Analyse der Bewegungen an der Umbiegung der „Peridriatischen Naht“ (Insubrische Linie/Pusterer Linie) in der Umgebung von Mauls (Südtirol)

Zusammenfassung Untersuchungen der magnetischen Suszeptibilitätsanisotropie an der Judikarien/Pusterer-Linie ergaben, daß an der Judikarien Linie und an der östlichen Pusterer Linie kompressionelle Vorgänge nachweisbar sind. Im W-Teil der Pusterer Linie (E Mauls) war die Kompression wesentlich schwächer. Diese Ergebnisse werden mit einer Bewegungsanalyse in Zusammenhang gebracht, die auf plattentektonischen Modellen, die diesen Raum betreffen, beruht. Demnach ist eine Gegenuhrzeigersinnrotation einer Platte, die die Periadriatische Naht beinhaltet, mit anschließender Kollision mit der Briançonischen Platte (Frisch 1977) für die Aktivierung (oder Reaktivierung) verantwortlich. Die gesamte Energie dieser Vorgänge entlädt sich an der Judikarien Linie und der östlichen Pusterer Linie.Schlüsselwörter: Suszeptibilitätsanisotropie; Magnetic Fabric; Brixener Granit; ostalpines Altkristallin; Periadriatische Naht; Plattentektonik.

---

Magnetic fabric analyses on samples from the junction of the Pusterer Line with the Judicarian Line in South Tyrol have been carried out to determine a model for the compressions, movements and dynamics of the Periadriatic Line (P. L.). The results have been incorporated into a plate-tectonic model whereby the P. L. was activated (or reactivated) by a collision of a plate containing the P. L. against the Briançonic Platform (Frisch 1977). The energy of the collision appears to have been dissipated in compression along the Judicarian Line and movement along the Pusterer Line.

---

Résumé Les analyses de texture d'échantillons magnétiques à la jonction de la ligne Judicarienne avec la ligne de Pusterer prouvent que sur la ligne Judicarienne et sur la ligne Est de Pusterer des phénomènes de compression sont démonstrables. Dans la partie Ouest de la ligne de Pusterer (E Mauls), la compression était considérablement plus faible. Ces résultats sont mis en relation avec une analyse de mouvements qui repose sur des modèles de plaques tectoniques qui concernent cet espace. Par conséquent, une rotation dans le sens inverse de l'aiguille d'une montre d'une plaque qui comporte la ligne Périadriatique et qui a une collision reliée à la plaque briançonique est responsable de l'activation (ou de la réactivation), (Frisch, 1977).Toute l'énergie de ces phénomènes se décharge sur la ligne Judicarienne et sur la ligne Est de Pusterer.

---

/ . (. ) . , . , ( ) , , (Frisch 1977). .

     

Amorphous,hydrous, ferric phosphatic dermal granules in Molpadia (Holothuroidea): Physical and chemical characterization and ecologic implications of the bioinorganic fraction

The bioinorganic fraction of the dermal granules of Molpadia intermedia from a wide variety of habitats has been studied by chemical analysis, electron microscopy, X-ray diffraction, thermal analysis, visible and infrared spectroscopy and magnetic susceptibility. It was found to have many similarities to polynuclear iron(III) proteins. Silica was found to be an integral component of the granules. The proportions of the major elements, P and Si, were found to vary with habitat as well as the minor elements, Ca and Mg, whereas the Fe content remained relatively constant. Models are proposed for the microstructure of the granules and the processes of their growth.     

Global Warming and Potential Changes in Fish Habitat in U.S. Streams

To project potential habitat changes of 57 fish species under global warming, their suitable thermal habitat at 764 stream gaging stations in the contiguous United States was studied. Global warming was specified by air temperature increases projected by the Canadian Centre of Climate Modelling General Circulation Model for a doubling of atmospheric CO₂. The aquatic thermal regime at each gaging station was related to air temperature using a nonlinear stream temperature/air temperature relationship.Suitable fish thermal habitat was assumed to be constrained by both maximum temperature and minimum temperature tolerances. For cold water fishes with a 0 °C lower temperature constraint, the number of stations with suitable thermal habitat under a 2×CO₂ climate scenario is projected to decrease by 36%, and for cool water fishes by 15%. These changes are associated with a northward shift of the range. For warm water fishes with a 2 °C lower temperature constraint, the potential number of stations with suitable thermal habitat is projected to increase by 31%.     

The Isthmus of Panama as a Crossroad for Prehistoric Migration of Domesticated Plants

For thousands of years, Indian tribes have gathered, selected, domesticated and spread useful plants over the whole American continent while mostly practicing shifting forms of horti-agriculture. It has been argued that origin and domestication of New World crops could be traced back to essentially two independent, narrowly circumscribed core regions, (i.e. Vavilov's genecentres) one in the highlands of Mexico and the other in the Andes of Peru. Those alleged centers of origin and genetic diversity have been synchronized with the main cradles of American agriculture. Based on long periods of research work in South America, we disagree with this opinion which is maintained primarily by anthropologists, sociologists and ethnologists. Except for marginal desert and mountain environments, there are no real biogeographical restrictions for plant domestication. Apparent geographical barriers, like the Darien gap, did not represent insurmountable hindrances for the diffusion and migration of useful species in the hands of indigenous peoples.     

Geodetic networks along the Caribbean-South-American plate boundary

Three major fault zones form the Caribbean-South-American plate boundary; these are the Bocono, Moron, and Pilar fault zones. The first geodetic networks were explored and installed in 1972–1973. First measurements were realized in 1973 and remeasurements were made at several intervals up to date. In total 18 sites were studied and explored for local geodetic networks; of these, only five are completely operational, the others are still waiting for monumentation and operation. Nevertheless, for these latter, the main part of the installation, the exploration work and the feasibility studies in geology and topography have already been realized. In the operational networks, the field and point vectors show movements and deformations. Max. values: Yacambu 88 mm/2 years, Mucubaji 32 mm/5 years. The deformational parts of displacements show principally compression vectors from both sides towards the plate boundary.     

