diaconu & Medesan, 1973;Puşcaş et al, 2013).…”

La erupción del volcán Irazú 1917-1921 (Costa Rica): dinámica y entorno social

“…La morfología de la cima varió sustancialmente entre 1917 y 1921. La evolución de los cráteres mantuvo una orientación noroeste-sureste coherente con una zona de falla que tendría ese rumbo y que atravesaría el macizo volcánico (Ulloa et al, 2018) (Figura 2b). Esto podría haber condicionado los mecanismos explosivos de las erupciones del 17 de diciembre de 1917 y la del 30 de noviembre de 1918.…”

“…b) Detalle de la cima del volcán Irazú con base en una imagen de Google Earth CNES/Airbus, Maxar Technologies de abril de 2023. Las fallas se indican según el trabajo de Ulloa et al (2018). c) Detalle del área del volcán Irazú, parte de San José y Cartago en el que se muestra el río Reventado y algunas localidades mencionadas en el texto.…”