Browsing by Author "Sánchez Goñi, Maria Fernanda"
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- Combination of insolation and ice-sheet forcing drive enhanced humidity in northern subtropical regions during MIS 13Publication . Oliveira, Dulce; Desprat, Stéphanie; Yin, Qiuzhen; Rodrigues, Teresa; Naughton, Filipa; Trigo, Ricardo M.; Su, Qianqian; Grimalt, Joan O.; Alonso-Garcia, Montserrat; H L Voelker, Antje; Abrantes, Fatima; Sánchez Goñi, Maria FernandaMarine Isotope Stage (MIS) 13, similar to 533-478 ka, has received particular attention due to the unexpected enhancement of monsoon systems under a cool climate characterized by lower atmospheric CO2 and larger ice volume than many other interglacials. Key questions remain about its regional expression (intensity, climate variability, length), and underlying forcing factors, in particular at the mid-latitudes. Here we examine the SW Iberian vegetation, terrestrial climate and sea surface temperature (SST) variability during MIS 13 by combining pollen and biomarker data from IODP Site U1385 with climate-model experiments. We show, for the first time, that despite strong precessional forcing, MIS 13 stands out for its large forest expansions with a reduced Mediterranean character alternating with muted forest contractions, indicating that this stage is marked by a cool-temperate climate regime with high levels of humidity. Results of our data-model comparison reveal that MIS 13 orbitally driven SW Iberian climate and vegetation changes are modulated by the relatively strong ice-sheet forcing. We find that the Northern Hemisphere ice-sheets prescribed at the MIS 13 climate optimum reinforce the insolation effect by increasing the tree fraction and both winter and summer precipitation. We propose that the interactions between ice-sheets and major atmospheric circulation systems may have resulted in the persistent influence of the mid-latitude cells over the SW Iberian region, which led to intensified moisture availability and reduced seasonality, and, in turn, to a pronounced expansion of the temperate forest.
- Millennial‐Scale Climate Variability Potentially Shaped the Early Interglacial Optimum in Southern EuropePublication . Desprat, Stéphanie; Guillem, Gauthier; Sánchez Goñi, Maria Fernanda; Rodrigues, Teresa; Yin, Qiuzhen; Grimalt, Joan O.The seasonal and latitudinal distribution of insolation is considered the main factor controlling the magnitude and timing of interglacial periods. However, despite small differences in insolation forcing, vegetation and hydrology in southern Europe during past interglacials are variable and the gradual change in insolation cannot explain the observed short‐lived forest optimum. Here we focus on vegetation and hydroclimatic changes at orbital‐ and suborbital‐scales in southwestern Europe during two past warm interglacial periods with reduced ice‐sheets, namely Marine Isotope Stages (MIS) 9e and 5e. We provide new pollen and sea surface temperatures records for MIS 9e from IODP Site U1385. This pollen record shows a forest expansion in southern Iberia over a 14 ky interval, bracketed by the millennial‐scale cooling events of Termination IV and MIS 9d. Between 334.5 and 332.5 ka, forest expansion reached a maximum, suggesting increased winter moisture during early MIS 9e. Model‐data comparison for MIS 9e and 5e shows that insolation is the main driver of the orbital‐scale vegetation and precipitation changes in Iberia, atmospheric CO2 forcing playing a secondary role. The high‐frequency component of the MIS 9e and 5e forest timeseries highlights the early interglacial forest and precipitation maxima as prominent suborbital events lasting ∼2 ky. We propose that the primarily insolation‐driven forest and precipitation optima were fostered by the non‐equilibrium conditions generated by the millennial‐scale deglacial variability during the early interglacials. Additionally, the early end of these optima may have been favored by a cooling and drying event that is part of the persistent intra‐interglacial variability.
- Neanderthal hunting grounds: the case of Teixoneres Cave (Spain) and Pié Lombard rockshelter (France)Publication . Uzunidis, Antigone; Blasco, Ruth; Brugal, Jean-Philip; Fourcade, Tiffanie; Ochando, Juan; Rosell, Jordi; Roussel, Audrey; Rufà, Anna; Sánchez Goñi, Maria Fernanda; Texier, Pierre-Jean; Rivals, FlorentThe study of Neanderthal-Environment interactions very often lacks precise data that match the chronogeographical frame of human activities. Here, we reconstruct Neanderthals' hunting grounds within three distinct habitats using dental microwear analysis combined with zooarchaeological data. The predation patterns toward ungulates are discussed in term of frequency (NISP/MNI) and potential meat intake (MAM). Unit IIIa of Teixoneres Cave (MIS 3, NE Spain) corresponds to a mosaic landscape, Unit IIIb was more forested, and, in the "Ensemble" II of Pie Lombard (MIS 4, SE France), forest cover dominated. At Pie Lombard, Neanderthals rely on a high diversity of taxa from closed and semi-open hunting grounds, mostly two ungulate species as well as rabbits and several bird taxa. At Teixoneres Cave, mainly open areas are exploited in summer with a predation mostly focused on large gregarious ungulates. The larger size of ungulate herds in open spaces may have allowed Neanderthals to restrict their subsistence behaviour only to very few species, in specific hunting strategies. In Unit IIIa, they do not appear to have made any selection within the most abundant species, while in Unit IIIb, they focused on aurochs and also opportunistically and heavily on newborn red deer. Neanderthal subsistence strategies seem, therefore, only partially linked to the hunting grounds they had access to. While it impacted the diversity of the prey they selected, Neanderthal groups were able to develop distinct hunting strategies within similar environments.
- Unraveling the forcings controlling the vegetation and climate of the best orbital analogues for the present interglacial in SW EuropePublication . Oliveira, Dulce; Desprat, Stéphanie; Yin, Qiuzhen; Naughton, Filipa; Trigo, Ricardo; Rodrigues, Teresa; Abrantes, Fatima; Sánchez Goñi, Maria FernandaThe suitability of MIS 11c and MIS 19c as analogues of our present interglacial and its natural evolution is still debated. Here we examine the regional expression of the Holocene and its orbital analogues over SW Iberia using a model-data comparison approach. Regional tree fraction and climate based on snapshot and transient experiments using the LOVECLIM model are evaluated against the terrestrial-marine profiles from Site U1385 documenting the regional vegetation and climatic changes. The pollen-based reconstructions show a larger forest optimum during the Holocene compared to MIS 11c and MIS 19c, putting into question their analogy in SW Europe. Pollen-based and model results indicate reduced MIS 11c forest cover compared to the Holocene primarily driven by lower winter precipitation, which is critical for Mediterranean forest development. Decreased precipitation was possibly induced by the amplified MIS 11c latitudinal insolation and temperature gradient that shifted the westerlies northwards. In contrast, the reconstructed lower forest optimum at MIS 19c is not reproduced by the simulations probably due to the lack of Eurasian ice sheets and its related feedbacks in the model. Transient experiments with time-varying insolation and CO2 reveal that the SW Iberian forest dynamics over the interglacials are mostly coupled to changes in winter precipitation mainly controlled by precession, CO2 playing a negligible role. Model simulations reproduce the observed persistent vegetation changes at millennial time scales in SW Iberia and the strong forest reductions marking the end of the interglacial "optimum".