应用CH_4/N_2指标估算塔里木盆地天然气热成熟度     

刘全有  刘文汇  戴金星  金之钧  Ralf Littke  Jan Hollenstein 《地学前缘》2008,15(1):209-216

通过对塔里木盆地满加尔凹陷低成熟煤岩在开放在线程序升温体系的热模拟实验,获得煤岩在不同温度点的热分解产物CH4、CO和N2,并对模拟后残留产物进行了镜质体反射率测试,建立了镜质体反射率与对应受热温度之间的关系。煤岩镜质体反射率与热温度之间的二阶关系表达为:Ro=0.0014×T+0.109,r=0.9931(Ro<0.6%);Ro=0.0067×T-1.5855,r=0.9996(Ro>0.6%)。通过上述方程建立CH4/N2值与煤岩镜质体反射率之间的对应关系,并利用CH4/N2值对塔里木盆地库车坳陷天然气热成熟度进行了预测。预测结果与实际地质分析结果相吻合,说明CH4/N2值可以作为塔里木盆地煤成气热成熟度预测指标应用于油气勘探中。  相似文献   

Ultra-high degree spherical harmonic analysis and synthesis using extended-range arithmetic   总被引：3，自引：2，他引：1  

Tobias Wittwer  Roland Klees  Kurt Seitz  Bernhard Heck 《Journal of Geodesy》2008,82(4-5):223-229

We present software for spherical harmonic analysis (SHA) and spherical harmonic synthesis (SHS), which can be used for essentially arbitrary degrees and all co-latitudes in the interval (0°, 180°). The routines use extended-range floating-point arithmetic, in particular for the computation of the associated Legendre functions. The price to be paid is an increased computation time; for degree 3,000, the extended-range arithmetic SHS program takes 49 times longer than its standard arithmetic counterpart. The extended-range SHS and SHA routines allow us to test existing routines for SHA and SHS. A comparison with the publicly available SHS routine GEOGFG18 by Wenzel and HARMONIC SYNTH by Holmes and Pavlis confirms what is known about the stability of these programs. GEOGFG18 gives errors <1 mm for latitudes [-89°57.5′, 89°57.5′] and maximum degree 1,800. Higher degrees significantly limit the range of acceptable latitudes for a given accuracy. HARMONIC SYNTH gives good results up to degree 2,700 for almost the whole latitude range. The errors increase towards the North pole and exceed 1 mm at latitude 82° for degree 2,700. For a maximum degree 3,000, HARMONIC SYNTH produces errors exceeding 1 mm at latitudes of about 60°, whereas GEOGFG18 is limited to latitudes below 45°. Further extending the latitudinal band towards the poles may produce errors of several metres for both programs. A SHA of a uniform random signal on the sphere shows significant errors beyond degree 1,700 for the SHA program SHA by Heck and Seitz.  相似文献   

The metamorphic evolution of migmatites from the Ötztal Complex (Tyrol,Austria) and constraints on the timing of the pre-Variscan high-T event in the Eastern Alps     

Werner F. Thöny  Peter Tropper  Friederike Schennach  Erwin Krenn  Friedrich Finger  Reinhard Kaindl  Franz Bernhard  Georg Hoinkes 《Swiss Journal of Geoscience》2008,101(1):111-126

Within the Ötztal Complex (ÖC), migmatites are the only geological evidence of the pre-Variscan metamorphic evolution, which led to the occurrence of partial anatexis in different areas of the complex. We investigated migmatites from three localities in the ÖC, the Winnebach migmatite in the central part and the Verpeil- and Nauderer Gaisloch migmatite in the western part. We determined metamorphic stages using textural relations and electron microprobe analyses. Furthermore, chemical microprobe ages of monazites were obtained in order to associate the inferred stages of mineral growth to metamorphic events. All three migmatites show evidence for a polymetamorphic evolution (pre-Variscan, Variscan) and only the Winnebach migmatite shows evidence for a P-accentuated Eo-Alpine metamorphic overprint in the central ÖC. The P-T data range from 670–750 °C and < 2.8 kbar for the pre-Variscan event, 550–650 °C and 4–7 kbar for the Variscan event and 430–490 °C and ca. 8.5 kbar for the P-accentuated Eo-Alpine metamorphic overprint. U-Th-Pb electron microprobe dating of monazites from the leucosomes from all three migmatites provides an average age of 441 ± 18 Ma, thus indicating a pervasive Ordovician-Silurian metamorphic event in the ÖC.  相似文献   

