Morphological and mineralogical characterization of speleothems from the Chimalacatepec lava tube system, Central Mexico

International Journal of Speleology

Ramón Espinasa-Pereña¹  Tomáš Lánczos²  Juan R. Vidal-Romaní³  Roman Aubrecht⁴  Hugo Beraldi-Campesi⁵  Juan P. Bernal Uruchurtu⁵  Ricardo Barragán⁵  Teresa Pi Puig⁵  Rafael López-Martínez⁵ 

[1] Centro Nacional de Prevención de Desastres, Mexico;Comenius University;Instituto Universitario de Geología, Spain;Slovak Academy of Sciences and Comenius University;Universidad Nacional Autónoma de México;

关键词: lava tubes;    siliceous speleothems;    Chichinautzin;    biospeleothems;   

DOI  :  10.5038/1827-806X.45.2.1927

来源: DOAJ

【 摘 要 】

Siliceous, opal-A speleothems of the Chimalacatepec lava tube system in central Mexico are characterized here for the first time. Morphologically, they can be classified into cylindrical and planar, and display a wide array of shapes, inner textures, and locations within the lava tube. All speleothems analyzed here are composed of opal-A, and their pores are filled with calcite and monohydrocalcite. Microscopic examination reveals a variety of microbial-looking, silicified filaments and cell casts embedded within the micro lamination of the structures. The abundance of biofilms in the Chimalacatepec lava tube may share similarities with other volcanic caves elsewhere. The direct presence of such bimorphs in the microstructure of the speleothems suggests the biological mediation of these structures. Potential mechanisms include nucleation and sorption of silica on extracellular polymeric substances in the biofilms that, along with the SiO2 saturation in the water film and evaporative effects, result in the formation of a speleothem. That said, the presence of microbes in these and other cave systems, or their inevitable interactions with the mineral phase of the speleothems, should not be surprising. In view of this, these structures can be most accurately described as biospeleothems. This study contributes to our understanding of the diversity of such structures in these types of cave systems and our ability to recognize the presence of microbes in these.

【 授权许可】

Unknown