New Publication on speleothem fluid inclusion climate reconstructions in Puerto Rico during the last glacial

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This study by Sophie Warken and Therese Weissbach et al. presents speleothem fluid inclusion stable isotope measurements from Larga Cave, Puerto Rico spanning 46.2 to 15.3ka before present. Two main clusters of the fluid inclusion water with respect to the global meteoric water line coincide with strong variations in the water content of the stalagmite. Cold and dry periods exhibit enriched isotope values caused by evaporation due to cave ventilation. Warmer and wetter Greenland interstadials yield negligible “in-cave” evaporation. Consequently, variations of last glacial hydro-climate and temperature in the western tropical Atlantic can be constrained. In general, fluid inclusion temperatures suggest an average cooling of c. 3°C during the LGM compared to modern cave temperature. During Heinrich Stadials 2 and 3, reconstructed cave temperatures yield an additional cooling of -1.4 ± 2.8°C and 3.6 ± 2.2°C, respectively. Higher δ18Of values of these samples further suggest that the drip water was dominated by orographic rainfall and/or cold fronts, along with weak or even absent convective activity. In contrast, during interstadial phases, reconstructed temperatures reached nearly modern values, and convective activity was comparable or only slightly weaker than today. The publication has been accepted by the journal Climate of the Past and is expected to appear online in due course here