Examinando por Autor "Terrasi, Filippo"
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Embargado Late- Pleistocene Wedge Structures Along The Patagonian Coast (Argentina): Chronological Constraints And Palaeo-Environmental Implications(2014) Ribolini, Adriano; Bini, Monica; Consoloni, Ilaria; Isola, Ilaria; Pappalardo, Marta; Zanchetta, Giovanni; Fucks, Enrique; Panzeri, Laura; Martini, Marco; Terrasi, FilippoThis paper investigates several wedge structures formed in continental deposits covering marine sediments deposited during MIS 5 along the central Patagonian coast of Argentina. The size and surface microtexture characteristics of the infilling sediments are consistent with a depositional environment dominated by aeolian transport. Fragments of Andean volcanic rocks (glass shards) in the wedge-fill suggest long-distance transport via a westerly component of wind direction. The wedges are interpreted as products of deep seasonal frost action in frozen ground, which produced open cracks that filled rapidly with partially non-local aeolian sediments. Many wedges cross cut carbonate crusts that formed under permafrost conditions in coastal Patagonia. The radiocarbon dating of carbonate crusts yielded an age of 25–27 kyrbp, while wedge-fill sediments are OSL dated to 14 670 ± 750 yrbp. This indicates that ground wedge formation occurred during a cold event (the Antarctic Cold Reversal period) that interrupted the permafrost degradation following the Last Glacial Maximum. - Artículo
Embargado Middle-to late-Holocene relative sea-level changes at Puerto Deseado (Patagonia, Argentina)(2014) Zanchetta, Giovanni; Bini, Mónica; Isola, Ilaria; Pappalardo, Marta; Ribolini, Adriano; Consoloni, Ilaria; Boretto, Gabriella; Fucks, Enrique; Ragaini, Luca; Terrasi, FilippoStratigraphic, 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 sincec.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 atc.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 lastc.3500 years ofc.1.8 mm/yr. Moreover, notches and morphological data indicate that the crest of the beach ridges exceeded the sea-level height byc.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. - Artículo
Embargado New insights on the Holocene marine transgression in the Bahía Camarones (Chubut, Argentina)(2012) Zanchetta, Giovanni; Consoloni, Ilaria; Isola, Ilaria; Pappalardo, Marta; Ribolini, Adriano; Aguirre, Marina; Fucks, Enrique; Baneschi, Ilaria; Bini, Monica; Ragaini, Luca; Terrasi, Filippo; Boretto, GabriellaThe stratigraphic reconstruction of the northern sector of theBahía Camarones (Chubut, Argentina) allowed to improve ourunderstanding of the Holocene marine transgression in the area.The first phase of the maximum of the transgression, is interpretedas dominated by the high rate of eustatic rise of sea level until ca.6-7 ka BP possiblyassociated to sedimentary starvation as suggestedby fossil accumulation. After this first phase, the general trend indi-cates a progressive fall of the relative sea level after the MiddleHolocene high stand as documented in other parts of south Amer-ica Atlantic coast. Our data, coupled with the robust radiocarbondata set available for the area from literature, indicate three mainlocal 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 yrcal BP), and ca. 1300-500 yr BP (ca. 1000-300 yr cal BP). A signifi-cant age gap in coastal aggradation is present between ca. 5300 and4400 yr BP (ca. 5600-4500 yr cal BP), and perhaps between ca 2000and 1300 yr BP (ca. 1700-1000 yr cal BP). These can be linked tophases of local sea level fall and/or phases of sedimentary starvationand/or changes in drift transport which can have produced localcoastal cannibalization. However, no conclusive data can beadvanced. Data obtained from careful measurements of sea levelmarkers represented by the top of marsh and fluvial terraces indi-cate lower values for the sea level estimation compared with thedata set previously proposed for the area. This stigmatizes the factthat field-oriented works are still the priority in the Patagonia coastalong with accurate age measurement, especially for obtaining thefundamental information we need for predicting the environmentalimpact, in these coastal areas,from accelerate sea level rise as effectof global warming.