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601.
High-temperature mass spectrometric studies have been made to determine the distribution of volatiles within glassy rims of submarine pillow basalts dredged from the east rift zone of Kilauea volcano, Hawaii. The CO2/H2O mole ratio for glass-vapor inclusions within olivine phenocrysts in the glassy rims is greater than 30 : 1 compared to 0.06 for matrix glasses. Enclosing matrix glasses contain 0.53–0.74 wt.% H2O, 0.02–0.04 wt.% carbon, 0.08–0.12 wt.% sulfur, 0.012–0.028 wt.% chlorine and 0.012–0.077 wt.% fluorine.  相似文献   
602.
603.
Rb/Sr geochronology on a folded greenstone-granitoid complex in the Agnew area, Western Australia, yields four distinct ages of igneous activity that conform with stratigraphic and intrusive relationships. They are (using λ 87Rb = 1.42 · 10?11a?1, NBS 70A = 522 ppm Rb and 65.3 ppm Sr):
  相似文献   
604.
Ambient, natural levels of selected heavy metals were assayed from deep, offshore populations of attached seaweeds from 1980 through 1983 from Pigeon Hill, 37 km from the nearest shoreline in the Gulf of Maine, and from Block Island, 23 km from the nearest mainland in Rhode Island Sound. Concentration levels of barium, cadmium, chromium, copper, mercury, lead and zinc were low when compared with concentration values published for a variety of seaweeds from the eastern and western North Atlantic. Values from Pigeon Hill and Block Island provide baseline data for long term monitoring of a relatively pristine, offshore, benthic community in the western North Atlantic.  相似文献   
605.
Site procedures and methods of analytical close range photogrammetry are described. The derived data are discussed in relation to the geomorphology of unstable hill slopes in Nepal. Acquisition of low cost multispectral aerial photography for a study of overall slope erosion is also described.  相似文献   
606.
Hydrogen peroxide concentrations in the Gulf of Mexico were measured on two cruises in May and August, 1982, in a variety of locations ranging from oligotrophic oceanic stations to highly productive coastal sites. Measurements were made using a fluorescence decay technique. Depth profiles of H2O2 exhibit surface maxima of 1?2 × 10?7 mol L?1 and decreasing concentrations with depth. Peroxide concentrations decreased only slightly or were invariant with depth in the mixed layer but decreased sharply to below the limit of detection (5 × 10?9 mol L?1) in the region of the pycnocline at the base of the mixed layer. Surface concentrations were generally highest in coastal regions but did not vary by more than a factor of three among all stations studied. There was a marked diel variation in peroxide profiles, with the highest values occurring during the late afternoon, and the lowest values occurring at dawn. Diel variations were more pronounced in coastal surface waters than in oligotrophic waters. The observations are consistent with photochemical formation of H2O2 by photooxidation of dissolved organic matter. However, other formation pathways, such as biological formation or atmospheric deposition, cannot be ruled out at this point.  相似文献   
607.
Rare earth element (REE) abundances determined by activation analysis in rocks, plagioclase and mafic separates from the Fiskenaesset Complex are presented together with data on major and trace elements in the minerals. The REE data for the rocks and plagioclases are distinct from those of many other anorthositic complexes and the abundances are some of the lowest recorded for plagioclase from terrestrial anorthosites. The bulk and trace element compositions of the Fiskenaesset plagioclases show a number of similarities to those of lunar plagioclases. The plagioclases show a positive Eu anomaly of about 10 and a depletion in the heavy REE relative to the light ones. The mafic separates are enriched in the heavy REE relative to the light ones, and show no Eu anomaly except in one sample with a positive anomaly not attributable to plagioclase contamination. It is estimated, from experimental partition coefficient data, that the REE pattern in the magma at an early stage of fractionation was La (17×) to Lu (0.7× chondrites) with a possible positive Eu anomaly. This highly fractionated REE pattern may be attributed to partial melting of a garnet-bearing source.  相似文献   
608.
Analysis of sediments taken from various levels in the lightly polluted River Blyth in Northumberland shows that quite high concentrations of metals can be accumulated in sediments.  相似文献   
609.
Many sets of data in the natural sciences have a hierarchical structure that is either inherent in the data or that is imposed on them during collection. These data structures can be defined using mathematical set-theory notation. If data from two or more computer-processable files are accessed simultaneously, the application of operations of set union and intersection leads to emergence of certain criteria which must be adhered to when managing data files using a generalized, database management system. One of the situations in which these principles come into play is illustrated by the merging of two computer-processable files of geotechnical data, the data for both files having been derived from the same source but structured differently.  相似文献   
610.
Ma87Sr/86Sr initial (IR)
(1) Differentiated gabbro-granophyre from a stratigraphically old (Kathleen Valley) greenstone sequence> 2718 ± 500.7007 ± 0.0004
(2) Voluminous tonalite, the Lawlers Tonalite2652 ± 200.70152 ± 0.00012
2576 ± 140.70218 ± 0.00021
(3) A less voluminous leucogranite, and a large complex pegmatite cutting the Perseverance nickel orebody2588 ± 180.7624 ± 0.0068
(4) Aplitic leucotonalite (very minor volumes but widespread)2474 ± 140.70193 ± 0.00012
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