Noble gas and carbon abundances of the Haverö, Dingo Pup Donga,and North Haig ureilites     

D.D. Bogard  E.K. Gibson  D.R. Moore  N.L. Turner  R.B. Wilkin 《Geochimica et cosmochimica acta》1973,37(3):547-557

Total carbon determinations on the Haverö, Dingo Pup Donga, and North Haig ureilites yield values of 2.07, 3.17, and 5.58 wt.%, respectively. Haverö and Dingo Pup Donga contain relatively large amounts of trapped Ar, Kr and Xe, which like the carbon content varies with grain size for Haverö. These two meteorites also contain dominant cosmic rayproduced He and Ne, and show ³He exposure ages of ~23 m.y. and ~7 m.y., respectively. North Haig contains much smaller amounts of trapped gases and spallogenic gases, which may result from loss due to terrestrial weathering. The isotopic composition of Xe in five grain size analyses of Haverö and a whole rock analysis of Dingo Pup Donga shows the presence of a major solar-like Xe component. The presence of this solar component adds an additional complication to the concept of forming ureilites from carbonaceous chondrites.  相似文献   

Late Pleistocene-Holocene oceanographic changes in the Northeastern Pacific     

Ted C. Moore 《Quaternary Research》1973,3(1):99-109

The distributions of the radiolarian assemblages in the Northeastern Pacific Ocean were determined and correlated with the average summer temperature of the near surface waters of this region. These assemblages were compared with those in three sediment cores taken beneath the Transition Zone waters. This comparison indicates that the assemblage off Oregon at the last maximum cold interval (24,000 yr B.P.) was like that now found off southern Alaska. The correlation of the radiolarian assemblages with temperature gives an estimate of 11°C for the average summer temperature at that time. This is approximately 4°C cooler than present day conditions in the area. Superimposed on the general warming trend that began 24,000 y.a., there are minor oscillations in the assemblages which correspond to estimates of temperature change of about 2°C in the Pleistocene and about 1°C in the Holocene. In the Holocene, these minor warm intervals appear to be approximately synchronous with advances in mountain glaciers.  相似文献   

The impact of seasonality on multi-scale feature extraction techniques     

Brian Moore  Jacob J. McKee 《International Journal of Digital Earth》2020,13(1):9-21

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Short gravity and capillary wave spectra from tower-based radar     

Lawner  R. Moore  R. 《Oceanic Engineering, IEEE Journal of》1984,9(5):317-324

Radar backscatter measurements made as part of Project MARSEN in 1979 from the Noordwijk tower off the Dutch coast are used to calculate apparent ripple (capillary and short-gravity wave) spectra by inverting the small-perturbation scattering theory. The measurements were made at 10 and 15 GHz for angles of incidence ranging from20degto70deg; this means that the range of Bragg-resonant spatial wavenumbers covered is from 1.43 to 5.90 cm^-1. Results of coincidentC- andX-band experiments by the Institute Francais du Petrole (IFP) andX-band experiments by a group of Dutch researchers (TNO) are compared with our results and good general agreement is found. Our initial results show a steeper falloff of the spectra with increasing wavenumber than reported previously, particularly at low windspeeds. When the spectra are modified to account for the difference between previous aircraft and tower measurements [1], the observed spectra agree well with the appropriate part of Pierson's wave spectrum as modified by Fung and Lee [2].  相似文献   

THE WILLOWBAR METEORITE*     

David E. Lange  Carleton B. Moore  Kendall Rhoton 《Meteoritics & planetary science》1973,8(3):263-275

The Willowbar, Oklahoma meteorite was found by Kendall Rhoton in December, 1971, lat 36° 44′ N.; long 102° 12′ W. It is a shocked brecciated L6 chondrite (Fa-24.3) with large black veins cutting areas of normal chondritic texture. It weighed 2.07 kg.  相似文献   

Explicit formula for the geoid-quasigeoid separation   总被引：1，自引：0，他引：1  

R. Tenzer  P. Novák  P. Moore  M. Kuhn  P. Vaníček 《Studia Geophysica et Geodaetica》2006,50(4):607-618

The explicit formula for the geoid-to-quasigeoid correction is derived in this paper. On comparing the geoidal height and height anomaly, this correction is found to be a function of the mean value of gravity disturbance along the plumbline within the topography. To evaluate the mean gravity disturbance, the gravity field of the Earth is decomposed into components generated by masses within the geoid, topography and atmosphere. Newton’s integration is then used for the computation of topography-and atmosphere-generated components of the mean gravity, while the combined solution for the downward continuation of gravity anomalies and Stokes’ boundary-value problem is utilized in computing the component of mean gravity disturbance generated by mass irregularities within the geoid. On application of this explicit formulism a theoretical accuracy of a few millimetres can be achieved in evaluation of the geoid-to-quasigeoid correction. However, the real accuracy could be lower due to deficiencies within the numerical methods and to errors within the input data (digital terrain and density models and gravity observations).  相似文献   

Two dimensional transient fundamental solution due to suddenly applied load in a half-space     

