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A multidisciplinary study from a number of drilled cores in the Guadalquivir estuary has made possible to identify as many as three extreme wave events and their facies in the 4th millennium BP (A: ~ 4000 cal yr BP, B: ~ 3550 cal yr BP, and C: ~ 3150 cal yr BP). These events, which caused strong erosion in the Guadalquivir sandy barrier and in the neighboring aeolian systems of El Abalario, brought about significant paleogeographical changes that may have affected human settlements established in the area during the Neolithic and Copper Age periods and during the Middle Bronze Age. The three events can be spatially correlated and their facies differentiated from more proximal to more distal from the coastline. The most proximal facies is characterized by a massive accumulation of shells, a sandy or sandy–muddy matrix, an erosive base, a highly diverse mixture of species (marine and estuarine), and lithoclasts. The most distal facies presents a muddy–sandy matrix, dominance of estuarine fauna, shell accumulation, presence of terrestrial species, mudpebbles, pebbles in a clayey matrix, and bioturbation. The evidence presented will further advance scientific knowledge about the impact of extreme wave events on coastal areas in SW Iberia and NW Africa. [ABSTRACT FROM AUTHOR]

The Messinian salinity crisis (late Miocene) is one of the most fascinating paleoceanographic events in the recent geological history of the Mediterranean Sea, defining a time when it partly or nearly completely dried out. However, the relative roles of tectonic processes and sea-level changes, as triggers for restriction and isolation of the Mediterranean Sea from the open ocean, are still under debate. In this study, we present a detailed pollen, dinoflagellate cyst (dinocyst), and magnetic susceptibility analysis of a sequence of late Neogene (between ca. 7.3 and 5.2 Ma) marine sediments from the Montemayor-1 core (lower Guadalquivir Basin, southwestern Spain), which provides a continuous record of paleoenvironmental variations in the Atlantic side of the Betic corridors during the late Miocene. Our results show that significant paired vegetation and sea-level changes occurred during the Messinian, likely triggered by orbital-scale climate change. Important cooling events and corresponding glacio-eustatic sea-level drops are observed in this study at ca. 5.95 and 5.75 Ma, coinciding with the timing and duration of oxygen isotopic events TG32 and TG22-20 recorded in marine sediments worldwide. It is generally accepted that the onset of the Messinian salinity crisis began at ca. 5.96 ± 0.02 Ma. Therefore, this study suggests that the restriction of the Mediterranean could have been triggered, at least in part, by a strong glacio-eustatic sea-level drop linked to a climate cooling event occurring at the time of initiation of the Messinian salinity crisis. [ABSTRACT FROM AUTHOR]

A multidisciplinary analysis of cores and geomorphic patterns in the marshes of Doñana National Park (SW Spain) has yielded new evidence regarding the sedimentary infilling and geomorphological evolution of the Guadalquivir estuary during the Holocene. The sedimentation and geomorphological disposition have been strongly conditioned by neotectonic activity along a set of SW-NE alignments, interrupted by other alignments that follow E-W and NW-SE directions. The most conspicuous of the SW-NE alignments is the Torre Carbonero-Marilópez Fault (TCMF). South of this fault, the estuary experienced a marked subsidence from about 4000 to 2000cal. yr BP through a series of sedimentary sequences of retrogradation and aggradation within the context of relative sea-level rise. From c. 2000cal. yr BP to the present the subsidence has remained relatively dormant, with progradation of the littoral systems and infilling of the marshland progressing within a context of sea-level stability. Our results reveal that neotectonic activity is a critical factor that must also be reckoned with in any attempt to understand the Holocene geomorphological evolution in the Guadalquivir estuary. [ABSTRACT FROM AUTHOR]