973 resultados para Mines and mineral resources.


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The fourth part has separate t.-p.: Locomotive sketches, with pen and pencil. From Philadelphia to Pittsburg. (13-192 p.)

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Physical properties (water content, bulk density, magnetic susceptibility, natural remanent magnetization, nature of magnetization, and composition of ferromagnetic fraction), chemical, and (optionally) mineral composition of bottom sediments from the north-west Sea of Japan have been studied. Their stratigraphic subdivision based on composition of diatoms has been carried out. Obtained data have allowed to find out some aspects of influence of paleogeographic conditions and diagenetic processes on change of physical properties of the sediments, as well as on their composition in Holocene and Late Pleistocene.

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Results of study of bottom sediments near Iceland and on the Jan Mayen Island are reported. It was found that in recent sediments chemical elements are mainly associated with pyro- and volcanoclastics. In some areas adjusted to deep-seated faults ancient iron-manganese crusts and sediments occur. They are rich in Ni, Co, V, Cu, Mo, Cd and other elements associated with endogenic matter.

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On the bed and on the ocean slope of the southern latitudinal part of the Mariana Trench ancient sediments, as well as sedimentary and igneous rocks are exposed. In the lower part of the sampled part of the studied section Late Oligocene to Early Miocene chalk-like limestones and marls occur. Upward marly tuffites and tuffs (apparently alternating with carbonate rocks) occur. These rocks are overlain by Early Miocene tuffaceous clays and siliceous-clayey muds. In the upper part of the section there are Pleistocene pelagic clays and ethmodiscus oozes.

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A detailed study of chemical composition of bottom sediments along a profile through the Northwest Pacific Basin has allowed to identify and describe four lithofacies types of bottom sediments. Distinguished types of sediments form a genetic series reflecting changing conditions of sedimentation from near-shore to central regions of the ocean. Along the strike of pelagic clays a gradual transition from ash containing clays to zeolite containing clays is established. Ash particles and zeolites have similar forms of occurrence. Together with other data it suggests that zeolites have been formed by diagenetic transformation of rhyolitic glass. Regular changes of CaCO3, amorphous SiO2, Fe and Mn contents in bottom sediments from the coast to the pelagic zone are shown.

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This layer is a georeferenced raster image of the historic paper map entitled: Carta jeogràfica del desierto i cordilleras de Atacama, levantada por la Comisión Esploradora de Atacama ; dibo. N. Boloña ; grabo A. Németh ; Lit. Alemana, Santiago. It was published by Dirección General de Obras Públicas. Seccion de Jeografia y Minas in 1892. Scale 1:1,000,000. Covers the Atacama Desert and Puna de Atacama region, Chile and Argentina. Map in Spanish. The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'Mercator' projection. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, human settlements, roads, railroads, mines and mineral location, water lines, points of triangulation, territorial boundaries, shoreline features, ports, and more. Relief shown by hachures. Includes 5 insets depiciting mountain ranges entitled : Royeccion Vertical, vista Panorámica ; 2 plans entitled: Rada de Antofagasta -- Plano de la ciudad de Copiapó. This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection and the Harvard University Library as part of the Open Collections Program at Harvard University project: Organizing Our World: Sponsored Exploration and Scientific Discovery in the Modern Age. Maps selected for the project correspond to various expeditions and represent a range of regions, originators, ground condition dates, scales, and purposes.

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The paper reports results of a study of clastic heavy mineral assemblages and geochemical features of some assemblages in several Permian-Mesozoic cherty and siliceous-clayey sequences of the Sikhote Alin Region. They are composed of pelagic and hemipelagic sediments of the Panthalassa (Paleopacific) Ocean. Four typical mineral assemblages and their environments are established. In one of the ocean segments, where the sedimentary cover formed during Late Paleozoic - Early Cretaceous, the Permian pelagic domain was characterized by the amphibole-pyroxene assemblage with heavy minerals derived from ophiolites. The Triassic-Jurassic stage was marked by development of the clinopyroxene assemblage with heavy minerals derived from intraplate alkaline volcanic complexes. Middle-Late Jurassic hemipelagic sediments host the zircon-clinopyroxene assemblage with greater role of continental environments and presence of volcanic products of the convergence zone. Another segment of the ocean accumulated red cherts and siliceous-clayey sediments during Jurassic - Early Cretaceous under influence of island-arc volcanism.