Global dynamical properties of the Fermi–Pasta–Ulam system     

Simone Paleari  Claude Froeschlé  Elena Lega 《Celestial Mechanics and Dynamical Astronomy》2008,102(1-3):241-254

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Sustainable development and anthropogenic induced geomorphic hazards in subsiding areas          下载免费PDF全文

Najib Abou Karaki  Simone Fiaschi  Damien Closson 《地球表面变化过程与地形》2016,41(15):2282-2295

In many areas of the world, subsidence related to the lowering of the water table is modifying the landscape and provoking costly environmental hazards. We consider the Dead Sea (the Earth's lowest lake) as a model. Its water level was 395 m bMSL in the 1960s. Due to water diversions in the catchment area, as of 2016, the level has dropped to about 430 m bMSL. Here, as in other parts of the Anthropocene world, from China, to Iran, to Turkey, to Canada and the United States, consequences of human interventions are rapidly modifying the environment. Aggressive geomorphic processes leading to accelerated degradations are taking place and affecting landforms and infrastructures. In Tectonic terms, the lake is a pull‐apart basin resulting from the motion of the Dead Sea Transform fault. Since the 1960s, a slice of brine of about 35 km³ has been lost. The water table is dropping more rapidly in the lake than in the coastal zone creating an ever‐increasing head difference. Consequently, groundwater moves towards the sea to compensate for the imbalance, provoking the reactivation of the area's paleo‐channels with subsidence, sinkholes, and landslides. Since the 1980s, industrial‐touristic infrastructure has covered newly emerging lands in geomorphic hazards‐prone areas of the coastal zone. Time series analysis of high to very high resolution visible/radar satellite images acquired from the 1970s to present, revealed major landscape evolution. Such dynamic systems prevailing in recent decades permitted the study of human/environment interactions to help minimize their effects. Major deformations of an industrial dike were analysed and quantified. The results underline the necessity in the Anthropocene of careful analysis of relevant data sources acquired before and during subsidence, particularly in karst topography zones and prior to the development of major human activities in economically appealing environments around the world. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Structural properties of central galaxies in groups and clusters     

Yicheng Guo  Daniel H. McIntosh †  H. J. Mo  Neal Katz  Frank C. van den Bosch  Martin Weinberg  Simone M. Weinmann  Anna Pasquali  Xiaohu Yang 《Monthly notices of the Royal Astronomical Society》2009,398(3):1129-1149

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Over 10 years of variation in Mediterranean reef benthic communities          下载免费PDF全文

Federico Betti  Giorgio Bavestrello  Marzia Bo  Valentina Asnaghi  Mariachiara Chiantore  Simone Bava  Riccardo Cattaneo‐Vietti 《Marine Ecology》2017,38(3)

During the last several decades, the Mediterranean littoral shallow water benthic communities have suffered significant changes in their structure and taxa composition. Despite numerous studies conducted to characterize these changes at various levels, it has always been very difficult to disentangle the effects of natural factors from anthropic ones. The main purpose of this work was to evaluate possible changes, over a 10‐year scale, in diversity and abundance of the most representative species of the benthic communities considered to be primarily and potentially affected by natural stressors in a highly protected area. Sets of macro‐photographs were taken in 2002–2003 of three sites inside a small bay called Ca’ dell'Oro, which is the “no entry—no take” zone of the Marine Protected Area of Portofino, in order to analyse the structure of the benthic communities at different depths over a short time scale. The same sampling was repeated 10 years later in 2013. In the 10‐year span, a significant change in the macroalgal coverage and composition was observed, while the overall richness and coverage of species remained almost unchanged. This process resulted in a significant reduction of the habitat complexity of the three‐dimensional algal components. Likewise, a remarkable change in terms of presence and abundance occurred among all zoobenthic components. The benthic communities seem to have suffered from detrimental effects probably caused by climatic events that have been occurring in recent years in the Ligurian Sea.  相似文献   