F. Guan  I.D. Moore  C.C. Spyrakos 《Soil Dynamics and Earthquake Engineering》1998,17(4):269-277

A transient Green function due to suddenly applied line loads in an isotropic and homogeneous half-space is reported in this paper. The derivation of the half-space Green function in the Laplace and the Fourier transform spaces is first reviewed. Following an explicit inversion of the Fourier transform, the inverse Laplace transform is implemented along the contour integral on the p-complex plane in an integral form. The half-space Green function consists of full-space Green functions and a singularity-free complementary term. It can be easily incorporated into current transient boundary elements using the transient full-space Green function. Combined with finite elements, the half-space Green function can be used in a hybrid procedure to solve transient half-space problems without discretization of the free surface. Numerical results are presented to illustrate transient wave propagation in a half-space.  相似文献   

Application of226Ra,228Ra,223Ra, and224Ra in coastal waters to assessing coastal mixing rates and groundwater discharge to oceans     

Willard S. Moore 《Journal of Earth System Science》1998,107(4):343-349

The fate of dissolved material delivered to the coastal ocean depends on its reactivity and the rate at which it is mixed offshore. To measure the rate of exchange of coastal waters, we employ two short-lived radium isotopes,²²³Ra and²²⁴Ra. Along the coast of South Carolina, shore-perpendicular profiles of²²³Ra and²²⁴Ra in surface waters show consistent gradients which may be modeled to yield eddy diffusion coefficients of 350–540 m²s⁻¹. Coupling the exchange rate with offshore concentration gradients yields estimates of offshore fluxes of dissolved materials. For systems in steady state, the offshore fluxes must be balanced by new inputs from rivers, groundwater, sewers or other sources. Two tracers that show promise in evaluating groundwater input are barium and²²⁶Ra. These tracers have high relative concentrations in the fluids and low-reactivity in the coastal ocean. Applying the eddy diffusion coefficients to the offshore gradient of²²⁶Ra concentration provides an estimate of the offshore flux of²²⁶Ra. Measuring the concentrations of²²⁶Ra in subsurface fluids provides an estimate of the fluid flux necessary to provide the²²⁶Ra. These estimates indicate that the volume of groundwater required to support these fluxes is of the order of 40% of the surface water flow.  相似文献   

Mid-infrared imaging of WL 16: the spatial distribution of the hydrocarbon emission features     

Moore  Emerson  Skinner  Meixner  Arens  & Jernigan 《Monthly notices of the Royal Astronomical Society》1998,299(4):1209-1214

We present arcsec-resolution images at 8.2, 10.0 and 11.3 μm of the unusual young object WL 16 in Ophiuchus, which has an extended envelope of fluorescing hydrocarbon molecules. To the limit of achieved sensitivity, the faint 10.0-μm continuum has a surface-brightness distribution that is not distinguishable from those at 8.2 and 11.3 μm, where the luminosity is known to be dominated by the polycyclic aromatic hydrocarbon (PAH) emission features. We conclude that the 10-μm continuum either arises from non-equilibrium heating of small dust grains that are well mixed with the hydrocarbons or is quasi-continuous emission from the PAH particles themselves, rather than thermal equilibrium emission from macroscopic dust grains, and that there is no significant silicate absorption variation across the source. The extended hydrocarbon emission may trace a flattened, equatorial distribution of circumstellar material or arise in bipolar lobes. The former case is slightly favoured, based on currently available data, and would imply that WL 16 is a relatively evolved Herbig Ae star, the equatorial plane of which has been almost cleared of normal dust, leaving only fluorescing hydrocarbons and larger coagulated particles as a possibly transient fossil of the original circumstellar disc.  相似文献   

Influence of an americium solid phase on americium concentrations in solutions     

Dhanpat Rai  R.G. Strickert  D.A. Moore  R.J. Serne 《Geochimica et cosmochimica acta》1981,45(11):2257-2265

Americium-241 concentrations in solutions contacting contaminated sediments for up to 2 yr were measured as a function of pH. Steady-state concentrations were reached within a few days. The solubility-limited Am concentration was found to decrease approximately 10-fold with one unit increase in pH. The log equilibrium constant for the solubility of Am_(soil) solid $\text{[Am}{}_{\mathrm{(soil)}}\text{+ H}{}^{\mathrm{+}}\text{? Am}{}_{\mathrm{(aq\; complex)}}{}^{\mathrm{+}}\text{]}$ was found to be ?4.12. The predictions based upon thermodynamic data suggest that Am_{(aq complex)}⁺ is likely to be Am(OH)₂⁺. Although the chemical formula of Am_(soil) was not determined, it does not appear to be Am(OH)₃(a).Published data on sorption coefficients of Am by different rocks, soils, and minerals were critically evaluated. Final Am solution concentrations calculated from the sorption coefficients of a variety of earth materials with several solutions agreed well with the concentrations predicted from the solubility of Am_(soil) solid, indicating that the sorption coefficient data are controlled by Am precipitation.  相似文献