The coalification pattern in the Northern Apennines and its palaeogeothermic and tectonic significance

The rocks of the Northern Apennines predominantly consist of non-metamorphic terrigeneous deposits (flysches and molasses) some of which are preorogenic, some synorogenic and others postorogenic with respect to the nappe tectonics (Miocene). As plant fragments frequently occur in these sediments, a study of coal rank based on reflectance measurements on vitrinites (% Rm = mean value of the random reflectance in non polarized light) contributes to the clarification of the relation between the orogenic and the palaeogeothermal development. The determination of the Rm values of more than 180 samples from outcrops and three deep drillings revealed some important features. Within the pile of Liguride and Tuscanide nappes, the coal rank increases from the uppermost nappe to the lower nappes until lowgrade metamorphism is reached in the Lower Tuscanides. In the single nappes the rank decreases from the Tyrrhenian coast (internal zone) towards the Po Plain (external zone). This regional trend is disturbed only locally by young post-coalification tectonics. In the uppermost Liguride nappe (M. Antola Unit) a pre-Oligocene (i. e. pre-Apenninic) thermal event was detected. Postorogenic heating is connected with the magmatic activity of Late Miocene to Pleistocene age in Tuscany. Except for these preorogenic and postorogenic thermal events, the main coalification is generally younger than the emplacement of the nappes in the nappe pile during the Apenninic orogeny in the Miocene, but it is older than the last thrust movements and the final tensional tectonics in the internal zones of the chain. For these reasons, the main regional thermal event has to be considered as synorogenic or, more precisely, as late-synorogenic.     

On the formation of the vein-type uranium „Yellow Ores“ from the Schwarzach Area (NE-Bavaria,Germany) and on the behaviour of P,As, V and Se during supergene processes

Most of the U occurrences situated at the western edge of the Bohemian Massif show in their upper parts secondary U minerals. The immigration (P, V, As and Se) from the country rocks and the ore body, via saprolite and paleosoils into the secondary ore minerals is investigated. The P content is suggested to be closely related to hydromorphic paleosoils. From those intermediate stages it may have been brought into the upper parts of the vein structures. No laterogenic impoverishment in the wall rocks with respect to phosphorus or apatite could be determined. The arsenic distributions is also governed as at other sulfide deposits by underlying sulfides and reducing conditions of a primary hypogene ore zone, whereas vanadium content in U secondary minerals is closely related to the enclosing country rocks. Granites, on account of their low content in mafic minerals, have low V contents in U secondary minerals. Besides the Schwarzach Area, U ore mineralisations from other U occurrences have been investigated. Some of the U deposits are certainly of “per ascensum” origin and their secondary U mineralisation can well be interpreted as having been derived from the underlying primary “black ores”. However, some mineralisations cannot be classified with certainty as being “per ascensum”. They include some properties pointing to “per ascensum” (e. g. sulfide association) as well as characteristics typical for “per descensum” (small depth, large amounts of U-VI minerals). The mode of formation may in some cases be as follows: Variscan or Alpine ore mineralisations of no economic significance may have formed a reducing environment and caused U to be concentrated. Younger redistribution processes influenced by modern tectonics (uplifting) and the fluviatile drainage pattern have taken place and in some cases destroyed the primary deposits or enhanced the ore mineralisation. These processes roughly resemble those described from sandstone — hosted roll front deposits.     

Plio-pleistocene volcanism in the Andean Cordillera of Central Chile (33∘ – 40∘ S. L.)

Recent field studies in the Andean Cordillera of Central Chile (33–40 S. L.) have shown a widespread distribution around the Chile-Argentina border of pliopleistocene volcanic and pyroclastic flow (5-1 m. y. K/Ar). The older ages are found in Rio Blanco (Santiago) area and the younger in the Cola de Zorro area. They cover horizontal to sub-horizontally, with strong unconformity their meso-cenozoic basement.In the Rio Blanco area the most silicic rocks are dactic and rhyolitic ignimbrites and lava flows. They are similar to the Rhyolitic Formation (Zeil andPichler, 1967) of northern Chile.South of 36 S. L. most of the rocks are calcalkaline basalts and andesites except for the samples from the Pino Hachado area, which plot nearRittman's alkaline field. Chemical inhomogenety of the plio-pleistocene volcanic rocks is thus present in the Andes of Central Chile.

