摘要:

Preliminary experiments were made to determine the partition coefficients of rare earth elements between garnet and liquid at 30 kb and 1275°C in the system diopside(30 wt%)‐pyrope(70%)‐water. REE were added to the system by titration at concentration levels in the range of natural basalts. The phases were separated by differential dissolution technique(DDT) and analized for REE by isotope dilution. The partition coefficients(solid/liquid) are: 0.021 for Ce, 0.087 for Nd, 0.217 for Sm, 0.320 for Eu, 0.498 for Gd, 1.06 for Er and 4.03 for Yb. They are in excellent agreement with those estimated from cpx‐liq and cpx‐gar relationships currently used in the li

ISSN:0094-8276    

DOI:10.1029/GL002i010p00413

年代:1975

数据来源: WILEY

摘要:

Both forsterite (Mg2SiO4) and enstatite (MgSiO3) enter a post‐oxide phase characterized by the orthorhombic perovskite structure when subjected to high pressure and temperature in the diamond‐anvil press coupled with laser heating. The lattice parameters for the perovskite phase of MgSiO3are ao= 4.790 ± 0.002, bo= 4.943 ± 0.002, and co= 6.897 ± 0.003 Å with Z = 4. The calculated density of MgSiO3(perovskite) is thus 4.083 g/cm³, or 2.8% denser than its isochemical mixed oxides with rocksalt and rutile structures. The density of a mixture of MgSiO3(perovskite) plus MgO (periclase) is 1.9% greater than that of the mixed oxides with the forsterite stoic

ISSN:0094-8276    

DOI:10.1029/GL002i010p00417

年代:1975

数据来源: WILEY

摘要:

A study intended to detect time‐dependent velocity decreases beneath the Aleutians and/or Alaska has resulted in the discovery of some remarkable plate effects on relative teleseismic P‐wave residuals. The data are relative residuals between an Aleutian station (ADK) and two Alaskan stations (PMR, GIL) from deep focus (>300 km) earthquakes in the Fiji‐Tonga source region. These stations have maximum differences of only 17° in distance and 12° in azimuth from this source. Differences of up to 2 sec in the relative residuals correlate very well with the geographic location of events at the source. The persistence of these differences in the residuals at 600–700 km depth indicates most likely the presence of velocity anomalies of large magnitude below 700 km beneath the slab. Observed changes in relative residuals with depth of focus appear bounded by 10% velocity differences at the source between station ray paths. A subset of these data shows no well defined velocity change near ADK before the magnitude 6.8 Adak Canyon earthquake of Ma

ISSN:0094-8276    

DOI:10.1029/GL002i010p00420

年代:1975

数据来源: WILEY

摘要:

Least squares prediction with MQ (multiquadric) functions is conceptually different from least squares prediction using covariance functions. MQ kernels are based on geometric or physical considerations rather than stochastic processes, and were found to be superior to covariance functions in topographic applications. This may be true also for gravity anomalies or other phenomena which result from marginally stationary, or non‐stationary random processes. The MQ harmonic kernel is used to develop a formula for estimating the best depth of point mass anomalies as a function of their number and areal extent on a sphere. Functional relationships between geoidal surface parameters are developed which provide linear equation analogs for the solution of Stokes and Vening Meinesz Integral Formulas as well as for the inversion of these classic problems. These relationships are extended to solutions at exterior equipotential surface

ISSN:0094-8276    

DOI:10.1029/GL002i010p00423

年代:1975

数据来源: WILEY

摘要:

A mean paleomagnetic direction of D = 286,6 and I = 44,5 (α95= 17°, pole position at 297 E, 16 N) was obtained from Upper Cretaceous limburgites at M. Cerviero, Northern Calabria. The amount of counterclockwise rotation of the area since the Upper Cretaceous is of about 73°, larger than any known rotation of the surrounding areas: Sicily, Apulia and Campania. According to this data Northern Calabria, which is considered to be wholly allochtonous on geologic grounds, was subject to further differential displacement in respect with Sicily which was relatively fixed to the African plate, as well as in respect with the rotations between the Apennines, the Sardinian‐Corsican microplate and Af

ISSN:0094-8276    

DOI:10.1029/GL002i010p00427

年代:1975

数据来源: WILEY

摘要:

Satellite imagery of the ice‐covered Canada Basin in the Arctic Ocean shows the presence of large‐scale, spatially rectilinear leads separated by distances of ∼100 km. Consideration of the scales and other characteristics of these phenomena indicated the underlying water mass to be the most likely driving agent. An interpretation in terms of the reflection of planetary waves originating from the northern Basin, self consistently and in accord with other information, describes many of the observational fea

ISSN:0094-8276    

DOI:10.1029/GL002i010p00431

年代:1975

数据来源: WILEY

摘要:

Thermal infrared imagery from the Synchronous Meteorological Satellite (SMS), located above the equator at 75°W, was used to produce a time‐lapse film of the Gulf Stream off Florida. Northward propagating cyclonic eddies with a speed of 39 cm/sec, spacial scale of 265 km, and low frequency (ω/f<0.15), where ω is a wave frequency and f is the Coriolis parameter, were detected at the inshore edge of the current's boundary. These results demonstrate an application of the SMS to the study of time dependent sea surface thermal patt

ISSN:0094-8276    

DOI:10.1029/GL002i010p00435

年代:1975

数据来源: WILEY

摘要:

A method for efficient collection of stratospheric hydrogen chloride has been developed. Initial measurements for HCl, HBr and particulate Cl and Br are given.

ISSN:0094-8276    

DOI:10.1029/GL002i010p00439

年代:1975

数据来源: WILEY

摘要:

The photochemistry of fluorine in the stratosphere is surveyed in order to estimate the effect on ozone of fluorine atoms released by the breakdown of chlorofluoromethanes. The catalytic efficiency for ozone destruction by fluorine is found to be less than 10−4that of chlorine in the altitude range from 25 to 50 k

ISSN:0094-8276    

DOI:10.1029/GL002i010p00443

年代:1975

数据来源: WILEY

摘要:

This is a brief note intended to report recent measurements of CCl3F and CCl2F2in stratospheric samples obtained in 1973 through 1975. The samples were collected by a balloon‐cryogenic sampling system which has been described previously(Lueb, Ehhalt, and Heidt, 1975). The method allows us to collect large air samples (10 ℓ STP) for the laboratory analysis of a number of trace gases. It has been used since September 1973. Aliquots of the samples had been stored and were analyzed this year for their halocarbon content by gas chromatography with an electron capture detector. Results of these measurements are compared to calculated predicti

ISSN:0094-8276    

DOI:10.1029/GL002i010p00445

年代:1975

数据来源: WILEY