An anticlockwise P–T–t path at high‐pressure,high‐temperature conditions for a migmatitic gneiss from the island of Fjørtoft,Western Gneiss Region,Norway, indicates two burial events during the Caledonian orogeny     

Penglei Liu  Hans‐Joachim Massonne 《Journal of Metamorphic Geology》2019,37(4):567-588

The Blåhø Nappe on the island of Fjørtoft, which represents an isolated portion of the Seve Nappe Complex in the Western Gneiss Region, Norway, has been suggested to have experienced two deep burial cycles during the Caledonian orogeny. However, evidence on this multiple burial process by the derivation of a pressure–temperature–time (P–T–t) path has never been given in the literature. In this study, the ‘diamondiferous’ kyanite–garnet gneiss from the Blåhø Nappe on Fjørtoft was revisited to determine if such a process was correct. Two types of garnet, porphyroblastic garnet‐1 and fine‐grained garnet‐2, were recognized in the gneiss. The core of garnet‐1 is poor in Ca and documents P–T conditions of 1.2–1.3 GPa at c. 880°C based on pseudosection modelling. The inner rims of garnet‐1 and the core of garnet‐2 are both richer in Ca, recording P–T conditions of 1.35–1.45 GPa and 770–820°C. Application of conventional geothermobarometry on the outer rim of garnet‐1 and the rim of garnet‐2 yielded retrograde P–T conditions of 0.75–0.90 GPa and 610–685°C. These estimates define an anticlockwise P–T path at pressures below 1.5 GPa. Accessory monazite was dated with the electron microscope. Relicts of detrital monazite in the gneiss point to Sveconorwegian and possibly also Cryogenian provenance for the detritus of the sedimentary protolith. Metamorphic monazite in the gneiss records a wide age range from 460 to 380 Ma, with a peak c. 435 Ma and a shoulder at 395 Ma. These data suggest that the original (Ediacaran?) Baltica margin sediment (gneiss protolith) was transported to the base of an overlying plate during the early Caledonian (pre‐Scandian) orogeny. A long residence time of the metasedimentary rock at this base caused its heating to 880°C and homogenization of the early garnet chemistry. The late Caledonian (Scandian) collision between Baltica and Laurentia led to further burial, during which the studied gneiss was close to the former surface of the downgoing continental plate and, thus, cooled. The reconstructed P–T–t path confirms the multiple burial history of the Blåhø Nappe but contradicts previous ideas of deep burial of the Fjørtoft gneiss to more than 100 km.  相似文献   

Downscaling daily precipitation time series using a combined circulation- and regression-based approach   总被引：2，自引：1，他引：1  

Wei Yang  András Bárdossy  Hans-Joachim Caspary 《Theoretical and Applied Climatology》2010,102(3-4):439-454

The aim of this paper is to introduce a new conditional statistical model for generating daily precipitation time series. The generated daily precipitation can thus be used for climate change impact studies, e.g., crop production, rainfall–runoff, and other water-related processes. It is a stochastic model that links local rainfall events to a continuous atmospheric predictor, moisture flux, in addition to classified atmospheric circulation patterns. The coupled moisture flux is proved to be capable of capturing continuous property of climate system and providing extra information to determine rainfall probability and rainfall amount. The application was made to simultaneously downscale daily precipitation at multiple sites within the Rhine River basin. The results show that the model can well reproduce statistical properties of daily precipitation time series. Especially for extreme rainfall events, the model is thought to better reflect rainfall variability compared to the pure CP-based downscaling approach.  相似文献   

Fluid‐induced breakdown of monazite in medium‐grade metasedimentary rocks of the Pontremoli basement (Northern Apennines,Italy)          下载免费PDF全文

