Wetlands as environments of early human occupation: A new classification for freshwater palaeowetlands

Abstract

Present wetlands have proven to be delicate, biodiverse ecosystems, that are natural sinks for CO2 and act as good indicators for climate changes. This means that ancient wetlands found in the fossil record may be very useful for inferring past climate changes. Since the times of early humans, wetlands have played an important role in providing resources for the ecosystems in which hominins and their associated fauna lived. The identification of palaeowetlands in the fossil record and their characterisation is therefore crucial to enable a better understanding of how early humans interacted with the landscape and its resources. Although there are many classification schemes for modern wetlands, developed for multiple purposes, only two have been found for ancient wetlands in the literature, and these cannot be used as a systematic tool to identify ancient wetlands in the geological record. A new classification for inland freshwater palaeowetlands, with a focus on carbonate wetlands, is proposed here, recognising key features that can be preserved in the fossil record. Its application requires templates to be used in the field and/or the core laboratory. To test the applicability of the classification, Pliocene-Pleistocene carbonate-dominated palaeowetlands identified in the Guadix Basin (southern Spain) have been classified using the proposed system. The information extracted from the geological record shows how useful the classification may be to characterise early human settings.