Holocene seasonal sea‐surface temperature variations in the southern Adriatic Sea inferred from a multiproxy approach     

Francesca Sangiorgi  Lucilla Capotondi  Nathalie Combourieu Nebout  Luigi Vigliotti  Henk Brinkhuis  Simona Giunta  Andr F. Lotter  Caterina Morigi  Alessandra Negri  Gert‐Jan Reichart 《第四纪科学杂志》2003,18(8):723-732

Holocene cooling events have been reconstructed for the southern Adriatic Sea (central Mediterranean) by means of analyses of organic walled dinoflagellate cysts, planktonic foraminifera, oxygen isotopes, calcareous nanoplankton, alkenones and pollen from a sediment core. Two cooling events have been detected, during which sea‐surface temperatures (SSTs) were ca. 2°C lower. Unravelling the SST signal into dominant seasonal components suggests maximum winter cooling of 2°C at around 6.0 ka, whereas the cooling at ca. 3.0 ka might be the result of a spring temperature cooling of 2–3°C. The events, lasting several hundred years, are apparently synchronous with those in the Aegean Sea, where they have been related to known cooling events from the Greenland ice‐core record. A distinct interruption in Adriatic Sea sapropel S1 is not clearly accompanied by a local drop in winter temperatures, but seems to be forced by ventilation, which probably occurred earlier in the Aegean Sea and was subsequently transmitted to the Adriatic Sea. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

The Meteoritical Bulletin,No. 92, 2007 September     

Harold C. Connolly  Caroline Smith  Gretchen Benedix  Luigi Folco  Kevin Righter  Jutta Zipfel  Akira Yamaguchi  Hasnaa Chennaoui Aoudjehane 《Meteoritics & planetary science》2007,42(9):1647-1694

Abstract— In this edition of The Meteoritical Bulletin, 1394 recognized meteorites are reported, 27 from specific locations within Africa, 133 from Northwest Africa, 1227 from Antarctica (from ANSMET, PNRA, and PRIC expeditions), and 7 from Asia. The Meteoritical Bulletin announces the approval of four new names series by the Nomenclature Committee of the Meteoritical Society, two from Africa and one from Asia, including Al Haggounia, from Al Haggounia, Morocco, which is projected to be on the order of 3 metric tons of material related to enstatite chondrites and aubrites. Approved are two falls from Africa, Bassikounou (Mauritania) and Gashua (Nigeria). Approved from areas other than Antarctica are one lunar, two Martian, 32 other achondrites, three mesosiderites, two pallasites, one CM, two CK, one CR2, two CV3, one CR2, and four R chondrites. The Nomenclature Committee of the Meteoritical Society announces 48 newly approved relict meteorites from two new name series, Österplana and Gullhögen (both from Sweden).  相似文献   

Prediction of the thermodynamic properties of metal–arsenate and metal–arsenite aqueous complexes to high temperatures and pressures and some geological consequences     

Luigi Marini  Marina Accornero 《Environmental Geology》2007,52(7):1343-1363

The standard thermodynamic properties at 25°C, 1 bar (ΔG _f^o, ΔH _f^o, S ^o, C _P^o, V ^o, ω) and the coefficients of the revised Helgeson–Kirkham–Flowers equations of state were evaluated for several aqueous complexes formed by dissolved metals and either arsenate or arsenite ions. The guidelines of Shock and Helgeson (Geochim Cosmochim Acta 52:2009–2036, 1988) and Sverjensky et al. (Geochim Cosmochim Acta 61:1359–1412, 1997) were followed and corroborated with alternative approaches, whenever possible. The SUPCRT92 computer code was used to generate the log K of the destruction reactions of these metal–arsenate and metal–arsenite aqueous complexes at pressures and temperatures required by the EQ3/6 software package, version 7.2b. Apart from the AlAsO₄^o and FeAsO₄^o complexes, our log K at 25°C, 1 bar are in fair agreement with those of Whiting (MS Thesis, Colorado School of Mines, Golden, CO, 1992). Moreover, the equilibrium constants evaluated in this study are in good to fair agreement with those determined experimentally for the Ca–dihydroarsenate and Ca–hydroarsenate complexes at 40°C (Mironov et al., Russ J Inorg Chem 40:1690, 1995) and for Fe(III)–hydroarsenate complex at 25°C (Raposo et al., J Sol Chem 35:79–94, 2006), whereas the disagreement with the log K measured for the Ca–arsenate complex at 40°C (Mironov et al., Russ J Inorg Chem 40:1690, 1995) might be due to uncertainties in this measured value. The implications of aqueous complexing between dissolved metals and arsenate/arsenite ions were investigated for seawater, high-temperature geothermal liquids and acid mine drainage and aqueous solutions deriving from mixing of acid mine waters and surface waters. Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.  相似文献   

A new project to monitor land subsidence in the northern Venice coastland (Italy)   总被引：1，自引：0，他引：1  

