UH Alumni Leads Study to Refine Paleoclimate Signals in Caribbean Cave
Gabriel Lopez has Published New Research in a Special Issue of the International Journal of Speleology
Gabriel E. López Borobia, an alumnus of the University of Houston’s Department of Earth and Atmospheric Sciences, recently published a peer-reviewed study as lead author in the International Journal of Speleology. The article, “Pre-calibration of δ¹⁸O for paleoclimatic interpretations using stalagmites in Cueva Ensueño, Puerto Rico,” provides new insights into how seasonal and hydrological processes influence oxygen isotope fractionation in tropical cave environments.
Research Overview
Stalagmites serve as valuable terrestrial climate archives because they record environmental conditions through stable isotope signatures. This study focused on calibrating the oxygen isotope fractionation factor (1000ln¹⁸α) between drip water and calcite in Cueva Ensueño, located in Puerto Rico’s northern karst region. Fieldwork during both dry and wet seasons allowed for the collection of drip water and carbonate samples from 10 stations inside the cave.
The team used a dual approach by analyzing naturally forming stalagmites and growing calcite in situ to capture seasonal variability. Results showed a clear seasonal bias in isotopic fractionation: higher values during the wet season and lower values during the dry season. The study also revealed a delay in isotopic signal transfer into the cave system, likely driven by epikarst storage and piston-flow recharge mechanisms.
Collaborative Context
This project was conducted under the guidance of Dr. Ny Riavo G. Voarintsoa, faculty member in the Department of Earth and Atmospheric Sciences and lead investigator of UH’s PaleoGeochem group. The group specializes in stable isotope geochemistry and paleoclimate reconstruction using speleothems and other terrestrial archives. The study also included collaborators from the University of Texas at Arlington and the Museo de Historia Natural y Conservación de Puerto Rico.
Scientific Contribution
This site-specific calibration improves the reliability of paleoclimate reconstructions in tropical regions and adds to the growing body of research on speleothem-based climate proxies. The findings highlight the importance of accounting for seasonal and hydrological dynamics when interpreting stalagmite records.
Citation
López Borobia, G.E., Voarintsoa, N.R.G., Sánchez-Murillo, R., & Llerandi Román, P.A. (2025). Pre-calibration of δ¹⁸O for paleoclimatic interpretations using stalagmites in Cueva Ensueño, Puerto Rico. International Journal of Speleology, 54(3), ijs2555. doi.org/10.5038/1827-806X.ijs2555