Unburned coal as a source of hydrocarbons in surface sediments     

Bruce W. Tripp  John W. Farrington  John M. Teal 《Marine pollution bulletin》1981,12(4):122-126

The isolation and quantification of the various sources of trace levels of hydrocarbons in environmental samples is a difficult analytical task. Based on the hydrocarbon concentrations found in non-polluted surface sediment and an estimate of the amounts of coal particles found in similar areas we conclude that unburned coal can be a significant source of sediment hydrocarbons in the coastal marine environment.  相似文献   

Prediction of limestone solution rates from rainfall and runoff data: Some comments     

John Gunn 《地球表面变化过程与地形》1981,6(6):595-597

Recent work by Láng (1977) on solutional erosion rates in limestone drainage basins in relation to rainfall contains serious errors and has a questionable logical basis. Although much sounder, Smith and Atkinson's (1976) work on erosion rates in relation to runoff also requires modification as it greatly overestimates erosion rates in two areas of New Zealand. Greater resolution could probably be obtained by relating autogenic runoff to the rate of solution by autogenic waters and by computing separate relationships for areas where solution takes place under open and closed system equilibrium conditions. These factors should be taken into account in the experimental design of future studies.  相似文献   

Creep,stable sliding,and premonitory slip   总被引：3，自引：0，他引：3  

John M. Logan 《Pure and Applied Geophysics》1978,116(4-5):773-789

Summary The current status of laboratory investigations into creep, stable sliding and premonitory slip is reviewed and some new material is presented. It is postulated that pre-cut rocks and those with simulated gouge layers undergo a transition with increasing confining pressure from (1) stable sliding to stick-slip, to (2) sliding along the pre-cut with deformation of the country rock, to (3) homogeneous flow of the specimen without slip along the pre-cut. Stick-slip behavior is not always present. Decreasing displacement rates are found to enhance stick-slip. Mixtures of gouge are found to be significant in controlling the behavior of sliding with 10–20 percent of anhydrite mixed with quartz or clays mixed with anhydrite shifting the sliding mode from stable stick-slip or stick-slip to stable sliding, respectively. Premonitory slip may be one of the most significant short term precursors of earthquakes. Although widely recognized in the laboratory, little systematic work has been completed. Variations in pore pressure, resistivity and seismic velocities have been investigated. Clearly much work needs to be done into these topics before a clear understanding is achieved.  相似文献   

A near-bottom geophysical traverse of the Reykjanes Ridge     

John S.F. Shih  Tanya Atwater  Marcia McNutt 《Earth and Planetary Science Letters》1978,39(1):75-83

We report here the results of a near-bottom geophysical survey of the Reykjanes Ridge, a mid-ocean ridge that is oriented obliquely to the perpendicular spreading direction. From a combination of the bathymetric profiles, side-scan sonar data, and regional bathymetric maps we infer that the present center of spreading is made up of a number of N15°E-trending en echelon ridge segments in the southern half of our survey area. Insufficient data prevent the identification of the spreading pattern in the northern half. The side-scan records show that the ridge flanks are highly fractured by inward-facing faults displaced 40 m or less and trending in a N21°E direction. The lack of side-scan features parallel to the spreading direction except in the southernmost portion of the survey area suggests that the ridge segments are not connected by transform faults in the usual sense. Although the mechanism by which en echelon ridge segments can be maintained during sea-floor spreading over time is unclear, similar patterns of crustal accretion have been reported on Iceland. It appears that the accretionary processes along the Reykjanes Ridge are more related to those of Iceland than to those of typical mid-ocean ridges.  相似文献   

Holocene tidal sedimentation. Edited by George de Vries Klein,Benchmark Papers in Geology, 30. Dowden,Hutchinson and Ross Inc. Stroudsburg,Pennsylvania. No. of pages: 423. Price: £22.00/U.S. $36.90     

John Hails 《地球表面变化过程与地形》1978,3(1):103-103

  相似文献   

Metal binding capacity of selected maine surface waters     

John P. Giesy Jr.  Linda A. Briese  Gordon J. Leversee 《Environmental Geology》1978,2(5):257-268

