Geophysical investigations on manned spacecrafts

Summary Review has been made of the first results and perspectives of investigations in geophysics and bordering sciences (geology, geography, agrobiology, etc.) by means of manned orbital space laboratories. Relatively detailed discussion is given to the problems of the interpretation of terrain feature pictures from space. Attentively considered are the technique and results of the photometric processing of atmospheric photographs near the horizon with the purpose of studying atmospheric optical non-homogeneities (in particular, aerosol layers). The possible investigations based on the use of data about the outgoing radiation spectra are mentioned. (, , .) . . ( , ) . .     

An empirical NaKCa geothermometer for natural waters

An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340°C. The data for most geothermal waters cluster near a straight line when plotted as the function $\text{log (}\text{Na}\text{K}\text{) + β log [ √}\text{(Ca)}\text{Na}\text{]}$ vs reciprocal of absolute temperature, where β is either $\text{1}\text{3}$ or $\text{4}\text{3}$ depending upon whether the water equilibrated above or below 100°C. For most waters tested, the method gives better results than the $\text{Na}\text{K}$ methods suggested by other workers. The ratio $\text{Na}\text{K}$ should not be used to estimate temperature if $\text{√ (}\text{M}{}_{\mathrm{Ca}}\text{)}\text{M}{}_{\mathrm{Na}}$ is greater than 1. The $\text{Na}\text{K}$ values of such waters generally yield calculated temperatures much higher than the actual temperature at which water interacted with the rock.A comparison of the composition of boiling hot-spring water with that obtained from a nearby well (170°C) in Yellowstone Park shows that continued water-rock reactions may occur during ascent of water even though that ascent is so rapid that little or no heat is lost to the country rock, i.e. the water cools adiabatically. As a result of such continued reaction, waters which dissolve additional Ca as they ascend from the aquifer to the surface will yield estimated aquifer temperatures that are too low. On the other hand, waters initially having enough Ca to deposit calcium carbonate during ascent may yield estimated aquifer temperatures that are too high if aqueous Na and K are prevented from further reaction with country rock owing to armoring by calcite or silica minerals.The Na-K-Ca geothermometer is of particular interest to those prospecting for geothermal energy. The method also may be of use in interpreting compositions of fluid inclusions.     

Lead orthophosphates—III. Stabilities of fluoropyromorphite and bromopyromorphite at 25°C

The reactions of secondary lead orthophosphate with approximately 10^?1 M sodium fluoride and sodium bromide solutions have been investigated at 25°C. Interpretation of the solubility data resulted in solubility product constants for fluoropyromorphite and bromopyromorphite of 10^?71.6 and 10^?78.1, respectively. According to these constants, the stability sequence for lead pyromorphites is Pb₅(PO₄)₃Cl > Pb₅(PO₄)₃Br > Pb₅(PO₄)₃OH > Pb₅(PO₄)₃F. The derived free energy data have been used to evaluate the respective stabilities of fluoro-pyromorphite and bromopyromorphite within the systems PbF₂-PbO-P₂O₅-H₂O and PbBr₂-PbO-P₂O₅-H₂O and to predict the equilibrium behavior of the Pb₅(PO₄)₃F-Pb₅(PO₄)₃OH solid solution under aqueous conditions.     

Luna 20: mineralogy and petrology of fragments less than 125 μm size

Two milligrams of less than 125 μm size particles from the Luna 20 soil sample (22001,17) have been examined. The results of the mineral identification and analysis verify earlier assumptions that the nature of the lunar highlands is predominantly anorthositic in composition. The presence of highly magnesian clinopyroxene, orthopyroxene and olivine suggests crystallization of Highland rocks in an ultrabasic environment. No fragments were observed that could be unequivocally assigned to mare basalt types.     

More on noble gases in Yellowstone National Park hot waters

Water and gas samples from research wells in hydrothermal areas of Yellowstone National Park, U.S.A., have been mass spectrometrically analyzed for their rare gas contents and isotopic composition. In agreement with previous findings, the rare gases have been found to originate from infiltrating run-off water, saturated with air at 10 to 20°C. The atmospheric rare gas retention values found for the water varied between 3 and 87 per cent. The fine structure of the Ar, Kr and Xe abundance pattern in the water reveals fraotionational enrichment of the heavier gases due to partial outgassing of the waters. Radiogenic He and Ar have been detected. No positive evidence for magmatic water contribution has been found. Nevertheless, additions of magmatic waters free of rare gas can not be excluded, but if present the proportion is significantly less than 13 to 36 per cent.     

Sillimanite—disordering enthalpy by calorimetry

Heat of solution measurements in an oxide-melt were performed on samples of natural sillimanite heat-treated in the range 1200–1700°C at pressures of 16–23 kbar. A distinct enthalpy of solution decrement relative to the unheated sillimanite of about 1.3 kc/mole is shown by samples run at 1400–1550°C. Pressure variations in the range 16–23 kbar cause little change in the heat of solution in this temperature range. This pressure-independent ‘plateau’ in heat of solution is interpreted to be due to Al-Si disordering on tetrahedral sites in the sillimanite structure. A simple temperature-dependent disordering model developed by navrotsky and Kleppa (1967) for spinels leads to an Al-Si interchange enthalpy, Δ_Hnt, of16 ± 1 kcal/mole, in good agreement with the value derived by Holdaway(1971) on entirely different grounds.Above 1550°C, larger heat of solution decrements were observed. Microprobe analyses of quenched samples indicate that the sillimanite has not deviated significantly from the ideal formula. Some unknown profound disordering process may account for the heat effects in the very high temperature range.Unit cell volumes of quenched samples also describe a ‘plateau’ region in the temperature range 1400–1550°C. This plateau consists of an increase of the 6 crystallographic axis beginning at 1350°C without much change in the other axes in the range 1350–1550°C. A sudden expansion of the α-axis occurs between 1550 and 1630°C.We conclude that Al-Si disorder of the type postulated by Beger et al. (1970), and Holdaway (1971) has been confirmed calorimetrically for samples heated under pressure in the temperature range 1400–1550°C.