An overview of climatic variability and its causal mechanisms

A variance spectrum of climatic variability is presented that spans all time scales of variability from about one hour (10⁻⁴ years) to the age of the Earth (4 × 10⁹ years). An interpretive overview of the spectrum is offered in which a distinction is made between sources of variability that arise through stochastic mechanisms internal to the climatic system (atmosphere-ocean-cryosphere) and those that arise through forcing of the system from the outside. All identifiable mechanisms, both internal and external, are briefly defined and clarified as to their essential nature. It is concluded that most features of the spectrum of climatic variability can be given tentatively reasonable interpretations, whereas some features (in particular the quasi-biennial oscillation and the neoglacial cycle of the Holocene) remain fundamentally unexplained. The overall spectrum suggests the existence of a modest degree of deterministic forms of climatic change, but sufficient nonsystematic variability to place significant constraints both on the extent to which climate can be predicted, and on the extent to which significant events in the paleoclimatic record can ever manage to be assigned specific causes.     

Nature of the carbon and sulfur phases and inorganic gases in the Kenna ureilite

Abundances of carbon and sulfur in the Kenna ureilite are 2.219 ± 0.060 wt. % C and 0.179 ± 0.008 wt. % S. Secondary carbonates resulting from terrestrial weathering account for 0.25 ± 0.02 wt. % C. No hydrocarbons were detected during gas release measurements. Most of the carbon is in graphite, diamond, or lonsdaleite. The sample of Kenna contained 0.95 ± 0.05 wt. % H₂O. Total carbon and sulfur measurements were made on three additional ureilites: Haverö, Dingo Pup Donga, and North Haig. Ureilite carbon abundances are similar to those of C-2 chondrites, whereas sulfur abundances are a factor of 10 less than C-2 chondrites and ordinary chondrites. The elemental abundances, ratios, and phases present in the ureilites rule out a direct genetic relationship between the ureilites and the carbonaceous chondrites.     

A review of applications of microwave radiometry to oceanography

The thermal microwave radiation from the ocean surface as seen from space is a function of the surface temperature and wind speed and is modified by liquid water and water vapor in the intervening atmosphere. Further, if the ocean surface is frozen, the emissivity is drastically increased and the effect of the intervening atmosphere is generally negligible. The emissivity of first-year ice is somewhat larger than that of multi-year ice.The data from the Electrically Scanning Microwave Radiometers (ESMR's) on the Nimbus-5 and —6 satellites operating at wavelengths of 1.55 cm and 8 mm, respectively, can be interpreted in terms of rain rate, ice coverage and first-year versus multi-year ice determination. The rain-rate data are being used to establish a climatology of rainfall over the oceans. The ice data are being used by the United States Navy in support of international scientific efforts in the Antactic region. Both ice and rain data sets have been generated for the Global Atmospheric Research Project Data Systems Test.It is possible, by making multifrequency measurements, to separate the surface and atmospheric effects and to make useful measurements of sea surface temperature, surface wind speed, and atmospheric parameters along with improved measurements of rain and ice.     

Third world settlement frontiers: modest population absorbers

Conclusions This study concludes that a relatively small part of the Third World's increasing populations may be absorbed in their frontiers. Throuh the 49 locations are scattered throughout that world three characteristics are emphasized: 1) these are the principal regions where studies of population absorption potential should be initiated before any new settling is undertaken, 2) the frontiers are not as convenient to areas of world population pressure as is desirable, and 3) what are mapped as areas may turn out to be a series of spots requiring considerable detailed planning at local levels.Overall there is reason for some encouragement. Frontiering could be executed now with degrees of success if proper respect is paid the complexity of the task and to previous experience. It is suggested that a contemporary planner of new settling is wiser to elect areas where the process may build on an existing minimal geographic base of settlers and transportation so as to start relatively quickly and be at least partly commercial. Frontiers these days are unlikely to take as long to develop as they did 25 or 50 years ago. Nor should they. Moreover, the drive to raise world standards of living is calling for a new order of economies and one corollary is apparent: frontiers for subsistence living have minimal value now and in the future and should be short-lived, if existent at all. But, most important, the frontiers provide the possibility of meeting a part of a burgeoning problem in a way that is familiar to the people and that could be efficient.     

