The aim of this paper is to show the stratigraphic record of the Late Pleistocene corresponding to the distal region of the Paraná River basin. It displays sedimentological, paleontological and ...geochronological evidences that characterise the last interglacial–glacial cycle. In particular, strong environmental records are shown for the Last Interglacial Stage (LIS). Salto Ander Egg Formation (SAEF) is defined as a new lithostratigraphic unit representative of the Late Pleistocene in southwestern Mesopotamia. This unit is formed of complex fluvial deposits, which contains a heterogeneous collection of sub-environments, of ages ranging from 120 to 60ky BP. The clast-supported gravel facies containing sparse boulders indicate high flow during a humid climate. The large and middle-scale architectures of fluvial sedimentary bodies evidence the relationship between the sediment accommodation and the sea level oscillations. Three sub-sequences identified in the succession suggest a transgressive trend during the MIS5e, a highstand stage in MIS5c, and a minor transgressive cycle during MIS3. A Brazilian faunal association collected at the bottom of the sequence and sedimentological interpretations display wet and warm climatic conditions, typical of tropical or subtropical environments. Such environmental conditions are characteristic of the maximum of the last interglacial stage (MIS5e) and show a signal stronger than the signal of the current interglacial stage. All these data show a direct correlation between the increases of paleodischarges and the elevation of the sea level. The whole sequence is completed with transitional swampy deposits, accumulated probably during the MIS3/MIS2 transition, and the typical loess of the Tezanos Pinto Formation, mantled during the Last Maximum Glacial.
•New lithostratigraphic unit corresponding to the Last Interglacial is presented.•Geochronological data suggest high sedimentation rate during the MIS5e.•An unprecedented Brazilian faunal assemblage in southern latitudes is reported.•Sequence Stratigraphy showed correlation between humid climate and high sea level.•Magnitudes of autocyclic and allocyclic signals on deposition could be estimated.
We experimentally and theoretically investigate the photonic generation of microwave signals using a long-wavelength single-transverse-mode vertical-cavity surface-emitting laser (VCSEL) subject to ...two-frequency orthogonal optical injection. We study if a significant reduction of the linewidth is achieved in the double injection locking regime. In this regime, the VCSEL is subject to optical injection by two master lasers in such a way that stable locking is also observed if only light from one of the master lasers is injected. Our model includes the effect of the injected light reflected at the VCSEL's mirror generalizing previous modeling of reflection-mode optical injection-locked VCSELs. Our model also describes the high coherence associated to stable injection locking states and takes into account phase fluctuations in both master lasers. We observe no significant reduction of the linewidth in the double injection locking regime because the linewidth is mainly determined by the phase fluctuations of the two master lasers.
This contribution aims to analyse the best-known paleovertebrate records from the beginning of the Late Pleistocene in Salto Ander Egg Formation (SAEF), Argentina. This fossil assemblage allowed us ...to infer the paleoenvironmental conditions for these deposits, and to discuss the biostratigraphic record within a geochronological framework. Salto Ander Egg Formation (SAEF), mapped in southwestern Entre Ríos province, is composed of fluvial deposits and was dated with ages ranging from 120 to 60ky. Three sub-sequences were identified in the succession, which suggests a transgressive cycle over the MIS5 composed of a rising trend during MIS5e, a high stand stage in MIS5c, and a minor transgressive cycle during MIS3. A quantitative analysis has shown that approximately 50% of the total richness estimated for the unit has been sampled up to the moment. Two biostratigraphic units could be discriminated based on the study of faunistic associations. One of them, with Brazilian fauna, is linked to the basal sequences of SAEF (SS1). The other, exhibiting Pampean affinities, corresponds to middle and upper levels of SAEF (SS2–SS3).
•Geo-Paleontological record from the Late Pleistocene lower limit in South America.•Discrimination of two biostratigraphic units.•Biostratigraphic evidence of the maximum humid peak from the Last Interglacial Stage.•Unusual Brazilian faunal record for the Late Pleistocene of SW South America.
We describe a new large species of marabou stork, Leptoptilus patagonicus (Ciconiiformes, Ciconiidae, Leptoptilini), from the late Miocene Puerto Madryn Formation, Chubut Province, Argentina. The ...specimen consists mainly of wing and leg bones, pelvis, sternum, cervical vertebrae, and a few fragments of the skull. We provisionally adopt the traditional systematic scheme of ciconiid tribes. The specimen is referred to the Leptoptilini on the basis of similarities in morphology and intramembral proportions with the extant genera Ephippiorhynchus, Jabiru, and Leptoptilos. The fossil specimen resembles in overall morphology and size the species of Leptoptilos, but also exhibits several exclusive characters of the sternum, humerus, carpometacarpus, tibiotarsus, and pelvis. Additionally, its wing proportions differ from those of any living taxon, providing support to erect a new species. This is the first record of the tribe Leptoptilini in the Tertiary of South America.
The Santa Cruz Formation constitutes one of the most representative units of the Early-Middle Miocene of South America for its abundant and rich fossil record of vertebrates. The diversity of extinct ...birds is known so far by at least 17 species grouped in 15 genera and at least 10 families. Most of the avian taxa described from these levels come from localities of the Santa Cruz Province placed next to or along the Atlantic coast. New specimens recovered from the Río Santa Cruz valley, with accurate geographic and stratigraphic provenances, are presented in this contribution. They include rheids, tinamids, and phorusrhacids.
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