Increasing the usability and accessibility of geodynamic modelling tools to the geoscience community: UnderworldGUI     

Shea Goyette  Masa Takatsuka  Stuart Clark  R. Dietmar Müller  Patrice Rey  Dave R. Stegman 《Visual Geosciences》2008,13(1):25-36

Geoscientists are faced with a number of complexities that represent obstacles to the development of realistic simulation of deep earth processes. Realistic 4D thermo-mechanical simulation using software packages like Underworld and Gale, when combined appropriately with geoscientific expertise, can lead to novel insights into the deformation of geological structures at a wide range of time and spatial scales. The challenge for end-user geoscientists lies in applying their knowledge within the framework of the software’s input specification, including initial, internal, and boundary conditions and output visualization parameters. We have built a Graphical User Interface (GUI) to remove many of the difficulties related to editing the Extensible Markup Language (XML) encoded input files of Underworld/Gale geomodels and therefore, to greatly broaden the user base of these software packages. By helping Underworld/Gale to meet a large audience, we provide a tool to the geoscience community that helps to move from untested conceptual models to physically valid, properly scaled modelling. Furthermore, the UnderworldGUI offers a mechanism for storing and retrieving experimental models in a centralised database, thus providing the geoscience community with a means to share the outcomes of its experimental research. Further details of the UnderworldGUI are available at the web site .

Shea GoyetteEmail:

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Complementary (secondary) metabolites in a soft coral: sex-specific variability, inter-clonal variability, and competition   总被引：2，自引：0，他引：2  

Beatriz Fleury  John Coll  & Paul Sammarco 《Marine Ecology》2006,27(3):204-218

Sex‐specific interactions involving competition for space between the dioecious alcyonacean soft coral Sarcophyton glaucum and the scleractinian coral Acropora robusta were assessed experimentally on Bald Rock, central region of the Great Barrier Reef. To examine this, plus inter‐clonal responses, one male colony of S. glaucum, known to produce sarcophytoxide as its predominant complementary (secondary) metabolite, was sectioned, producing 10 clones. The same was done for a female colony. These two sets of clones were then relocated to grids and placed in contact with Acropora clones. Relocated and non‐relocated controls were also monitored. High levels of tissue necrosis were observed in the hard coral under contact conditions with both the male and female clones after 20 days. The development of a protective polysaccharide layer in the alcyonacean was also observed. Differences observed in the concentrations of complementary metabolites within the two different S. glaucum colonies were related to sex. Both under competition and non‐competition conditions, females exhibited significantly higher concentrations of sarcophytoxide than males, and this increased with time. Fatty ester concentration was also higher in females than males, varying significantly through time, and falling dramatically just after spawning. Fatty ester concentrations decreased linearly through time in the male clones. When involved in competition for space, females possessed higher concentrations of fatty esters than males, both at the site of contact and in non‐contact sites, again, decreasing after spawning. No significant changes in sarcophytoxide levels were noted in the parental colonies, but such changes were observed in fatty esters, with the female producing higher concentrations until after spawning. The use of these two variates in the form of a ratio (sarcophytoxide concentration:fatty ester concentration) yielded a variable Rho (ρ) which was a more sensitive indicator of biochemical change than either of its components alone. These two sets of compounds appeared to have a negative association through time and varied highly significantly between sexes. The diterpene sarcophytoxide may be considered an allelopathic or stress metabolite, while the lipids act as energy storage metabolites.  相似文献   

Rotating flow past a short,sliced cylinder at finite Rossby number     

K. A. Polzin  M. Angelats I Coll  M. R. Foster 《地球物理与天体物理流体动力学》2013,107(1-2):67-103

Abstract

Flow past a short obstacle in a rotating reference frame generates a wake that is crucial to the overall flow structure if the Rossby number is of the order of the quarter power of the Ekman number. We present here a theory for such flows for the case when the obstacle's top is an oblique, planar surface. The results arise from a combination of asymptotic analysis and numerical computation, and show that even weak asymmetry generates significant global effect on the entire flow-field. Comparisons with the experiments reported by Foster and Davies (1996) are generally good when the high edge is at 90° to the oncoming flow.  相似文献   

Deep crustal source of gneiss dome revealed by eclogite in migmatite (Montagne Noire,French Massif Central)     

Donna L. Whitney  Clémentine Hamelin  Christian Teyssier  Natalie H. Raia  Megan S. Korchinski  Nicholas C. A. Seaton  Brian C. Bagley  Anette von der Handt  Françoise Roger  Patrice F. Rey 《Journal of Metamorphic Geology》2020,38(3):297-327

