Oxygen isotope evidence for paleoclimate change during the Vandal Minimum climate episode from Ariopsis felis otoliths and Mercenaria campechiensis shells, southwest Florida

The Vandal Minimum climate episode (500-800 AD) was first documented in European proxy records as cold and dry with increased frequency of severe weather. Archaeological evidence from coastal southwest Florida suggests this region and its local inhabitants, the Calusa, were affected by the Vandal Minimum climate. Drought and cooling may have been responsible for the Calusa people’s abandonment of coastal southwest Florida by 750 AD. To provide a paleoclimate context during this time, we reconstructed the Vandal Minimum climate using high-resolution oxygen isotope records from otoliths (ear bones) of the hardhead catfish, Ariopsis felis, and shells from the southern hard clam, Mercenaria campechiensis. Four otoliths and eight shells from Calusa archaeological deposits dating between 450 and 750 AD were selected and microsampled for isotopic analysis. Climate reconstruction based on the isotopic ratios of archaeological otoliths and shells is in good agreement with archaeological evidence and climate conditions documented in Europe