Paleoenvironmental conditions during the Medieval Climatic Anomaly, the Little Ice Age and social impacts in the Oriental Mesoamerican region

The Medieval Climatic Anomaly and the Little Ice Age periods are the most relevant climatic events in the last 1000 yr BP. Although some research describes the effects on Mesoamerican paleoenvironmental conditions and the potential atmospheric-oceanic drivers involved, more studies are needed. While most paleoenvironmental records reveal a Medieval Climatic Anomaly dominated by arid conditions, the paleoclimatic signature of the Little Ice Age seems to be more controversial. Some records display pre-vailing drought conditions and a minor number of records suggest wetter conditions. Here, we present a new high-resolution paleoenvironmental record from the Serdan Oriental Basin, located in the Oriental Mesoamerican region. We employed the partly laminated sedimentary sequence from the Alchichica crater maar lake. A multi-proxy study by means of microfacies analyses, geochemical analyses, miner-alogical composition and magnetic analysis was conducted. Enhanced endogenic calcium carbonate precipitation in the Alchichica lake points to dominant dry conditions during the Medieval Climatic Anomaly. On the other hand, the Little Ice Age represented the rise of predominantly wetter conditions interrupted by short drought intervals. The wetter event is described by increased varve preservation, detrital input, and decreased calcium carbonate precipitation. Furthermore, we argue that the variability of the North Atlantic Oscillation in conjunction with hurricane activity could have influenced the hy-drological patterns during both climatic anomalies in the Oriental Mesoamerican sector. Finally, we hypothesize that severe drought conditions registered during the Medieval Climatic Anomaly, which encompasses the Postclassic archeological period, had severe implications in two important landscape elements useful to the agriculture lifestyle: El Salado lacustrine plain and piedmonts. (c) 2022 Elsevier Ltd. All rights reserved.