Attenuation of multiphase surface waves in the Basin and Range Province—III. Inversion for crustal anelasticity     

Brian J. Mitchell  Jia-kang Xie 《Geophysical Journal International》1994,116(2):468-484

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The St George Basin environment and possible consequences of planned offshore oil and gas development, 1982: Proceedings of a ‘Synthesis Meeting’, Anchorage,Alaska, April 1981. M. J. Hameedi (ed.). Office of Marine Pollution Assessment,N.O.A.A. Publication No. 247, 162pp     

Brian Dicks 《Marine pollution bulletin》1983,14(9):361-362

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An Early Pleistocene cold marine episode in the North Sea: pollen and faunal assemblages at Covehithe, Suffolk, England     

Richard O. West  Brian M. Funnell  Peter E. P. Norton 《Boreas: An International Journal of Quaternary Research》1980,9(1):1-10

Pollen spectra indicating grass-heath with Empetrum are recorded from a c. 2 m thick Baventian marine clay bed at Covehithe, Suffolk, deposited in a sublittoral to intertidal environment. For the first time arctic assemblages of both foraminifers and molluscs are recorded from this Baventian clay, which is now confirmed as representing the first cold stage of truly glacial intensity in the English marine Early Pleistocene succession.  相似文献   

The condensation origin of zoned metal grains in Queen Alexandra Range 94411: Implications for the formation of the Bencubbin‐like chondrites     

Mikhail I. PETAEV  Anders MEIBOM  Alexander N. KROT  John A. WOOD  Klaus KEIL 《Meteoritics & planetary science》2001,36(1):93-106

Abstract— Thermodynamic analysis of the compositional profiles across large chemically‐zoned Fe, Ni metal grains in the Bencubbin‐like chondrite Queen Alexandra Range (QUE) 94411 suggests that these grains formed by non‐equilibrium gas‐solid condensation under variable oxidizing conditions, isolation degree, and Cr depletion factors. The oxidizing conditions must have resulted from the complete vaporization of nebular regions with enhanced dust/gas ratios (～ 10–40 × solar). Because the origin of each of the metal grains studied requires different condensation parameters (dust/gas ratio, isolation degree, and Cr depletion factor), a high degree of heterogeneity in the formation region of the Bencubbin‐like chondrite metal is required. To preserve compositional zoning of the metal grains and prevent their melting and sulfidization, the grains must have been removed from the hot condensation region into cold regions where the accretion of the Bencubbin‐like asteroidal body took place.  相似文献   

Three-dimensional modelling and inversion of dc resistivity data incorporating topography – II. Inversion     

Thomas Günther  Carsten Rücker  Klaus Spitzer 《Geophysical Journal International》2006,166(2):506-517

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Hypothesis grids: improving long baseline navigation for autonomous underwater vehicles     

Brian Bingham Seering  W. 《Oceanic Engineering, IEEE Journal of》2006,31(1):209-218

Navigation continues to fundamentally limit our ability to understand the underwater world. Long baseline navigation uses range measurements to localize a remote vehicle using acoustic time-of-flight estimates. For autonomous surveys requiring high precision navigation, current solutions do not satisfy the performance or robustness requirements. Hypothesis grids represent the survey environment capturing the spatial dependence of acoustic range measurement, providing a framework for improving navigation precision and increasing the robustness with respect to non-Gaussian range observations. Prior association probabilities quantify the measurement quality as a belief that subsequent observations will correspond to the direct-path, a multipath, or an outlier as a function of the estimated location. Such a characterization is directly applicable to Bayesian navigation techniques. The algorithm for creating the representation has three main components: Mixed-density sensor model using Gaussian and uniform probability distributions, measurement classification and multipath model identification using expectation-maximization (EM), and grid-based spatial representation. We illustrate the creation of a set of hypothesis grids, the feasibility of the approach, and the utility of the representation using survey data from the autonomous benthic explorer (ABE).  相似文献   

Exospheric zonal winds between 540 and 620 km from the orbit of Explorer 24     

Peter W. Blum  Klaus G.H. Schuchardt 《Planetary and Space Science》1976,24(6):529-539

Data on the variation of the orbital inclination of the balloon satellite Explorer 24 (1964-76A) from 1964 to 1968 have been used to determine zonal winds between 540 and 620 km. In this height region the effect of zonal winds on the orbital inclination may become very small compared to other perturbations like accelerations due to the geopotential, lunisolar gravitation and the solar radiation pressure. It is demonstrated especially that the solar radiation pressure may become the most significant force changing the orbital inclination. The diurnal mean zonal winds derived from Explorer 24 point to an exospheric rotation rate which is about 6–10% less than the rotation rate of the Earth in the analyzed height region. Since the possible errors of the data analysis are of a similar order of magnitude, it can not be excluded that the exosphere corotates with the Earth. Furthermore, a local time dependence of the zonal winds could be detected. The diurnal varitation of the zonal wind is shown to be in good agreement with the theoretical model of Blum and Harris. Our results are discussed and compared with all previous investigations of orbital inclination changes of satellites above 350 km.  相似文献   

IMPLICATIONS OF POIKILITIC TEXTURES IN LL-GROUP CHONDRITES     

R.V. Fodor  Klaus Keil 《Meteoritics & planetary science》1975,10(4):325-339

Lithic fragments in LL-group chondrites commonly have poikilitic textures, in part or in whole, where mainly olivine is enclosed by orthopyroxene. Partially poikilitic fragments also have grano-blastic areas and anhedral olivine larger than the olivine enclosed by pyroxene. In analogy to lunar poikilitic rocks and lithic fragments, poikilitic lithic fragments in LL-group chondrites, i.e., meteorites which are highly brecciated due to repeated impacts, are also interpreted as being related to impact events on meteorite parent bodies where melting and reheating of protolith occurred. Compositional characteristics of minerals in certain fragments, such as highly-unequilibrated clinopyroxene (CaO, 14.5 to 17.3 wt %; Al₂O₃, 6.7%) and relatively high CaO (0.70 to 2.5 wt %) in orthopyroxene in a Ngawi fragment, seem to indicate a melt origin. However, as in the lunar case, it is difficult to decide whether the meteoritic poikilitic textures resulted from complete or partial melting or largely by solid-state recrystallization, although the large olivines that may be relict crystals appear to indicate that at least partial melting was involved. In all probability, all three processes are responsible for the poikilitic textures in chondrites, since temperature regimes produced by impact processes are likely to range widely. These interpretations may also apply to the poikilitic-textured Shaw chondrite, L-group, which may owe its poikilitic texture to impact partial-melting processes while in the parent body regolith.  相似文献   

Das Sandriffsystem vor dem Südteil der Insel Sylt (Deutsche Bucht,Nordsee)     

Dr. Klaus Figge 《Ocean Dynamics》1976,29(1):32-40

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AQD occurrence at Addis Ababa,Trivandrum and Alibag     

Brian J. Last  David A. Emilia  Alan K. Outhred 《Planetary and Space Science》1976,24(6):567-572

The effect of the equatorial electrojet is sufficient to reduce the probability of an abnormal quiet day occurring at Addis Ababa, Trivandrum and Alibag. Addis Ababa AQD occurrence exhibits an anomalous or subdued relationship to solar intensity, compared to that of Alibag, Trivandrum, and Greenwich/Abinger/Hartland; this is thought to be due to some unknown characteristic of the PM electrojet. Few AQD's are common to Addis Ababa and Trivandrum, Addis Ababa and Alibag, and Trivandrum and Alibag compared to the number common to Abinger and Wingst.  相似文献