D. Lo Pò  R. Braga  H.‐J. Massonne  G. Molli  A. Montanini  T. Theye 《Journal of Metamorphic Geology》2016,34(1):63-84

The last (decompression) stages of the metamorphic evolution can modify monazite microstructure and composition, making it difficult to link monazite dates with pressure and temperature conditions. Monazite and its breakdown products under fluid‐present conditions were studied in micaschist recovered from the cuttings of the Pontremoli1 well, Tuscany. Coronitic microstructures around monazite consist of concentric zones of apatite + Th‐silicate, allanite and epidote. The chemistry and microstructure of the monazite grains, which preserve a wide range of chemical dates ranging from Upper Carboniferous to Tertiary times, suggest that this mineral underwent a fluid‐mediated coupled dissolution–reprecipitation and crystallization processes. Consideration of the chemical zoning (major and selected trace elements) in garnet, its inclusion mineralogy (including xenotime), monazite breakdown products and phase diagram modelling allow the reaction history among accessory minerals to be linked with the reconstructed P–T evolution. The partial dissolution and replacement by rare earth element‐accessory minerals (apatite–allanite–epidote) occurred during a fluid‐present decompression at 510 ± 35 °C. These conditions represent the last stage of a metamorphic history consisting of a thermal metamorphic peak at 575 °C and 7 kbar, followed by the peak pressure stage occurring at 520 °C and 8 kbar. An anticlockwise P–T path or two clockwise P–T loops can fit the above P–T constraints. The former path may be related to a context of late Variscan strike‐slip‐dominated exhumation with minor Tertiary (Alpine‐related) reworking and fluid infiltration, while the latter requires an Oligocene–Miocene fluid‐present tectono‐metamorphic overprint on the Variscan paragenesis.  相似文献   

Stable isotope and mineralogical investigation of the genesis of amethyst geodes in the Los Catalanes gemological district,Uruguay, southernmost Paraná volcanic province     

Lauren C. Duarte  Leo A. Hartmann  Luiz H. Ronchi  Zsolt Berner  Thomas Theye  Hans J. Massonne 《Mineralium Deposita》2011,46(3):239-255

Stable isotopes (C, O, S) and mineralogical studies of the world-class amethyst-geode deposits of the Los Catalanes gemological district, Uruguay, constrain processes operative during mineral deposition. The mineralized basaltic andesites from the Cretaceous Paraná volcanic province are intensely altered to zeolites (clinoptilolite) and clay minerals. Variations in the δ¹⁸O values of silica minerals in geodes (chalcedony, quartz, and amethyst) are much larger and the values generally somewhat lower (21.2–31.5‰) in the Uruguayan deposits than in the Ametista do Sul area of southern Brazil. The range of δ³⁴S values (−15.0 to −0.3‰) of altered basaltic rocks requires (in addition to sulfur of magmatic origin) the involvement of ³⁴S-depleted sedimentary sulfur from bacterial sulfate reduction. The results delimit the mineralizing processes to a post-eruption environment characterized by low temperature and strong interaction of the lava flows with meteoric water.  相似文献   

Floodplain sediments on the divide between Huang He and Chang Jiang,Gansu Province,NW China     

Hans-Joachim Pachur  Bernd Wünnemann  Linyuan Zhang  Hucai Zhang  Yuzheng Ma 《GeoJournal》1994,34(1):97-106

At Lingfeng, (34°17'N, 104°08'E) on the northern slopes of the Qinling Mountains, a stratigraphic survey was made of a 21-m-profile of floodplain sediments on the watershed between the Chang Jiang (Yangtze River) and Huang He (Yellow River) at 2500 m above sea level. The sediments contain <2 m thick layers of peat and detritical plant matter that had been deposited on the floodplain of the Langouhe. If the radiometric dates are reliable, the chronology of the site spans some 80,000 years, covering an accumulation process from the terminal Last Interglacial up to <24 ka BP. The phase >73 ka BP had cool and wet conditions with a coniferous forest vegetation. Between 73 ka and > 40 ka colder and drier conditions were likely. The vegetation changed from aPicea-Pinus forest to aPicea-Abies-Larix forest with a later increase of non-arboreal pollen. Around 40 ka the climate was warm and moist. The accumulation of silt and organic matter as well as the development of a mixed coniferous forest with high rates of thermophilous trees(Quercus, Castanea) characterize the interstadial conditions at this time. Later on, the climate changed to cool and moist conditions, evidenced by silt and peat accumulation and a coniferous forest vegetation up to <24 ka BP. The loess in this area was deposited after 24 ka and erosion by the tributaries of Chang Jiang and Huang He to a depth of at least 40 m created the watershed between the two river systems.  相似文献   

