Chronostratigraphy in karst records from the Epipaleolithic to the Early Neolithic (c. 13.0 – 6.0 cal ka BP) in the Catalan Coastal Mountains of NE Iberia: environmental changes, sedimentary processes and human activity

The stratigraphic, sedimentary and palaeoenvironmental features reflected in cavities in the Catalan Coastal Ranges of NE Iberia (Can Sadurní and Guineu caves) characterize the periods of pronounced climatic and human complexity that occurred c. 13.0–6.0 cal ka BP. This includes the stages of the Younger Dryas and Mid/Early Holocene, the latter being one of the periods of so-called Rapid Climatic Changes (RCCs). These caves, like others in Mediterranean contexts, are the result of an old duct originating in the saturated zone of the karst system and open to the outside; recording a succession of different detrital and anthropic episodes of the Epipaleolithic, Mesolithic and Neolithic communities.
From this study it can be seen that paleoclimatic events do not always present clear signals in the karst records, especially c. 12.7–7.4 cal ka BP, corresponding to the Epipaleolithic and Mesolithic. It is characterized by a stratigraphic discontinuity in which there are phases with predominantly detrital sedimentation alternating with hiatus intervals. Detrital sedimentation formed by fine material colluvium with gravitational movements or solifluction processes in fresh and humid conditions. It appears in the following chronological intervals: 12.7–12.2 cal ka BP, 11.5/11.1–10.7/10.4 cal ka BP and 8.2–8.0 cal ka BP (less humid). Hiatus phases are represented in the rest of the sequence up to c. 7.4 cal ka BP. From the sedimentary point of view these stages of hiatus are indicative of phases of stability or lack of episodes with seasonal contrasts; a fact that would cause interruptions to detrital deposition in the interior of the caves. In contrast, in the period c. 7.4 to 6.0 cal ka BP, attributed to the Middle and Early Neolithic, there is a certain stratigraphic continuity. From the sedimentary point of view it is distinguished by a variability of processes that responds to accumulative episodes of short duration characteristic of morphogenesis of the slopes in an arid Mediterranean environment, identified in our records as RCCs, (c. 7.4–7.2 cal ka BP- Cardial Neolithic; c. 6.8–6.3 cal ka BP-Early Postcardial Middle Neolithic and c. 6.2–5.7 cal ka BP- Late Postcardial Middle Neolithic) alternating with episodes of stability, more humid and coinciding with a better sedimentary record of the pastoral activity in the cavities during Epicardial and Late Cardial Neolithic (c. 7.1–6.7 cal ka BP) and Postcardial Middle Neolithic (c. 6.6–5.9 cal ka BP). It is during this period that Holocene climate variability has better resolution in caves in the Catalan Coastal Ranges of NE Iberia.