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991.
Prof. Dr. A. Pabst 《Mineralogy and Petrology》1978,25(4):245-256
Zusammenfassung Taramellit kommt im westlichen Nordamerika an mindestens acht Fundstellen vor, wo er bis jetzt wenig beachtet wurde. Die Taramellite dieser Fundstellen sind alle sehr Ti-reich. Bisher wurde Taramellit nach dem ersten Vorkommen, Candoglia in Italien, meist als faserig beschrieben. Die Ti-reichen Taramellite in Nordamerika, besonders die in California, welche mit Sanbornit und Gillespit vorkommen, erscheinen aber als gut ausgebildete Einkristalle. Es wurden viele solche Kristalle goniometrisch gemessen. Obgleich etwa dreißig Formen verzeichnet wurden, ist der Habitus der orthorhombischen Kristalle meist durch das Vorherrschen der Pinakoide und einiger {hk0} und {0kl} Prismen bedingt. Am häufigsten ist der tafelige habitus nach {100}.
Mit 3 Abbildungen
herrn Prof. Dr.H. Meizner zum 70. Geburtstag gewidmet. 相似文献
On the morphology of taramellite
Summary Taramellite is known from at least eight localities in western North America but has received little notice. The taramellite at all of these localities is especially Ti-rich. Hitherto taramellite has mostly been described as fibrous after its habit at the type locality, Candoglia, Italy. The Ti-rich taramellites of North America, especially those found with sanbornite and gillespite in California, occur as well-developed single crystals. Many such crystals were measured goniometrically. Though about thirty forms were recorded, the habit of the orthorhombic crystals is mostly determined by the pinacoids and a few {hk0} and {0kl} prisms. A tabular habit with {100} dominant is most common.
Mit 3 Abbildungen
herrn Prof. Dr.H. Meizner zum 70. Geburtstag gewidmet. 相似文献
992.
An examination of day-to-day and monthly mean positions of the electrojet axis in relation to the changes in the apparent solar declination, in the Indian equatorial region shows marked association between the two. For relatively quiet days, significant correlations are observed between the solar declination and each of the parameters, the northernSq focal latitude, the jet axis and the line of maximumSq(H). From the significant mutual association of these parameters, it has been suggested that the equatorial electrojet could be a part of the world-wideSq current system. 相似文献
993.
This paper is one of a series that commemorates the fiftieth anniversary of the founding of the Society of Economic Paleontologists and Mineralogists in 1926. At that time, thought about tectonics and sedimentation was dominated by the ruling hypothesis of continental accretion. Marginal geosynclines were thought to have been filled with sediments derived from borderlands of Precambrian rocks, and then welded tectonically to the continent. In the 1930s, the fundamental distinction noted by Bailey and Jones between graded graywacke- graptolitic slate suites and cross-bedded sandstone-shelly carbonate suites provided a prelude to Krynine's petrographic-tectonic sandstone clans. In the 1940s sedimentary petrography finally emerged from its heavy mineral era to broaden its vistas. Prior notions of evolutionary successions of sediment types linked to a supposed tectonic cycle (e.g. the European ophiolite-flysch-molasse sequence) became more explicit. Refinements of sandstone classifications by Folk, Pettijohn, Gilbert and others, coupled with Krynine's tectonic cycle and the stratigraphic syntheses of Krumbein, Sloss, Dapples, and others, led in the 1940s to the belief that tectonics is the ultimate sedimentary control.Meanwhile the geosyncline had been dissected by Stille and Kay (1936–1951). Ideas about sources of geosynclinal sediments and paleogeography were revised to include volcanic islands and tectonic lands raisedwithin geosynclines rather than borderlands of Precambrian rocks standing outside the geosynclines. In the 1950s and 1960s, sedimentologists exploited the turbidity current revolution and the combined paleocurrent-petrographic approach pioneered by Pettijohn to delineate in detail the paleography and provenances of orogenic belts. Provenance studies have recently reached a high level of sophistication thanks to the efforts of many workers (e.g. Blatt, Crook, Dickinson, Füchtbauer, McBride, Schwab, Suttner, etc.). This work has demonstrated clearly that the cratonic, volcanic and tectonic source land types proposed by Kay had all been important, but to varying degrees at different times and places. When plate tectonics arrived in the late 1960s, sedimentologists were all equipped to reinterpret their rocks using petrographic, paleocurrent and sedimentary structure analyses to help diagnose different types of plate boundaries and to aid in making palinspastic plate restorations. Thus the study of tectonics and sedimentation is alive and thriving a century later. 相似文献
994.
