Cronología, bioestratigrafía y paleoecología del Pleistoceno Medio de Galería (Sierra de Atapuerca, España)

Abstract

Resumen: El yacimiento de Galería es uno los rellenos cársticos pleistocenos situados en la Trinchera del Ferrocarril de la Sierra de Atapuerca. El relleno sedimentario se divide en seis unidades estratigráficas (GI a GVI). La base de la sucesión estratigráfica corresponde al Pleistoceno Inferior y es estéril. Las unidades fosilíferas con evidencias de ocupación humana (GIT y GITT) son de la segunda mitad del Pleistoceno Medio. Las especies de mamíferos permanecen evolutivamente estables; solo se observan cambios menores en los roedores Iberomys breccensis, Microtus aff. arvalis y Arvicola sp. No obstante, se detectan variaciones en las frecuencias de micro- y macrovertebrados y en las comunidades de aves. La subunidad Glla se interpreta como formada durante una fase cálida.

Abstract: The site of Galeria is one of the cave deposits located at the Railways Trench of the Sierra de Atapuerca. The sedimentary infill is divided into six stratigraphic units (Gl-GVI). The base of the stratigraphic succession is sterile and dates from the Lower Pleistocene. The fossiliferous units with evidence of human occupation (GII and GUI) date from the upper Middle Pleistocene. From an evolutionary point of view, the mammal species remain stable along the stratigraphic succession. There are, however, changes in the frequency of small and large vertebrates, and more especially in birds species. The rodents lberomys breccensis, Microtus aff. arvalis y Arvico/a sp. display slight changes in size towards the top of the stratigraphic succession. The GIIa subunit is interpreted as the result of a warm period, likely corresponding to the oxygen isotopic stages 11 or 9. The Gilb subunit records the transition from 9 to 8 isotopic stages, whereas the base of GIii was deposited during the isotopic stage 8. Finally, the top of GITT and the different stretches of the GJY may correspond to the fluctuations of the oxygen isotopic stage 7. It is proposed that the Galeria fossiliferuos units record an increase in the environmental moist, reaching a maximum in a time interval which can be correlated with the oxygen isotope stage 8.