P-Wave Scattering in the Earth's Crust and Upper Mantle     

J. R. Cleary  D. W. King  R. A. W. Haddon 《Geophysical Journal International》1975,43(3):861-872

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CHONDRULE VOLUME PERCENTS: STATISTICAL BEHAVIOR AND VISUAL-ESTIMATION GUIDES PRODUCED BY NUMERICAL SIMULATION     

A. Woronow  E.A. King 《Meteoritics & planetary science》1985,20(1):103-112

Estimates of the volume percents of chondrules in petrographic thin sections are notoriously unreliable, ranging widely among different observers for the same meteorite or even for the same thin section. The set of visual-estimation guides presented herein should help narrow the uncertainties in such estimates and lead to a more consistent picture of chondrule abundances than is now apparent from the literature. In generating this set of guides other quantitative measures were also retained and examined. First, the expected error in the volume abundance of chondrules, due solely to sampling of homogeneous rocks by random thin sections, decreases as the inverse of the volume abundance of the chondrules. Second, our experiments of “softly” settled chondrules could not exceed chondrule abundances of 60 vol %. If chondrule-bearing rocks are found to exceed this value, the physical environment where they accreted must have had a greater gravity field than is available on asteroid-size bodies.  相似文献   

Evaluation of throughflow interceptors for controlling secondary soil and water salinity in dryland agricultural areas of southwestern Australia : II. Hydrological study     

A.J. Conacher  S.D. Neville  P.D. King 《Applied geography (Sevenoaks, England)》1983,3(2):115-132

Short-term hydrological measurements at one site show that throughflow provided the dominant input of water but not of soluble salts to the salt-affected land. Interceptors will therefore reduce saltland waterlogging caused by inputs of throughflow from valley sides. Leakages through and beneath the monitored interceptors are problems which are partly attributable to incorrect design and construction, and partly to unfavourable soil properties.The salinity of deeper groundwaters was also too low to account for the quantities of soluble salts being exported from the site. This finding suggests that a proportion of the salts accumulated in situ and have only recently been mobilized within the site by increased inputs of fresh throughflow and relatively fresh groundwaters from the catchment of the salt-affected area.Control of deeper groundwater movements as well as throughflow is probably necessary in most locations, but the precise combinations in different situations, and the most appropriate techniques for controlling these water movements, require further research. Increased groundwater discharges are attributed to reduced transpiration by the replacement of deep-rooted, indigenous vegetation with shallow-rooted, seasonally growing exotic crops and pastures, rather than to increased groundwater recharge. The ideal method of controlling both water systems is likely to involve farm management strategies on saltland catchments, employing commercially useful vegetation which simulates the hydrological role of the native species, in conjunction with improvement of soil properties.  相似文献   

THE INMAN,McPHERSON COUNTY,KANSAS METEORITE     

Klaus Keil  Gayle Lux  D.G. Brookins  Elbert A. King  Trude V.V. King  Eugene Jarosewich 《Meteoritics & planetary science》1978,13(1):11-22

Inman (find, 1966) is a single, relatively unweathered stone of 7.25 kg that contains fresh metal and only few weathering products away from fractures. It has a pronounced chondritic texture, with 38 vol % of the meteorite being made up of chondrules of virtually all textural types. The recalculated bulk analysis, particularly the ratios of Fe_total/SiO₂ (0.46), Fe°/Fe_total (0.35), and Fe°/Ni° (6.67) and the contents of Fe_total (19.45%) and metallic nickel-iron (7.94%), indicate that Inman is an L-group chondrite. The pronounced chondritic texture; the compositional variabilities of olivine, pyroxene, chromite, and ilmenite; the presence of a fine-grained, nearly opaque matrix, glass and twinned monoclinic low-Ca pyroxene indicate that the chondrite belongs to petrologic type 3.  相似文献   

THE DEL RIO ATAXITE,TEXAS     

Edward P. Henderson  Elbert A. King 《Meteoritics & planetary science》1977,12(1):1-12

Del Rio is a new ataxite from Texas that is not related to either Monahans or Nordheim, the only previously known ataxites from Texas. Del Rio has a nickel content of approximately 12.9 weight percent, apparently has been shocked prior to its fall, and contains minor inclusions of daubreelite, schreibersite and troilite.  相似文献   

Oil and gas in offshore tracts: Bias in estimates of reserves     

L. A. Thomsen  Matt Joggerst 《Mathematical Geology》1985,17(4):353-365

Two independent data sets show that current means of estimating reserves of oil and gas in offshore fields are biased. The bias which is established here is that small fields (with less than about 10 million barrels of oil equivalent) are overestimated, and larger fields (at least up to 200 MMBOE) are underestimated. This systematic bias occurs with or without a significant overall bias, and in addition to a large scatter. Because bias (as opposed to scatter) has serious implications for national energy policy, and in particular for conduct of offshore lease sales, these results indicate that evaluation methods should be revised, or that ad hoc adjustments (based on historical data) should be applied.  相似文献   