---

Zusammenfassung Neue Arbeiten über die Geologie der Cordillera de los Andes im zentralen Abschnitt Chiles (33–40 S) haben eine enorme Verbreitung von plio/pleistozänen Vulkaniten (5-1 m. a.) vor allem in der Grenzregion mit Argentinien ergeben. Die höheren Alter fand man im Gebiet von Rio Blanco (Santiago) und die jüngsten im Gebiet von Cola de Zorro.Die Vulkanite bedecken mit einer horizontalen bis subhorizontalen Verbreitung und mit einer scharfen Diskordanz alle Gesteinsserien des Mesozoikums und Känozoikums.Im Gebiet von Rio Blanco handelt es sich um Ignimbrite rhyolitischer und dacitischer Zusammensetzung. Die kieselsäurereichsten Proben sind ähnlich den Gesteinen der Rhyolit-Formation vonZeil &Pichler (1967) in Nordchile.Südlich von 36 S hat die Mehrheit der Proben eine andesitische und basaltische Zusammensetzung. Es sind kalkalkaline Gesteine mit Ausnahme der Proben von Pino Hachado, die einen starken alkalinen Trend nach dem Diagramm vonRittmann haben. Auf diese Weise ergibt sich eine chemische Inhomogenität bei den plio/pleistozänen Vulkaniten von Zentralchile.

---

Resumen Los más recientes trabajos de geología de campo en la Cordillera de los Andes de Chile Central (33–40 L. S.) han evidenciado enormes extensiones de rocas volcánicas pliopleistocénicas (5-1 m. a.) sobre todo en el área limítrofe con Argentina. Las mayores edades fueron encontradas en el area de Rio Blanco (Santiago) y las más jóvenes en el area de Cola de Zorro.Las rocas volcánicas plio-pleistocénicas cubren con disposición horizontal a subhorizontal y con fuerte discordancia a todas las rocas subyacentes del Meso y Cenozoico.En el area de Río Blanco las rocas son ignimbritas de composición riolítica a dacítica y corresponden a las muestras más silícicas similar a rocas de la Formación Riolítica del norte de Chile deZeil yPichler (1967).Al sur del paralelo 36 S la mayoría de las muestras son de composición andesítica y basáltica de naturaleza calcoalcalina excepto las muestras de Pino Hachado que presentan fuerte afînidad alcalina según el diagrama deRittmann. De esta manera se muestra que existe inhomogeneidad química en las rocas volcánicas plios-pleistocénicas de Chile Central.

---

Cordillera de los Andes (33°–40° S) , . - (), --. , , . - . 36° . - , . . . , - .

     

Damage of topaz and other minerals in the electron microscope

Summary Hydroxyl bearing topaz suffers beam-damage in the electron microscope. Irradiation by the beam rapidly produces contrast from strain fields around small needle-shaped pores about 2–5 nm wide and 30–120 nm long, produced by the loss of hydrogen as water and/or hydrogen fluoride. In the majority of cases the damage ceases after a short period of time, and the topaz electron diffraction pattern remains apparently unchanged. In a few cases complete breakdown of the topaz occurs to produce mullite and/or fine-grained -alumina, the latter usually being sputtered onto the carbon support film. The different degrees of breakdown which are found in the electron beam are similar to reactions which occur on heating in air. Although the main factor which determines the degree of beam-induced damage which occurs is believed to be temperature, the heating effect of the beam is alone unlikely to cause the reactions. The lowering of reaction temperature is attributed to mechanically induced enhancement of diffusion in the electron beam and to the weakening of chemical bonds by ionisation effects. The strain fields found in topaz were also produced in samples of humite and apatite observed in the electron microscope, and the formation of fine-grained metal oxides was found in several silicates and phosphates.

