Geochemical anomalies of potentially hazardous elements reflect catchment geology: An example from the Tyrrhenian coast of Italy

Assessing soil contamination by hazardous metals and estimating the extent to which metal concentrations in surficial sediments may pose risks to human health are increasingly important environmental issues. An integrated sedimentological and geochemical study of 57 Holocene beach sands from the shallow subsurface (120–130 cm depth) of the heavily urbanized Tyrrhenian Sea coast of Italy (Tuscany and adjacent coastal stretches) allowed a remarkable compositional heterogeneity to be identified as a function of spatial variations in riverine sediment supply and alongshore sediment dispersal patterns. Concentrations of Cr, Ni, and As exceeding maximum permissible limits for recreational/industrial sites (150 mg/kg, 120 mg/kg, and 20 mg/kg, respectively) reveal spatial trends that fit the petrography of modern beach sands and closely reflect the geology of river catchments, thus indicating a geogenic origin. Extremely high concentrations of Cr (and Ni), even 10 times greater than threshold values, are interpreted to reflect sediment supply from river catchments rich in ultramafic rocks (ophiolite sequences of Cecina and Campiglia areas), with subsequent transport via the longshore drift. On the other hand, high As concentrations in the Campiglia region and along the southern stretch of coast reflect leaching of felsic volcanic and plutonic parent rocks and hydrothermal products related to the Tuscan and Roman magmatic provinces cropping out in the Fiora, Albegna, and Cornia river catchments. This study shows that coastal sediment derived from particular source rocks is likely to contain potentially harmful metals in predictable proportions, which may easily exceed maximum allowable concentrations. Assessing spatial distribution of such metals based on catchment geology and sediment transport pathways may help separate natural concentrations from the anthropogenic contribution, providing a valuable source of information for appropriate remediation strategies and management options. © 2020 Elsevier B.V

Ephemeral rollover points and clinothem evolution in the modern Po Delta based on repeated bathymetric surveys

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Timing and mechanisms of sediment accumulation and pedogenesis: Insights from the Po Plain (northern Italy)

The relationships between pedogenetic processes and fluvial-coastal dynamics in the Po Plain have been reconstructed through sedimentological analysis and correlation of ca. 170 core data chronologically constrained by 376 radiocarbon dates. Vertically stacked, weakly developed paleosols within Upper Pleistocene and Holocene mud-prone strata testify to intermittent pedogenesis, periodically interrupted by overbank sedimentation. Individual paleosols are laterally traceable for tens of km and exhibit A-Bk-Bw, A-Bk or A-Bw profiles. Strati graphically ordered 14C calibrated ages from A organo-mineral horizons testify to slow aggradation during 4-6 thousand years-long exposure periods. Burial ages, with an error of few centuries, are provided by plant debris at the top of A horizons.Millennial-scale climate oscillations and glacio-eustasy are the main drivers of the pedo-sedimentary evolution of the area during the last 50 kyr. Upper Pleistocene paleosols (P1-P3) developed in well-drained floodplain environments, during relatively warm periods.Paleosol burial occurred during colder phases. High-sediment supply during the Last Glacial Maximum hindered pedogenesis and led to the accumulation of 3-10 m-thick overbank strata. Widespread soil development (paleosol PH) occurred at the end of Last Glacial Maximum, following the retreat of Alpine glaciers and the afforestation of Apennine drainage basins. At distal locations, paleosol PH was progressively buried under estuarine sediments during the Holocene phases of post-glacial sea level rise. Beyond the area of marine influence, burial ages of paleosol PH change from a place to another without specific spatial trends and reflect upstream fluvial sedimentation dominated by avulsions and deposition of spatially restricted alluvial units. Holocene (H1-H2) paleosols show a poor correlation potential and laterally variable degree of maturity that reflect avulsive sedimentation patterns and crevassing. This paper provides insights on the timing and mechanisms of formation and burial of weakly-developed paleosols. The outcomes of this research are applicable to similar Quaternary alluvial systems, and may help interpreting ancient paleosolbearing successions

Palynological characterization of the Po delta succession (northern Italy): Holocene vegetation dynamics, stratigraphic patterns and palaeoclimate variability

The 40 m-long core EM2, recovered in the innermost portion of Po delta plain, was sampled for palynological analysis, in order to link coastal-deltaic facies architecture to vegetation dynamics and Holocene climate variability. Pollen data refine facies characterization of the 25 m-thick Holocene succession: freshwater swamp clays alternating with overbank/channel sands document millennial to centennial-scale water table oscillations that invariably peak in correspondence of peaty layers. Pollen signature allows identification of the landward equivalent of the Maximum Flooding Surface atop the 7.6 ka-dated peaty interval and furnishes new insights on the relationship between coastal facies patterns and climate events

