21 US-Mexico Exchange on Cave and Karst Science and Conservation (Posters)

This poster session welcomes poster submissions in fields related with cave and karst science and management in Mexico, with a special interest in geoheritage, inter- and multidisciplinary approaches and community outreach projects.

Thursday, 23 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel

Paleoenvironmental dynamics of a Quaternary paleoepikarst system recorded in calcretes and paleosols, central Yucatán Peninsula, Mexico

Paper number: 21-0
Program: Technical Sessions
Time: 8:00 AM – 8:15 AM

Authors

Abstract

Quaternary carbonate deposits in the central Yucatán Peninsula (Kaua area) are dominated by calcarenites exhibiting advanced karst development, together with red clay paleosols and calcrete horizons. These features define paleoepikarst levels that constitute valuable archives of terrestrial paleoenvironments, which remain poorly documented in the region. This study focuses on an exposed stratigraphic section at the Kaua quarry, integrating detailed field observations with micromorphological, mineralogical, and stable isotope (δ¹³C and δ¹⁸O) analyses of soils and calcretes.

The results allow characterization of the sedimentary, pedogenetic, and karst processes operating during landscape evolution, and reveal the presence of at least two paleoepikarst surfaces marked by collapse breccias, dissolution conduits, and karst pockets infilled with red to brown lithified paleosols. These paleosols locally display calcite cementation, angular blocky microstructure, redoximorphic features, and incipient rhizoconcretion development. Clay mineral assemblages in both paleosols and the modern soil are comparable and dominated by halloysite and vermiculite, indicating weathering under a seasonal tropical climate broadly similar to present-day conditions.

A positive correlation between δ¹³C and δ¹⁸O values in calcrete horizons points to a strong evaporative control during calcrete formation, a key process in the genesis of these pedogenic carbonates. Mean δ¹³C values in the calcrete at the base of a doline (–10.5‰) and in the surface calcrete (–9.81‰ to –10.11‰) suggest vegetation dominated by C₃ photosynthetic pathways. Overall, this study highlights the significance of paleoepikarst as a combined geochemical and micromorphological archive for reconstructing paleoenvironmental conditions and understanding the Quaternary evolution of the karst landscape in the Yucatán Peninsula

 

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410872

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