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Ragaini, L.
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- PublicationRestrictedMiddle- to late-Holocene relative sea-level changes at Puerto Deseado (Patagonia, Argentina)(2014)
; ; ; ; ; ; ; ; ; ; ;Zanchetta, G.; DST Università di Pisa ;Bini, M.; DST Università di Pisa ;Isola, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Pappalardo, M.; DST Università di Pisa ;Ribolini, A.; DST Università di Pisa ;Consoloni, I.; DST Università di Pisa ;Boretto, G.; Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), Argentina ;Fucks, E.; Universidad Nacional de La Plata, Argentina ;Ragaini, L.; DST Università di Pisa ;Terrasi, F.; Second University of Naples, Italy; ; ; ; ; ; ; ; ; Stratigraphic, morphologic and radiocarbon data from Puerto Deseado coastal area (Santa Cruz Province, Argentina) indicate that the Holocene coastline formed in response to the discontinuous aggradation of coarse gravely beaches since c. 6300 cal. yr BP related to a progressive falling of relative sea level. Beach ridge crests crudely approximate to the sea level showing at least three steps of aggradation and relative sea-level lowering. Two inactive abrasive notches at c. 7.9 and 3.4 m a.s.l. have recorded this sea-level trend, suggesting two important phases when sea level was stationary. This allows the estimation of a rate of relative sea-level fall in the last c. 3500 years of c. 1.8 mm/yr. Moreover, notches and morphological data indicate that the crest of the beach ridges exceeded the sea-level height by c. 2 ± 0.5 m. This value provides a reasonable regional estimate to be applied to produce comparable relative sea-level curve for Atlantic Patagonia coast.304 20 - PublicationRestrictedNew insights on the Holocene marine transgression in the Bahía Camarones (Chubut, Argentina)(2012)
; ; ; ; ; ; ; ; ; ; ; ; ;Zanchetta, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Consoloni, I.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Isola, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Pappalardo, M.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Ribolini, A.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Aguirre, M.; CONICET, INGEA UNLP, Laboratorio 6 (Malacofauna Cuaternaria), La Plata, Argentina; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, INGEA, La Plata, Argentina. ;Fucks, E.; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, INGEA, La Plata, Argentina ;Baneschi, I.; IGG-CNR, Pisa, Italy ;Bini, M.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Ragaini, L.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Terrasi, F.; CIRCE, Department of Environmental Sciences, Second University of Naples, Caserta, Italy ;Boretto, G.; CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), Còrdoba, Argentina.; ; ; ; ; ; ; ; ; ; ; The stratigraphic reconstruction of the northern sector of the Bahía Camarones (Chubut, Argentina) allowed to improve our understanding of the Holocene marine transgression in the area. The first phase of the maximum of the transgression, is interpreted as dominated by the high rate of eustatic rise of sea level until ca. 6-7 ka BP possibly associated to sedimentary starvation as suggested by fossil accumulation. After this first phase, the general trend indicates a progressive fall of the relative sea level after the Middle Holocene high stand as documented in other parts of south America Atlantic coast. Our data, coupled with the robust radiocarbon data set available for the area from literature, indicate three main local steps of coastal aggradation between ca. 6600 and 5400 yr BP (ca. 7000-5600 yr cal BP), ca. 3300 and 2000 yr BP (ca. 3100-1700 yr cal BP), and ca. 1300-500 yr BP (ca. 1000-300 yr cal BP). A significant age gap in coastal aggradation is present between ca. 5300 and 4400 yr BP (ca. 5600-4500 yr cal BP), and perhaps between ca 2000 and 1300 yr BP (ca. 1700-1000 yr cal BP). These can be linked to phases of local sea level fall and/or phases of sedimentary starvation and/or changes in drift transport which can have produced local coastal cannibalization. However, no conclusive data can be advanced. Data obtained from careful measurements of sea level markers represented by the top of marsh and fluvial terraces indicate lower values for the sea level estimation compared with the data set previously proposed for the area. This stigmatizes the fact that field-oriented works are still the priority in the Patagonia coast along with accurate age measurement, especially for obtaining the fundamental information we need for predicting the environmental impact, in these coastal areas, from accelerate sea level rise as effect of global warming.224 22 - PublicationRestrictedAbrasive notches along the Atlantic Patagonian coast and their potential use as sea level markers: the case of Puerto Deseado (Santa Cruz, Argentina).(2014)
; ; ; ; ; ; ; ;Bini, M.; DST Università di Pisa ;Isola, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Ribolini, A.; DST Università di Pisa ;Pappalardo, M.; DST Università di Pisa ;Favalli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Ragaini, L.; DST Università di Pisa ;Zanchetta, G.; DST Università di Pisa; ; ; ; ; ; Patagonia Argentina is a key area for the study of sea level changes in the southern hemisphere, but the availability of reliable sea level markers in this area is still problematic. In fact the storm deposits (beach ridge) commonly used here to reconstruct past sea level oscillations introduce a wide error. Along the Puerto Deseado coast (Santa Cruz), morphometric analyses of 11 features were carried out using traditional measurement tools and a digital software-based method (tested on one selected feature) with the aim to investigate the possibility of their use as sea level markers. By undertaking accurate topographic profiles we identified the relationship between notches and current sea level. In detail, we identified two clusters of notch retreat point elevations, with a very low internal variability. The lower was located a little below the mean high tide level (mHT) and the upper located at least 0.5m above the maximum high tide level (MHT). Field observations of tidal levels and the position of notches suggest that the lower notches are active and the upper are inactive. This study on the abrasive notches attests their quality as sea level markers and opens up the use of fossil abrasive notches as palaeo sea level markers because the error linked to these features is substantially smaller than that introduced by beach ridges commonly used in the study area254 22 - PublicationOpen AccessGeomorphologic Map of Northeastern Sector of San Jorge Gulf (Chubut, Argentina)(2011)
; ; ; ; ; ; ; ; ; ;Isola, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Bini, M.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, ITALY ;Ribolini, A.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, ITALY ;Pappalardo, M.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, ITALY ;Consoloni, I.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, ITALY ;Fucks, E.; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, INGEA, La Plata, ARGENTINA. ;Boretto, G.; CICTERRA (Centro de Investigaciones en Ciencias de la Tierra) Avenida Vélez Sárfield 1611. CP 5016. Córdoba, ARGENTINA. ;Ragaini, L.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, ITALY. ;Zanchetta, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; ; ; ; ; ; This paper presents a 1:100,000 scale geomorphologic map of the Northeastern sector of San Jorge Gulf (Chubut Province) in Patagonia, Argentina, covering more than 1,000 km2. Derived from remote sensing data and validated by three field surveys, it has been compiled in order to understand the past and recent evolution of the area with particular reference to sea-level oscillation studies, for which this map is the basic tool. The very low human impact and rates of dynamic landscape change allow the preservation of extensive palaeo deposits and landforms, including those indicative of sea-level variations. The relative change of sea level dominates landscape evolution, allowing the formation of widespread marine and lagoon deposits often interfingering with fluvial deposits and reworked by aeolian process in the framework of consequent beach progradation.179 226