Concentrations of Ca, Cd, Cu, Fe, and Pb and binding capacities for Cd, Cu, and Pb were determined for water samples collected from 12 lakes in southwestern Maine using atomic absorption and ion-selective electrodes, respectively. Surface waters in this area are soft and characterized by low pH. Some lakes were highly colored with refractory organics, whereas others had very low organic carbon concentrations. Both Cu and Pb concentrations were positively correlated with organic carbon content. Copper and Pb binding capacities were significantly correlated with organic carbon content, whereas Cd binding capacity was positively correlated with pH, but not with organic carbon. Surface water binding capacity for Pb was greater than that for Cu or Cd. More than 99% of the Ca from all waters studied was removed onto cationic exchange resins. Less than 1% of the total Cu existed as cationic species in highly humic waters, whereas as much as 65% existed as cationic species in less huic waters. Conversely, more than 99% of the Cd present in humic waters existed as cationic species, whereas as little as 50% existed as cationic species in less humic, more alkaline waters. These correlative studies indicate that binding by organic carbon is important for both Cu and Pb in this area and must be considered in models of trace metal speciation. However, Cd binding in the same waters is not correlated with organic carbon, which does not need to be considered in speciation models for Cd.  相似文献   

Geologic mapping for coastal zone planning in California—Background and examples     

John W. Williams  Trinda L. Bedrossian 《Environmental Geology》1978,2(3):151-163

With increasing pressure for development on one of California's greatest natural resources, her coastline, comprehensive land-use planning becomes a necessity. One aspect of land-use planning is effective geologic mapping for the delineation of geologic hazards. Geologists from the California Division of Mines and Geology undertook an evaluation of the feasibility of local government implementation of the geologic policies in the 1975 California Coastal Plan, a plan designed to facilitate and direct comprehensive coastal land-use planning. Operating under restrictions similar to those that would be encountered by local agencies attempting to implement the policies, the Division of Mines and Geology personnel applied the geologic guidelines to two areas in Mendocino County on the northern coast of California. Using limited data and reconnaissance mapping techniques, reports and maps were prepared which delineated the geologic hazards that should be considered in coastal land-use planning. It was apparent from the two studies that the types and detail of data required for the implementation of the geologic policies of the Coastal Plan could be developed by local agencies only by augmenting their staffs to include trained geologists or by using the services of outside consultant geologists. Paper based on data collected for California Division of Mines and Geology Open-File Reports.  相似文献   

Geologic assessment of environmental impact in Lake Macatawa,Michigan     

John B. Anderson  Richard Wheeler  Charles P. Dunning  Sue Shepley  Marion Fowke 《Environmental Geology》1978,2(2):67-78

A historical record of the effects of human development upon Lake Macatawa is established using geologic criteria. Significant cultural events are recognized using the pollen record, particularly ambrosia/vesiculate pollen ratios, and occurrences of detrital and chemical contaminants within the more recent sedimentary column. Detrital contaminants include such things as cinder and ash from coal burning power plants and animal hair from early tanning operations. Trace metal contaminants, frequently associated with specific industrial events, are particularly useful in establishing a modern sedimentary chronology. The impact of human activity upon Lake Macatawa is measured using fossil diatoms. The advantage of this method of environmental impact assessment is that it provides a historical perspective in which changes within an environment are related to its natural conditions.  相似文献   

Uplift rates of the Loyalty Islands as determined by ${}^{230}\text{Th}{}^{234}\text{U}$ dating of raised coral terraces     

John F. Marshall  Jean Launay 《Quaternary Research》1978,9(2):186-192

Uplift rates of the Loyalty Islands (S.W. Pacific) have been determined from ${}^{230}\text{Th}{}^{234}\text{U}$ dating of raised coral terraces standing 2 to 7.5 m above sea level. The ages of the terraces on Ouvéa and Lifou correspond closely to previously documented periods of high sea levels at 120,000 and 180,000 yr BP. A +2-m terrace on Beautemps-Beaupré is considered to be beyond the range of the dating technique. The uplift rates of the various islands show a decrease toward the west. This lends support to the hypothesis of a lithospheric bulge of the leading edge of the Australian plate prior to its subduction at the level of the New Hebrides trench.  相似文献   

Reviews     

J. E. Robinson  John H. Doveton  D. F. Merriam 《Mathematical Geosciences》1975,7(2):185-189

  相似文献