Luigi Tosi  Pietro Teatini  Laura Carbognin  Jane Frankenfield 《Environmental Geology》2007,52(5):889-898

The paper deals with the implementation of a levelling and Global Positioning System (GPS) network to control land subsidence in the coastal area north of the Venice Lagoon. About 480 km of levelling lines with 527 benchmarks, 45 of which suited for Differential GPS measurements, were established in 2004. A complete survey of the net was carried out in 2004 soon after its establishment. The 2004 records have been compared with previous scattered data obtained by the use of levelling surveys, DGPS and SAR interferometry. The results show a trend in land settlement that increases from the lagoon margin to the north and jeopardize the Venice coastland. Groundwater withdrawals for domestic, agricultural, and health spas uses, peat oxidation of reclaimed marshlands for farming, natural consolidation of the Holocene deposits, and tectonics of the pre-Quaternary basement are the causes of land subsidence in the study area. Since most of the area lies below the mean sea level and on account of the expected sea level rise due to global change, a detailed monitoring of land displacements in the near future will be of paramount importance to plan necessary works for coastland protection.  相似文献   

Frontier Mountain 93001: A coarse‐grained,enstatite‐augite‐oligoclase‐rich,igneous rock from the acapulcoite‐lodranite parent asteroid     

Luigi Folco  Massimo D'Orazio  Alessandro Burroni 《Meteoritics & planetary science》2006,41(8):1183-1198

Abstract— The Frontier Mountain (FRO) 93001 meteorite is a 4.86 g fragment of an unshocked, medium‐ to coarse‐grained rock from the acapulcoite‐lodranite (AL) parent body. It consists of anhedral orthoenstatite (Fs_{13.3 ± 0.4}Wo_{3.1 ± 0.2}), augite (Fs_{6.1 ± 0.7}Wo_{42.3 ± 0.9}; Cr₂O₃ = 1.54 ± 0.03), and oligoclase (Ab_{80.5 ± 3.3}Or_{3.1 ± 0.6}) up to >1 cm in size enclosing polycrystalline aggregates of fine‐grained olivine (average grain size: 460 ± 210 μm) showing granoblastic textures, often associated with Fe,Ni metal, troilite, chromite (cr# = 0.91 ± 0.03; fe# = 0.62 ± 0.04), schreibersite, and phosphates. Such aggregates appear to have been corroded by a melt. They are interpreted as lodranitic xenoliths. After the igneous (the term “igneous” is used here strictly to describe rocks or minerals that solidified from molten material) lithology intruding an acapulcoite host in Lewis Cliff (LEW) 86220, FRO 93001 is the second‐known silicate‐rich melt from the AL parent asteroid. Despite some similarities, the silicate igneous component of FRO 93001 (i.e., the pyroxene‐plagioclase mineral assemblage) differs in being coarser‐grained and containing abundant enstatite. Melting‐crystallization modeling suggests that FRO 93001 formed through high‐degree partial melting (≥35 wt%; namely, ≥15 wt% silicate melting and ?20 wt% metal melting) of an acapulcoitic source rock, or its chondritic precursor, at temperatures ≥1200 °C, under reducing conditions. The resulting magnesium‐rich silicate melt then underwent equilibrium crystallization; prior to complete crystallization at ?1040 °C, it incorporated lodranitic xenoliths. FRO 93001 is the highest‐temperature melt from the AL parent‐body so far available in laboratory. The fact that FRO 93001 could form by partial melting and crystallization under equilibrium conditions, coupled with the lack of quench‐textures and evidence for shock deformation in the xenoliths, suggests that FRO 93001 is a magmatic rock produced by endogenic heating rather than impact melting.  相似文献   

A model for the calculation of the seismic properties of geologic units     

Luigi Burlini 《Surveys in Geophysics》1994,15(5):593-617

A model for the calculation of a representative complete elastic tensor of a geologic body is presented here, in order to fill the gap between the small scale sample and the complex structural and lithological association of a geologic body, which may be of the same large scale as the wavelength used on the seismic survey. The major problems arising during the modelling are discussed, namely the representativity of a suite of hand samples and the evaluation of the volume fraction of the different lithologies comprising a formation. An application example is presented of a metapelitic sequence spanning the tectonic boundary of the Ivrea-Verbano zone with the Serie dei Laghi in Valle Cannobina (N. Italy). It is shown that the effective formation anisotropy is drastically reduced relative to that of hand samples when the structure is averaged over a large area, except for the sheared and mylonitic sub-areas comprising the tectonic contact zone (the Cossato-Mergozzo-Brissago- and Pogallo lines). In these subareas the effective anisotropy is slightly reduced (a few points of a percent) from the hand sample scale to that of the geologic formation. Moreover, because the polarization of the fastest shear wave and the plane of maximum shear wave splitting of the most common crustal rock types coincide with the foliation, there is an opportunity to infer the structure of deep rock formations from teleseismic shear waves.  相似文献   

