974 resultados para North-central China


Relevância:

80.00% 80.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: A new and accurate map of the county of Cornwall : from an actual survey, made by Thos. Martyn. It was printed and sold by Robt. Sayer, map & print seller opposite Fetter Lane Fleet Street in 1748. Scale [ca. 1:65,000]. This layer is image 1 of 7 total images of the nine sheet source map, representing a north central portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'British National Grid' coordinate system. 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, cities and other human settlements, roads, administrative boundaries, shoreline features, and more. Relief shown pictorially. Includes inset of the Isles of Scilly and illus. of "The arms of the nobility and gentry that have subscrib'd for this map."This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: A new and accurate map of the county of Cornwall : from an actual survey, made by Thos. Martyn. It was printed and sold by Robt. Sayer, map & print seller opposite Fetter Lane Fleet Street in 1748. Scale [ca. 1:65,000]. This layer is image 7 of 7 total images of the nine sheet source map, representing a north central portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'British National Grid' coordinate system. 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, cities and other human settlements, roads, administrative boundaries, shoreline features, and more. Relief shown pictorially. Includes inset of the Isles of Scilly and illus. of "The arms of the nobility and gentry that have subscrib'd for this map."This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Eolian dust preserved in deep-sea sediment cores provides a valuable indicator of past atmospheric circulation and continental paleoclimate. In order to identify the provenance of eolian dust, Nd and Sr isotopic compositions and Rb, Sr and rare earth element (REE) concentrations have been determined for the silicate fractions of deep-sea sediments from the north and central Pacific Ocean. Different regions of the Pacific Ocean are characterized by distinct air-borne inputs, producing a large range in epsolin-Nd (-10 to +1), 87Sr/86Sr (0.705-0.721), La/Yb (5-15), EuN/EuN* (0.6-1.0) and Sr/Nd (4-33). The average Nd isotopic composition of Pacific deep-sea sediments (epsilon-Nd = -6), is more radiogenic than the average from the Atlantic (epsilon-Nd = -8). In contrast, the average147Sm/144Nd ratio for Pacific sediments (0.114) is identical to that of Atlantic sediments and to that of global average riverine suspended material. The values of epsilon-Nd and147Sm/144Nd are positively correlated for the Pacific samples but negatively correlated for Atlantic samples, reflecting a fundamental difference between the dominant components in the end members with radiogenic Nd (island-arc components in the Pacific and LREE-enriched intraplate ocean island components in the Atlantic). Samples from the north central Pacific have distinctive unradiogenic epsilon-Nd values of -10, 87Sr/86Sr > 0.715, high La/Yb (> 12), and low EuN/EuN* (0.6) and Sr/Nd (3-6). These data are virtually identical to the values for loess from Asia and endorse the use of these sediments as indicators of Asian paleoclimate and paleowind directions. Island-arc contributions appear to dominate in the northwest Pacific, resulting in higher epsilon Nd (-1 to +1) and lower 87Sr/86Sr (~ 0.705) and La/Yb (~ 5). Sediments from the eastern Pacific tend to have intermediate Sr and Nd isotopic compositions but regionally variable Sr/Nd and REE patterns; they appear to be derived from the west margin of the North and South American continents, rather than from Asia. Our results confirm that dust provenance can be constrained by isotopic and geochemical analyses, which will facilitate reconstructions of past atmospheric circulation and continental paleoclimate.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Recent coccoliths from 74 surface sediment samples recovered from the southeastern Pacific off Chile were examined quantitatively to investigate modern regional gradients of sea surface productivity and temperature. All findings are based on coccolith accumulation rates. Therefore an approach was designed to estimate recent sedimentation rates based on 210Pb and bulk chemistry analyses of the same set of surface samples. Highest total coccolith accumulation rates were found off north-central Chile, where seasonal upwelling takes place. Based on amultiple linear regression between calculated coccolith accumulation rates andWorld Ocean Atlas derived sea surface temperatures, a calibrationmodel to reconstruct annual average temperatures of the uppermost 75 mof thewater column is provided. Themodelwas cross-validated and the SST estimateswere compared with SST observed and SST estimates based on diatoms and planktonic foraminifera, showing a good correlation.

Relevância:

80.00% 80.00%

Publicador:

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mineral and chemical compositions of a set of crust samples collected from the North, Central and South Atlantic were examined by means of analytical electron microscopy and ICP-MS, chemical, and microchemical elemental analysis. Vernadite, asbolane, and goethite are dominant mineral phases of the crusts, ferrihydrite is minor, hematite and feroxyhyte are rare. The samples show wide variability in major and trace element contents; however, their characteristic geochemical signatures indicate hydrogenous origin. A comparison between compositions of oceanic hydrogenous and hydrothermal crusts and metalliferous hydrothermal sediments from different ocean areas suggests that the geochemical approach may be insufficient in some cases and fail to identify hydrothermal input in ferromanganese crusts of mixed composition.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Cover title.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

" ... contribution to North Central Project NC-137, 'Effect of changes in transportation on performance of the U.S. Agricultural Transportation System, 'and to Southern Regional Project S-176 Interregional marketing systems for grains and soybeans.'"--P. iii.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Some numbers after 677 called: Bulletin.