In orogens worldwide and throughout geologic time, large volumes of deep continental crust have been exhumed in domal structures. Extension-driven ascent of bodies of deep, hot crust is a very efficient mechanism for rapid heat and mass transfer from deep to shallow crustal levels and is therefore an important mechanism in the evolution of continents. The dominant rock type in exhumed domes is quartzofeldspathic gneiss (typically migmatitic) that does not record its former high-pressure (HP) conditions in its equilibrium mineral assemblage; rather, it records the conditions of emplacement and cooling in the mid/shallow crust. Mafic rocks included in gneiss may, however, contain a fragmentary record of a HP history, and are evidence that their host rocks were also deeply sourced. An excellent example of exhumed deep crust that retains a partial HP record is in the Montagne Noire dome, French Massif Central, which contains well-preserved eclogite (garnet+omphacite+rutile+quartz) in migmatite in two locations: one in the dome core and the other at the dome margin. Both eclogites record P ~ 1.5 ± 0.2 GPa at T  ~  700 ± 20°C, but differ from each other in whole-rock and mineral composition, deformation features (shape and crystallographic preferred orientation, CPO), extent of record of prograde metamorphism in garnet and zircon, and degree of preservation of inherited zircon. Rim ages of zircon in both eclogites overlap with the oldest crystallization ages of host gneiss at c. 310 Ma, interpreted based on zircon rare earth element abundance in eclogite zircon as the age of HP metamorphism. Dome-margin eclogite zircon retains a widespread record of protolith age (c. 470–450 Ma, the same as host gneiss protolith age), whereas dome-core eclogite zircon has more scarce preservation of inherited zircon. Possible explanations for differences in the two eclogites relate to differences in the protolith mafic magma composition and history and/or the duration of metamorphic heating and extent of interaction with aqueous fluid, affecting zircon crystallization. Differences in HP deformation fabrics may relate to the position of the eclogite facies rocks relative to zones of transpression and transtension at an early stage of dome development. Regardless of differences, both eclogites experienced HP metamorphism and deformation in the deep crust at c. 310 Ma and were exhumed by lithospheric extension—with their host migmatite—near the end of the Variscan orogeny. The deep crust in this region was rapidly exhumed from ~50 to <10 km, where it equilibrated under low-P/high-T conditions, leaving a sparse but compelling record of the deep origin of most of the crust now exposed in the dome.  相似文献   

The use of a micro-scale index to identify potential death risk areas due to coastal flood surges: lessons from Storm Xynthia on the French Atlantic coast     

Axel Creach  Sophie Pardo  Patrice Guillotreau  Denis Mercier 《Natural Hazards》2015,77(3):1679-1710

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Food-web traits of the North Aegean Sea ecosystem (Eastern Mediterranean) and comparison with other Mediterranean ecosystems     

K. Tsagarakis  M. Coll  M. Giannoulaki  S. Somarakis  C. Papaconstantinou  A. Machias 《Estuarine, Coastal and Shelf Science》2010

A mass-balance trophic model was built to describe the food-web traits of the North Aegean Sea (Strymonikos Gulf and Thracian Sea, Greece, Eastern Mediterranean) during the mid-2000s and to explore the impacts of fishing. This is the first food-web model representing the Aegean Sea, and results were presented and discussed in comparison to other previous ecosystems modelled from the western and the central areas of the basin (South Catalan and North-Central Adriatic Seas).  相似文献   

LINET—An international lightning detection network in Europe   总被引：1，自引：0，他引：1  

Hans D. Betz  Kersten Schmidt  Pierre Laroche  Patrice Blanchet  Wolf P. Oettinger  Eric Defer  Z. Dziewit  J. Konarski 《Atmospheric Research》2009,91(2-4):564-573

During the past years a VLF/LF lightning detection network (LINET) was developed at the University of Munich, which provides continuous data for both research and operational purposes. In particular, the network introduces five new features: a) total lightning capability: both cloud-to-ground strokes (CG) and cloud lightning (IC) are measured; b) low-amplitude reporting: weak lightning events from discharge channel with currents well below 5 kA are detected within the central part of the network, whereby IC events dominate; c) new 3D-discrimination: a time-of-arrival method is utilized to separate CG from IC with good reliability, provided that the sensor baseline does not exceed ~ 250 km; d) IC emission height: for each cloud event a height is determined which is thought to reflect the central region of the involved channel; and e) optimised location accuracy: due to precision and combined action of all influential network components, complemented by site-error corrections, the position accuracy of strokes reaches an average value as small as ~ 150 m, whereby false locations (‘outliers’) rarely occur. During international co-operations LINET has been deployed in four continents: Europe (initially Germany), South America (area of Bauru, Brazil), Australia (around Darwin), and Central Africa (Benin). Since the features quoted above could be verified in the tests, a 65-sensor network was established in Europe and started on May 1, 2006, in co-operation with the service company nowcast. LINET covers a wide area approximately from longitude − 10° to 25° to latitude 35° to 66°; it is available for scientific projects and officially utilized by the German Weather Service for operational purposes. Meanwhile, the network was extended by deployment of additional sites so that it comprises about 90 sensors in 17 countries.  相似文献   

