Zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃) are key minerals in SYNROC, a ceramic material developed for the immobilization of high level nuclear reactor wastes. When these are incorporated in SYNROC, the long-lived radioactive actinide elements are preferentially partitioned into zirconolite and perovskite which are therefore subjected to the effects of alpha-recoil, resulting from the decay of these elements. These effects have been studied via X-ray and electron diffraction investigations of natural samples of zirconolite and perovskite of varying ages and varying uranium and thorium contents. The samples studied have received cumulative alpha doses ranging from 1.0 × 10¹⁸ to 1.1 × 10²⁰α/g. The upper limit corresponds to the alpha irradiation which would be received by the zirconolite in SYNROC containing 10 percent of high level waste over a period of 5 × 10⁸ years. These studies show that zirconolites remain crystalline up to and beyond alpha doses of 2 × 10¹⁹α/g. This dose would have accumulated in such a SYNROC zirconolite after a million years of storage. Electron microscopy revealed that the grains were composed of small crystalline domains which possessed the defect fluorite-type structure. After a dose exceeding that which would be received by SYNROC in 100 million years, zirconolites appeared metamict when studied by X-ray diffraction. However, the electron micrographs and diffraction patterns clearly demonstrate that the mineral continues to retain a large degree of short range order and in no way resembles a glass. The density changes produced in these zirconolites by irradiation are small and range from 0 to 3 % at saturation. Perovskite samples which have SYNROC ages up to 20, 000 years decrease in density by 1.8 ± 0.1 %. Their X-ray powder patterns are essentially unaffected. Comparative studies show that the perovskite lattice is even more resistant to the effects of alpha-recoil than the zirconolite lattice. The results demonstrate that zirconolite and perovskite are extremely resistant to the effects of nuclear radiation and will provide stable crystal structures for the containment of the radioactive waste elements during the time required for the radioactivity to decay to safe levels (typically 10⁵-10⁶ years).

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The Earth's atmosphere was produced by exhaustive degassing of the upper mantle during the first 200My, but the lower mantle has retained an appreciable fraction of its initial inventory of primordial ³He. The lower mantle has retained most of its initial inventory of the heavy noble gases, and it is presently accumulating radiogenic ⁴He and ⁴⁰Ar. Most of the radiogenic ⁴⁰Ar in air was produced in the crust during the first 2.5 Gy. Extinct radionuclides have augmented the atmospheric inventory of ¹³⁶Xe by less than 1 % and that of ¹²⁹Xe by about 5%. Terrestrial Ar, Kr, and Xe are type-Y, but the He and Ne are of solar wind origin. Terrestrial Xe may not be isotopically unique in the solar system; its composition can be related to that in meteorites by consideration of nucleogenetic heterogeneities and mass dependent fractionation. The atmospheres of the terrestrial planets were produced by exhaustive degassing of specific regions. Observed similarities in the abundance patterns of noble gases in meteorites and in the terrestrial planets rule out elemental fractionation in the evolution of their atmospheres. The degassed portions of Mars, Earth, and Venus are estimated to be 1-2%, 17% and 100%, respectively. The iron cores of these bodies were produced by heterogeneous accretion.

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Rear-earth abundances were determined precisely for twenty-four volcanoes of the Northeastern Japan Islands. The inclination of the pattern for lighter REE span was found to depend sensitively on the distance of the volcano from the volcanic front. The f_w value (residual liquid fraction) for the volcano situated near the volcanic front is about unity and decreases rapidly with the distance from the volcanic front. The rate of change of f_w is almost parallel with the rate of change in the volume of volcanic products with the distance from the volcanic front. Also it is emphatically noted that the relatively chondritic REE pattern not only actually emerges as a rather special case at the front but can be significant in consideration of possibly incipient magma. Moreover, it is suggested that there can be two kinds of sources of genetically different natures for apparently chondritic, initial melts.

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The mechanism of phosphate coprecipitation with calcite is proposed on the basis of homogeneous distribution of phosphate in the crystal at 20°C and pH 7.9-9.5. At a constant pH, phosphate content of calcite is proportional to total phosphate concentration in aqueous solution. PO^3-₄ ions are uptaken into the calcite lattice, where 3 CO^2-₃ ions are replaced by 2 PO^3-₄ ions in aqueous solution, as described by the ion exchange equilibrium: 3(CO^2-₃)_S + 2(PO^3-₄)_L ↔ 3(CO^2-₃)_L + 2(PO^3-₄)_S where S and L represent calcite and aqueous solution, respectively.

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A ball mill made of pyrex glass with an alumina ball was devised. The features are as follows, 1) quartz and rocks can be powdered manually in a short period of time, 2) pulverization is possible in the pressure range from 10^-3torr to about 3 atm and the temperature up to about 300°C, 3) interior of the mill is visible, and 4) the mill is handy to manipulate and easy to repair. The mill may be useful for varieties of crushing experiments.

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