Comment on Manuella et al. “The Hyblean xenolith suite (Sicily): an unexpected legacy of the Ionian–Tethys realm”     

Luigi Beccaluva  Gianluca Bianchini  Massimo Coltorti  Claudio Natali 《International Journal of Earth Sciences》2015,104(6):1679-1684

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The value of pocket penetration tests for the high‐resolution palaeosol stratigraphy of late Quaternary deposits     

Alessandro Amorosi  Luigi Bruno  Bruno Campo  Agnese Morelli 《Geological Journal》2015,50(5):670-682

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Chemical and structural defensive external strategies in six sabellid worms (Annelida)     

Adriana Giangrande  Margherita Licciano  Roberto Schirosi  Luigi Musco  Loredana Stabili 《Marine Ecology》2014,35(1):36-45

In the marine environment, sessile invertebrates have developed an impressive array of mechanisms to avoid predation, bacterial exploitation, and epibiotic overgrowth. In the present study we investigated several defensive strategies adopted by six sabellids: the hard bottom species Sabella spallanzanii (Gmelin, 1791), Branchiomma luctuosum Grube, 1869, Branchiomma bairdi (McIntosh, 1885), and Sabellastarte spectabilis (Grube, 1878), and the soft bottom species Myxicola infundibulum (Renier, 1804), and Megalomma lanigera (Grube, 1846), which have different morphological characteristics and geographical distribution. We examined and compared some defensive features such as branchial crown toughness, tube structure and strength, amount of released mucus, and antibacterial lysozyme‐activity in the mucus. The investigated species utilize a combination of defence and deterrence strategies that seems to be related to the colonized habitat. Tube strength was, higher in the hard bottom species compared with the soft bottom ones, where the tubes are generally buried and protected within the sediment. Branchial crown appeared stronger and resistant in hard bottom species, except for S. spallanzanii, which is the species showing the strongest tube. Sabella spallanzanii, M. infundibulum and S. spectabilis secreted high amount of mucus with high lysozyme‐like activity. By contrast, B. luctuosum, B. bairdi, and M. lanigera produced low amounts of mucus exerting lower antibacterial activity.  相似文献   

Stratigraphy and eruptive dynamics of a pulsating Plinian eruption of Somma-Vesuvius: the Pomici di Mercato (8900 years B.P.)     

Daniela Mele  Roberto Sulpizio  Pierfrancesco Dellino  Luigi La Volpe 《Bulletin of Volcanology》2011,73(3):257-278

New volcanological studies allow reconstruction of the eruption dynamics of the Pomici di Mercato eruption (ca 8,900 cal. yr B.P.) of Somma-Vesuvius. Three main Eruptive Phases are distinguished based on two distinct erosion surfaces that interrupt stratigraphic continuity of the deposits, indicating that time breaks occurred during the eruption. Absence of reworked volcaniclastic deposits on top of the erosion surfaces suggests that quiescent periods between eruptive phases were short perhaps lasting only days to weeks. Each of the Eruptive Phases was characterised by deposition of alternating fall and pyroclastic density current (PDC) deposits. The fallout deposits blanketed a wide area toward the east, while the more restricted PDC deposits inundated the volcano slopes. Eruptive dynamics were driven by brittle magmatic fragmentation of a phonolitic magma, which, because of its mechanical fragility, produced a significant amount of fine ash. External water did not significantly contribute either to fragmentation dynamics or to mechanical energy release during the eruption. Column heights were between 18 and 22 km, corresponding to mass discharge rates between 1.4 and 6 × 10⁷ kg s⁻¹. The estimated on land volume of fall deposits ranges from a minimum of 2.3 km³ to a maximum of 7.4 km³. Calculation of physical parameters of the dilute pyroclastic density currents indicates speeds of a few tens of m s⁻¹ and densities of a few kg m⁻³ (average of the lowermost 10 m of the currents), resulting in dynamic pressures lower than 3 kPa. These data suggest that the potential impact of pyroclastic density currents of the Pomici di Mercato eruption was smaller than those of other Plinian and sub-Plinian eruptions of Somma-Vesuvius, especially those of 1631 AD and 472 AD (4–14 kPa), which represent reference values for the Vesuvian emergency plan. The pulsating and long-lasting behaviour of the Pomici di Mercato eruption is unique in the history of large explosive eruptions of Somma-Vesuvius. We suggest an eruptive scheme in which discrete magma batches rose from the magma chamber through a network of fractures. The injection and rise of the different magma batches was controlled by the interplay between magma chamber overpressure and local stress. The intermittent discharge of magma during a large explosive eruption is unusual for Somma-Vesuvius, as well as for other volcanoes worldwide, and yields new insights for improving our knowledge of the dynamics of explosive eruptions.  相似文献