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841.
Thiruvengadam Sudharsan Murphy Matthew Edmund Tan Jei Shian Watling Roger John Stewart James Ian Miller Karol 《Mathematical Geosciences》2020,52(7):865-928
Mathematical Geosciences - In geochemistry, the elevated concentrations of certain elements in rock or mineral samples are used for the assessment of a mineralising system’s important... 相似文献
842.
Scott D. King Julie C. Castillo‐Rogez M. J. Toplis Michael T. Bland Carol A. Raymond Christopher T. Russell 《Meteoritics & planetary science》2018,53(9):1999-2007
Thermal evolution modeling has yielded a variety of interior structures for Ceres, ranging from a modestly differentiated interior to more advanced evolution with a dry silicate core, a hydrated silicate mantle, and a volatile‐rich crust. Here we compute the mass and hydrostatic flattening from more than one hundred billion three‐layer density models for Ceres and describe the characteristics of the population of density structures that are consistent with the Dawn observations. We show that the mass and hydrostatic flattening constraints from Ceres indicate the presence of a high‐density core with greater than a 1σ probability, but provide little constraint on the density, allowing for core compositions that range from hydrous and/or anhydrous silicates to a mixture of metal and silicates. The crustal densities are consistent with surface observations of salts, water ice, carbonates, and ammoniated clays, which indicate hydrothermal alteration, partial fractionation, and the possible settling of heavy sulfide and metallic particles, which provide a potential process for increasing mass with depth. 相似文献
843.
Open data strategies are being adopted in disaster-related data particularly because of the need to provide information on global targets and indicators for implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030. In all phases of disaster risk management including forecasting, emergency response and post-disaster reconstruction, the need for interconnected multidisciplinary open data for collaborative reporting as well as study and analysis are apparent, in order to determine disaster impact data in timely and reportable manner. The extraordinary progress in computing and information technology in the past decade, such as broad local and wide-area network connectivity (e.g. Internet), high-performance computing, service and cloud computing, big data methods and mobile devices, provides the technical foundation for connecting open data to support disaster risk research. A new generation of disaster data infrastructure based on interconnected open data is evolving rapidly. There are two levels in the conceptual model of Linked Open Data for Global Disaster Risk Research (LODGD) Working Group of the Committee on Data for Science and Technology (CODATA), which is the Committee on Data of the International Council for Science (ICSU): data characterization and data connection. In data characterization, the knowledge about disaster taxonomy and data dependency on disaster events requires specific scientific study as it aims to understand and present the correlation between specific disaster events and scientific data through the integration of literature analysis and semantic knowledge discovery. Data connection concepts deal with technical methods to connect distributed data resources identified by data characterization of disaster type. In the science community, interconnected open data for disaster risk impact assessment are beginning to influence how disaster data are shared, and this will need to extend data coverage and provide better ways of utilizing data across domains where innovation and integration are now necessarily needed. 相似文献
844.
David J. Stewart 《Geoarchaeology》1999,14(6):565-587
Although the formation processes operating on submerged archaeological sites are just as varied as those affecting terrestrial ones, nautical archaeologists have not yet devoted much attention to them. Most studies to date are concerned with formation processes at particular sites. This article provides an overview of the major depositional and postdepositional formation processes affecting underwater sites. The most obvious depositional process is shipwreck, which takes several different forms. Submerged sites may also be formed by the drowning of coastal areas due to tectonic or eustatic sea level changes. In these cases, rapid submergence preserves sites better than slow inundation, which allows time for waves and currents to tear the site apart. For both shipwrecks and coastal sites, once submergence occurs, the single most important factor for preservation is rapid burial by sediment. A cover of sediment protects both the artifacts themselves and their spatial patterning from destruction by water and marine organisms. Once deposited, underwater sites are subject to modification by both cultural and natural processes. The best understood postdepositional processes include salvaging, treasure hunting, and destruction by marine borers. Others, such as dredging, construction, and bioturbation, have hardly been investigated at this time. Archaeologists need to devote more attention to the effects of marine animals that live in close association with the seabed, as well as marine plants, whose roots may disturb sites located in shallow water. From this study it is clear that maritime archaeologists must consider formation processes when planning projects, rather than thinking of underwater sites as simply “time capsules.” © 1999 John Wiley & Sons, Inc. 相似文献