Multi-proxy paleohydrological and paleoecological reconstruction of a subaquatic cave in western Cuba

Abstract

Submerged caves are potentially rich but relatively untapped sources of paleoenvironmental, paleontological, and archaeological data. The purpose of this study is to undertake a paleohydrological and paleoecological reconstruction of an underwater cave, Cueva Chicharrones, in Matanzas, Cuba. Technical cave divers collected sediment cores from within the cave, which were studied for grain size, seeds, ostracods, and pollen, and were dated by radiocarbon and luminescence methods. The chronology of the sediments and the resulting paleohydrological reconstruction, based on the interpretation of the sedimentary facies, help to constrain the timing of water level changes in the cave, which appear to be driven by a combination of relative sea level and regional climatic variability. Specifically, the results indicate that the cave was likely dry prior to 7000 cal yr BP, and was flooded by 6500 cal yr BP (a time consistent with humid conditions in much of the northern Caribbean). Then, water levels decreased between 6500 and 2000 cal yr BP, when regional climate was drier, and increased around 1000 cal yr BP, due to a shift to a more humid climate. The seeds found in some of the cores consist of the genera Ficus, Cecropia, and Solanum and may have been deposited by frugivorous bats, although the possibility of transport by storm water cannot be ruled out. The pollen data are consistent with the information derived from the seeds, and indicate that pollen spectra variability was probably driven by changes in water level, environmental and climatic conditions, and possibly bat activity. This study is the first of its kind from a submerged cave in Cuba and highlights the potential of underwater caves as archives of regional paleoclimatic and relative sea level data. In addition, given the presence of abundant vertebrate fossils present in the cave, our work will provide important context for the study of these remains and help inform on Caribbean paleoecology and paleontology.