Hydroclimate During Marine Isotope Stage 7 (MIS 7) at Lake Petén Itzá, Guatemala

To better understand the role of the neotropics in global climate, we need new, well-dated and high-resolution reconstructions of climate variability from underexplored regions and time intervals. Karst Lake Petén Itzá, located in northern Guatemala (16°55’N, 89°50’W), was drilled in 2006 as a part of the International Continental Scientific Drilling Program, which recovered a continuous record of the last 400,000 years, spanning multiple glacial-interglacial cycles. The lake is sensitive to climate changes, and can thus provide critical information about both regional climate changes and possible connections to high latitude climate.

Here, we present a new hydroclimate record of Marine Isotope Stage 7 (MIS 7, 178-252 ka) from Lake Petén Itzá using organic biomarkers, terrestrial leaf wax compounds (long chain n-alkanes) preserved in sediments. We focus on MIS 7 because it is the coldest interglacial that occurred following the Mid-Brunhes Event ~430 ka (characterized by increase of ice volume), with changes in ice volume and atmospheric CO₂. The influences that controlled the global temperature and ice volume variability during MIS 7 and its impact in the neotropics climate are still unknown. Our results show hydroclimate variations within the Petén Itzá region have strong global and high latitude influences.