Boron isotope composition of geothermal fluids and borate minerals from salar deposits (central Andes/NW Argentina)     

Simone A. Kasemann  Anette Meixner  Jrg Erzinger  Jos G. Viramonte  Ricardo N. Alonso  Gerhard Franz 《Journal of South American Earth Sciences》2004,16(8):2562

We have measured the boron concentration and isotope composition of regionally expansive borate deposits and geothermal fluids from the Cenozoic geothermal system of the Argentine Puna Plateau in the central Andes. The borate minerals borax, colemanite, hydroboracite, inderite, inyoite, kernite, teruggite, tincalconite, and ulexite span a wide range of δ¹¹B values from −29.5 to −0.3‰, whereas fluids cover a range from −18.3 to 0.7‰. The data from recent coexisting borate minerals and fluids allow for the calculation of the isotope composition of the ancient mineralizing fluids and thus for the constraint of the isotope composition of the source rocks sampled by the fluids. The boron isotope composition of ancient mineralizing fluids appears uniform throughout the section of precipitates at a given locality and similar to values obtained from recent thermal fluids. These findings support models that suggest uniform and stable climatic, magmatic, and tectonic conditions during the past 8 million years in this part of the central Andes. Boron in fluids is derived from different sources, depending on the drainage system and local country rocks. One significant boron source is the Paleozoic basement, which has a whole-rock isotopic composition of δ¹¹B=−8.9±2.2‰ (1 SD); another important boron contribution comes from Neogene-Pleistocene ignimbrites (δ¹¹B=−3.8±2.8‰, 1 SD). Cenozoic andesites and Mesozoic limestones (δ¹¹B≤+8‰) provide a potential third boron source.  相似文献   

Carbonate lithofacies as paleolatitude indicators: problems and limitations     

G. Carannante  M. Esteban  J. D. Milliman  L. Simone 《Sedimentary Geology》1988,60(1-4):333-346

Detailed study of Miocene carbonates in the Mediterranean region and their analogues on modern carbonate shelves (in the Mediterranean Sea, Brazil and other areas) reveals at least three major types of carbonate platform lithofacies in addition to the classic tropical coral reef (chlorozoan) lithofacies: (a) chloralgal lithofacies, similar to the chlorozoan, but without hermatypic corals; (b) rhodalgal lithofacies, characterized by abundant encrusting coralline algae; and (c) molechfor lithofacies, consisting of benthic foraminifers, molluscs, echinoids, bryozoans and barnacles. These carbonate lithofacies present complex distribution patterns seemingly related primarily to latitude and depth that control water temperature, although other factors (e.g., water circulation, river discharge, suspended sediment) controlling water salinity and temperature, nutrient content, light penetration, etc., also play important roles. Chloralgal and rhodalgal lithofacies can be considered two transitional terms between the two end-members: the chlorozoan lithofacies, which characterizes shallow tropical shelves; and the molechfor lithofacies, which characterizes colder and/or deeper areas. Detailed textural and sequential analysis are required for satisfactory interpretation of these lithofacies in ancient rocks.  相似文献   

Time-based correlation of biogenic,lithogenic and authigenic sediment components with anthropogenic inputs in the Gulf of Mexico NECOP study area     

Terry A. Nelsen  Pat Blackwelder  Terri Hood  Brent McKee  Nidia Romer  Carlos Alvarez-Zarikian  Simone Metz 《Estuaries and Coasts》1994,17(4):873-885

