Palaeoenvironmental reconstruction of late Quaternary foraminifera and molluscs from the ENEA borehole (Versilian plain, Tuscany, Italy)     

M. Gabriella Carboni  Luisa Bergamin  Daniela Esu  Emanuela Pisegna Cerone  Vladimiro Verrubbi 《Quaternary Research》2010,74(2):265-128

Foraminifera and molluscs from the 90 m deep ENEA borehole (Versilian plain, central Italy) were studied for paleoenvironmental purposes. Palaeontological analyses, integrated with U/Th and radiocarbon data, helped to recognize late Quaternary sea-level changes and supplied results on tectonic mobility of the area. The study highlighted four sedimentary phases. The first phase consists of a shore environment attributed to MIS 7.1. A hiatus corresponding to MIS 6 is hypothesized at the top of this interval. Recognition of the paleo-shoreline of MIS 7.1 at − 72.8 m signifies a vertical displacement due to the extensional tectonics of the Apennine orogenesis. The second phase consists of a transgressive succession with evidence of warm temperatures, which was interpreted as part of the transgression leading to the MIS 5.5 highstand. The third phase includes sub-aerial and lacustrine deposits. Radiocarbon dates and palaeoecological reconstruction led us to attribute this interval to MIS 4, MIS 3 and MIS 2. The fourth phase begins with a lagoon environment attributable to Holocene sea-level rise and ends with marsh episodes, signifying the progradation of the alluvial plain. This reconstruction confirms the hypothesis of tectonic stability for the Versilian area during the Holocene.  相似文献   

Hydrogeochemical analysis on Italian bottled mineral waters: Effects of geology     

E. Dinelli  A. Lima  B. De Vivo  S. Albanese  D. Cicchella  P. Valera 《Journal of Geochemical Exploration》2010

The use of bottled mineral waters use is increasingly becoming popular and the need for better knowledge of their chemical composition is a key issue for defining their quality, particularly for those elements that are not monitored on a regular basis. The link between geology and water chemistry is well known and can lead to extreme differences in element distribution and is an issue that needs to be addressed. Such an opportunity has been provided by a project of the EuroGeoSurvey Geochemistry Expert Group aimed at the characterization of groundwater geochemistry using bottled mineral waters purchased in supermarkets all over Europe. On these waters pH, conductivity and concentrations of 69 elements and ions were measured at the BGR geochemical laboratories. On a total of 1785 “samples”, 158 represent waters bottled in Italy in 126 different sites scattered throughout the country. Most of the purchased mineral water is packaged in PET bottles. In this paper, the dataset concerning Italy has been used to provide an overview on the relationship between natural concentration of the determined chemical elements in groundwater and geo-lithological features. These relationships have been investigated mostly taking into account the surface geology and other information available on water sources. Application of R-Mode factor analysis to the data set allowed the determination of the possible relationship between the distribution of individual elements and lithology or other surface enrichment phenomena. In particular waters draining through volcanic rocks are enriched in elements such as As, B, Br⁻, Cl⁻, Cs, I, K, Li, Na, NO₃⁻, PO₄³⁻, Rb, Sc, SiO₂, Sr, Te, Ti, and V up to 3 orders of magnitude higher than waters draining through other lithologies. REE and Y show significant difference in median concentration due to interaction of waters with plutonic rocks. Many elements have a large spread of concentrations, which reflects natural variations and interaction with particular lithologies. One of the five R-mode factor analysis associations, recognized as being representative of elements analysed shows high nitrate and V loadings along with As, PO₄³⁻ and Se. The latter association probably reflects a sign of anthropogenic contribution in some aquifers in volcano-sedimentary or silico-clastic deposits and in intensively cultivated areas.  相似文献   

The role of lower continental crust and lithospheric mantle in the genesis of Plio–Pleistocene volcanic rocks from Sardinia (Italy)     

Michele Lustrino  Leone Melluso  Vincenzo Morra 《Earth and Planetary Science Letters》2000,180(3-4):259-270

The first comprehensive chemical and Sr–Nd–Pb isotopic data set of Plio–Pleistocene tholeiitic and alkaline volcanic rocks cropping out in Sardinia (Italy) is presented here. These rocks are alkali basalts, hawaiites, basanites, tholeiitic basalts and basaltic andesites, and were divided into two groups with distinct isotopic compositions. The vast majority of lavas have relatively high ⁸⁷Sr/⁸⁶Sr (0.7043–0.7051), low ¹⁴³Nd/¹⁴⁴Nd (0.5124–0.5126), and are characterised by the least radiogenic Pb isotopic composition so far recorded in Italian (and European) Neogene-to-Recent mafic volcanic rocks (²⁰⁶Pb/²⁰⁴Pb=17.55–18.01) (unradiogenic Pb volcanic rocks, UPV); these rocks crop out in central and northern Sardinia. Lavas of more limited areal extent have chemical and Sr–Nd–Pb isotopic ratios indicative of a markedly different source (⁸⁷Sr/⁸⁶Sr=0.7031–0.7040; ¹⁴³Nd/¹⁴⁴Nd=0.5127–0.5129; ²⁰⁶Pb/²⁰⁴Pb=18.8–19.4) (radiogenic Pb volcanic rocks, RPV), and crop out only in the southern part of the island. The isotopic ratios of these latter rocks match the values found in the roughly coeval anorogenic (i.e. not related to recent subduction events in space and time) mafic volcanic rocks of Italy (i.e. Mt. Etna, Hyblean Mts., Pantelleria, Linosa), and Cenozoic European volcanic rocks. The mafic rocks of the two Sardinian rock groups also show distinct trace element contents and ratios (e.g. Ba/Nb>14, Ce/Pb=8–25 and Nb/U=29–38 for the UPV; Ba/Nb<9, Ce/Pb=24–28 and Nb/U=46–54 for the RPV). The sources of the UPV could have been stabilised in the Precambrian after low amounts of lower crustal input (about 3%), or later, during the Hercynian Orogeny, after input of Precambrian lower crust in the source region, whereas the sources of the RPV could be related to processes that occurred in the late Palaeozoic–early Mesozoic, possibly via recycling of proto-Tethys oceanic lithosphere by subduction.  相似文献   

