Palaeoenvironmental Changes In The Iberian Central System During The Late-Glacial And Holocene As Inferred From Geochemical Data: A Case Study Of The Navamuno Depression In Western Spain

The Iberian Central System (ICS) is a clue region to reveal Mediterranean/Atlantic inferences over Iberia. We present a multidisciplinary study from western Spain conducted in the Navamuno depression (ND), covering the last 16.8 ka (cal BP). A reconstruction of the palaeotemperature from the resulting geochemical data highlights four cold and dry intervals, namely, the Oldest Dryas, Older Dryas, Intra-Allerod Cold Period (IACP), and the Younger Dryas, along with warmer intervals: the Bolling (14.7-14 ka) and the Allerod (12.9-12.6 ka); however, the Greenland Interstadial GI-1c (13.4-13.1 ka) is barely distinguishable in the ND. Despite the shortage of biomass to sustain fire, the earliest charcoals are from similar to 14.4-13.8 ka. Evidence of ash/dust events overprinting the geochemical background starts at similar to 13.8-12.8 ka. Significant fire activity in the Early Holocene at similar to 11.7-10.6 ka affected the ND, matching the westernmost ICS data. This period includes short oceanic spells inferred from Cl peaks at similar to 10.9-10.2 ka and three cold intervals at 11.4, 9.3, and 8.2 ka disrupted the progressive temperature increase. The Mid-Holocene showed a continuously increasing trend towards an arid climate, peaking at 4.2 ka under a pervasive dust influx from North Africa, which has prevailed since almost similar to 7.9 ka. A prominent volcanic event at similar to 6.8-5.8 ka is in Navamuno and Ronanzas (Asturias, N Spain; Gallego et al., 2013) identified from heavy metal-rich layer, synchronous with the last known eruption of the Calatrava volcanic field (South-Central Spain; Poblete-Piedrabuena et al., 2019). This volcanic eruption could affect many other regions half north of Iberia. The pervasive presence of oceanic aerosols in the last three millennia (2.8 ka similar to) allowed the formation of a Cl-rich peat layer during the Ibero-Roman humid period similar to 2.1 ka, before a changing around similar to 0.4 ka toward colder and drier conditions at the Little Ice Age (LIA) period.