1,970 research outputs found
Ricordo di Gino Bellagamba all'Università di Padova. Un maestro per i giovani insegnanti. Nicola Barbieri
No full textIl saggio rievoca il rapporto professionale e di amicizia con Gino Bellagamba: maestro, direttore didattico, consulente del Ministero della Pubblica Istruzione, docente universitario a Sicenze Motorie all'Università di Padov
Experimental Evaluation of the Impact of Network Frequency Synchronization on GSM Quality of Service During Handover
No full textS. Francisco, CA, US
Commento alla circolare del Ministero per le Politiche Comunitarie in materia di offerte anomale
No full textBenthic foraminifera or Ostracoda? Comparing the accuracy of palaeoenvironmental indicators from a Pleistocene lagoon of the Romagna coastal plain (Italy)
No full textIntegrated analyses of multiple groups of microfossils are frequently performed to unravel the palaeoenvironmental evolution of subsurface coastal successions, where the complex interaction among several palaeoecological factors can be detected with benthic assemblages. This work investigates the palaeoenvironmental resolution potential provided by benthic foraminifera and ostracoda within a Pleistocene lagoonal succession of the Romagna coastal plain (northern Italy). Quantitative approaches and statistical techniques have been applied to both groups in order to understand the main factors that controlled the composition of assemblages and compare the palaeoecological record provided by single fossil groups. The two faunal groups are characterized by the high dominance of opportunistic species (Ammonia tepida-Ammonia parkinsoniana and Cyprideis torosa); however, detailed palaeoecological information is inferred from less common taxa. Benthic foraminiferal assemblages are mainly determined by the frequencies of abnormal individuals and species related to high concentrations of organic matter, showing two assemblages: a stressed assemblage, consistent with a brackish-water environment subject to salinity and oxygen fluctuations, and an unstressed assemblage, which indicates more stable conditions. Despite the lower number of species, ostracoda show more significant differences in terms of species composition and ecological structure between their three assemblages, formed in response to a salinity gradient and indicative of inner, central, and outer lagoon conditions. The stratigraphic distribution of ostracod assemblages shows a general transgressive-regressive trend with minor fluctuations, whereas benthic foraminifera highlight the presence of a significant palaeoenvironmental stress. In this case, the higher abundance along the stratigraphic succession, the higher differentiation of the assemblages, and the well-defined relationship between taxa and ecological parameters determine Ostracoda as the most reliable fossil group for precise palaeoenvironmental reconstructions. Nevertheless, benthic foraminifera indicate palaeoenvironmental stress and can be used to refine the environmental interpretation in the presence of monospecific ostracod assemblages
ROSSI A., G. PISTOLA, L. BARBIERI, C. CANTISANI, S. CALVIERI Hair shaft measurement in subjects affected by androgenetic alopecia in treatment with finasteride
No full textImpact of sea-level variations on transitional settings: micropaleontological evidences from the Holocene succession of core 240 S6 (Po coastal plain)
No full textTransitional environments are extremely sensitive to environmental changes, both of natural and
anthropogenic origin. Nevertheless, abundant human activities and natural resources are hosted in
back barrier to coastal settings. Among the major threatening factors that pose at risk the existence of
such environments (exploitation of natural resources, heavy metal and organic pollution, etc.), the
recent sea-level rise is one of the most pressing and already acting from low to high latitudes (Horton
et al., 2018). Sediment successions represent a great archive where to study the response of
transitional environments to the Holocene sea-level rise. The role of microfossils as proxies for
paleoenvironmental reconstructions is widely recognize, also within back barrier to coastal settings,
where benthic foraminifers and ostracod can provide abundant insights on many (paleo-
)environmental parameters, such as salinity, organic matter and sediment inputs, oxygen conditions,
and degree of confinement (e.g., Athersuch et al., 1989; Murray, 2006). Even though benthic
foraminifers are abundant in brackish to marine conditions, ostracods are also present within
freshwater environments; moreover, the two groups seem to be driven by distinct (paleo-
)environmental drivers, which make them excellent proxies in transitional settings (Barbieri et al.,
2018). Well-developed transitional sediment successions of Holocene age are recorded locally
beneath the modern Po coastal plain and their microfossil content allowed to obtain detailed
paleoenvironmental reconstructions, also in relationship with drainage network changes (Dinelli et
al., 2013). The micropaleontological record (benthic foraminifers, ostracods) of the back barrier to
coastal sediment succession of core 240 S6 is presented here. The main aim is getting insights on the
evolution of transitional settings under the influence of the increasing sea level during the Holocene
transgression, in relationship with local (autogenic) factors, such as subsidence or river inputs.