Dr. A. Blasi 《Mineralogy and Petrology》1979,26(3):139-148
Summary Direct and reciprocal lattice constant variance-covariance matrices when involved in the Law of Propagation of Errors can be used to gain a full evaluation of the error terms in mineralogical quantities expressed in terms of lattice constants. Properties and relationships which mutually connect the two matrices are discussed, with emphasis placed on physical dimensions. A practical application is given by calculating the error terms in the structural indicators (bc) and (**) of alkali feldspars. The differences between values obtained by using both variances plus covariances and those obtained using variances alone, are very small. However, as the calculations are completely automated, the full formulation using variances plus covariances represents a suitable better approach.
With 1 Figure 相似文献
Mineralogische Anwendungen der Varianz-Kovarianz-Matrizen der Gitterkonstanten
Zusammenfassung Varianz-Kovarianz-Matrizen der direkten und reziproken Gitterkonstanten können beim Fehlerfortpflanzungsgesetz benützt werden, um eine vollständige Auswertung der Fehlerausdrücke mineralogischer Größen, ausgedrückt durch Gitterkonstanten, zu erhalten. Eigenschaften und Beziehungen, welche diese beiden Matrizen gegenseitig verknüpfen, werden mit Betonung physikalischer Dimensionen diskutiert. Eine praktische Anwendung wird gegeben, indem die Fehlerausdrücke der strukturellen Indikatoren (bc) und (**) von alkalifeldspäten berechnet werden. Die Differenzen zwischen den Werten, die bei Benützung von Varianzen und Kovarianzen, bzw. nur von Varianzen erhalten wurden, sind sehr klein. Da aber die Berechnungen voll automatisiert sind, bietet die vollständige Formulierung mit Varianzen plus Kovarianzen eine brauchbare bessere Methode.
With 1 Figure 相似文献
995.
M. T. Krupenin A. V. Maslov I. D. Tsybulenko R. A. Nafikov V. G. Petrishcheva 《Lithology and Mineral Resources》2000,35(3):267-277
A property of swelling on heating to yield firm lightweight granules has first been revealed for lowcarbonaceous shales (LCS)
from the Riphean stratotype in the Bashkirian Megaanticlinorium, Southern Urals. These granules possess all technological
properties of “keramzite” or claydite (an artificial, expanded clayey material) and can successfully substitute this material.
Moreover, the procedure of their manufacture, analogous to the manufacture of “shungizite” (an artificial carbonaceous-clayey
material) from Lower Proterozoic clayey rocks of Karelia, is more economical than that for keramzit. Productive beds of the
homogeneous LCS make up extended bodies tens of meters thick. At the present time, they can be used as cover rocks during
the exploitation of the Bakal siderite deposits. The LCS represent fine-grained quartz-chlorite-sericite aggregates (with
variable relationships between the major components), bearing fine-dispersed shungite in amounts of 0.5–1.0%. High-quality
raw material of this kind is characterized by a fine-dispersed admixture of a mixed-layer clayey material bearing montmorillonite
and vermiculite. Geological, lithological, mineralogical, and chemical prognostic criteria have been developed for the shungizite
raw material. It has been concluded that this construction material, new for the Urals, is promising for industrial use 相似文献
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