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81.
Cupric carbonate and cupric bicarbonate complexation constants were determined in natural seawater and in a variety of synthetic media. The formation constants of CuHCO3+, CuCO30 and Cu(CO3)22? at 25°C and zero ionic strength are: log βH0 = 1.8, log β10 = 6.82 and log β02 = 10.6. Formation constants of these species appropriate to 0.7 molar ionic strength and 25°C are log βH ~- 1, log β1 = 5.73, log β2 = 9.3. Our results indicate that the inorganic speciation scheme of Cu(II) in seawater is dominated by CuCO30 and that the ternary species, CuCO3OH?, is of substantial importance. 相似文献
82.
Distribution of forms of sulfur in peats from saline environments in the Florida Everglades 总被引:1,自引:0,他引:1
Although there is published information on the mechanism of sedimentary pyrite formation resulting from bacterial reduction of sulfate, little is known about the distribution of forms of sulfur, including organic, in peats. In order to increase understanding of the geochemistry of sulfur in coals, we have determined distributions of forms of sulfur in five cores of saline peat and one of brackish peat, all from areas near the Shark River and Whitewater Bay in the coastal swamps of south Florida. All concentrations vary widely with depth. Total sulfur concentrations range up to 6% of dry solids. Minor amounts of sulfur are present as H2S, S0, SO42−, and acid-soluble sulfide, but the principal forms are usually pyritic and organic. The ratio, organic/pyritic, is highly variable, but at a majority of levels in a profile is considerably greater than unity. It is inferred that topochemical factors are important in determining the distribution of sulfur forms in any element of volume. 相似文献
83.
Molluscan fossils collected from shallow water marine sediment across NW Europe and nearby Arctic regions have been analysed for the extent of isoleucine epimerization (
ratio) in indigenous protein residues. The
ratios confirm that essentially all ‘classical’ Eemian sites from NW Europe are of the same age, and are correlative with the type locality near Amersfoort in the Netherlands; shells from interglacial marine sediment beneath the type Weichselian till in Poland also correlate with the type Eemian site.
ratios in Holsteinian marine shells (0.29) are substantially higher than in their Eemian counterparts (0.17); ‘Late Cromerian’ shells yield even higher ratios (0.46).
ratios in late glacial shells (0.06) and Middle Weichselian shells (0.09) permit differentiation from modern (0.01) and last interglacial material. Based on the position of the Matuyama-Brunhes boundary and the differences in
ratios, the Eemian must correlate with isotope substage 5e, whereas the Holsteinian is most likely substage 7c, possibly stage 9 but certainly younger than stage 11. Intra-Saalian warm periods may be terrestrial equivalents of the younger substages of stage 7. Extensive pre-Eemian marine sediments along the SW coast of Denmark previously correlated with the Holsteinian are shown to be of ‘Late Cromerian’ age. The underlying till there is the first widespread evidence of a pre-Elsterian till in NW Europe.
ratios in molluscs from last interglacial sites along the Arctic coast of the USSR, the Arctic Islands and eastern Greenland are substantially lower than in their European counterparts due to their low thermal histories. The combined mid- and high-latitude data are used to develop a predictive model for the expected
ratio in any of several moderate epimerization-rate taxa for last interglacial sites with mean temperatures between −20 and +15°C.Not all sites could be unambiguously assigned to an established interglacial. The Fjøsanger (Norway) and Margareteberg (Sweden) sites previously thought to be Eemian, yield
ratios higher than in secure nearby Eemian material. It is yet unresolved whether these are aberrant sites or if they predate the last interglacial. In situ shoreline deposits encountered in borings in SW Belgium and in exposures on the Belgium coastal plain contain molluscs that yield
ratios intermediate between secure Eemian and Late Weichselian ratios, raising the possibility that a late stage 5 high-sea-level event attained near-modern levels in the southern North Sea basin. Resolution of these uncertainties is the focus of future work. 相似文献
84.
