Impact of a Power Plant on the Ground-Water System of a Wetland     

Charles B. Andrews  Mary P. Anderson 《Ground water》1978,16(2):105-111

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The Impact of the Use of Heat Pumps on Ground-Water Temperatures   总被引：1，自引：0，他引：1  

Charles B. Andrews 《Ground water》1978,16(6):437-443

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Field and geochemical data bearing on the development of a mesozoic volcano-tectonic rift zone and back-arc basin in southernmost South America     

Ronald L. Bruhn  Charles R. Stern  Maarten J. De Wit 《Earth and Planetary Science Letters》1978,41(1):32-46

A broad zone of dominantly subaerial silicic volcanism associated with regional extensional faulting developed in southern South America during the Middle Jurassic, contemporaneously with the initiation of plutonism along the present Pacific continental margin. Stratigraphic variations observed in cross sections through the silicic Jurassic volcanics along the Pacific margin of southernmost South America indicate that this region of the rift zone developed as volcanism continued during faulting, subsidence and marine innundation. A deep, fault-bounded submarine trough formed near the Pacific margin of the southern part of the volcano-tectonic rift zone during the Late Jurassic. Tholeiitic magma intruded within the trough formed the mafic portion of the floor of this down-faulted basin. During the Early Cretaceous this basin separated an active calc-alkaline volcanic arc, founded on a sliver of continental crust, from the then volcanically quiescent South American continent. Geochemical data suggest that the Jurassic silicic volcanics along the Pacific margin of the volcano-tectonic rift zone were derived by crustal anatexis. Mafic lavas and sills which occur within the silicic volcanics have geochemical affinities with both the tholeiitic basalts forming the ophiolitic lenses which are the remnants of the mafic part of the back-arc basin floor, and also the calc-alkaline rocks of the adjacent Patagonian batholith and their flanking lavas which represent the eroded late Mesozoic calc-alkaline volcanic arc. The source of these tholeiitic and calc-alkaline igneous rocks was partially melted upper mantle material. The igneous and tectonic processes responsible for the development of the volcano-tectonic rift zone and the subsequent back-arc basin are attributed to diapirism in the upper mantle beneath southern South America. The tectonic setting and sequence of igneous and tectonic events suggest that diapirism may have been initiated in response to subduction.  相似文献   

Ophiolite metamorphism in northeast Borneo     

Charles S. Hutchison 《Lithos》1978,11(3):195-208

The Darvel Bay ophiolite consists of a conformable sequence of mantle harzburgite, a gabbro layer of about 2 km thickness, a basalt layer and associated chert-spilite association of Late Cretaceous to Eocene age, and overlying Miocene melange and olistostrome deposits. The ophiolite is an extension into Borneo of the recently inactive Sulu Archipelago non-volcanic arc. Generally the gabbro layer has been converted to banded plagioclase-amphibole gneisses and the basalt layer to crudely foliated epidote amphibolite. Igneous relicts occur sporadically, especially in the lower gabbro horizons. They have either cumulus granular or gabbroic textures and contain diopsidic augite, bronzite, and a dark brown pargasitic hornblende. The labradorite is occasionally clouded. The partitioning of Fe/Mg between the two pyroxenes and the hornblende suggests an igneous paragenesis and the former allocation of these pyroxene-bearing rocks to the granulite facies is now rejected.The basites have undergone metamorphic re-equlibration, frequently sporadic and imperfec, through amphibolite facies, characterized by hornblende, to greenschist facies, characterized by actinolite. Igneous labradorite frequently persists to the lower grades. The partitioning of Ca/Na between amphibole and plagioclase may be correlated with metamorphic grade.Sub sea-floor retrogressive metamorphism, combined with large scale metasomatism resulting from the circulation of hot brine, appears to be the most appropriate mechanism to explain the sodium enrichment in the basalt layer and the imperfect metamorphic re-equilibration of the ophiolite generally.  相似文献   

Simultaneous determinations of the sensible and latent heat transfer coefficients for tree leaves     

Charles E. Murphy Jr.  Kenneth R. Knoerr 《Boundary-Layer Meteorology》1977,11(2):223-241

The heat and mass transfer coefficients for exchange across the fluid dynamic boundary layer over tree leaves were simultaneously determined in a controlled environment chamber. The mass transfer coefficients were calculated from measured values of evaporation, air specific humidity and a value of leaf specific humidity at leaf temperature. The heat transfer coefficients were calculated from measured values of air temperature, leaf temperature and an estimate of the sensible heat flux density calculated as the measured net radiation at the leaf surfaces minus the latent heat flux density. The experiments described in this paper indicate that the equations based on laminar boundary-layer theory can give reasonable estimates of the transfer coefficients of real tree leaves for the velocities most commonly experienced in plant canopies, if they are adjusted by a constant multiplier greater than one. Calculations of local mass transfer coefficients based on temperature measurements at three locations at different distances from the leading edge of the leaves, indicate that the deviation from theory is probably the result of transition to turbulent boundary-layer flow at some distance from the leading edge.  相似文献   

