An Improved Data-Driven Multiple Criteria Decision-Making Procedure for Spatial Modeling of Mineral Prospectivity: Adaption of Prediction–Area Plot and Logistic Functions     

Ghezelbash  Reza  Maghsoudi  Abbas  Carranza  Emmanuel John M. 《Natural Resources Research》2019,28(4):1299-1316

Natural Resources Research - Assigning realistic weights to targeting criteria in order to synthesize various geo-spatial datasets is one of the most important challenging tasks for mineral...  相似文献   

GIS derived synthetic rating curves and HAND model to support on-the-fly flood mapping     

Scriven  Blair William Gerald  McGrath  Heather  Stefanakis  Emmanuel 《Natural Hazards》2021,108(2):1629-1657

Natural Hazards - Acknowledging the devastating consequences of past earthquakes, current research efforts focus on the development of tools for assessing and controlling the risk and losses...  相似文献   

Genetic structure of the reef grouper Epinephelus merra in the West Indian Ocean appears congruent with biogeographic and oceanographic boundaries          下载免费PDF全文

Delphine Muths  Emmanuel Tessier  Jerome Bourjea 《Marine Ecology》2015,36(3):447-461

The reef fauna connectivity of the West Indian Ocean (WIO) is one of the least studied globally. Here we use genetic analyses of the grouper Epinephelus merra (Bloch 1793) to determine patterns of connectivity and to identify barriers to dispersal in this WIO marine area. Phylogeographic and population‐level analyses were conducted on cytochrome b sequences and microsatellites (13 loci) from 557 individuals sampled in 15 localities distributed across the West Indian Ocean. Additional samples from the Pacific Ocean were used to benchmark the WIO population structure. The high level of divergence revealed between Indian and Pacific localities (of about 4.5% in sequences) might be the signature of the major tectonic and climatic changes operating at the Plio‐Pleistocene transition, congruently with numerous examples of Indo‐Pacific speciation. In comparison, the E. merra sequences from the Indian Ocean constitute a monophyletic clade with a low average genetic distance (d < 0.5%). However both genetic markers indicated some structure within this ocean. The main structure revealed was the isolation of the Maldives from the WIO localities (a different group signature identified by clustering analysis, great values of differentiation). Both marker types reveal further significant structure within the WIO, mainly the isolation of the Mascarene Islands (significant AMOVA and isolation‐by‐distance patterns) and some patchy structure between the northernmost localities and within the Mozambique Channel. The WIO genetic structure of E. merra appeared congruent with main biogeographic boundaries and oceanographic currents.  相似文献   

Leaching experiments on a Mn-rich slag from the recycling of alkaline batteries – Solid phase characterization and geochemical modeling     

Priscilla Pareuil  François Bordas  Emmanuel Joussein  Philippe Vieillard  Jean-Claude Bollinger 《Applied Geochemistry》2010

Square sections of a Mn-rich slag from an alkaline battery recycling plant were submitted to 6-month batch leaching procedures. High-Purity Water (HPW), acidic (pH 4) and alkaline (pH 12) conditions were used in order to observe the behavior of primary solid phases as well as the constituent elements (Mn, Mg, Al, Si, Ca). The experiments were coupled with both KINDIS(P) modeling and mineralogical study (SEM-EDS). Experimental results showed that the Mn-rich slag was sensitive to acidic conditions which induced the dissolution of primary phases. Moreover, pH 4 conditions did not result in the formation of newly formed solid products, leading to the greatest mobilization of metallic elements (especially Mn). Alkaline conditions favored the precipitation of secondary phases, especially rhodochrosite, calcite and Mg-saponite, inducing low mobilization of the contained elements. The KINDIS(P) modeling allowed the stability of primary phases and newly formed products to be predicted. Although the modeled results have to be considered with caution, they allow the assessment and understanding of future environmental behavior of the solid material in given conditions. In this case, the reuse of Mn-rich slag in acidic conditions has to be avoided because of the acidic dissolution of the primary phases.  相似文献   

Lithium isotope systematics in a forested granitic catchment (Strengbach, Vosges Mountains, France)   总被引：1，自引：0，他引：1  

Emmanuel Lemarchand  François Chabaux  Marie-Claire Pierret 《Geochimica et cosmochimica acta》2010,74(16):4612-7724

