Changes in Paleoenvironment Across the Neogene/Quaternary Boundary in Spain

Late Neogene and Early Quaternary Paleoenvironmental and Paleoclimatic Conditions in

Southwestern Europe: Isotopic Analyses on Mammalian Taxa

Authors:

1. Laura Domingo (a)
2. Paul L. Koch (a)
3. Manuel Hernández Fernández (b,c)
4. David L. Fox (d)
5. M. Soledad Domingo (e)
6. María Teresa Alberdi (f)

Affiliations:

a. Earth and Planetary Sciences Department. University of California Santa Cruz, Santa Cruz, California, United States of America

b. Departamento de Paleontología, Universidad Complutense de Madrid, Madrid, Spain

c. Departamento de Cambio Medioambiental, Instituto de Geociencias (UCM, CSIC), Madrid, Spain

d. Department of Earth Sciences. University of Minnesota, Minneapolis, Minnesota, United States of America

e. Museum of Paleontology, University of Michigan, Ann Arbor, Michigan, United States of America

f. Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain

Abstract:

Climatic and environmental shifts have had profound impacts on faunal and floral assemblages globally since the end of the Miocene. We explore the regional expression of these fluctuations in southwestern Europe by constructing long-term records (from ~11.1 to 0.8 Ma, late Miocene–middle Pleistocene) of carbon and oxygen isotope variations in tooth enamel of different large herbivorous mammals from Spain. Isotopic differences among taxa illuminate differences in ecological niches. The δ13C values (relative to VPDB, mean −10.3±1.1‰; range −13.0 to −7.4‰) are consistent with consumption of C3 vegetation; C4 plants did not contribute significantly to the diets of the selected taxa. When averaged by time interval to examine secular trends, δ13C values increase at ~9.5 Ma (MN9–MN10), probably related to the Middle Vallesian Crisis when there was a replacement of vegetation adapted to more humid conditions by vegetation adapted to drier and more seasonal conditions, and resulting in the disappearance of forested mammalian fauna. The mean δ13C value drops significantly at ~4.2−3.7 Ma (MN14–MN15) during the Pliocene Warm Period, which brought more humid conditions to Europe, and returns to higher δ13C values from ~2.6 Ma onwards (MN16), most likely reflecting more arid conditions as a consequence of the onset of the Northern Hemisphere glaciation. The most notable feature in oxygen isotope records (and mean annual temperature reconstructed from these records) is a gradual drop between MN13 and the middle Pleistocene (~6.3−0.8 Ma) most likely due to cooling associated with Northern Hemisphere glaciation.