Examinando por Autor "Consoloni, Ilaria"

Mostrando 1 - 6 de 6
  • Artículo
    Embargado
    Coastal landscape evolution and sea-level change: a case study from Central Patagonia (Argentina)
    (2015) Pappalardo, Marta; Aguirre, Marina L.; Bini, Mónica; Consoloni, Ilaria; Fucks, Enrique; Hellstrom, John; Isola, Ilaria; Ribolini, Adriano; Zanchetta, Giovanni
    The coastal fringe of Central Patagonia preserves a unique and spectacular succession of landforms discontinuously formed since MIS 11 up to the Holocene. The study area, stretching from 44° 34′ to 44° 54′ S of latitude, is crucial to analyze the complexity of multitemporal shorelines formation and preservation along the Atlantic coast of South America. We used depositional and erosional landforms to get reliable and well chronologically constrained sea level markers. In particular, multistoried swale infillings, produced by a complex relationship between river discharge and marine activity, were considered the most accurate sea level markers. Palaeo sea level elevation was assessed cross checking evidence obtained from different marker types and considering the original position of each of the measured features with respect to its contemporary sea level. A dedicated field measurement of the markers current elevation was necessary, considering the macrotidal regime that currently affects this coastal area. Literature and new data provide an excellent set of dating, useful to chronologically constrain all the palaeo shorelines that have been identified. On the whole five sea level highstands have confidently been referred to Holocene (maximum transgression peak), MIS 5, 7, 9 and 11. Sea level elevation for each of them was stated respectively at 2.5, 7.5, 10.5, 22.5 and 32.5 m a.s.l., but different error bars and levels of accuracy are assigned to each of these estimates, based on innovative criterions that are widely discussed in the text. Our work enabled us to obtain new, self-consistent values of the last 400 ka uplift rates for this coastal tract and to compare them with those calculated by other authors, suggesting for the investigated time span a moderate coastal uplift.
  • Artículo
    Acceso Abierto
    Geomorphologic Map of Northeastern Sector of San Jorge Gulf (Chubut, Argentina)
    (2011) Isola, Ilaria; Bini, Monica; Ribolini, Adriano; Pappalardo, Marta; Consoloni, Ilaria; Fucks, Enrique; Boretto, Gabriela; Ragaini, Luca; Zanchetta, Giovanno
    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.
  • Artículo
    Embargado
    Holocene Beach Ridges and Coastal Evolution in the Cabo Raso Bay (Atlantic Patagonian Coast, Argentina)
    (2011) Ribolini, Adriano; Aguirre, Marina L.; Baneschi, Ilaria; Consoloni, Ilaria; Fucks, Enrique; Isola, Ilaria; Mazzarini, Francesco; Pappalardo, Marta; Zanchetta, Giovanni; Bini, Monica
    The Holocene evolution of the Cabo Raso bay (Atlantic Patagonian coast) was reconstructed by means of geomorphological, stratigraphic, and palaeontological analyses, assisted by radiocarbon dating. Six beach ridges were individuated and mapped in the field, as well as some rocky erosional landforms,e.g.,inner margins of marine terraces. Thanks to quarry sections, the internal structure of beach ridges, their relationship with continental deposits, and the fossil contents were determined. Two specimens ofAulacomya atraandBrachidontes purpuratuswere radiocarbon dated at 6055 and 4500 ± 20 YBP, respectively. The bedrock outcrops at the base of an analysed section allowed us to associate the age of the samples collected to the elevation of the marine transgression surface upon which the entire deposit rests. Because a beach ridge is a regressive form, the elevation of the base of the dated deposit was assumed to be equivalent to or slightly lower than the maximum sea-level stationing, represented by the inner margin of the coheval marine terrace. The altimetric correlation between the base of the beach ridge dated at 6055 ± 20 YBP and the inner margin of the corresponding marine terraces allowed us to constrain the maximum Holocene marine transgression to about 3 to 2m above sea level. This elevation for the maximum Holocene transgression is lower than that shown by most of the previous data for Patagonian coast, but it shows a crude agreement with recent estimates coming from geophysical models that report, for this area, a departure from the eustatic value of sea level, mainly caused by glacioisostatic process. This means that the employment of marine erosional landforms, associated with other multisource field data, proved to be determinant for reconstructing the sea-level variation in the Patagonian coast.
  • Artículo
    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, Filippo
    This 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, Filippo
    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 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, Gabriella
    The 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.