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This paper studies the malacofauna of four sediment cores collected in an old cove of the Tinto-Odiel estuary (SW Spain) to establish the chronology and spatial extent of MIS-1 transgression in this area. The paleoenvironmental interpretation based on facies analysis and the malacological record point to an evolution from a Miocene marine substrate to a final anthropic filling. During the late Pleistocene?-lower Holocene, this substrate was eroded by the fluvial network and alluvial sediments were deposited. During the maximum of the MIS-1 transgression (~ ca 6.5–5.4 kyr BP), this area was flooded and malacofauna is revealed as an excellent proxy of this transgression. Mesolittoral paleoenvironments dominated by the gastropod Peringia ulvae characterized the inner zones of the cove, while phanerogam meadows with abundant specimens of the gastropod Bittium reticulatum developed in the outermost areas. During the last 5400 years, this cove was progressively covered by marshes, although some mesolittoral paleoenvironments persisted until 4000 years BP.

A multidisciplinar analysis of sediments collected in diferent environments of the Doñana National Park (Guadalquivir estuary, SW Spain) provides an overview of the textural, mineralogical and physico-chemical parameters that control the distribution of benthic foraminiferal tests in this Biosphere Reserve. These microorganisms are absent in the fne quartzitic sands that constitute the substrate of temporary ponds with brief hydroperiods located in the dune systems and spits, as well as in other ponds with low conductivities or hypersaline conditions located in the inner marshlands or near the Guadalquivir river banks. Dead benthic foraminifera are mainly found on phyllosilicate-rich, silty-clayey substrates. The taphonomic analysis of the main species (Ammonia tepida, Haynesina germanica, Trochammina infata, Entzia macrescens) points to its deposit in situ. Cluster analysis permits to delimitate six foraminiferal assemblages. Cluster II (A. tepida+H. germanica) is the dominant assemblage in the central ponds and the margins of the main channels, while cluster IV (T. infata+E. macrescens) is restricted to some ponds located on the high marsh and cluster VI (Ammonia beccarii+Quinqueloculina spp.) is abundant on external beaches. Tidal fuxes cause the transport of these last marine benthic species and some plaktonic forms both to the inner areas of the estuary and to these beaches. info:eu-repo/semantics/publishedVersion

Valencina (Seville, Spain) is one of the most important megalithic sites of the third millennium BCE in Western Europe. Among its most celebrated monuments are the tholoi of Montelirio, La Pastora, Matarrubilla, and Structure 10.042-10.049. Although sharing the same architectural tradition, these monuments were raised at different times of Valencina’s history and present important formal differences. In particular, the tholoi of La Pastora and Matarrubilla contrast with that of Montelirio in that they are devoid of artistic ornamentation such as paintings and engravings, showing instead an inordinate number of natural geological features. This study, focusing on La Pastora and Matarrubilla, offers an innovative approach to the notion of “megalithic art.” Firstly, these elements are characterized and classified and their natural origin established. Thus, the calcareous sandstone blocks dated from the Tertiary reveal structures on their surfaces generated by biological (bioturbation) and physical (by currents) processes during the Neogene. The surfaces of certain slabs of identical lithology at La Pastora experienced more recent intense marine bioerosion and bioconstructions in the form of Ostrea preserved to this date. Secondly, we emphasize the choice of different rock types following a certain pattern or serving to highlight a particular constructive element. In sum, all the natural elements bear highly aesthetic qualities and appear to have been deliberately chosen to highlight specific decorative or symbolic aspects. As a result, we suggest that future research on “megalithic art” should include analogous geological examinations in order to discern the origin and nature of the different elements.

In environmental age dating the 230Th/232Th activity ratio is widely used as an indicator of detrital contamination. A clear relationship between this activity ratio and the carbonate sample’s age has previously been demonstrated, whereby a detrital correction must be applied when the 230Th/232Th activity ratio of the leach drops to 20. We demonstrate that in some cases carbonate samples with 230Th/232Th well above 20 must be corrected, otherwise an overestimation of the sample’s age is obtained. Evaluation of the relationship between 230Th/234U and 230Th/232Th in the carbonate’s aliquots will enable evalua-tion of the limit at which a carbonate can be considered pure or impure. European Union (UE) EU MEDOC Programme: 2002-02-4.1-U-048