Geophysical investigation of buried Pleistocene subglacial valleys in Northern Germany   总被引：1，自引：0，他引：1  

Gerald Gabriel  Reinhard Kirsch  Bernhard Siemon  Helga Wiederhold 《Journal of Applied Geophysics》2003,53(4):159

Buried Pleistocene subglacial valleys are extensively used as groundwater reservoirs by waterworks in northern Germany, although little is known about the locations and size of these valleys and the internal structure of the sediment fill. This lack of knowledge about important groundwater reservoirs is a challenge for geophysics.This paper summarizes the geophysical investigation of two buried Pleistocene subglacial valleys in northern Germany—the Ellerbeker Rinne and the Bremerhaven–Cuxhavener Rinne—including seismic, gravity, and airborne electromagnetic (AEM) surveys. Seismic sections show the detailed structure of the paleovalleys. The reliability of interpretation is enhanced by vertical seismic profiles in wells. The maximum depths of the Ellerbeker Rinne and the Bremerhaven–Cuxhavener Rinne were found to be 360 and about 400 m, respectively. Gravity survey revealed Bouguer anomalies above the sediment fill of both buried valleys. The Ellerbeker Rinne produces a negative residual anomaly of −0.5 mGal, whereas the sediments of the Bremerhaven–Cuxhavener Rinne produce a positive anomaly. The latter one is superimposed by negative gravity anomalies due to near-surface structures. The Bremerhaven–Cuxhavener Rinne can be mapped by airborne electromagnetics at locations without saltwater intrusion, which would affect the measurements. The electrical conductivity of the clay layer at the top of the valley fill differs significantly from that of the surrounding sand. The combined use of these three geophysical methods, which measure different physical parameters, leads to a better understanding of the subsurface geology and the hydrogeology of the Pleistocene subglacial valleys.  相似文献   

Induced Calcite Precipitation by Cyanobacterium Synechococcus     

Maria Dittrich  Beat Müller  Denis Mavrocordatos  Bernhard Wehrli 《洁净——土壤、空气、水》2003,31(2):162-169

This study investigated the role of the solution composition on calcite precipitation induced by cyanobacteria. The precipitation of calcium carbonate was induced by addition of cyanobacterium cells Synechococcus strain PCC 7942 in two artificial solutions with a different composition at similar saturation states in respect to calcite. Ion‐selective electrodes for pH, Ca²⁺, and COequation/tex2gif-stack-1.gif monitored the experiments, and the morphology of precipitated crystals was analysed by scanning electron microscopy. The calcite precipitation was observed in all experiments after the addition of the cells. The composition of solution (the ratio of dissolved inorganic carbon to dissolved calcium) strongly influenced the calcite precipitation. Based on laboratory experiment results, a possible mechanism for precipitation induced by Synechococcus is proposed linking precipitation with the conditions near to cell walls rather than with the saturation conditions in the bulk solution.  相似文献   

The Influence of Thermal Effects on the Wind Speed Profile of the Coastal Marine Boundary Layer   总被引：1，自引：3，他引：1  

Bernhard Lange  Søren Larsen  Jørgen Højstrup  Rebecca Barthelmie 《Boundary-Layer Meteorology》2004,112(3):587-617