Over the last decade it has become apparent that Li isotopes may be a good proxy to trace silicate weathering. However, the exact mechanisms which drive the behaviour of Li isotopes in surface environments are not totally understood and there is a need to better calibrate and characterize this proxy. In this study, we analysed the Li concentrations and isotopic compositions in the various surface reservoirs (soils, rocks, waters and plants) of a small forested granitic catchment located in the Vosges Mountains (Strengbach catchment, France, OHGE http://ohge.u-strasbg.fr). Li fluxes were calculated in both soil profiles and at the basin scale and it was found that even in this forested basin, atmospheric inputs and litter fall represented a minor flux compared to input derived from the weathering of rocks and soil minerals (which together represent a minimum of 70% of dissolved Li). Li isotope ratios in soil pore waters show large depth dependent variations. Average dissolved δ⁷Li decreases from −1.1‰ to −14.4‰ between 0 and −30 cm, but is +30.7‰ at −60 cm. This range of Li isotopic compositions is very large and it encompasses almost the entire range of terrestrial Li isotope compositions that have been previously reported. We interpret these variations to result from both the dissolution and precipitation of secondary phases. Large isotopic variations were also measured in the springs and stream waters, with δ⁷Li varying from +5.3‰ to +19.6‰. δ⁷Li increases from the top to the bottom of the basin and also covaries with discharge at the outlet. These variations are interpreted to reflect isotopic fractionations occurring during secondary phase precipitation along the water pathway through the rocks. We suggest that the dissolved δ⁷Li increases with increasing residence time of waters through the rocks, and so with increasing time of interaction between waters and solids. A dissolution precipitation model was used to fit the dissolved Li isotopic compositions. It was found that the isotopic compositions of springs and stream waters are explicable by an isotopic fractionation of −5‰ to −14‰ (best fit −10.8‰), in agreement with Li incorporation into clay. In soil solutions, it was found that isotopic fractionation during secondary precipitation is larger (at least −23‰), suggesting a major role for different secondary phases, such as iron oxides that maybe incorporate Li with a higher isotope fractionation.  相似文献   

Interfacial energy effects and the evolution of pore size distributions during quartz precipitation in sandstone     

Simon Emmanuel  Jay J. Ague 《Geochimica et cosmochimica acta》2010,74(12):3539-18706

Pore size is usually thought to control the rate of crystal growth in porous geological media by determining the ratio of mineral surface area to fluid volume. However, theory suggests that in micron-scale to nanometer scale pores, interfacial energy (surface energy) effects can also become important. Interfacial energy typically increases the solubility of very small crystals growing in tiny pores, and when the fluid is close to equilibrium - as is often the case in geological systems - mineral precipitation could occur in relatively large pores, while in very small adjacent pores crystal growth might be suppressed. Such a mechanism would effectively restrict the reactive surface area of the porous medium, thereby reducing the bulk reaction rate. We investigated the pore size distributions in naturally cemented sandstone adjacent to an isolated stylolite and found that quartz precipitation was inhibited in pores smaller than 10 μm in diameter. Furthermore, we demonstrate that kinetic formulations which assume constant solubility cannot reproduce the observed pore size patterns in mineralized samples; by contrast, excellent fits with the data are obtained when interfacial energy effects are taken into account. Reaction rates in geological media determined in field studies can be orders of magnitude lower than those measured in laboratory experiments, and we propose that reduced reaction rates in porous media with micron and submicron-scale porosity could account for much of the apparent paradox.  相似文献   

Improved Wildcat Modelling of Mineral Prospectivity     

Emmanuel John M. Carranza 《Resource Geology》2010,60(2):129-149

Wildcat modelling of mineral prospectivity has been proposed for greenfields geologically-permissive terranes where mineral targets have not yet been discovered but a geological map is available as a source of spatial data of predictors of mineral prospectivity. This paper (i) revisits the initial way of assigning wildcat scores (S_c) to predictors of mineral prospectivity and (ii) proposes an improvement by transforming S_c into improved wildcat scores (IS_c) by using a logistic function. This was shown in wildcat modelling of prospectivity for low-sulphidation epithermal-Au (LSEG) deposits in Aroroy district (Philippines). Based on knowledge of characteristics of and controls on LSEG mineralization in the Philippines, the spatial predictors of LSEG prospectivity used in the study are proximity to porphyry plutonic stocks, faults/fractures and fault/fracture intersections. The S_c and IS_c of spatial predictors are input separately to principal components analysis to extract a favourability function that can be interpreted as a wildcat model of LSEG prospectivity. The predictive capacity of the wildcat model of LSEG prospectivity based on the IS_c of geological predictors is roughly 70% higher than that of the wildcat model of LSEG prospectivity based on the S_c of geological predictors. A slight increase of predictive capacity of wildcat modelling of LSEG prospectivity is also achieved when the IS_c of geological predictors are integrated with the IS_c of geochemical anomalies, but not with the S_c of geochemical anomalies. The proposed improvement is significant because if the study district were a greenfields exploration area, then a wildcat model of LSEG prospectivity based on the old wildcat methodology would have caused several LSEG targets to be missed.  相似文献   