H. V. KLAPDOR (ed.): Weak and Electromagnetic Interactions in Nuclei,Proceedings of the International Symposium,Heidelberg, July 1–5, 1986, Springer-Verlag,Berlin-Heidelberg, 1986. Preis: DM 149,—. ISBN 3-540-17255-6     

Hans-Joachim Haubold 《Astronomische Nachrichten》1988,309(3):176-176

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Complementary roles of European and national institutions under the Common Fisheries Policy and the Marine Strategy Framework Directive     

Hans-Joachim Rätz  Hendrik Dörner  Robert Scott  Thomas Barbas 《Marine Policy》2010

Exploited fish and shellfish stocks in European marine waters underlie the Common Fisheries Policy (CFP). The next round of reform of the CFP is due for completion in 2012. The exploitation at maximum sustainable yield (MSY) may be confirmed as the common environmental objective for good environment status (GES) of exploited fish and shellfish stocks of the reformed CFP and the Marine Strategy Framework Directive (MSFD). The foreseen time horizon to achieve or maintain GES by 2020 appears inconsistent with the World Summit on Sustainable Development UN agreement in 2002, which stipulates that maintenance or restoring of stocks to produce MSY be realized by 2015. The MSFD requires instead that by 2015 the national programmes of measures be designed in order to become operational the following year (2016).  相似文献   

Ozeane: Ergebnisse der 7. Sitzung der Kommission für nachhaltige Entwicklung (CSD) der Vereinten Nationen     

Schlimm  Jutta  Stietzel  Hans-Joachim 《Ocean Dynamics》1999,51(10):103-107

Ocean Dynamics - Die 7. Sitzung der Kommission für nachhaltige Entwicklung (Commission on Sustainable Development, CSD) der Vereinten Nationen fand vom 19. bis 30. April 1999 im...  相似文献   

Tectono-thermal evolution of a part of a Variscan magmatic arc: The Odenwald in the Mid-German Crystalline Rise     

A. P. Willner  H. -J. Massonne  A. Krohe 《International Journal of Earth Sciences》1991,80(2):369-389

Geothermobarometric studies of plutonic and medium to high grade metamorphic rocks of the Odenwald (SW Germany) provide data for the construction of PT-paths of four different crustal sections within a part of a magmatic arc of the Mid-European Hercynian orogen.The evolution of the thermal structure of the Odenwald is characterized by an early geotherm of 35–40°C/km after crustal stacking involving rocks with medium pressure relics. Peak PT-conditons reached 4–5 kbar and 650°C. Only rocks of the northernmost Odenwald show evidence for PT conditions related to a higher geotherm at this time. Early uplift occurred during normal oblique sinistral strike shear. The central Odenwald was uplifted into a level corresponding to 3 kbar during intrusion of calcalkaline magmas. The northernmost Odenwald subsided at the same time, as proved by an anticlockwise PT-path. Subsequently, in the southern and eastern Odenwald, rapid uplift caused a further increase of the geotherm to 60–80°C/km. This is concomitant with extension and granitoid intrusions.Crustal thickening in the Odenwald is restricted to an early phase during the Devonian. The magmatic arc developed within a »pull-apart«-like structure during the Lower Carboniferous.

