The sudden and prolonged Mesoamerican megadrought (1400-1600 CE) during the early LIA

The Little Ice Age (LIA) was a predominant anomalously cold event on Earth that occurred from c. 1350 to c. 1850 with a near-global signature.  Many records from different paleo archives located throughout the greater Caribbean show hydroclimate heterogeneity throughout all or part of this period. Here we present new evidence from the Guatemalan stalagmite GU-Xi-1 that contains a prolonged period of persistently heavy oxygen isotope values indicating a long-term major dry event (MDE) which started rather abruptly around 1400 CE and lasted for about approximately 200 years (age uncertainty c.50 years), with both onset and termination likely occurring within a couple of decades. The age model and hence, the timing of the Xibalba MDE is regarded as robust because they are consistent with a change in calcite precipitation that produced the “L” layer in the Xibalba speleothem.  This layer which is associated with drying in speleothems could be precisely dated and bracketed using U/Th.  In this contribution, we present the Gu-Xi-1 record and discuss possible mechanisms underlying the reconstructed Mesoamerican megadrought and their connection with natural climate forcing agents active in the period.