Core 240 S6 was drilled in the Po coastal plain, ca. 5 km afar from the modern coastline (Figure 1),
through a wire-line perforation system that guarantees a high percentage of recovery (>90%).
Sedimentology and stratigraphy of the core are reported in Cibin et al. (2005). Here, we summarize
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the qualitative benthic foraminifer and ostracod content of 44 samples analyzed from 24.50 to 10.10
m core depth, where back-barrier to coastal sediments are recorded. Sediments devoid of benthic
foraminifers and ostracods or including scattered, reworked individuals are present in the remaining
intervals. Samples were treated using the standard procedure for micropaleontological samples
previously adopted in other reference work of the Po Plain area (e.g., Rossi and Vaiani, 2008).
Residues were observed under a binocular microscope to determine the microfossil content, following
the original taxonomic descriptions and reference works focused on the Mediterranean area. Within
the lower portion of the analyzed succession, from 24.50 to 17.20 m core depth, benthic foraminifers
and ostracod indicate the presence of thin, alternated swamp and lagoon sediment intervals.
Specifically, rare transported benthic foraminifers associated to abundant valves of the limneticoligohaline
Ilyocypris decipiens, indicative of a swamp paleoenvironment, are followed up to 22.60
m core depth by a brackish water microfauna dominated by the euryhaline ostracod Cyprideis torosa
and the oligo-mesohaline Candona neglecta, along with rare brackish water benthic foraminifers,
mostly Ammonia tepida, Aubignyna perlucida and Haynesina germanica. Such a microfossil
assemblage, indicative of inner lagoon, is overlaid up to 21.80 m by ostracod assemblages with
dominant C. torosa and P. albicans associated to oligo-mesohaline taxa such as Candona candida,
Candona neglecta and Loxoconcha elliptica that are indicative of a swamp paleoenvironment. The
ostracod assemblage from 21.80 to 21.40 m core depth indicates the development of inner to central
lagoon conditions, as also supported by the abundance of the brackish water benthic foraminifers A.
tepida, A. parkinsoniana and H. germanica in the upper portion of the interval. Swamp and lagoon
microfossil assemblages are developed, again, in the 21.40-18.90 and 18.90-17.20 m core depth.
Overall, three swamp-lagoon intervals are recorded and connected with the Holocene sea-level rise
and the subsequent progradation during short phases of sea-level stillstand, in accordance with the
step-like retrogradation of coastal systems recorded throughout the Po Plain sediment succession
(Amorosi et al., 2017). Nevertheless, local factors such as elevation with respect to the sea level and
morphology of the paleo-lagoonal basin could have influenced the development of swamp-lagoon
alternations. A few km inland, alternations of coastal plain, swamp and lagoon deposits (Dinelli et al.,
2013) represent the inland portion of the transitional system, but it seems difficult to establish a
precise correlation between each interval due to the high facies variability of transitional settings.
Upcore, between 17.20-13.00 m core depth, ostracod assemblages with abundant brackish-water
species (C. torosa, Loxoconcha elliptica, and Leptocythere ex gr. castanea) mostly associated to the
brackish to marine benthic foraminifers A. tepida, A. parkinsoniana, H. germanica and
Cribroelphidium oceanense and other inner shelf species indicate the development of an outer lagoon
paleoenvironment. The maximum transgression is recorded with the onset of a shoreface
paleoenvironment, where both microfossil groups are characterized by diversified communities with
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marine taxa (e.g., Ammonia beccarii, Cribroelphidium spp., Elphidium spp., Pontocythere turbida,
Semicytherura spp.). During this last phase, the sea level acceleration drove the passage towards outer
lagoon and shoreface conditions, whereas a few km inland a thick lagoon succession suggests that
widespread flooding occurred (Dinelli et al., 2013). Upcore, beach ridge sands and coastal plain
sediments with rare, transported marine microfossils mark the onset of regressive conditions. Our
study case highlights the complex response of coastal systems to sea-level changes. Under natural
conditions, the balance between eustatic conditions and river input points determined a fragile
equilibrium of transitional (paleo-)environments. Nevertheless, under reduced sediment input or rapid
increase of the sea-level, retreat of paralic and coastal settings induce strong (paleo-)environmental
changes
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