Over the last decades, there has been an increasing interest on the chronology, distribution and mammal taxonomy (including hominins) related with the faunal turnovers that took place around the Pliocene-Pleistocene transition [ca. 1.8 mega-annum (Ma)] in Europe. However, these turnovers are not fully understood due to: the precarious nature of the period's fossil record; the "non-coexistence" in this record of many of the species involved; and the enormous geographical area encompassed. This palaeontological information gap can now be in part bridged with data from the Fonelas P-1 site (Granada, Spain), whose faunal composition and late Upper Pliocene date shed light on some of the problems concerning the timing and geography of the dispersals.This rich fossil site yielded 32 species of mammals, among which autochthonous species of the European Upper Villafranchian coexist with canids (Canis), ovibovines (Praeovibos) and giraffids (Mitilanotherium) from Asia. Typical African species, such as the brown hyena (Hyaena brunnea) and the bush pig (Potamochoerus) are also present.This assemblage is taxonomically and palaeobiogeographically unique, and suggests that fewer dispersal events than was previously thought (possibly only one close to 2.0 Ma) are responsible for the changes seen around 1.9-1.7 Ma ago in the fauna of the two continents.
Este trabajo ha sido financiado por
los proyectos de investigacion BTE
2003-05047 (Ministerio de Ciencia y
Tecnologia) y GV04B-629
(Generalitat Valenciana).
The stratigraphic architecture of the continental infilling is the result of the stacking of three depositional sequences, controlled by tectonics and climate that affected the relief of the margins, and by subsidence and by variations of the general base level. Each depositional sequence arises out of a complex interrelation between several depositional systems (the longitudinal system, coinciding with the axis of the basin and the areas of lacustrine sedimentation, and the transverse systems), and its sequential organization depends on the dynamic behaviour of the different depositional systems and on the fluctuations in base level (lake level).
Abstract The Lorca and Fortuna basins are two intramontane Neogene basins located in the eastern Betic Cordillera (SE Spain). During the Late Tortonian—Early Messinian, marine and continental evaporites precipitated in these basins as a consequence of increased marine restriction and isolation. Here we show a stratigraphic correlation between the evaporite records of these basins based on geochemical indicators. We use SO 4 isotope compositions and Sr isotopic ratios in gypsum, and halite Br contents to characterize these units and to identify the marine or continental source of the waters feeding the evaporite basins. In addition, we review the available chronological information used to date these evaporites in Lorca (La Serrata Fm), including a thick saline deposit, that we correlate with the First Evaporitic Group in Fortuna (Los Baños Fm). This correlation is also supported by micropalaeontological data, giving a Late Tortonian age for this sequence. The Second Evaporitic Group, (Chicamo Fm), and the Third Evaporitic Group (Rambla Salada Fm) developed only in Fortuna during the Messinian. According to the palaeogeographical scheme presented here, the evaporites of the Lorca and Fortuna basins were formed during the Late Tortonian—Early Messinian, close to the Betic Seaway closure. Sulphate isotope compositions and Sr isotopic ratios of the Ribera Gypsum Mb, at the base of the Rambla Salada Fm (Fortuna basin), match those of the Late Messinian selenite gypsum beds in San Miguel de Salinas, in the near Bajo Segura basin (40 km to the East), and other Messinian Salinity Crisis gypsum deposits in the Mediterranean. According to these geochemical indicators and the uncertainty of the chronology of this unit, the assignment of the Rambla Salada Fm to the MSC cannot be ruled out.
The Barcelon section, located at the inner sector of the Aguilas Arc (Eastern Betic Cordillera), records the Pliocene reflooding. This section comprises a basal unit A, made up of conglomerates, overlain by unit B, consisting of silty marls and glauconitic sandstones. Ichnological traits sculptured over blocks of unitA are attributable to the Entobia ichnofacies, and suggest a rapid transgression. In unit B three benthic foraminiferal assemblages are recognized: an assemblage I, related to epibathyal settings, followed by a circalittoral one, II, and finally, an infralittoral assemblage, III. Overall features point to eutrophic conditions, environmental stress at the bottom, and events of high energy bottom-currents.
The Guadix Basin became established as an intramontane basin in the central sector of the Betic Cordillera at the beginning of Late Miocene time. Its geodynamic evolution starts with a unit of Tortonian marine sediments and is completed by a unit of Late Turolian–Pleistocene continental sediments. In the two units, six depositional sequences have been differentiated whose boundaries, in most cases, coincide with tectonic events. Geohistorical diagrams show the results of quantitative analyses of subsidence in the northern sector of the basin and permit correlation of the main events with significant changes in the history of subsidence and uplift. A period of strong subsidence occurred at the beginning of Tortonian time causing the formation of a marine basin 800 m deep. The mid- and end-Tortonian tectonic events involved periods of uplift leading to shallowing in the basin. After continentalization at the end of the Tortonian, the basin was uplifted continuously from Late Turolian to Late Pleistocene times, finally accumulating sediments at a height of 1000 m.