Abstract
Guatemala is located at the core of one of the largest warming pools in the planet, the Western Hemisphere Warm Pool, an important source of tropical moisture to middle and high latitudes and, thus, a key area for paleoclimatic studies. This, along the karst pervasiveness in the area provides the opportunity to obtain high-resolution records of past hydroclimatic conditions using stalagmites. Despite this, the atmospheric and geochemical processes that might affect the variability of geochemical proxies in stalagmites are yet to be constrained, as no cave-monitoring in the area has been carried out previously. Here, we present a 2.5-year cave-monitoring study from Gruta del Rey Marcos, Guatemala, which allows to understand the effect of external atmospheric and environmental conditions upon the variability of δ18O, Mg/Ca, Sr/Ca, and Ba/Ca in drip water. By incorporating cave ventilation dynamics, isotopic information of local rainfall and cave-river water, we are able to understand the most relevant processes that affect the variability of the geochemical proxies in drip water, hence stalagmites. Our results suggest that two-isotopically distinct rainfall regimes, as well as tropical cyclones affecting the area contribute to the composition of the drip-water, hence the resulting stalagmites, with low δ18O (∼-6‰ VSMOW) values indicative of strong convective activity, whilst high δ18O values (−4.5 and −5‰ VSMOW), are indicative of poor convection and proportionally more significant winter-frontal rainfall. We also demonstrate that the trace-element composition of drip water is largely modulated by PCP, and thus, the variability in underlying stalagmites can be interpreted to reflect changes in karst humidity, with low E/Ca ratios (E = Mg, Sr, Ba), indicative of a wet epikarst and high E/Ca ratios indicative of a dry epikarst. Our results provide essential information for the interpretation of the δ18O and trace element variability in stalagmites, which can result in robust paleoclimatic reconstructions from Gruta del Rey Marcos and elsewhere in central America and southern Mexico.
| Original language | English (US) |
|---|---|
| Article number | 1112957 |
| Journal | Frontiers in Earth Science |
| Volume | 11 |
| DOIs | |
| State | Published - 2023 |
Funding
This work was carried out during a very complex period for everybody, and thus, required extraordinary assistance from different parties. The authors would like to thank Diego Fern\u00E1ndez at Gruta del Rey Marcos for allowing continuous access to the cave even during the most challenging period of the COVID-19 pandemic. Otto Inque Chavarria Robles and Otto Inque Chavarria Sr are thanked for providing access to Monte Azul Farm and welcome us at their home during several trips, and dutifully collecting rain samples during the early stages of this project. Sergio Mor\u00E1n at USAC-CUNOR for logistical support throughout the project. Nancy Pistole, provided original indications for the cave as well as the original map, which was plotted by her and Matt Oliphant, Salvador Brizuela, Peter Haberland, Matt Krammar, Oscar Rivera, Mike Shawcross, and upon which is based. M en C. Ofelia P\u00E9rez-Arvizu, M. en C. Liliana Corona, M. en C Carolina Mu\u00F1oz-Torres, and Q. Jessica Olivares Amador are thanked for essential laboratory support. This work was supported through a UNAM-PAPIIT grant IN108419 to JPB, IA202222 to FLH, and NSF grant AGS-1804263 to MSL. The authors would like to acknowledge the comments and suggestions by two reviewers, whose comments significantly enhanced the clarity of the manuscript. This work is published in Memoriam of Santiago Capella Vizca\u00EDno (1948\u20132022), who set up some of the analytical instrumentation and provided guidance for several years to some of the authors of this manuscript.
Keywords
- Guatemala
- cave-monitoring
- drip sites
- epikarst
- oxygen isotopes
- trace elements
ASJC Scopus subject areas
- General Earth and Planetary Sciences