R. T. Miller 《Ground water》1984,22(5):532-537
The U.S. Geological Survey is studying the potential for storage of heated water in a sandstone aquifer in St. Paul, Minnesota. The efficiency of the aquifer to store thermal energy is related, in part, to the hydrogeologic characteristics of the aquifer. The movement of heat away from the injection well is directly related to the anisotropy. Aquifer tests were conducted to determine the anisotropy near the heated-water injection well. The maximum and minimum values of transmissivity along the principal directions of the hydraulic conductivity tensors of the Ironton and Galesville Sandstones in St. Paul, Minnesota are approximately 1,090 and 480 feet squared per day. The storage coefficient is 4.5 × 10−5. These values represent the average of four determinations of nonsteady flow to a well in an idealized infinite anisotropic aquifer. Analysis of the values of transmissivity and storage coefficient for hypothetical changes in location of two of the monitoring wells where depth-deviation surveys were not available indicates that computed transmissivities vary less than 5 percent and storage coefficients vary less than ±6 percent. 相似文献
85.
86.
A global atmospheric model is used to calculate the monthly river flow for nine of the world's major high latitude rivers for the present climate and for a doubled CO2 climate. The model has a horizontal resolution of 4° × 5°, but the model's runoff from each grid box is quartered and added to the appropriate river drainage basin on a 2° × 2.5° resolution. A routing scheme is used to move runoff from a grid box to its neighboring downstream grid box and ultimately to the mouth of the river. In a model simulation in which atmospheric carbon dioxide is doubled, mean annual precipitation and river flow increase for all of these rivers, increased outflow at the river mouths begins earlier in the spring, and the maximum outflow occurs approximately one month sooner due to an earlier snow melt season. In the doubled CO2 climate, snow mass decreases for the Yukon and Mackenzie rivers in North America and for rivers in northwestern Asia, but snow mass increases for rivers in northeastern Asia. 相似文献
87.
Stanley M. Miller 《Mathematical Geosciences》1983,15(2):317-328
For any specific rock unit in a discontinuous rock mass, the determination of structural domain boundaries is important because geologic and hydrologic properties vary from one domain to another. A domain can be considered as a structural population characterized by a distinct pattern of structure orientations (i.e., fracture, bedding, or foliation orientations).Boundaries are usually determined by comparing samples of structural data, each of which consists of a Schmidt plot that commonly displays at least 150 poles to fractures. When fracture orientations appear dispersed and random on the plots, visual comparisons are not sufficient to determine whether the samples were obtained from the same structural domain. An appropriate x 2 test has been adapted to this situation and is capable of evaluating the homogeneity of structural populations. The method uses a contingency table analysis based on the frequencies of fracture poles that occur in corresponding patches on the Schmidt plots being compared. 相似文献
88.
Field relations, mineralogy and major and trace element data for the very felsic, peraluminous Sweetwater Wash pluton establish a differentiation sequence dominantly controlled by fractional crystallization processes. Elements Ba and Sr show depletion by factors of 50–60X from the earliest granite unit analyzed to the late-stage pegmatites and aplites. The strong Ba depletion is largely due to the partitioning behavior of this element in K-feldspar, while the Sr depletion is due to the combined effects of the two feldspars. The 4-fold increase in Rb during crystallization is also predictable from mineral/ melt partition coefficients.Coefficients for the light rare-earth elements (LREE) in major mineral species predict that these elements should behave incompatibly during crystallization and increase with fractionation. In fact, the LREE abundances decrease by a factor of 10–20X during crystallization. This anomalous behavior is commonly observed in felsic plutonic and volcanic sequences. In the Sweetwater Wash pluton monazite occurs in minute quantities, but it is sufficiently abundant to govern the partitioning of LREE and Th during crystallization. Petrographic observations indicate that monazite was on the liquidus throughout most of the crystallization. Analyses of silicate mineral separates suggest that the monazite contains more than 75% of the LREE in the whole rocks.Fractionation of REE-rich accessories (in particular monazite) from felsic magmas may be the general cause of REE depletion during differentiation of these melts. Monazite can easily be mistaken for zircon and, because it typically contains 50% LREE, extremely minute and easily overlooked quantities of monazite can control LREE abundances. 相似文献
89.
90.
We investigate the estimation of interfacial areas, curvatures, and common curve lengths in multiphase porous medium systems. Algorithms are developed to obtain estimates of these quantities based upon a variety of potential data sources and estimation approaches. The accuracy of the derived approximations are evaluated as a function of the data type and resolution of the data. The methods advanced improve upon standard approaches now in use and show excellent accuracy at resolutions on the order of five lattice points per minimum radius of curvature of the object being resolved. Finally, we suggest a promising class of extensions that could lead to further improvements in the accuracy of such methods. 相似文献