Hydraulic investigations on the utilization of geothermal water resources for energy production

The paper deals with hydraulic problems, arising with the development of geothermal deep ground-water flow. It begins with a brief comment upon the most important principles of flow, regarding the influence of temperature of water. Further it is explained what kind of hydraulic investigations on deep boreholes are necessary and how they have to be done.Finally, it will be reported about hydraulic investigations on particular geothermal water resources in Austria. Results of a pumping test, made at a deep well and lasting 15 months, show that by thermohydraulic investigations, particularly in connexion with geophysical measurements, fundamental statements can be made about available geothermal resources of the earth's crust for the technical planning and economic working of a geothermal energy production plant. The paper ends with a brief report about experiences made with the first geothermal heat supply plant that has been installed in Austria (Waltersdorf/East Styria).     

Metamorphic an magmatic events in the Uweinat — Bir Safsaf Uplift (Western Desert/Egypt)

The Uweinat — Bir Safsaf Uplift, Western Desert/Egypt, four episodes of deformation and related metamorphism and anatexis occurred until the final cratonisation during the Late Pan-African event was completed. From that time on, probably six independent (Table 4) magmatic episodes can be recognized up to the Quaternary. This anorogenic type of magmatism is mainly related to a fracture system which originated in the Late Precambrian as a result of intraplate block faulting. Periodical reactivation of these older fracture zones throughout the Phanerozoic gave way to the different types of plutonic and volcanic rock assemblages.

---

Zusammenfassung Die Grundgebirgsschwelle zwischen Gebel Uweinat und Bir Safsaf (Western Desert/ Ägypten) war während des Präkambriums durch vier Episoden von Deformation, Metamorphose und Anatexis gekennzeichnet. Die endgültige Kratonisierung erfolgte im Jungproterozoikum im Verlauf eines Pan-Afrikanischen Thermalereignisses. Die während des Jungproterozoikums als Folge großräumiger Intraplattentektonik entstandenen Bruchsysteme wurden während des Phanerozoikums periodisch reaktiviert. Die Platznahme anorogener Magmen erfolgte in mindestens sechs verschiedenen Zeiträumen hauptsächlich entlang dieser Bruchstrukturen.

---

Résumé Le massif soulevé compris entre le Gebel Uweinat et Bir Safsaf, dans le Désert occidental de l'Egypte, a été le siège de 4 épisodes de déformations avec métamorphisme et anatexie jusqu'à sa cratonisation finale au cours de la Phase Pan-africaine tardive. A partir de ce moment, probablement six épisodes magmatiques indépendants peuvent être reconnus jusqu'au Quaternaire. Ce type anorogénique de magmatisme est principalement en relation avec un système de fractures qui a pris naissance au Précambrien supérieur comme le résultat d'une régime de fracturation intraplaque. La réactivation périodique des ces zones de fractures anciennes durant le Phanérozoïque a conduit à la formation de ces différents types d'associations de roches volcaniques et plutoniques.

---

Gebei Uweinat Bir Safsaf ( . ) 4 , . . , , . . , - , .

     

Siderophile geochemistry of ureilites: A record of early stages of planetesimal core formation

New bulk-compositional data, including trace siderophile elements such as Ir, Os, Au, and Ni, are presented for 25 ureilites. Without exception, ureilites have siderophile abundances too high to plausibly have formed as cumulates. Ureilites undoubtedly underwent a variety of “smelting,” by which C was oxidized to CO gas while olivine FeO was reduced to Fe-metal. However, pressure-buffered equilibrium smelting is not a plausible model for engendering the wide range (75-96 mol%) of mafic-silicate core mg among ureilites. The smelting reaction produces too much CO gas. Even supposing a disequilibrium process with the smelt-gas leaking out of the mantle, none of the ureilites, least of all the ureilite with the most “reduced” (highest) olivine-core mg (ALH84136), has the high Fe-metal abundance predicted by the smelted-cores model. In principle, the Fe-metal generated by smelting could have been subsequently lost, but siderophile data show that ureilites never underwent efficient depletion of Fe-metal. Ureilites display strong correlations among siderophile ratios such as Au/Ir, Ni/Ir, Co/Ir, As/Ir, Se/Ir, and Sb/Ir. Ureilite siderophile depletion patterns loosely resemble siderophile fractionations, presumably nebular in origin, among carbonaceous chondrites. However, Zn, for an element of moderate volatility, is anomalously high in ureilites. A tight correlation between Au and Ni extrapolates to the low-Ni/Au side of the compositional range of carbonaceous chondrites. From this mismatch, mild but nonetheless significant depletions of refractory siderophile elements such as Ir and Os, and moderate depletions of strongly siderophile, weakly chalcophile elements such as Ni and Au, we infer that the ureilite siderophile fractionations are largely the result of a non-nebular process, i.e., removal of S-rich metallic melt, possibly with minor entrainment of Fe-metal. Several lines of trace-element evidence indicate that melt porosity during ureilite anatexis was at least moderate. The ureilite pattern of very mild depletions of extremely siderophile elements, but much deeper depletions of moderately siderophile, chalcophile elements, suggests that asteroidal core formation probably occurs in two discrete stages. In general, separation of a considerable proportion (several wt%) of S-rich metallic melt probably occurs long before, and at a far lower temperature than, separation of the remaining S-poor Fe-metal. Apart from the Fe-metal itself, only extremely siderophile elements wait until the second stage to sequester mainly into the core.