Two-feldspar geothermometry in granulite facies metamorphic rocks

A geothermometric technique based on equilibria between coexisting plagioclase and alkali feldspar was applied to quartzo-feldspathic granulites from Salvador, BA, Brazil. The conditions of metamorphism were determined to be in the range 750 ° C–800 ° C, 4–8 Kb, by comparison with experimental data on the stabilities of sapphirine, phlogopite and other minerals occurring in the associated rocks. Selected feldspar data gives temperatures near, but slightly below, this range. Several variants of the Wood and Banno model, as well as an empirical two-pyroxene geothermometer, were also tested and found to give temperatures which were apparently 50 °–100 ° high. The solubility of Al₂O₃ in orthopyroxene indicates temperatures which are about 200 ° to high, suggesting that Fe in the natural assemblages significantly changes relationships observed experimentally in MgO-Al₂O₃-SiO₂ systems.     

Recent volcanism at Schonchin and Cinder Buttes,northern California

Recent volcanism on the northern flank of the Medicine Lake Highland consists of a series of basalt to andesite spatter and cinder cones and their associated flows. Two particular structures, Cinder Butte and Schonchin Butte, have erupted materials that are very similar in terms of age, volume, modal mineralogy, and many major and trace elements. Significant differences with respect to TiO₂, K₂O, P₂O₅, Sr, Ba, Zr, and LREE can be related to possible changes in the mineralogy within the source region of these volcanic rocks. Apatite and priderite are the two minor constituents that best satisfy the constraints set by the mineral and chemical data. An inhomogeneous upper mantle or lower crust beneath the Medicine Lake Highland is indicated.     

Moon—An albite depleted giant Skaergaard?

The chemical composition of 2188 terrestrial igneous rocks ranging from ultrabasic to granitic composition was analyzed statistically using the method of factor analysis (principal components). The resultant first and second factors were: $$\begin{gathered} {\text{ }}F_1 = 0.933{\text{ Na}}_{\text{2}} {\text{O + 0}}{\text{.143 SiO}}_{\text{2}} + 0.206{\text{ K}}_{\text{2}} {\text{O}} - 0.346{\text{ CaO}} - 0.263{\text{ MgO}} - \hfill \\ .203{\text{ FeO}} \pm \cdot \cdot \cdot \hfill \\ {\text{ }}F_2 = 0.979{\text{ Al}}_{\text{2}} {\text{O}}_{\text{3}} - 0.269{\text{ MgO}} - 0.151{\text{ SiO}}_{\text{2}} - 0.112{\text{ FeO}} \pm \cdot \cdot \cdot \hfill \\ \end{gathered} $$ where oxides are in weight percent. A plot of the first factor against the second results in a useful igneous variation diagram. When the compositions of the 2188 terrestrial rocks and 604 lunar rocks are plotted on this diagram, the two groups of rocks are clearly separated within an albite-anorthite-forsterite-fayalite-quartz polygon. None of the terrestrial differentiation trends are significant for lunar rocks. The major difference in the chemistry of lunar and terrestrial rocks lies in the former being albite poor. Removal of most of the albite from the compositions of terrestrial layered intrusives such as the Skaergaard results in an excellent match between the compositions of the two groups of rocks. Albite subtracted compositions of Skaergaard rocks in particular cover the entire range of chemical variation in the lunar rocks. The statistical results prompt us to speculate further on the similarity of the moon and Skaergaard. We note that the average composition of the moon (Wanke et al., 1974) is similar to the albite subtracted composition of the Skaergaard magma. The lunar crust and a significant part of the lunar interior may match the albite subtracted and somewhat Mg enriched Skaergaard magma.