Präorogene Versenkungstiefe und Orogenese als Diagenesefaktoren für altpaläozoische Kontinentalrandbildungen der Nördlichen Appalachen in Quebec,Kanada     

Reinhard Hesse  Olugbenga Ogunyomi 《International Journal of Earth Sciences》1980,69(2):546-566

This paper presents data and preliminary interpretations on the diagenesis of Early Paleozoic continental margin deposits along a traverse of the Quebec Appalachians near Quebec City, Canada. Regional variations in diagenesis were studied using the thermal maturation of organic matter in shales (reflectance measured on asphaltic bitumen, 105 samples) and illite crystallinity (330 samples). These revealed a regional southeastward increase in grade from the late middle and late stage of diagenesis to epimetamorphism, which is reflected in the distinction of four zones: Zone I representing the late middle diagenetic stage has a mean reflectance in oil (R₀) between 1.0 and 1.5% and illite crystallinity between 5.5 and 8.0 mm. Zone II (late diagenetic stage) is characterized by R₀=1.5–2.6% and illite crystallinity between 3.5 and 5.5 mm. Anomalously poor illite crystallinities in Zone II (i. e. 5.5 to 8.0 mm) were obtained for black shales, in which improvement of crystallinity lags behind red and green shales. Zone II is subdivided into subzones IIA and IIB. In the former, reflectance and illite crystallinity increase, within individual nappes, as a function of age or depth of burial. In the latter no such dependence is observed, instead diagenetic grade increases regionally in a southeastward direction as it does in zones III and IV. Zone III represents the anchizone in which observed reflectance values R₀ range from 2.6 to 4.0% and illite crystallinities from 2.0 to 3.1 mm. In Zone IV (epizone) illite crystallinity is less than 2.0 mm (In terms of reflectance the anchi-zone/epizone boundary was not defined). Zones I and IIA are anomalous in that lower tectonic units are diagenetically less altered than higher tectonic units: R₀ varies from 1.71 to 2.30% for the highest tectonic unit (Cambrian Chaudière Nappe), 1.53 to 1.90% (Cambro-Ordovician Bacchus Nappe) and 1.08 to 1.46% (Lower Ordovician Pointe-de-Lévy Nappe) for the middle tectonic units, and 1.01 to 1.15% for the lowest tectonic unit (Middle Ordovician Quebec Promotory Nappe). Thermal maturation and mineral diagenesis in zone IIA are probably due solely to sedimentary burial at the original site of deposition (by an estimated 6 to 7 km of younger sediments) because in this zone the highest diagenetic grade occurs in the highest tectonic unit. Diagenesis in the nappes of zone I probably required additional tectonic burial by the higher nappes because original sedimentary thicknesses that once overlay these Lower and Middle Ordovician rocks appear insufficient to have caused the observed degree of diagenesis. Diagenesis in zone IIA, therefore, was most likely formed entirely before orogenesis; in zone I it is probably partly pre-orogenic in origin and has been transported during nappe-movement. In contrast, diagenesis and metamorphism in zones IIB to IV are interpreted as related to regional synorogenic heating in conjunction with the Taconic orogeny. Thermal maturation levels in zone I indicate that the rocks have not yet passed the “oil window” which is of interest for petroleum exploration in Quebec. An extended English version of this paper is in preparation for the Bulletin of Canadian Petroleum Geology (Ogunyomi et al., ms.).  相似文献   

Secondary Ion Mass Spectrometry Bias on Isotope Ratios in Dolomite–Ankerite,Part I: δ18O Matrix Effects          下载免费PDF全文

Maciej G. Śliwiński  Kouki Kitajima  Reinhard Kozdon  Michael J. Spicuzza  John H. Fournelle  Adam Denny  John W. Valley 《Geostandards and Geoanalytical Research》2016,40(2):157-172