Factors controlling natural subsidence in the Po Plain

Understanding the causes and mechanisms of land subsidence is crucial, especially in densely populated coastal plains. In this work, we calculated subsidence rates (SR) in the Po coastal plain, averaged over the last 5.6 and 120 kyr, providing information about land movements on intermediate (103–105 years) time scales. The calculation of SR relied upon core-based correlation of two lagoon horizons over tens of km. Subsidence in the last 120 kyr appears to be controlled mainly by the location of buried tectonic structures, which in turn controlled sedimentation rates and location of highly compressible depositional facies. Numerical modelling shows that subsidence in the last 5.6 kyr is mainly due to compaction of the Late Pleistocene and Holocene deposits (uppermost 30 m)

Ostracod fauna from the ancient Magdala harbor (Kinneret lake, Israel)

none4noneV. Rossi; A. Amorosi; I. Sammartino; G. SartiV. Rossi; A. Amorosi; I. Sammartino; G. Sart

Deriving Natural Background Levels of Arsenic at the Meso-Scale Using Site-Specific Datasets: An Unorthodox Method

Arsenic is found in groundwater above regulatory limits in many countries and its origin is often from natural sources, making the definition of Natural Background Levels (NBLs) crucial. NBL is commonly assessed based on either dedicated small-scale monitoring campaigns or large-scale national/regional groundwater monitoring networks that may not grab local-scale heterogeneities. An alternative method is represented by site-specific monitoring networks in contaminated/polluted sites under remediation. As a main drawback, groundwater quality at these sites is affected by human activities. This paper explores the potential for groundwater data from an assemblage of site-specific datasets of contaminated/polluted sites to define NBLs of arsenic (As) at the meso-scale (order of 1000 km2). Common procedures for the assessment of human influence cannot be applied to this type of dataset due to limited data homogeneity. Thus, an \u201cunorthodox\u201d method is applied involving the definition of a consistent working dataset followed by a statistical identification and critical analysis of the outliers. The study was conducted in a highly anthropized area (Ferrara, N Italy), where As concentrations often exceed national threshold limits in a shallow aquifer. The results show that site-specific datasets, if properly pre-treated, are an effective alternative for the derivation of NBLs when regional monitoring networks fail to catch local-scale variability

Diagénesis y evolución de la porosidad de las areniscas turbidíticas del Cretácico de la Cuenca de Vøring en el margen pasivo de Noruega

The Vøring Basin forms an integrated part of the passive margin off central Norway. Cretaceous sandstones are among the most important hydrocarbon exploration targets in the basin. One of the most significant features of the sandstone reservoirs is the excellent reservoir quality. The lack of early pervasive diagenetic cements and the high compositional maturity have contributed to the preservation of primary porosity. Reservoir quality evolution of the sandstones was equally controlled by cementation and compaction. Primary porosity was subjected to overall successive deterioration with increase in burial depth until the precipitation of post-compaction (mesogenetic) cements (quartz overgrowths, rhombic dolomite/ankerite, saddle dolomite and calcite). However, reservoir quality was improved through the partial to total dissolution of framework grains (mainly feldspars). The sources of acidic fluid to accomplish this dissolution are uncertain, but could be organic acids derived form thermal maturation of organic matter.La Cuenca de Vøring forma parte del margen pasivo de la costa Noruega. En esta cuenca, las areniscas Cretácicas constituyen uno de los más importantes objetivos en la exploración petrolífera de la zona. Estas areniscas destacan por su excelente calidad como reservorio. La ausencia de cementos eodiagenéticos y la elevada madurez composicional han contribuido a la preservación de la porosidad primaria. La evolución de la calidad del almacén estuvo controlada en la misma magnitud por la cementación y la compactación. La porosidad primaria disminuyó progresivamente con el enterramiento hasta la precipitación de cementos mesodiagenéticos (sobrecrecimientos de cuarzo, dolomita/ankerita rómbica, dolomita saddle y calcita). Sin embargo, la calidad como reservorio de las areniscas estudiadas mejoró debido a la disolución parcial a total de los granos del esqueleto (principalmente feldespatos). La fuente de los fluidos ácidos implicados en el proceso de disolución se desconoce, pero podría estar relacionada con la maduración térmica de la materia orgánica.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEEuropean Science FoundationMinisterio de Educación y Cienciapu

PRENOLIN project. Results of the validation phase at sendai site

One of the objectives of the PRENOLIN project is the assessment of uncertainties associated with non-linear simulation of 1D site effects. An international benchmark is underway to test several numerical codes, including various non-linear soil constitutive models, to compute the non-linear seismic site response. The preliminary verification phase (i.e. comparison between numerical codes on simple, idealistic cases) is now followed by the validation phase, which compares predictions of such numerical estimations with actual strong motion data recorded from well-known sites. The benchmark presently involves 21 teams and 21 different non-linear computations. Extensive site characterization was performed at three sites of the Japanese KiK-net and PARI networks. This paper focuses on SENDAI site. The first results indicate that a careful analysis of the data for the lab measurement is required. The linear site response is overestimated while the non-linear effects are underestimated in the first iteration. According to these observations, a first set of recommendations for defining the non-linear soil parameters from lab measurements is proposed. PRENOLIN is part of two larger projects: SINAPS@, funded by the ANR (French National Research Agency) and SIGMA, funded by a consortium of nuclear operators (EDF, CEA, AREVA, ENL)