UVolution, a photochemistry experiment in low earth orbit: Investigation of the photostability of carbonates exposed to martian-like UV radiation conditions     

Fabien Stalport  Yuan Yong Guan  Patrice Coll  Frédérique Macari  Didier Chaput  Hervé Cottin 《Planetary and Space Science》2010,58(12):1617-1624

The detection and identification of carbonates on Mars are of prime importance to establish the evolution of its atmosphere, correlated to the history of the liquid water, or even to determine the existence of a possible ancient biological activity. Till date, no large deposits of carbonates have been found. In fact, their detection is specific to local areas and in very low amounts. The absence of such deposits is commonly attributed to the harsh environmental conditions at the surface of Mars. Additionally, the presence of UV radiation has been proposed to explain their photodecomposition and hence their absence. However, contradictory results from laboratory experiments mimicking Mars’ surface UV radiation did not resolve the behaviour of carbonates in such an environment, which is why we exposed, in low Earth orbit and in laboratory experiments, both abiotic and biotic calcium carbonates to UV radiation of wavelength above 200 nm, the same spectral distribution as the one reaching the surface of Mars. For low Earth orbit (LEO) exposure, this was done for the UVolution experiment on board the BIOPAN ESA module, which was set outside a Russian Foton automated capsule, and exposed to space conditions for 12 days in September 2007. The targeted carbonates are biominerals and abiotic samples. Our laboratory results mainly show that the exposed carbonates appear to be stable to UV radiation if directly exposed to it. The LEO experiment results tend to the same conclusion, but the integrated exposition time to Solar UV during the experiment is not sufficient to be conclusive. However, the stability of the biominerals derived from the laboratory experiment could strengthen the interest to explore deeper their potential as life records at Mars. Hence, they should be considered as primary targets for in situ analyses during future missions.  相似文献   

Surfaces and atmospheres of the outer planets, their satellites and ring systems: Part VI     

Athena Coustenis  Sushil Atreya  Patrice Coll 《Planetary and Space Science》2010,58(13):1665-1666

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New constrains on the thickness of the Semail ophiolite in the Northern Emirates     

Charles Naville  Martine Ancel  Paul Andriessen  Patrice Ricarte  François Roure 《Arabian Journal of Geosciences》2010,3(4):459-475

Near-critical angle and refraction studies were performed at IFP as piggyback studies during a wider programme of crustal imagery operated by WesternGeco on behalf of the Ministry of Energy of the United Arab Emirates. The main objective is to illuminate the base of the Semail Ophiolite along part of a regional transect (D1) crossing the Northern Emirates from the Gulf of Oman in the east up to the Arabian Gulf in the west. Results confirm that the sole thrust of the ophiolite has been folded during the Miocene stacking of the underlying Arabian Platform. The thickness of the ophiolite grades from zero in the core of the Masafi tectonic window, up to a maximum of 1.7 km below the axial part of a successor basin which has been preserved on top of the serpentinite west of the current exposure of the main ultramafic bodies. Apatite grains extracted from plagiogranites of the Semail ophiolite also provide evidences for an early unroofing of the gabbros and plagiogranites during the Late Cretaceous, with cooling ages of 72–76 Ma at the top of the ophiolite in the east (not far from the Fujairah coast line), which are coeval and also consistent with the occurrence of Late Cretaceous paleo-soils, rudists and paleo-reef deposits on top of serpentinized ultramafics in the west. Younger cooling ages of 20 Ma have been also found at the base of the ophiolite near Masafi, in the core of the nappe anticline, thus providing a Neogene age for the refolding of the allochthon and stacking of underlying parautochthonous platform carbonate units. These results, together with the occurrence of a thick sedimentary pile illuminated below the metamorphic sole along the north-trending, strike-profile D2 running parallel to the axis of the Masafi window, should stimulate a renewal of the exploration in the central part of the Emirate foothills, where the ophiolite thickness is currently limited, and was already drastically reduced by the end of its Late Cretaceous obduction.  相似文献