We document the development of a suite of carbonate mineral reference materials for calibrating SIMS determinations of δ¹⁸O in samples with compositions along the dolomite–ankerite solid solution series [CaMg(CO₃)₂–CaFe(CO₃)₂]. Under routine operating conditions for the analysis of carbonates for δ¹⁸O with a CAMECA IMS 1280 instrument (at WiscSIMS, University of Wisconsin‐Madison), the magnitude of instrumental bias along the dolomite–ankerite series decreased exponentially by ~ 10‰ with increasing Fe content in the dolomite structure, but appeared insensitive to minor Mn substitution [< 2.6 mol% Mn/(Ca+Mg+Fe+Mn)]. The compositional dependence of bias (i.e., the sample matrix effect) was calibrated using the Hill equation, which relates bias to the Fe# of dolomite–ankerite [i.e., molar Fe/(Mg+Fe)] for thirteen reference materials (Fe# = 0.004–0.789); for calibrations employing either 10 or 3 μm diameter spot size measurements, this yielded residual values ≤ 0.3–0.4‰ relative to CRM NBS 19 for most reference materials in the suite. Analytical precision was ± 0.3‰ (2s, standard deviations) for 10‐μm spots and ± 0.7‰ (2s) for 3‐μm spots, based on the spot‐to‐spot repeatability of a drift monitor material that ‘bracketed’ each set of ten sample‐spot analyses. Analytical uncertainty for individual sample analyses was approximated by a combination of precision and calibration residual values (propagated in quadrature), suggesting an uncertainty of ± 0.5‰ (2s) for 10‐μm spots and ± 1‰ (2s) for 3‐μm spots.  相似文献   

Sensitivity of the last glacial inception to initial and surface conditions     

Claudia Kubatzki  Martin Claussen  Reinhard Calov  Andrey Ganopolski 《Climate Dynamics》2006,27(4):333-344

We investigate the sensitivity of simulations of the last glacial inception (LGI) with respect to initial (size of the Greenland ice sheet) and surface (state of ocean/vegetation) conditions and two different CO₂ reconstructions. Utilizing the CLIMBER-2 Earth system model, we obtain the following results: (a) ice-sheet expansion in North America at the end of the Eemian can be reduced or even completely suppressed when pre-industrial or Eemian ocean/vegetation is prescribed. (b) A warmer surrounding ocean and, in particular, a large Laurentide ice sheet reduce the size of the Greenland ice sheet before and during the LGI. (c) A changing ocean contributes much stronger to the expansion of the Laurentide ice sheet when we apply the CO₂ reconstruction according to Barnola et al. (Nature 329:408–414, 1987) instead of Petit et al. (Nature 399:429–436, 1999). (d) In the fully coupled model, the CO₂ reconstruction used has only a small impact on the simulated ice sheets but it does impact the course of the climatic variables. (e) For the Greenland ice sheet, two equilibrium states exist under the insolation and CO₂ forcing at 128,000 years before present (128 kyear BP); the one with an ice sheet reduced by about one quarter as compared to its simulated pre-industrial size and the other with nearly no inland ice in Greenland. (f) Even the extreme assumption of no ice sheet in Greenland at the beginning of our transient simulations does not alter the simulated expansion of northern hemispheric ice sheets at the LGI.  相似文献   

A Sustainability Framework for Enhancing the Long-Term Success of Lulucf Projects     

Reinhard Madlener  Carmenza Robledo  Bart Muys  Javier T. Blanco Freja 《Climatic change》2006,75(1-2):241-271

Collateral impacts of land use and land-use change and forestry (LULUCF) projects, especially those concerning social and environmental aspects, have been recognized as important by the Marrakech Accords. The same applies to the necessity of assessing and, if possible, of quantifying the magnitude of these impacts. This article aims to define, clarify and structure the relevant social, economic and environmental issues to be addressed and to give examples of indicators that ought to be included in the planning, design, implementation, monitoring, and ex post evaluation of LULUCF projects. This is being done by providing a conceptual framework for the assessment of the sustainability of such projects that can be used as a checklist when dealing with concrete projects, and that in principle is applicable to both Annex I and non-Annex I countries. Finally, a set of recommendations is provided to further develop and promote the proposed framework.  相似文献   

AMS 14C dating of tundra lake sediments using chironomid head capsules     

Marie-Andrée Fallu  Reinhard Pienitz  Ian R. Walker  Jonathan Overpeck 《Journal of Paleolimnology》2004,31(1):11-22

