Ecosystem Impact of the Campanian Ignimbrite Eruption in Late Pleistocene Europe     

Francesco G. Fedele  Biagio Giaccio  Roberto Isaia  Giovanni Orsi 《Quaternary Research》2002,57(3):420

The dating of the Campanian Ignimbrite (CI) eruption to 37,000 cal yr B.P. draws attention to the coincidence of this volcanic catastrophe and the suite of coeval, Late Pleistocene biocultural changes that occurred within and outside the Mediterranean region. These included the Middle to Upper Paleolithic cultural transition and the supposed change from Neanderthal to “modern” Homo sapiens anatomy, a subject of sustained debate. No less than 150 km³ of magma were extruded in the CI eruption, the signal of which can be detected in Greenland ice cores. As widespread discontinuities in archaeological sequences are observed at or following the CI event, a significant interference with ongoing human processes in Mediterranean Europe is hypothesized.  相似文献   

Particle accumulation in a cylindrical sediment trap under laminar and turbulent steady flow: An experimental approach   总被引：1，自引：0，他引：1  

Giselher Gust  Walter Bowles  Steven Giordano  Markus Hüttel 《Aquatic Sciences - Research Across Boundaries》1996,58(4):297-326

The hydrodynamical, fluid and particle parameters which control flushing rates, flow cells, and accumulation rates of particulate matter in cylindrical (MultiPIT) sediment traps were quantified in a flume simulation using a seeding technique for 25–45 µm particles. Particle collection was found to be a trap- and particle-specific filtering process encompassing advective and gravitational entry of particles over a reduced trap aperture area, and gravitational-turbulent removal of particles at the bottom of the internal flow cell. Trapping efficiency increased up to 10-fold with increasing horizontal flow velocity (1–30 cm · s^–1). For given flow velocity, the trap over-and undercollected particles relative to their weight, i.e. (theoretical) Stokes settling velocity. The trapping efficiency increased with increasing trap Reynolds number Re_T, changed by the approaching velocity in our experiments. Opposite findings from earlier experiments using the flume seeding technique and changing Re_T by altering the trap diameter (Butman, 1986) are discussed. Semi-empirical equations are derived for the accumulation process of light, heavy and intermediate particles. From these, measured trap fluxes can be converted into in-situ verticle particle flux except for light particles.  相似文献   

Holocene stratigraphy and depositional architecture of eastern Pozzuoli Bay (eastern Tyrrhenian Sea margin,Italy): the influence of tectonics and wave-induced currents     

Alfonsa Milia  Francesco Giordano 《Geo-Marine Letters》2002,22(1):42-50

Pozzuoli Bay is located in the eastern Tyrrhenian Sea and is an area characterized by active tectonics and volcanism. On the basis of high-resolution seismic reflection profiles, it was possible to reconstruct the stratigraphy and three-dimensional stratal architecture of the Holocene succession. Two volcanic units and three sedimentary ones were recognized. The basal unit NC consists of volcanic deposits and dates at 10.0-8.0 ka B.P. It is followed by unit D, deposited between 8.0 and 5.5 ka B.P., which displays a backstepping configuration in the central area and a forestepping configuration in the northern area. Unit D is covered by the progradational unit B which is elongated in a SE-NW direction. Unit C is interbedded between unit B and is interpreted as the volcanic products of the Agnano-Monte Spina eruption which occurred 4.4 B.P. Unit A, the youngest unit, shows a progradational configuration and is elongated in a E-W direction. The sedimentary units record the transgressive and highstand of the eustatic sea level. They show vertical and lateral variations in the depositional architecture. Changes in the stacking pattern record variations in tectonic subsidence and hydrodynamic regimes.  相似文献   

Distribution of free gas in marine sediments: a global overview   总被引：2，自引：8，他引：2  

P. Fleischer  T. Orsi  M. Richardson  A. Anderson 《Geo-Marine Letters》2001,21(2):103-122

To quantify the global distribution of free gas in shallow marine sediments, we have identified and indexed over 100 documented cases in the scientific and engineering literature. Our survey confirms previous assumptions, primarily that gas bubbles are ubiquitous in the organic-rich muds of coastal waters and shallow adjacent seas. Acoustic turbidity, as recorded during seismo-acoustic surveys, is the most frequently cited evidence used to infer the presence of seafloor gas. Biogenic methane predominates within these shallow subbottom deposits. Because of their global prevalence, growing interest in gassy marine sediments is understandable, as their presence can have profound scientific, engineering and environmental significance.  相似文献   

Interannual abundance patterns of copepods during an ENSO event in Icy Strait, southeastern Alaska     

Park  Wongyu; Sturdevant  Molly; Orsi  Joseph; Wertheimer  Alex; Fergusson  Emily; Heard  William; Shirley  Thomas 《ICES Journal of Marine Science》2004,61(4):464-477

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Tertiary anorogenic granites of the western border of the Yemen Plateau     

G. Capaldi  S. Chiesa  P. Manetti  G. Orsi  G. Poli 《Lithos》1987,20(6):433-444

North Yemen (Y.A.R.) was affected, from 30 to 20 Ma ago, by intense magmatic activity (Trap Series), contemporary with the main tensional tectonic phases of the Afro-Arabian Plate. In the Trap activity, two main phases have been recognized; the former, mainly basaltic, between 30 and 26 Ma; and the second, mainly acidic, between 23 and 20 Ma. During the latter period of activity, a basaltic dyke swarm and stock-like bodies and dykes (granophyres) were emplaced along the escarpment and coastal plain. Some granitic bodies intruded the Trap Series towards the end of the first phase and during the second one.

