115 research outputs found

    Glacier extent and climate in the Maritime Alps during the Younger Dryas

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    We would like to acknowledge: Prof. Rea and Dr Pellitero for fruitful discussions on various aspects of this work, and in particular on the use of glacier reconstruction and ELA GIS tools and extraction of climatic variables at a glacier ELA; Dr Ortu for kindly providing easy access to pollen data and for discussions on the climate of the Younger Dryas across the Alps; Prof. Edwards for discussions on pollen analyses; and Prof. Federici, for inspiring glaciological research in this beautiful region. The constructive and useful feedback provided by Dr Monegato and an anonymous reviewer is greatly appreciated. L. Cignoni is thanked for reviewing the English. MS acknowledges support from NERC (CIAF 9092.1010).Peer reviewedPostprin

    Geoarchaeology as a tool for reconstructing the evolution of the Apuo-Versilian Plain (NW Italy)

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    A geoarchaeological approach integrating geomorphological, stratigraphical and archaeologic data was adopted to reconstruct the palaeogeographic evolution of an area of the Apuo-Versilian plain since the Etruscan age. We produced a geomorphological map, analyzed stratigraphy data from sections/boreholes in the plain, and compiled a dataset of archaeological findings with a particular focus on the Acquarella site which is an outstanding settlement in the area. The plotting of the archaeological findings on the geomorphological map allowed to better constraint the landforms surveyed by field work and remote sensing analyses. The analyzed stratigraphic data suggests a discontinuous trend of coastal progradation. Oscillations in this trend are testified by four small scale transgressive - regressive parasequences that occurred after 4600 yrs cal B.C.. In agreement with the archaeological findings on the surface, the base of the uppermost sequence was dated to ca 500 cal AD, implying that since the Early Middles Ages the progradation trend has been continuous. Furthermore, a pronounced increase in progradation was observed after the 16th century, probably linked to both climatic influence (Little Ice Age) and human impacts (deforestation). The Acquarella rustic building has developed in this coastal-piedmont context since the Etruscan age. The reason for its longevity (eh century B.C. - Early Middle Ages) was related to a suite of environmental aspects such as the protection offered by the surrounding hills, water availability, and the elevation above a coastal plain experiencing periodic flooding Moreover, a crucial element was identified in the position of the site in respect to the main ancient roads connecting Pisa to Luni (Via Aurelia/Aemilia) and the coastal area with the inland. The correlation of the geomorphology with the archeological data from Acquarella, along with the other findings along the coastal-piedmont area allowed to depict the landscape scenarios relative to the Etruscan, Roman, Early Middle ages and Modern ages

    Reconstructing temperatures in the Maritime Alps, Italy, since the Last Glacial Maximum using cosmogenic noble gas paleothermometry

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    The Gesso Valley, located in the southwestern-most, Maritime portion of the European Alps, contains an exceptionally well-preserved record of glacial advances during the late Pleistocene and Holocene. Detailed geomorphic mapping, geochronology of glacial deposits, and glacier reconstructions indicate that glaciers in this Mediterranean region responded to millennial scale climate variability differently than glaciers in the interior of the European Alps. This suggests that the Mediterranean Sea somehow modulated the climate of this region. However, since glaciers respond to changes in temperature and precipitation, both variables were potentially influenced by proximity to the Sea. To disentangle the competing effects of temperature and precipitation changes on glacier size, we are constraining past temperature variations in the Gesso Valley since the Last Glacial Maximum (LGM) using cosmogenic noble gas paleothermometry. The cosmogenic noble gases 3He and 21Ne experience diffusive loss from common minerals like quartz and feldspars at Earth surface temperatures. Cosmogenic noble gas paleothermometry utilizes this open-system behavior to quantitatively constrain thermal histories of rocks during exposure to cosmic ray particles at the Earth’s surface. We will present measurements of cosmogenic 3He in quartz sampled from moraines in the Gesso Valley with LGM, Bühl stadial, and Younger Dryas ages. With these 3He measurements and experimental data quantifying the diffusion kinetics of 3He in quartz, we will provide a preliminary temperature reconstruction for the Gesso Valley since the LGM. Future work on samples from younger moraines in the valley system will be used to fill in details of the more recent temperature history