Hypotheses related to variability in seasonal hypoxic conditions, coastal nutrient enhancement, and off-shelf transport of carbon on the Louisiana continental shelf were tested by characterization of biogenic, lithogenic, and authigenic components from two shelf and one Mississippi Canyon sediment cores. The authigenic-phase glauconite occurs above detection limits only in the core from the hypoxic area. A major increase in glauconite concentration was coincident with the onset (≈1940) of the increased use of commercial fertilizers in the United States. In the same hypoxic-area core, benthic foraminifera species diversity decreases upcore from approximately the turn of the century to the present in a manner concurrent with glauconite and fertilizer increases. A subset of opportunistic benthic foraminifera species, known to become more prominent in stressed environments (i.e., hypoxic), increased upcore from ～52% of the total population at core bottom to ≈90% at core top. These benthic foraminifera population and diversity changes were not apparent in a “control” core outside the area of documented hypoxia. Seaward of the shelf, in the Mississippi Canyon, coincident increases in sediment accumulation rate, percentages of coarse fraction and of organic carbon at core top indicate increased offshelf transport of carbon and other components. Quartz percentages indicate that episodic down-canyon transport has been active to core bottom (prior to the mid 1800s).  相似文献   

Electron microprobe dating of monazite from high-T shear zones in the São José de Campestre Massif, NE Brazil     

Zorano Srgio de Souza  Jean-Marc Montel  Simone Maria Lima Costa Gioia  Maria Helena Bezerra Maia de Hollanda  Marcos Antonio Leite do Nascimento  Emanuel Ferraz Jardim de S  Venerando Eustquio Amaro  Mrcio Martins Pimentel  Jean-Marc Lardeaux  Michelle Veschambre 《Gondwana Research》2006,9(4):441-455

The easternmost domain of the Borborema Province, northeastern Brazil, presents widespread, extensional-related high-temperature metamorphism during the Brasiliano (=Pan-African) orogeny. This event reached the upper amphibolite to granulite facies and provoked generalized migmatization of Proterozoic metapelitic rocks of the Seridó Group and tonalitic to granodioritic orthogneisses of the Archean to Paleoproterozoic basement. We report new geochronological data based on electron microprobe dating of monazite from metapelitic migmatite and leuconorite within the high-T shear zones that make up the eastern continuation of the huge E–W Patos shear belt. These data were also constrained by using the Sm–Nd isotopic systematic on garnet from a syntectonic alkaline granite and two garnet-bearing leucosomes. The results suggest an age of about 578 to 574 Ma for the peak of the widespread high-T metamorphism. This event is best recorded by Sm–Nd garnet-whole rock ages. The U–Th–Pb isotopes on monazite of the metapelitic migmatite show a younger thermal event at 553 ± 10 Ma. When compared to the Sm–Nd garnet-whole rock ages, the U–Th–Pb electron probe monazite ages seem to record an event of slightly lower temperatures after the peak of the high-T metamorphism. This may reflect the difference in the isotopic behavior of the geochronological methods employed. Otherwise, the U–Th–Pb ages on monazites could indicate an event not yet very well defined. In anyway, this paper reveals the partial or even complete re-opening and resetting of the U–Th–Pb isotopic system produced by the action of low-T Ca-rich fluid.  相似文献   

Petroleum systems modeling in tectonically complex areas — A 2D migration study from the Neuquen Basin, Argentina     

Carolyn Lampe  Kristijan Kornpihl  Simone Sciamanna  Toms Zapata  Gonzalo Zamora  Roberto Varad 《Journal of Geochemical Exploration》2006,89(1-3):201

A roughly 30 km 2D section across the Faja Plegada y Corrida del Agrio in the Neuquen Basin, Argentina, is the basis for a petroleum systems study, including structural restoration through time, deposition and erosion, pressure, temperature and migration modeling. Integrating tectonic and petroleum systems modeling proved critical to properly evaluate sub-thrust plays. Multi-dimensional modeling of dynamic processes allows accurate assessment and prediction of the potential of petroleum systems in tectonically complex areas such as the Neuquen Basin.  相似文献   

Reply to the Comment on “Chronology of Vesuvius' activity from A.D. 79 to 1631 based on archeomagnetism of lavas and historical sources” by R. Lanza and E. Zanella     

Claudia Principe  Jean-Claude Tanguy  Simone Arrighi  Maxime Le Goff 《Bulletin of Volcanology》2006,68(4):397-398

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