# Environmental Changes and Cultural Transitions in SW Iberia during the Early-Mid Holocene
## 2 Materials and Methods  
Twin sediment cores 19-01 and 19-02 (referenced as GeoB23519-01/-02 in the MARUM core repository in Bremen, Germany) were retrieved in the Algarve continental shelf (37\({}^{\circ}\) 00.656, 008\({}^{\circ}\) 52.247 and 37\({}^{\circ}\) 00.654, 008\({}^{\circ}\) 52.26, respectively) at _ca._ 65 m water depth and approximately 3 km from the coast using a vibracorer. The 3.64 m-long core 19-01 was sampled for pathological analysis and the neighboring core 19-02 (3.62 m-length) is added to increase data and resolution on sedimentation rates and chronology. In both cores, stratigraphic units were identified by visual description of the sediment. From bottom to top (Figure 2), both cores are composed of greenish fine sands covered by muddy sediments and capped by coarse silt to silty sand (uppermost 1.5 m). Shells are common as well-preserved specimens and the clastic fraction is composed by bioclasts, siliclastics, and lithic fragments. X-ray fluorescence scans (XRF) were measured using an ITRAX core scanner (resolution 2 mm, 20 s exposure time, 30 kV, 55 mA). Carbonate (Ca, Sr), siliciclastic (Si, Al, Ti, Zr, Rb), organic matter (Br, Mo incoherent and coherent scatter [Mo inc, Mo coh]), and redox geochemical (Mn, Fe) proxies were chosen (Figure 2) and some useful ratios were analyzed (Ca/Si, Si/Al, Zr/Al, Zr/Rb, Mn/Fe, Mo inc/coh) [38]. Anomalous values were removed by comparison to the core photographs to minimize the effect of coarse grains, cracks, and surface irregularities. The remaining data were normalized by count per row to unit by column and smoothed with an arbitrary 11-point running mean filter to reduce the inherent data noise. Seven articulated bivalves from core 19-01 and six more articulated valves from 19-02 were \({}^{14}\)C-dated at the Beta Analytic Inc. and the University of California-Irvine (USA). Calibration was performed with CALIB 8.2 [39] using the Marine20 calibration dataset [40] and different \(\Delta\)R calculated from the original datasets of [41; 42; 43; 44; 45] by using the online application of [46] (Table 1). After comparison of the sedimentological and geochemical logs, it was possible to correlate both cores by depth. The age model is based on a simple linear interpolation and sedimentation rates were calculated for each dated interval (Figure 3). Palynological samples were collected from core 19-01 with an interval of 3-7 cm. All samples were chemically treated with HCl to remove carbonates, KOH to remove humic acids, and sodium polytungstate (SPT: 3 Na2 WO4.9 WO3.H2O) at 2.0-2.1 cm\({}^{3}\) for densitetric separation. The final residue obtained after the treatment was mounted on slides with the use of glycerol mixed with phenol. Palynomorphs were counted using an optical microscope at 400\(\times\) and 1000\(\times\) to a minimum pollen sum of 150 terrestrial pollen grains. Fossil pollen grains, spores, and non-pollen palynomorphs were identified using published keys [47; 48; 49; 50; 51; 52] and the modern pollen reference collection of the CSIC in Madrid (Spain). Microcharcoal particles >125 m were counted alongside the identification of pollen grains and interpreted as indicators of regional fires [53]. Pollen and microcharcoal concentrations (grains/gr and particles/gr of dry sediment, respectively) were estimated by adding one Lycopodium clavatum tablet to each sample [54]. Diagrams were plotted versus age using TiliaIT software (version 2.1.1, Illinois State Museum, Research and Collection Center. Springfield, IL, USA) Palynological assemblage zones were determined by Constrained Cluster Analysis Sum Squares (CONISS) based on a square root transformation (Edwards & Cavalli-Sforza chord distance).