---

Zerstörung von Topas und anderen Mineralen im Elektronenmikroskop

Zusammenfassung Hydroxil-hältige Topase unterliegen im Elektronenmikroskop einer Zerstörung durch den Elektronenstrahl. Durch die Bestrahlung entstehen rasch Kontraste von gestörten Bereichen rund um kleine nadelförmige Poren von etwa 2–5 nm Durchmesser und 30–120 nm Länge, die durch den Verlust von Wasserstoff als Wasser und/oder Hydrogenfluorid verursacht werden. Meist hört die Zerstörung nach kurzer Zeit auf und das Elektronen-Beugungsbild des Topases bleibt anscheinend unverändert. In wenigen Fällen kommt es zu einem kompletten Zusammenbruch des Topases und es entsteht Mullit und/oder feinkörniges -Al₂O₃. Die unterschiedlichen Grade des Zusammenbruchs, die im Elektronenstrahl beobachtet werden, sind Reaktionen ähnlich, die beim Erhitzen in Luft auftreten. Obwohl als Hauptfaktor, der den Grad der Strahlinduzierten Zerstörung bestimmt, die Temperatur angenommen werden kann, ist es unwahrscheinlich, daß der Hitzeeffekt des Strahls allein die Reaktionen verursacht. Die Erniedrigung der Reaktionstemperatur wird der mechanisch bedingten Erhöhung der Durchdringungsfähigkeit des Elektronenstrahls und der Schwächung der chemischen Bindung durch Ionisierungseffekte zugeschrieben. Die im Elektronenmikroskop in Topas gefundenen gestörten Bereiche wurden auch in Proben von Humit und Apatit beobachtet; in verschiedenen Silikaten und Phosphaten wurde die Bildung feinkörniger Metalloxide gefunden.

---

---

With 3 Figures

---

Dedicated to Professor Dr.Josef Zemann on the occasion of his 6oth birthday.     

New data on the „Indosinian“ Orogeny from Central Thailand

The main aspects of the geosynclinal and orogenic evolution of the Petchabun foldbelt in Central Thailand are described. This area was previously thought to be deformed by the Indosinian (Triassic) orogeny. The new data show that the main orogenic event in Thailand can be dated: Post Lower Permian — Pre Uppermost Permian. Evidence is given that Paleotethys closed on Thai territory during this orogenic event. The known Upper Triassic deformations in Northern Thailand are supposed to be strictly intracontinental and therefore of minor importance.

---

Zusammenfassung Die Grundzüge der geosynklinalen und orogenen Entwicklung des Faltengürtels von Petchabun werden beschrieben. Bisher wurde angenommen, daß dieses Gebiet während der Indosinischen Orogenese (Trias) deformiert wurde. Die neuen Daten belegen, daß die bedeutendste Orogenese in Thailand nach dem Unter Perm einsetzte (West-Thailand) und vor dem höchsten Perm abgeschlossen war (Petchabun). Die sog. Paleotethys wurde während dieser Orogenese hier geschlossen. Die bekannten obertriadischen Deformationen sind dagegen rein intrakontinental und somit von untergeordneter Bedeutung.

---

Résumé Les traits principaux du développement géosynclinal et orogénique de la ceinture plissée du Petchabun (Thailande) sont décrits. Jusqu'à présent on pensait que cette région avait été déformée pendant l'orogenèse «Indosinienne» (Trias). Les données nouvelles indiquent que l'orogenèse la plus importante a commencée après le Permien inférieur (dans l'Ouest de la Thailande) et qu'elle s'est terminée avant le Permien supérieur (région de Petchabun). Ici, la soi-disant «Paléotéthys» s'est fermée au cours de cette orogenèse. Les déformations bien connues du Trias supérieur sont exclusivement intracontinentales et n'ont ainsi qu'une signification subordonnée.

---

Petchabun. , (). , ( ) (Petchabun). . . .

     

Fracturation tertiaire et évolution des contraintes en Bavière orientale: le Jura franconien et la forêt bavaroise (R.F.A.)

Résumé L'analyse géométrique et cinématique de la fracturation dans le Jura franconien et la bordure occidentale du Massif bohémien met en évidence les mécanismes de la tectonique cassante d'âge teriaire, essentiellement ceux des grands accidents SE-NW (lignes de Pfahl et de Franconie) qui ont présenté successivement des jeux en coulissement dextre, en faille normale et en faille inverse. Cinq états de contrainte ont été caractérisés et comparés à ceux définis antérieurement dans le Jura souabe, en liaison avec la cinématique des plaques Europe et Afrique: compression N-S, distension E-W, compression NE-SW puis E-W, distension N-S.

