Data from used in the manuscript: Manifestations of sulfuric acid speleogenesis in the Mulapampa travertine, Central Andes of Peru: evidence from the Gruta con Lago

Manuscript Abstract: Sulfuric acid speleogenesis (SAS) is a form of hypogene speleogenesis characterized by the formation of caves in carbonate rocks due to the presence of sulfuric acid. This study focuses on the Gruta con Lago, one of three caves identified in the Mulapampa travertine, located in the Central Andes of Peru. These caves are accessed through collapse sinkholes, and much of their morphology results from roof breakdown. The bottom of the studied cave is situated at the current water table. Despite the absence of typical solutional features associated with SAS caves, mineralogical and geochemical evidence of speleogenesis involving H2SO4 has been found in Gruta con Lago. Significant accumulations of gypsum deposits on the cave floor and replacement gypsum crusts on walls – both considered by-products of SAS – are present. Cave gypsum samples exhibit negative sulfur isotopic composition (ranging from -19.4 to -8.2‰) and oxygen (ranging from -9.0 to -1.3‰), which are indicative of sulfide (H2S) oxidation. This article discusses potential scenarios of SAS events in the evolution of hypogene karst in the Mulapampa travertine. It also considers the significance of the proximity of the active volcanoes of the Ampato-Sabancaya Volcanic Complex (ASVC) and seismogenic crustal faults in the formation of a thick travertine cover and the potential for SAS processes.

In this dataset, we make available supplementary information including 3 figures and 3 tables:

Fig. S1. Gruta Campana. A – Bell-shaped collapse sinkhole; B – Steep passage to the bottom with sediments washed into the cave during heavy rain from surrounding farmland; C – Remnants of gypsum crust in a side passage.

Fig. S2. Gruta Lechuza. A – cave survey and its relationship to the whole collapse sinkhole; B – cave entrance and upper part of talus cone formed by collapsed blocks overgrown by plants; C – location of the cave entrance under the collapse sinkhole wall; D – steep floor of the cave formed by collapsed travertine blocks; E – the lowest part of the cone of collapsed blocks (ca. 75 m below the surface); E, F – cave bottom (ca. 85 m below surface) covered with clastic sediments washed from the surface and efflorescences of secondary sulfate minerals; G – cupolas on the cave roof in the lower part of the cave.

Fig. S3. Broken line graph of certain trace elements in waters from the Gruta con Lago (C1/1 – C1/6) and from Huambo springs (H1, H2); a logarithmic scale was used to present the values of trace elements. 

Table S1. Chemical and isotopic composition of water samples from Gruta con Lago and Huambo springs.

Table S2. Sulfur and oxygen isotopic composition of sulfur-containing minerals form the Gruta con Lago and sulfate ion in water from cave lake and Manco Cápac spring.

Table S3. Chosen ionic ratios in water samples from Gruta con Lago and Huambo springs.