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Zusammenfassung Geothermobarometrische Untersuchungen an Plutoniten und mittelbis hochgradigen Metamorphiten des Odenwaldes ermöglichen die Konstruktion von PT-Pfaden für vier Krustenabschnitte in einem Teil eines variszischen magmatischen Gürtels.Zu Beginn der Entwicklung der thermischen Struktur des magmatischen Gürtels stellte sich ein Geotherm von 35–40°C/km nach einer Krustenstapelung ein, in die Gesteine mit Mitteldruckrelikten einbezogen wurden. Die PT-Bedingungen zum Höhepunkt der Metamorphose erreichten 4–5 kbar und 650°C. Nur Gesteine des nördlichen Odenwaldes belegen PT-Bedingungen, die auf einen höheren Geotherm zu dieser Zeit hinweisen. Frühe Hebung fand entlang von Schrägabschiebungen statt. Der zentrale Odenwald wurde bei gleichzeitiger Intrusion kalkalkaliner Magmen in ein Niveau entsprechend 3 kbar gehoben. Der nördliche Odenwald sank gleichzeitig ab, wie durch einen gegen den Uhrzeigersinn gerichteten PT-Pfad belegt wird. Im südlichen und östlichen Odenwald bewirkte danach schnelle Hebung einen weiteren Anstieg des Geotherms auf 60–80°C/km verbunden mit Dehnung und Intrusion granitoider Magmen.Während Krustenverdickung auf eine frühe Phase im Devon beschränkt ist, entwickelt sich der magmatische Gürtel im Bereich des Odenwaldes im Unterkarbon innerhalb einer » pull apart «-ähnlichen Struktur.

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Résumé Dans l'Odenwald (sud-ouest de l'Allemagne), l'étude géothermobarométrique de roches plutoniques et de roches métamorphiques de degré moyen à élevé fournit les données qui permettent la construction de trajets (P, T) relatifs à quatre sections crustales dans une partie d'un arc magmatique de l'orogène varisque d'Europe.Le début de l'évolution de la structure thermique de l'Odenwald a été marqué par un gradient géothermique de 35–40°C/Km, en suite à un empilement crustal impliquant des roches qui contiennent des reliques de pression moyenne. Les conditions (P, T) du métamorphisme maximal furent de 4–5 Kbar et 650°C. Seules les roches de l'Odenwald septentrional témoignent d'un gradient plus élevé à cette époque. Un soulèvement hâtif s'est produit le long de zones de cisaillement sénestres. Concomitamment à l'intrusion de magmas calcoalcalins, l'Odenwald central a été le siège d'un soulèvement jusqu'à un niveau correspondant à 3 Kbar. En même temps, l'Odenwald septentrional s'affaissait, comme en témoigne uu trajet (P, T) anti-horlogique. Par la suite, dans l'Odenwald méridional et oriental, une montée rapide associée à un processus d'extension et à l'intrusion de magmas granitoïdes a amené le gradient géothermique à des valeurs de 60 à 80° /Km.L'épaississement crustal est cantonné à une phaseprécoce d'âge dévonien, tandis que l'arc magmatique s'est développé dans une structure ra pullapart « au cours du Carbonifère inférieur.

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T- . , , , 35–40°/ . T- 650° 4–5 , T- , . . , 3 , - . , T-, . 60–80°/, . , , «pullapart» .

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Thermodynamics of the xanthoconite-proustite and pyrostilpnite-pyrargyrite phase transition as determined by abrasive stripping voltammetry     

Birgit Lange  Fritz Scholz  Hans-Joachim Bautsch  Ferdinand Damaschun  Gert Wappler 《Physics and Chemistry of Minerals》1993,19(7):486-491

The electrochemical reduction of xanthoconite, proustite, pyrostilpnite, and pyrargyrite was studied by abrasive stripping voltammetry, a technique which is based upon a preliminary mechanical transfer of trace amounts of the mineral onto the surface of a paraffin impregnated graphite electrode. Because the electrochemical reduction proceeds near to reversibility and is very similar for each pair of minerals, the peak potentials in differential pulse voltammetry can be used to calculate the standard enthalpy of phase transformation of xanthoconite to proustite and of pyrostilpnite to pyrargyrite: _T H _{(xanth proust)} ^O = 35.46 ± 14.15 kJ/mol and _T H _{(pyrostilp pyrarg)} ^O = 38.85 ± 6.60 kJ/mol. These values are not accessible otherwise until now.  相似文献