---

The analysis of both the geometric and the kinematic cenozoic faulting in the Franconian Jura and in western Bohemia enables to characterize the mechanisms of cenozoic tectonics. More especially dextral strike-slip, normal fault and reverse fault have successively occurred along large SE-NW fault line, as the Pfahl and the Franconian fault systems. Five main stress patterns have thus been identified and then compared with those previously described in Swabian Jura. They are related to the kinematic of Europe and Africa plates, i. e.: (1) N-S compression, (2) E-W distension, (3) SW-NE compression, (4) E-W compression, (5) N-S distension.

---

Zusammenfassung Durch die geometrische und kinematische Analyse der Brüche wird die tertiäre Bruchtektonik (tectonique cassante) im Fränkischen Jura und am westlichen Rand des Böhmischen Massifs belegt. Es handelt sich im wesentlichen um die großen SE-NW orientierten Störungen der Linie von Pfahl und der Fränkischen Linie, die nacheinander als dextrale Blattverschiebungen, als Normalverwerfungen und als inverse Verwerfungen wirkten. Fünf Spannungszustände können charakterisiert und mit jenen, die bereits im Schwäbischen Jura definiert wurden, verglichen werden. Sie spiegeln die verschiedenen Stadien der kinematischen Entwicklung der europäischen und afrikanischen Platte wider: Kompression N-S, Zerrung E-W, Kompression NE-SW, sodann E-W, Zerrung N-S.

---

(tectonique cassante) . , , SE-NW , , , . 5 . : - , - , - , - - .

     

Earthquakes in Switzerland and surrounding regions during 2006

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2006. During this period, 572 earthquakes and 91 quarry blasts were detected and located in the region under consideration. Of these earthquakes, two occurred in conjunction with the construction of the new Gotthard railway tunnel and 165 were induced artificially by the stimulation of a proposed geothermal reservoir beneath the city of Basel. With 20 events with M _L ≥ 2.5, five of which were artificially induced, the seismic activity in the year 2006 was far below the average over the previous 31 years. Nevertheless, six events were felt by the public, most prominently the strongest of the induced Basel events (M _L 3.4), which caused some non-structural building damage. Noteworthy are also the two earthquakes near Cortaillod (M _L 3.2), on the shore of Lake Neuchatel, and in Val Mora (M _L 3.5), between the Engadin and Val Müstair, as well as the 42 aftershocks of the M _L 4.9 Vallorcine earthquake, between Martigny and Chamonix, of September 2005. Editorial handling: Stefan Bucher     

Continuous,Direct Gas-Geochemical Monitoring in Hydrothermal Vents: Installation and Long-Term Operation on Nisyros Island (Greece)

In this paper the installation and long-term operation of a system for continuous monitoring of fumarolic gases is described. Several physicochemical and gas-geochemical parameters such as the concentration of CO₂, H₂S and CO in the fumarolic emissions, as well as the temperatures of the hydrothermal steam and soil in close vicinity of the fumarole and steam pressure are measured in short-time intervals (typically 15 seconds). Data are logged on-site and in parallel transferred to a remote station by digital telemetry. Specially developed software enables the real-time observation of the local conditions in the crater and full bidirectional control of the monitoring system. Fluctuations in the monitored parameters are also reported. From the data presented it can be concluded that environmental conditions (direction and strength of wind, precipitation) will interact with some of the parameters monitored. These influences can only be revealed by continuously operated monitoring systems.     

Conceptualising State‐Controlled Resort Islands for an Environment‐Friendly Development of Tourism: The Maldivian Experience

The Maldives host a sophisticated and competitive international tourist industry which has replaced fishing as the dominant economic activity. With their rich tropical reef ecosystems and the abundant biodiversity of their marine environment, a total of 86 uninhabited islands had been converted into Resort Islands by the end of 2000. Resort Islands are equipped with comprehensive facilities for accommodation, food, recreation and leisure. They are also strictly reserved for foreign tourists and guarantee complete privacy. This gives the benefit of averting conflicts of acculturation with local islanders. In the arena of impacts on the physical environment, however, the consumptive leisure lifestyle of the tourists has been harmful to the Resort Islands as seen in sewage, garbage and waste pollution, as well as reef destruction and beach erosion. While the government of the Maldives takes great effort to harmonise tourism and the environment, the growth of mass tourism in the last 20 years has engendered grave environmental impacts. For future sustainable development of the Resort Islands, the tourists' environmental awareness must be increased to promote greater responsibility for the protection of the fragile coral and reef ecosystems of the Maldives.