    The lagoonal harbour of Portus Pisanus (N Tyrrhen- ian Sea, Italy): a long history of human adaptation to changing coastline

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    During the last millennia human and natural processes have become increasingly intertwined, especially in the Mediterranean coastal and alluvial plains where major urban and trade centres developed since protohistoric times. The construction of ports represents one of the human activities that have mostly contributed to modify coastal environments, inducing a variety of hydrodynamic and hydrochemical changes especially since Roman times (Marriner et al., 2014). Exceptions in this common manner to plan harbours have been recognised along the N Tyrrhenian coast, where no high-impact defense works are explicitly documented by either historical sources or archaeological excavations for three main harbours developed during Etruscan-Roman times (IV-I century BC): Portus Lunae (Bini et al., 2012), Portus Pisanus and Vada Volterrana. Roman literary sources (i.e., Itinerarium Maritimum 501; Rutilio Namaziano) mentioned Portus Pisanus as a flourishing commercial site within a natural protected area (called Sinus Pisanus by Tacito) characterized by Posidonia meadows and located at the foot of Leghorn hills, ca. 18.5 km south of the Pisa city. Accordingly, recent excavations undertaken close to the hills slope, 3 km inland from modern coastline, unearthed a wooden palisade, stone piers and a warehouse dated to the Roman period (Pasquinucci, 2013; Morhange et al., 2015). However, the precise location of the lagoonal harbour basin is still controversial. This study aims to contribute to fill this knowledge gap and shed new light on the main stages of harbour history in the framework of the mid-late Holocene palaeogeographic evolution of the Pisa Plain. The application of a multidisciplinary approach (sedimentological and micropalaeontological core analyses, radiocarbon dating, geomorphological field survey, remote sensing and historical cartography) has revealed that a wide lagoonal basin formed in the study area during the marine transgression peak (ca. 8000 cal yr BP). This basin, recorded by a m-thick subsurface succession of soft grey clays with brackish meiofauna, persisted for several millennia and corresponds to Sinus Pisanus. The available stratigraphic data document that during Roman times the lagoon became progressively less connected to the sea and turned into a coastal lake/pond. Filling processes started two-three millennia later respect to the lagoon occupying the Pisa city area during the Holocene (Rossi et al., 2011). This seaward facies shift forced the westward transferring of the Middle Ages harbour. These results show that natural sheltered conditions along with the distance from coeval Arno River made more advantageous for humans following the shoreline changes, rather than making high-impact interventions. 2012, Bini M., Bruckner H., Chelli A., Da Prato S., Gervasini L., Palaeogeographies of the Magra Valley coastal plain to costrain the location of the Roman harbour of Luna (NW Italy), Palaeogeography, Palaeoclimatology, Palaeoecology, 337-338, 37–51. 2014, Marriner N., Morhange C., Kaniewski D., Carayon N., Ancient harbour infrastructure in the Levant: tracking the birth and rise of new forms of anthropogenic pressure, Nature Scientific Reports, 4, 5554. 2015, Morhange C., Marriner N., Baralis A., Blot M.L., Bony G., Carayon N., Carmona P., Flaux C., Giaime M., Goiran J.-P., Kouka M., Lena A., Oueslati A., Pasquinucci M., Porotov A., Dynamiques géomorphologiques et typologie géoarcheologique des ports antiques en contextes lagunaires, Quaternaire, 26, (2), 117–139. 2013, Pasquinucci M., Guida all’archeologia delle coste livornesi. Nardini Editore. Provincia di Livorno. 271 pp. 2011, Rossi V., Amorosi A., Sarti G., Potenza M., Influence of inherited topography on the Holocene sedimentary evolution of coastal systems: An example from Arno coastal plain (Tuscany, Italy), Geomorphology, 135 (1-2), 117–128

    Last Glacial Maximum and early deglaciation in the Stura Valley, southwestern European Alps

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    Acknowledgments: The fund “The termination I. The environmental and palaeoclimatic variations occurred during the 25–11 ka period” (leader A. Ribolini) supported this work (Progetti di Ricerca di Ateneo PRA, 2020–21, University of Pisa). Exposure dating was completed with the support of the National Science Foundation, Continental Dynamics Program grant EAR-0208169 (RETREAT) and by PRIME Lab, Purdue University, West Lafayette, IN, USA. We thank Cal Ruleman and Will Odom for thorough and constructive reviews. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewedPostprin

    Glare, a GIS tool to reconstruct the 3D surface of palaeoglaciers

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    Acknowledgements This research has been supported by the Leverhulme Trust International Network Grant IN-2012-140. Processing and collecting of ground penetrating data in Forgefonna was part of Elend Førre's master's project that was completed in 2009 at the Department of Geography, University of Bergen. We also acknowledge Dr Andreas Bauder for providing the subglacial topography data for Griessgletscher and Simone Tarquini for granting access to the high resolution TIN of Italy, a cut of which is provided to the reader to practice the tools (see Appendix). Referees Dr. Iestyn Barr, Dr. Jeremy Ely and Dr. Marc Oliva are thanked for their constructive comments and tool testing, which significantly improved the final output.Peer reviewedPostprin

    Sand supply from shoreface to foredunes: aeolian transport measurements and morphological evolution of a Tuscany beach stretch (Italy)

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    The coastal dunes are a highly dynamic sedimentary environment characterized by a continuous time-space readjustment in terms of morphology, shape and dimension. This is mainly due to the periodic fluctuation of the volume of sand available and by the force of the deflation processes, which are in turn driven by the interplay among pattern of vegetation cover, surface roughness and local-regional wind regime. The aim of our research is to quantify the deflation, transport and deposition of sands in a natural coastal field dune system located in the northern coast of Tuscany, Italy. The northern part of the investigated area is characterized by stable coastline condition while southwards strong erosive processes took place since 1800 year. Sedimentological data come from a series of sand collectors spaced along transects orthogonal to the coastline from the backshore to the semi stable dune field. The collectors were constructed of PVC pipe 100 x height 10 cm, with two openings 7 cm wide and 50 cm tall arranged on opposite sides of the tube. Opening willing to windward served for sand collection, and to leeward, covered with a metal wire 60ÎĽm opening. Collectors were buried along, until the base of the free window coincide with the surface of the ground about 1,5 m. The sand trapped within each collector was sampled every two hours for three consecutive times. In laboratory sand samples were weighed and subject to grain size analysis by means of mechanical sieves. The local winds parameters and their fluctuation with the time were acquired through a Meteorological mobile station. The station is equipped with three ammeters located to three different heights from ground surface: 40, 120 and 180 cm. A wireless sensor allows the constant output of data (each 5 sec) to a device. Temperature, and relative humidity value are furnished every 30 minutes. Analysis of data has evidenced the time-space fluctuation of sand volume in the two study area (stable area and under erosion). Basing on this methodological approach the time-space fluctuation of sand volume experienced by the two study areas (stable area and under erosion) has been estimated

    Geomorphologic Map of Northeastern Sector of San Jorge Gulf (Chubut, Argentina)

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    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 km 2. 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.Facultad de Ciencias Naturales y Muse

    Responses of small mountain glaciers in the Maritime Alps (south-western European Alps) to climatic changes during the Last Glacial Maximum

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    The authors would like to thank Lucy Ashpitel for assisting with field work, Ewelina BrĂłs for guidance in the sample preparation, and all members of the Laboratory of Ion Beam Physics at ETH Zurich for producing excellent exposure ages. This work received funding from the Royal Society (grant number: IEC/R2/202123) and through the RADIATE Transnational Access programme (proposal number: 22002973). Their financial and logistical support is gratefully acknowledged.Peer reviewedPublisher PD

    Temperatures recorded by cosmogenic noble gases since the last glacial maximum in the Maritime Alps

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    MMT and DLS acknowledge support from the National Science Foundation (NSF) Petrology and Geochemistry Program (EAR- -1322086 to DLS), the UC Berkeley Larsen Grant, and the Ann and Gordon Getty Foundation. MMT was supported by an NSF Graduate Research Fellowship. MS acknowledges support from the Royal Society (IE150603), the Leverhulme Trust (IAF-2016-001), and NERC (CIAF 9092.1010). AR acknowledges support from the University of Pisa fund PRA (2017). M. Uebner and S. Woodmansee are thanked for help with sample preparation. We also thank Associate Editor Kathleen R. Johnson, Jakob Heyman, and an anonymous reviewer for constructive feedback on this work.Peer reviewedPostprin
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