Dr. Christian Haberland (PI)
Prof. Dr. Dieter F. Mertz (Scientific Participant)
Manfred Stiller (Scientific Participant)
Geologisches Alter: neogene
Regionen & Städte:
Located between 36° and 40°N on the southeastern side of the Iberian Peninsula are a series of Late Neogene continental basins. Their deposits represent an archive of paleoclimate and faunal evolution at the nexus between the continents of Europe and Africa, and the marine environments of the Mediterranean and Atlantic. During the last decade, our field and laboratory research has focused on the large (40km x 140km), fully enclosed Baza Basin. The combination of lithostratigraphy, geochronology and field geology has revealed an extensive Late Neogene infilling (>700m of the marginal facies), while others have recently published geophysical surveys (multi-channel seismic, gravity) that reveal a thick central facies (>2,500m) in the sub-surface. We are proposing to expand our holistic examination of the Baza Basin archives with the inclusion of both shallow (<400m) and deep (>2,000m) core recovery. While our goals continue to be multi-faceted, the events and records of Pliocene climate remain as the matrix of this research. Enclosed basins, such as the Baza Basin, are particularly sensitive repositories for the influences and reactions to climate forcing. Paleo-environmentally controlled facies respond quickly and predictably to changes in climate, especially in this shallow gradient valley. Our outcrop-based fieldwork shows a Pliocene-Pleistocene paleogeography with extensive grassland slopes around the Basin and a permanent central saline lake. Between these paleo-environments were wide mudflats dominated by gypsum and carbonate. African dust appears to have been a major contributor to all fine-grained facies. Climate cycles with increased rainfall forced the expansion and onlap of central lacustrine facies. Drier cycles forced the basinward expansion of the grassland slope facies (paleosols) and the contraction of the lacustrine facies. This restricted gypsum precipitation to the central lake and local ponds. The target of this proposed drilling activity will be the recovery of samples from the accumulated deposits of the central facies of paleo-lake Baza. About 2,500m of these central deposits are in the sub-surface, with less than 200m exposed as outcrop (representing the Late Pliocene and Early Pleistocene). A key observation from the central facies is the absence of sub-aerial features or lithologies, thus indicating permanence of paleo-lake Baza. This long record of the central facies includes the entire Pliocene and its boundaries with the Late Miocene and Early Pleistocene. Understanding the Early Pliocene climate requires more detailed knowledge about the unique, terminal Miocene climate and the ancillary affects on nearby continental basins caused by the Messinian Salinity Crisis.