Sensitivity analysis on the input parameters in probabilistic seismic hazard assessment     

A. Rebez  D. Slejko   《Soil Dynamics and Earthquake Engineering》2000,20(5-8):341-351

A project has been implemented in recent years for assessing seismic hazard in the Italian territory on probabilistic bases, to be used as scientific background for the revision of the current seismic zonation. A consolidated approach was considered for the purpose; seismic hazard was estimated in terms of peak ground acceleration and macroseismic intensity. As the computer code employed allows the user to make specific choices on some input data, some rather unorthodox decisions were taken regarding earthquake catalogue completeness, seismicity rates, boundaries of the seismogenic zones, definition of the maximum magnitude, attenuation relation, etc. The overwhelming amount of geological and seismological data for Italy (just consider, for example, that the earthquake catalogue collects events which occurred over the last ten centuries) permits the operator to make different choices, more or less cautiously. It is quite interesting, then, to evaluate the influence of the specific choices on the final hazard results as a comparison to traditional possibilities. The tests performed clearly indicate the critical choices and quantify their contribution. In particular, we consider thorough comprehension of the space geometry of the earthquake source boundaries and the adequacy of the attenuation relation in modelling the radiation pattern very important.  相似文献   

The Umbria-Marche (central Italy) earthquakes: relation between rupture directivity and sequence evolution for the Mw > 5 shocks     

N.A. Pino  S. Mazza 《Journal of Seismology》2000,4(4):451-461

We derive the relative moment rate function for the shocks with M_w > 5 in the 1997-98 central Italy seismic sequence, started with the M_w = 5.7, 09/26/97 00:33 event, by applying an empirical Green functionmethod. By using three conveniently placed broadband MedNet stations we obtain apparent source time functions indicating clear directivity effects for all of the analysed earthquakes, with rupture propagation generally directed outward from the epicentral area of the09/03/97 foreshock sequence. Taking a simple source model, forward modeling is utilized for determining fault parameters such as length, rupture propagation velocity and direction and, for the three major events,slip distribution. The effects of the break propagation directions onthe sequence evolution is discussed. A possible inconsistencyresults for the shallow 04/03/98 shock, which could be avoided if alink with the deep 03/26/98 event is assumed.Our analysis evidences the importance of a quick determination for the fault parameters in order to image the possible induction of fracturing on nearby structures.  相似文献   

Quaternary normal faulting in southeastern Sicily (Italy):a seismic source for the 1693 large earthquake   总被引：5，自引：0，他引：5  

Marcello Bianca  Carmelo Monaco  Luigi Tortorici  Licio Cernobori 《Geophysical Journal International》1999,139(2):370-394

We present geological and morphological data, combined with an analysis of seismic reflection lines across the Ionian offshore zone and information on historical earthquakes, in order to yield new constraints on active faulting in southeastern Sicily. This region, one of the most seismically active of the Mediterranean, is affected by WNW–ESE regional extension producing normal faulting of the southern edge of the Siculo–Calabrian rift zone. Our data describe two systems of Quaternary normal faults, characterized by different ages and related to distinct tectonic processes. The older NW–SE-trending normal fault segments developed up to ≈400  kyr ago and, striking perpendicular to the main front of the Maghrebian thrust belt, bound the small basins occurring along the eastern coast of the Hyblean Plateau. The younger fault system is represented by prominent NNW–SSE-trending normal fault segments and extends along the Ionian offshore zone following the NE–SW-trending Avola and Rosolini–Ispica normal faults. These faults are characterized by vertical slip rates of 0.7–3.3  mm  yr ⁻¹ and might be associated with the large seismic events of January 1693. We suggest that the main shock of the January 1693 earthquakes ( M ~ 7) could be related to a 45  km long normal fault with a right-lateral component of motion. A long-term net slip rate of about 3.7  mm  yr ⁻¹ is calculated, and a recurrence interval of about 550 ± 50  yr is proposed for large events similar to that of January 1693.  相似文献   

