Benthic paleoenvironmental response to late Pleistocene climate variability at the SW Iberian Margin: an ichnofabric approach

The interval spanning Marine Isotope Stages (MIS) 12 to 9 represents a key phase of the Pleistocene, marked by pronounced climatic oscillations and high‑amplitude glacial–interglacial transitions. This study presents a detailed ichnofabric analysis of sediment cores from International Ocean Discovery Program (IODP) Site U1385, located on the SW Iberian Margin, with the aim of reconstructing seafloor palaeoenvironmental conditions and assessing the response of macrobenthic communities to climate variability at multiple scales. Four ichnofabrics are identified—Thalassinoides, Ophiomorpha, Zoophycos, and Chondrites—whose distribution is conditioned by changes in bottom‑water oxygenation and organic‑matter supply. Thalassinoides and Ophiomorpha ichnofabrics dominate the record, reflecting well‑oxygenated and relatively stable conditions, particularly during interglacial periods. In contrast, Zoophycos and Chondrites ichnofabrics indicate reduced oxygen levels and enhanced preservation of organic matter, occurring mainly during glacial intervals, terminations, and episodes associated with Heinrich‑type events. These iceberg‑discharge events correspond to marked decreases in oxygenation, whereas abrupt cooling events recorded in the study period show no clear impact on macrobenthic tracemaker communities. The results highlight the sensitivity of deep‑sea benthic ecosystems to oxygen and nutrient dynamics and demonstrate the value of ichnofabric analysis as a tool for interpreting palaeoenvironmental change and improving our understanding of Pleistocene climate evolution on the Iberian Margin.