Nuclear spin temperature of ammonia in Comet 9P/Tempel 1 before and after the Deep Impact event     

Hideyo Kawakita  Emmanuel Jehin  Jean Manfroid 《Icarus》2007,187(1):272-275

The Deep Impact mission succeeded in excavating inner materials from the nucleus of Comet 9P/Tempel 1 on 2005 July 04 (at 05:52 UT). Comet 9P/Tempel 1 is one of Jupiter family short period comets, which might originate in the Kuiper belt region in the solar nebula. In order to characterize the comet and to support the mission from the ground-based observatory, optical high-dispersion spectroscopic observations were carried out with the echelle spectrograph (UVES) mounted on the 8-m telescope VLT (UT2) before and after the Deep Impact event. Ortho-to-para abundance ratios (OPRs) of cometary ammonia were determined from the NH₂ emission spectra. The OPRs of ammonia on July 3.996 UT and 4.997 UT were derived to be 1.28±0.07 (nuclear spin temperature: Tspin=24±2 K) and 1.26±0.08 (Tspin=25±2 K), respectively. There is no significant change between before and after the impact. Actually, most materials ejected from the impact site could have moved away from the nucleus on July 4.997 UT, about 17 h after the impact. However, a small fraction of the ejected materials might remain in the slit of UVES instrument at that time because an excess of about 20% in the NH₂ emission flux is observed above the normal activity level was found [Manfroid, J., Hutsemékers, D., Jehin, E., Cochran, A.L., Arpigny, C., Jackson, W.M., Meech, K.J., Schulz, R., Zucconi, J.-M., 2007. Icarus. This issue]. If the excess of NH₂ on July 04.997 UT was produced from icy materials excavated by the Deep Impact, then an upper-limit of the ammonia OPR would be 1.75 (Tspin>17 K) for those materials. On the other hand, the OPR of ammonia produced from the quiescent sources was similar to that of the Oort cloud comets observed so far. This fact may imply that physical conditions where cometary ices formed were similar between Comet 9P/Tempel 1 and the Oort cloud comets.  相似文献   

An open-source web service for creating quadrilateral grids based on the rHEALPix Discrete Global Grid System     

David Bowater  Emmanuel Stefanakis 《International Journal of Digital Earth》2020,13(9):1055-1071

ABSTRACT

The foundation of modern Digital Earth frameworks is the Discrete Global Grid System (DGGS). To standardize the DGGS model, the Open Geospatial Consortium (OGC) recently created the DGGS Abstract Specification, which also aims to increase usability and interoperability between DGGSs. To support these demands and aid future research, open implementations are necessary. However, several OGC conformant DGGSs are not available for researchers to use. This has motivated us to develop an open-source web service that allows users to create quadrilateral grids based on the rHEALPix DGGS. In this paper, we describe the implementation of the web service, including issues and limitations, and demonstrate how discrete global grids and regional grids can be created. Lastly, we present examples that show how vector data sets can be modeled and integrated at different levels of resolution – a key benefit of the DGGS model.  相似文献   

Richardson number profiles through shear instability wave regions observed in the lower planetary boundary layer     

C. B. Emmanuel 《Boundary-Layer Meteorology》1973,5(1-2):19-27

Remote sensing of the lower planetary boundary layer in the vicinity of a meteorological tower on many occasions reveals the existence of shear instability (Kelvin-Helmholtz) waves. In general, such waves are found within shallow strata which are marked by strong thermal stability and large vertical wind shear. The independent and concurrent measurements of the vector wind and temperature, made on a 152-m high tower, allow the construction of wind and temperature profiles. From such measurements, the Richardson number profile is constructed as well as the instability regime according to Drazin's criterion. The results show that regions of shear-instability waves as depicted by the remote sensor (an acoustic sounder) agree well with Drazin's instability regime, and that within such regions the Richardson number is indeed 0.25.  相似文献