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61.
62.
The phenocryst assemblage of cummingtonite, orthopyroxene, quartz, titanomagnetite and ilmenite in rhyolites of New Zealand has been used to calculate P
total and
. The values of P
total and
depend strongly upon whether an ideal mixing, or an ordered, model is used for the solid-solutions, but in both cases
P
total.The rhyolite magma contained over 9 per cent water (by weight) when the cummingtonite phenocrysts precipitated, and possibly as much as 12 per cent, so that it is surprising that one of these rhyolites is a coherent lava. The calculated values of P
total and
are very sensitive to uncertainty in both the composition of the solid-solutions and temperature. Calculations show that
>0.7–0.8 P
total for cummingtonite to precipitate in rhyolites, and that iron-rich olivine and cummingtonite could only exist in rhyolites over a small temperature range at a pressure near 5 kilobars. Hornblende phenocrysts co-existing with fayalitic olivine in rhyolites accordingly have a very low activity of Mg7Si8O22(OH)2. 相似文献
63.
A case of poisoning following consumption of Neptunea occurred in Scotland in 1970. The organism is caught in traps with the Edible Whelk where it constitutes less than 0·5% of the catch. Toxin in the salivary gland demonstrated by mouse bioassay could be distinguished from PSP toxin. It is concluded that the public health risk from consumption of the Edible Whelk is negligible. 相似文献
64.
L. A. Wood 《国际地质力学数值与分析法杂志》1977,1(4):397-405
An approximate method, using a simplified soil model, for predicting the behaviour of raft foundations subjected to applied vertical forces and moments will be outlined. Results obtained for circular rafts of finite rigidity are compared with those obtained, from more rigorous solutions, by other authors. Satisfactory agreement is obtained for the surface settlements and raft bending moments over a wide range of soil inhomogeneity. Finally, the versatility of the method of analysis is illustrated for an unusual asymmetrical structure. Computed total and differential settlements are shown to be in reasonable agreement with measured values and those predicted by an independent plane strain finite element analysis. 相似文献
65.
66.
68.
Widely extended, cation stacking faults in experimentally deformed Mg2GeO4 spinel have been studied using transmission electron microscopy (TEM). The faults lie on {110} planes. The displacement vector is of the form \(\frac{1}{4}\left\langle {1\bar 10} \right\rangle \) and is normal to the fault plane. The partial dislocations which bound the stacking fault have colinear Burgers vectors of the form \(\frac{1}{4}\left\langle {1\bar 10} \right\rangle \) which are normal to the fault plane. 相似文献
69.
Analyses are presented of137Cs,238Pu, and239,240Pu, in relation to depth in sediment, in 21 gravity cores. These cores span the ranges of times 1964–1975, and of water depths 12–2000 m; they come from three distinct sedimentation areas off the northeast coast of the United States. Although the ranges of total sediment inventories of239,240Pu and of137Cs from the various areas hardly overlap, the range of ratios of the inventories of these two nuclides is probably the same in all the areas. In the shallow-water cores the239,240Pu/137Cs ratio regularly diminishes with depth in the core, and a tendency is seen for curves of this function to have similar slopes in each area; ratios of238Pu/239,240Pu show no change with depth in these shallow-water cores. In the deeper-water cores, the239,240Pu/137Cs ratio shows no systematic change with depth, but sometimes the238Pu/239,240Pu ratio shows a minimum at the sediment surface, and is much higher deeper in the cores. We believe that these phenomena can be explained in terms of a complicated bioturbational process moving the nuclides, together, down into the sediments, of chemical resolubilization, at depth, of plutonium only, and of its subsequent upward translocation in the interstitial solution. Some re-immobilization of plutonium near the sediment surface is implied, and a mechanism is suggested for this, based on displacement of plutonium from organic complexes by the increasing concentrations, in upper layers of the sediment, of re-oxidized dissolved iron. 相似文献
70.