Book Reviews     

《The Professional geographer》2000,52(3):567-590

Books reviewed: John Bale and Chris Philo Body Cultures: Essays on Sport, Space and Identity by Henning Eichberg. William A.V. Clark The California Cauldron: Immigration and the Fortunes of Local Communities. Tom Daniels When City and Country Collide: Managing Growth in the Metropolitan Fringe. David Delaney Race, Place, and the Law, 1836 – 1948. Allan K. Fitzsimmons Defending Illusions: Federal Protection of Ecosystems. Brian Graham Modern Europe: Place, Culture and Identity. William Least Heat‐Moon River Horse: The Logbook of a Boat Across America. George L. Henderson California and the Fictions of Capital. Martha Honey Ecotourism and Sustainable Development: Who Owns Paradise? Peter J. Hugill Global Communications Since 1844: Geopolitics and Technology. Thomas Klak Globalization and Neoliberalism: The Caribbean Context. David Knighton Fluvial Forms and Processes: A New Perspective. Gustavo Leclerc, Raul Villa, and Michael J. Dear Urban Latino Cultures: La Vida Latina en L.A. Daniel Miller, Peter Jackson, Nigel Thrift, Beverly Holbrook, and Michael Rowlands Shopping, Place and Identity. Martin Reuss Designing the Bayous: The Control of Water in the Atchafalaya Basin 1800–1995. Alan R. Townsend Making a Living in Europe: Human Geographies of Economic Change. Jennifer Wolch and Jody Emel Animal Geographies: Place, Politics and Identity in the Nature‐Culture Borderlands.  相似文献   

CN algorithm and long-lasting changes in reported magnitudes: the case of Italy     

A. Peresan  G. F. Panza  & G. Costa 《Geophysical Journal International》2000,141(2):425-437

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Devonian graptolites from southwestern Europe: a review with new data     

A. C. Lenz  M. Robardet  J. C. Gutirrez-Marco  J. M. Piarra 《Geological Journal》1996,31(4):349-358

Lower Devonian graptolite faunas have been recognized in the Normandy and southeastern regions of the Armorican Massif, France; the Pyrenees and Catalonian Coastal Ranges regions and northern Minorca, Balearic Islands, Spain; the southern Hesperian Massif (Ossa Morena Zone) of the Iberian Peninsula; and from southeastern Sardinia, Italy. All but one the of the graptolite faunas collected throughout this large region are from Lochkovian age strata, representing the Monograptus uniformis, Monograptus praehercynicus, and Monograptus hercynicus biozones corresponding to the lower, middle and upper Lochkovian, respectively, and mostly represented by monospecific or low diversity assemblages. Although many individual sections contain representatives of two of the biozones, relatively few reveal all three. A single, poorly preserved faunule, collected in the Ossa Morena region of Spain from strata dated by brachiopods as Pragian–early Emsian may represent the only known graptoloid fauna of post-Lochkovian age. Almost all graptolites have been recovered from condensed successions of black shales and limestone nodules, similar to those of other proto-Tethyan (i.e. outer shelf, with dominantly pelagic faunas) regions such as Thuringia, Bohemia, the Carnic Alps and northwestern Africa. The two exceptions are an occurrence in a shallow-water, coarser clastic sequences at the Carteret locality in Normandy and in deep water turbidites on the island of Minorca. Graptolites are not known from any other thick, shallow water clastic sequences, although whether this is because of paleo environmental exclusion or simply lack of recovery to date is unknown. Other fossil evidence (e.g. chitinozoans), however, indicates continuous marine sedimentation from the Silurian to Devonian. © 1996 John Wiley & Sons, Ltd.  相似文献   

Stability of streambanks formed in partially saturated soils and effects of negative pore water pressures: the Sieve River (Italy)     

Massimo Rinaldi  Nicola Casagli 《Geomorphology》1999,26(4):707

Streambanks of alluvial channels are usually composed of loose materials, which are unsaturated in ambient conditions. Unsaturated soils are subject to negative pore water pressures, which cause an apparent cohesion. The latter is the main factor in allowing the stability of near-vertical banks. Even during moderate in-bank flow events, the apparent cohesion can be strongly reduced as the material approaches full saturation; therefore, during the drawdown phase, as the confining pressure of the water in the channel disappears, a bank failure is likely to occur. Channel bed-level lowering along the Sieve River, Central Italy, has caused widespread bank instability. A geomorphological reconnaissance of forms and processes was followed by in situ tests to determine the shear strength of the banks. Interpretation of the tests and a streambank stability analysis were based on concepts of soil mechanics for unsaturated soils, in order to obtain relations between bank angle and height in limit equilibrium conditions. A stability chart was obtained with curves for different apparent cohesion values, and a stability analysis was performed taking into account the effects of flow events. In order to investigate the pore pressure effects, a series of piezo-tensiometers were installed in a streambank of the Sieve River. Data from a 1 year monitoring period show variations in pore water pressure and matric suction as a consequence of rainfall, evapotranspiration, and water stage variations. A planar failure with a tension crack occurred in the upper cohesive part of the bank during December 1996. The safety factor has been expressed as a function of the geometry of the bank and of the shear strength of the material. Safety factor variations through time are therefore shown as a function of seasonal variations in matric suction.  相似文献