Distribution of viral and bacterial pathogens in a coastal canal community     

Charles P. Gerba  Sagar M. Goyal  Eric M. Smith  Joseph L. Melnick 《Marine pollution bulletin》1977,8(12):279-282

Significant concentrations of human enteric viruses and bacteria were found to be present in the water and sediment of a coastal canal community into which secondarily treated sewage was being discharged.  相似文献   

Electron microprobe analysis of glass shards from tephra assigned to set W,Mount St. Helens,Washington     

Henry W. Smith  Rose Okazaki  Charles R. Knowles 《Quaternary Research》1977,7(2):207-217

We have extended the fallout areas for each of two members of tephra-set W, erupted from Mount St. Helens about 1500 ad, by several hundred kilometers beyond the limits mapped in 1975. We traced one member (We) east into Idaho, and the other (Wn) northeast into British Columbia. After using stratigraphic and petrographic observations to assign more than 100 tephra samples to set W, we found 26 of these, selected for chemical analysis, to be closely similar in content of Ca, Fe, and K in glass shards. But improved homogeneity was evident when the 26 sampling localities for tephra W were segregated geographically, east vs. northeast of the volcano. When Ca:Fe:K proportions were plotted on a ternary diagram, there was no overlap of the plotting areas for these two groups of tephra W samples. Without such data, tephra layers We and Wn are currently separable only from stratigraphic and geographic information. Partial glass analysis is also an aid, along with stratigraphic position and petrographic characteristics, in distinguishing tephra W from associated tephra layers. These include tephra layers T and Yn from Mount St. Helens, as well as older tephra layers from Mount Mazama and Glacier Peak.  相似文献   

Electron microprobe data for tephra attributed to Glacier Peak,Washington     

Henry W. Smith  Rose Okazaki  Charles R. Knowles 《Quaternary Research》1977,7(2):197-206

Reference samples of three prominent pumice units of Glacier Peak tephra collected east of the volcano within a distance of 100 km are similar petrographically to units described by earlier workers. Glass shards isolated from these samples were analyzed by electron microprobe to determine the content of Ca, Fe, and K. Resulting data, plus those published for two other references samples, provide a basis for attributing certain outlying tephra layers from 14 locations in eastern Washington, Idaho, Wyoming, and Montana to eruptions of Glacier Peak. Ten of the samples have properties of both Glacier Peak tephra and Mount St. Helens set J tephra, but proportions of Ca:Fe:K in glass shards indicate that 9 of the 10 outlying samples came from Glacier Peak, whereas one is assigned to Mount St. Helens set J. The remaining six outlying samples, all from southeastern Washington, contain cummingtonite phenocrysts and are chemically similar to some parts of Mount St. Helens tephra sets that are older than 12,000 BP.  相似文献   

The effect of intrinsic model noise upon resistivity inversion     

Richard Barakat  Charles H. Stoyer 《Pure and Applied Geophysics》1980,119(4):841-853

Model uncertainty is introduced into direct-current resistivity data by adding random changes to layer thicknesses in a ten-layer model. The resulting information is then aliased by generating a sounding curve which contains less information than the ten resistivities and nine thicknesses. These sounding curves are then inverted via the Backus-Gilbert algorithm using singular value decomposition to obtain solutions in terms of simpler two-or three-layer models. Quantitative results confirm what has been known qualitatively for many years as the principle of equivalence. An interesting result is that the geometric average of a given suite of noisy models is virtually identical to the best-fit model for the average of the noisy curves. The results show that the inversion of resistivity data by nonlinear least-squares parameter fitting is stable in the sense that noise in the data inverts to the same magnitude of noise in the model.  相似文献   

Morphometric analysis of cinder cone degradation   总被引：2，自引：0，他引：2  

Charles A. Wood   《Journal of Volcanology and Geothermal Research》1980,8(2-4)

Measurements of Vie geometry of cinder cones can be used to determine the morphological effects and rates of degradation. Cinder cones in the San Francisco volcanic field, Arizona (where radiometric dates and stratigraphic studies have determined cone ages) decrease in height, height/width ratio and slope through time. The ratio of crater diameter to cone basal diameter does not appear to change with degradation, nor, as suggested previously, with chemical composition or particle size. Similar results obtained for cinder cones in Nevada, Oregon, Manchuria, Italy and Reunion suggest that the morphometric patterns of degradation are similar for all cinder-cones. The rates of degradation vary tremendously however, with rainfall and temperature being perhaps the most important factors. Since the initial geometries of cinder cones are remarkably similar, degraded cones may be ideal gauges of long-term climatic change.Degradation can be readily modelled for two cases: burial of cinder cone flanks by subsequent lava flows, and erosion and mass wasting. Although the former is locally important, degradation appears to occur principally by the second process: cinders weather to clay, which is gullied by rainfall, with the debris sliding downslope. Such erosion and mass wasting produces a degradation curve in general agreement with observations. Erosion rates can be accelerated orders of magnitude, however, by the mantling of old cones with easily eroded ash deposited during nearby eruptions. Comparison of cinder zone isopach radii and cone separation distances suggests it to be a common effect.  相似文献