Origin and history of chondrite regolith,fragmental and impact-melt breccias from Spain     

I. Casanova  K. Keil  R. Wieler  A. San Miguel  E. A. King 《Meteoritics & planetary science》1990,25(2):127-135

Abstract— Six ordinary chondrite breccias from the Museo Nacional de Ciencias Naturales, Madrid (Spain), are described and classified as follows: the solar gas-rich regolith breccia Oviedo (H5); the pre-metamorphic fragmental breccias Cabezo de Mayo (type 6, L-LL), and Sevilla (LL4); the fragmental breccias Cañellas (H4) and Gerona (H5); and the impact melt breccia, Madrid (L6). We confirm that chondrites with typical light-dark structures and petrographic properties typical of regolith breccias may (Oviedo) or may not (Cañellas) be solar gas-rich. Cabezo de Mayo and Sevilla show convincing evidence that they were assembled prior to peak metamorphism and were equilibrated during subsequent reheating. These meteorites contain small melt rock clasts that were incorporated into the host chondrite while still molten and/or plastic and cooled rapidly and, yet, are totally equilibrated with their hosts. Compositions of olivine and low-Ca pyroxene in host chondrite and breccia clasts in Cabezo de Mayo are transitional between groups L and LL. It is suggested, based on mineralogic and oxygen isotopic compositions of host and clasts, that the rock formed on the L parent body by mixing, prior to peak metamorphism. This was followed by partial equilibration of two different materials: the indigenous L chondrite host and exotic LL melt rock clasts.  相似文献   

Earthquake hydrology and chemistry     

Chi-Yu King 《Pure and Applied Geophysics》1984,122(2-4):141-142

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The kinematics of gouge deformation   总被引：13，自引：0，他引：13  

Charles Sammis  Geoffrey King  Ronald Biegel 《Pure and Applied Geophysics》1987,125(5):777-812

The methods and first results of a new approach to examining fault gouge are described. Samples of undisturbed fault gouge from the exhumed Lopez fault zone in the San Gabriel Mountains, California were impregnated with low viscosity epoxy resin and sectioned to produce microscope slides. The slides were photographed using optical and electron microscopy with magnifications ranging in factors of 2 from 12.5 to 1600. At all scales, the particles appeared angular with planar faces, suggesting tensile failure. No shear zones were discernable. The particle size distribution was studied. At each magnification the particles were sorted by diameter into four classes, differing in mean diameter by factors of 2. The numbers in each class were then scaled by the characteristic class dimension. The process revealed a remarkable degree of self-similarity. Over the range examined, the fractal dimension was within 5% of 2.60.On the basis of the observations, a new model for the mechanical processes that generate gouge is offered. It is argued that self-similarity results from repeated tensile splitting of grains. Unlike earlier models that consider splitting probability to be either independent of particle size or due to the preexisting distribution of defects, we propose that failure probability depends largely on the relative size of nearest neighbors. If nearest neighbors of the same size are preferentially broken, any initial distribution of particles will tend toward a self-similar distribution having a fractal dimension of 2.58.The model allows us to outline a procedure whereby the observed comminution in a fault zone can be related to the shear strain that the zone has accommodated and propose a theoretical frequency magnitude relation for the seismic energy emitted by the fracture process.  相似文献   

The neotectonics of the Aegean: An alternative view     

J.A. Jackson  G. King  C. Vita-Finzi 《Earth and Planetary Science Letters》1982,61(2):303-318

Flow directions are estimated from the measurement of the magnetic fabric of 106 samples, collected at 18 sites in four welded tuff units in the central San Juan Mountains of southern Colorado. The estimates assume that the tuffs generally flowed directly away from the extrusive vents and that the lineations of magnetic grains within the tuffs represent the flow direction at individual sites. Errors in the estimation may arise from topographic variation, rheomorphism (post-emplacement mass flow) within the tuff, and other factors. Magnetic lineation is defined as the site mean anisotropy of magnetic susceptibility maximum azimuth. A test on the flow directions for individual units is based on the projection of lineation azimuths and their intersection within or near the known source caldera for the tuff. This test is positive for the four units examined. Paleomagnetic results for these tuffs are probably reliable indicators of the geomagnetic field direction in southwest Colorado, during the time (28.2–26.5 Ma) of emplacement.  相似文献