“Right on time”reconstructing the biography of the lacustrine site of la draga (lake Banyoles, Spain). micromorphological analysis and chronological modelling of depositional EVENTS

Abstract

Reconstruction of the biography of the site of La Draga (Lake Banyoles) was attempted in this research through the identification of a set of depositional events as the consequence of both anthropic activities and geogenic key forces altering the deposition of materials. Depositional events are thus defined by what, how and when something happened. “How” and “when” build the chronological context of human and natural activities, while “what” helps identifying the activities per se. 62 14C dates are analyzed in combination with a recently established local floating tree-ring sequence for the Early Neolithic site of La Draga (Banyoles, Northeast Iberian Peninsula). Archaeological data, radiometric and dendrochronological dates, as well as sedimentary and micro-stratigraphical information are used to build a Bayesian chronological model, using the ChronoModel 2.0 and OxCal 4.4 computer programs, and IntCal 2020 calibration curve. The dendrochronological sequence is analyzed, and partially fixed to the calendrical scale using a Wiggle-Matching approach. Depositional events and the general stratigraphic sequence are expressed in expanded Harris Matrix diagrams and ordered in a temporal sequence using Allen Algebra. Post-depositional processes affecting the stratigraphic sequence are related both to the phreatic water level and the contemporaneous lakeshore. The most probable chronological model suggests two main Neolithic occupations, that can be divided into no less than three different “phases”, including the construction, use and repair of the foundational wooden platforms, as well as evidence for later constructions after the reorganization of the ground surface using travertine slabs. The installation horizon at La Draga is dated at 5292 cal BC and is characterized by the construction of pile-dwellings on a lake marl substrate. This is a usually applied practice in the pile-dwellings settlements in Europe. The chronological model is discussed considering both the modern debate on the Climatic oscillations in the period 8000-4800 cal BC, and the origins of the Early Neolithic in the western Mediterranean region.