On the basis of geochemical and petrological data, the Tertiary granites of Yemen belong to alkaline or peralkaline associations of A-type. The textural characteristics indicate that the granites are either hypersolvus or subsolvus. The mafic mineral assemblages allow three main types of granites to be distinguished by their different environments of crystallization.

As regards the origin of these kinds of granites, several hypotheses account for the peculiarities observed. The lack of crustal xenoliths, the preliminary data on the Sr isotopic ratio, the data on major and trace elements point to a direct origin by fractional crystallization, without substantial crustal interaction. This agrees well with the strong tensile tectonics, linked with the uplift of the Afro-Arabian dome and with the lithosphere thinning, which provide a minimal opportunity for interaction of the magmas with the crust.  相似文献   

The Green Tuff of Pantelleria: Rheoignimbrite or rheomorphic fall?     

G. Orsi  M. F. Sheridan 《Bulletin of Volcanology》1984,47(3):611-626

Detailed stratigraphic analysis of the Green Tuff of Pantelleria shows that this formation can be divided into several members designateda throughh from base to top. These members have a coherent pattern when traced from outcrop to outcrop throughout the island shedding light on their origin. Only memberg completely mantles the entire island. The distribution of the other members is controlled by prevailing wind direction or by topography. Membera is entirely of fall origin. Membersc ande are of fall and/or surge type. Membersb,d, andh have the characteristics of thin welded ash-flow tuffs. Membersf andg are ash-flow tuffs with textural characteristics of compound cooling units. Most of the ash-flow tuffs exhibit characteristics of ignimbrites: vertical fluidization pipes, local concentrations of lithic lapilli, imbrication of clasts, and valley ponding. Memberg is unusual in that it is highly-welded, exhibits large-scale rheomorphic structures, contains huge lithic clasts, and has near-vertical foliation where it adheres to cliffs and caldera walls.Granulometric data from the members identified in the field as ignimbrites confirms this conclusion, as do density profiles through the various members.  相似文献   

Place and Politics in Modern Italy     

Benito Giordano 《Area》2004,36(1):94-96

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Empirical seismic fragility models for Nepalese school buildings     

Giordano  Nicola  De Luca  Flavia  Sextos  Anastasios  Ramirez Cortes  Fernando  Fonseca Ferreira  Carina  Wu  Jingzhe 《Natural Hazards》2021,105(1):339-362

Natural Hazards - Empirical vulnerability models are fundamental tools to assess the impact of future earthquakes on urban settlements and communities. Generally, they consist of sets of fragility...  相似文献   

Linking the Abundance of Estuarine Fish and Crustaceans in Nearshore Waters to Shoreline Hardening and Land Cover     

Matthew S. Kornis  Denise Breitburg  Richard Balouskus  Donna M. Bilkovic  Lori A. Davias  Steve Giordano  Keira Heggie  Anson H. Hines  John M. Jacobs  Thomas E. Jordan  Ryan S. King  Christopher J. Patrick  Rochelle D. Seitz  Heather Soulen  Timothy E. Targett  Donald E. Weller  Dennis F. Whigham  Jim UphoffJr 《Estuaries and Coasts》2017,40(5):1464-1486

Human alteration of land cover (e.g., urban and agricultural land use) and shoreline hardening (e.g., bulkheading and rip rap revetment) are intensifying due to increasing human populations and sea level rise. Fishes and crustaceans that are ecologically and economically valuable to coastal systems may be affected by these changes, but direct links between these stressors and faunal populations have been elusive at large spatial scales. We examined nearshore abundance patterns of 15 common taxa across gradients of urban and agricultural land cover as well as wetland and hardened shoreline in tributary subestuaries of the Chesapeake Bay and Delaware Coastal Bays. We used a comprehensive landscape-scale study design that included 587 sites in 39 subestuaries. Our analyses indicate shoreline hardening has predominantly negative effects on estuarine fauna in water directly adjacent to the hardened shoreline and at the larger system-scale as cumulative hardened shoreline increased in the subestuary. In contrast, abundances of 12 of 15 species increased with the proportion of shoreline comprised of wetlands. Abundances of several species were also significantly related to watershed cropland cover, submerged aquatic vegetation, and total nitrogen, suggesting land-use-mediated effects on prey and refuge habitat. Specifically, abundances of four bottom-oriented species were negatively related to cropland cover, which is correlated with elevated nitrogen and reduced submerged and wetland vegetation in the receiving subestuary. These empirical relationships raise important considerations for conservation and management strategies in coastal environments.  相似文献