Radiocarbon dating of late-Quaternary sediments from high-latitude lakes is often complicated by the influx of old carbon, reservoir effects, or both. If terrestrial plant macrofossils are also absent, the dating of bulk sediment often provides the only means to establish chronologies for these problematic sediment sequences. Given that chironomid (non-biting midge) remains are sufficiently abundant in many northern lakes to be ¹⁴C-dated via the accelerator mass spectrometry (AMS) method, we decided to explore their utility in age-model development. Five age determinations based on chironomid material were obtained from a lake sediment core sampled in the shrub tundra of northern Québec. These results were compared to six AMS bulk sediment ages, as well as to a date obtained from Drepanocladus spp. The chironomids yielded consistently younger ages (with increasing age offset upcore), confirming both the presence of a reservoir effect and the value of chironomids in establishing more reliable ¹⁴C chronologies.  相似文献   

Multi-scale rock surface area quantification—a systematic method to evaluate the reactive surface area of rocks     

Cornelius Fischer  Reinhard Gaupp 《Chemie der Erde / Geochemistry》2004,64(3):241-256

An integration of methods to quantify the surface area of porous solid materials with a broad span of spatial resolution is presented. The application of it is to detect and quantify the rock surface area modifications caused by fluid-rock interactions on different scales from several nanometres to metres. The new approach is to study the fluid-accessible surface area of rock fragments during dissolution processes.In this paper, diverse methods for surface quantification at different levels of surface detail were adapted for the application of rock surface quantification and porosimetry measurements. The geometric external surface area of rock fragments can be determined by paraffin wax coating and, in special cases, by parallelepiped surface estimations. This geometrical surface area of rock polyhedrons is equal to the macroscopic bounding surface area of a rock volume. Representative surface details on the scale of micrometres to millimetres on geometrical surface area can be quantified by mechanical roughness analyses. The resultant roughness factors are compared to optical roughness quantifications by confocal laser scanning microscopy and white light interferometry and can indicate modifications of the pore space up to several hundred nanometres. The comparison of rock pore space data, measured by both mercury intrusion porosimetry and nitrogen adsorption, quantifies the surface area of pores with a diameter of approximately 2 nm.These various surface data at different levels of detail were integrated to get an estimation of this surface area, which affects fluid-rock interactions. The proposed concept has the potential to trace the multi-scale rock surface area evolution in response to fluid-rock interaction processes.The importance of this concept is its application beyond the laboratory survey. For example, additionally to their specific surface area, the reactive surface area of rock particles in a mining dump is controlled by geometrical size and surface roughness of particles.  相似文献   

Meteorologische Faktoren im Gelände nahe Tromsö während der Schneeschmelze     

Reinhard H. G. Mook 《Pure and Applied Geophysics》1965,60(1):201-216

Zusammenfassung Für ein schmelzendes Schneefeld im Gebirge bei Tromsö wird die Energieaufnahme abgeschätzt. Stichprobenhafte Beobachtungen von Strahlung, Temperatur, Feuchtigkeit und Wind im Gelände werden auf Registrierungen in Tromsö bezogen und aus stochastischen Zusammenhängen die tägliche Schmelzwassermenge während zwei Monaten überschlagsmässig bestimmt. Sie wird mit dem beobachteten Abfluss verglichen.

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Summary For a melting snow field in the mountains near Tromsö the energy input is estimated. Samplelike observations of radiation, temperature, humidity and wind in the field are referred to registrations of these variables at Tromsö. From the stochastic relations the daily snow melt is approximately calculated through two months, and is compared with observed runoff.

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Symbole A atmosphärische Gegenstrahlung - a Konstante - Albedo - b Konstante - c Konstante - D Richtung - Differenz - E effektive Entfernung (Korrelation) - e Dampfdruck - F relative Feuchte - G Globalstrahlung - H spezifische Feuchte - K kurzwelliger Strahlungssaldo - k Konstante - L langwelliger Strahlungssaldo - N Niederschlagsmenge - n Anzahl Beobachtungen - Gebietsfläche - p Korrelationsparameter - Q Saldo sensibel und latent übertragener Wärme - q Wärmeübergangszahl - Stefan-Boltzmann-Konstante - T Temperatur - V Windgeschwindigkeit - W Schmelzwassermenge;W ₁ undW ₂ abgeschätzte und beobachtete Abflussintensität - Bewölkungsgrad - Z vertikale Höhe - Æ Äquivalenttemperatur - bezüglich Bewölkung 3/10 - bezüglich Bewölkung >3/10 - * bezüglich Schneeoberfläche - ' (Index) bezeichnet Referenzwert  相似文献   

über Vereisungsperioden und Vereisungsspuren in Brasilien     

Reinhard Maack 《International Journal of Earth Sciences》1957,45(3):547-595

Zusammenfassung In Brasilien wurden Vereisungsspuren vom Präkambrium bis zum Oberkarbon festgestellt. Aus den bisherigen Untersuchungen ergibt sich, daß das gesamte Paläozoikum bis zum Beginn des Perm kalt war. Präkambrische bis kambrische Glazialschichten weisen die Lavras-Serie in Minas und Bahia auf. Gotlandische Tillite und Driftablagerungen liegen im Staate Paraná; unmittelbar darüber beobachtet man unterdevonische Sandsteine mit glazialem Driftmaterial. Auch das Oberdevon in Nordost-Brasilien enthält Tillite. In der vorliegenden Arbeit werden besonders die Vereisungsspuren in Südbrasilien eingehender behandelt. Die jetzt getrennten Gondwanablöcke von Südamerika und Afrika bildeten früher eine geschlossene Einheit. Ohne transversale Krustenverschiebungen sind die auf den verschiedenen Gondwanaländern verteilten Vereisungsspuren nicht zu erklären. Damit entfällt die Existenz eines südatlantischen Urozeans.  相似文献   

Assessment of freshwater diatoms as quantitative indicators of past climatic change in the Yukon and Northwest Territories,Canada   总被引：3，自引：0，他引：3  

Reinhard Pienitz  John P. Smol  H. John B. Birks 《Journal of Paleolimnology》1995,13(1):21-49

We identified, enumerated, and interpreted the diatom assemblages preserved in the surface sediments of 59 lakes located between Whitehorse in the Yukon and Tuktoyaktuk in the Northwest Territories (Canada). The lakes are distributed along a latitudinal gradient that includes several ecoclimatic zones. It also spans large gradients in limnological variables. Thus, the study lakes are ideal for environmental calibration of modern diatom assemblages. Canonical correspondence analysis, with forward selection and Monte Carlo permutation tests, showed that maximum lake depth and summer surface-water temperature were the two environmental variables that accounted for most of the variance in the diatom data. The concentrations of sodium and calcium were also important explanatory variables. Using weighted-averaging regression and calibration techniques, we developed a predictive statistical model to infer lake surface-water temperature, and we evaluated the feasibility of using diatoms as paleoclimate proxies. This model may be used to derive paleotemperature inferences from fossil diatom assemblages at appropriate sites in the western Canadian Arctic.  相似文献   

Relations for local magnitude at seismic station Berggiesshübel     

Vladimír Tobyáš  Reinhard Mittag 《Studia Geophysica et Geodaetica》1993,37(2):159-167

Summary New calibrating functions for the local magnitude M_L based on the maximum ratio of amplitude and period of the S_g - wave, the short-period surface wave and the duration of the whole seismogram and its part starting with the arrival of the S_g -wave recorded by the short-period vertical seismograph at Berggiesshübel (BRG) have been derived. The consistency of these magnitudes was tested for weak earthquakes and industrial blasts in the magnitude range of 1.7–3.5 and epicentral distances up to 80 km. Their differences were 0.2 of a magnitude unit at most, with the exception of the surface wave magnitudes which were systematic by about 0.9 of a magnitude unit greater. The calibrating function for the S_g - wave was compared with the functions for M_L(POT) and M_L(TRI) which were derived by other authors for several Central European seismic stations, including BRG.  相似文献