The wind speed profile in a coastal marine environment is investigated with observations from the measurement program Rødsand, where meteorological data are collected with a 50 m high mast in the Danish Baltic Sea, about 11 km from the coast. When compared with the standard Monin—Obukhov theory the measured wind speed increase between 10 m and 50 m height is found to be systematically larger than predicted for stable and near-neutral conditions. The data indicate that the deviation is smaller for short (10–20 km) distances to the coast than for larger (>30 km) distances. The theory of the planetary boundary layer with an inversion lid offers a qualitative explanation for these findings. When warm air is advected over colder water, a capping inversion typically develops. The air below is constantly cooled by the water and gradually develops into a well-mixed layer with near-neutral stratification. Typical examples as well as scatter plots of the data are consistent with this explanation. The deviation of measured and predicted wind speed profiles is shown to be correlated with the estimated height and strength of the inversion layer.  相似文献   

Zonation of flora and vegetation of the Northern declivity of the Karakoram/Kunlun mountains (SW Xinjiang China)     

Wolf Bernhard Dickoré 《GeoJournal》1991,25(2-3):265-284

Botanical results of the “Sino-German Joint Expedition to K2, 1986” are presented with remarks on vegetation of SW Kashgaria, the W Kunlun Shan and the N declivity of the central Karakoram mountains. The vertical and horizontal zonation of the vegetation and flora of a cross-section of the Karakoram/Kunlun N declivity from the edge of the Tarim basin to the summit-pyramid of K2 is outlined. The transect covers altitudes between c. 1300 and 5200 m. Altitudinal vegetation belts distinguished along the transect, their extension, and characteristic species are: An annotated list of 301 species collected (1 Charophyta, 2 Pteridophyta, 6 Gymnospermae, 292 Angiospermae) is given. Floristical and vegetation features of the Karakoram/Kunlun N declivity are discussed in connection with environmental factors and their variation, and in relation to pleistocene glaciation.  相似文献   

Application of multiple-isotope and groundwater-age data to identify factors affecting the extent of denitrification in a shallow aquifer near a river in South Korea     

Dugin Kaown  Eun-Hee Koh  Bernhard Mayer  Heejung Kim  Dong Kyu Park  Byeong-Hak Park  Kang-Kun Lee 《Hydrogeology Journal》2018,26(6):2009-2020

The extent of denitrification in a small agricultural area near a river in Yangpyeong, South Korea, was determined using multiple isotopes, groundwater age, and physicochemical data for groundwater. The shallow groundwater at one monitoring site had high concentrations of NO₃-N (74–83 mg L^?1). The δ¹⁵N-NO₃ values for groundwater in the study area ranged between +9.1 and +24.6‰ in June 2014 and +12.2 to +21.6‰ in October 2014. High δ¹⁵N-NO₃ values (+10.7 to +12.5‰) in both sampling periods indicated that the high concentrations of nitrate in the groundwater originated from application of organic fertilizers and manure. In the northern part of the study area, some groundwater samples showed elevated δ¹⁵N-NO₃ and δ¹⁸O-NO₃ values, which suggest that nitrate was removed from the groundwater via denitrification, with N isotope enrichment factors ranging between ?4.8 and ?7.9‰ and O isotope enrichment factors varying between ?3.8 and ?4.9‰. Similar δD and δ¹⁸O values of the surface water and groundwater in the south appear to indicate that groundwater in that area was affected by surface-water infiltration. The mean residence times (MRTs) of groundwater showed younger ages in the south (10–20 years) than in the north (20–30 years). Hence, it was concluded that denitrification processes under anaerobic conditions with longer groundwater MRT in the northern part of the study area removed considerable amounts of nitrate. This study demonstrates that multi-isotope data combined with physicochemical data and age-dating information can be effectively applied to characterize nitrate contaminant sources and attenuation processes.  相似文献   

Climate change impact on extreme precipitation and peak flood magnitude and frequency: observations from CMIP6 and hydrological models     

Meresa  Hadush  Tischbein  Bernhard  Mekonnen  Tewodros 《Natural Hazards》2022,111(3):2649-2679

Natural Hazards - Changes in climate intensity and frequency, including extreme events, heavy and intense rainfall, have the greatest impact on water resource management and flood risk management....  相似文献   

Erratum to: The Alpine nappe stack in western Austria: a crustal-scale cross section     

Hannah Pomella  Hugo Ortner  Michael Zerlauth  Bernhard Fügenschuh 《International Journal of Earth Sciences》2015,104(3):747-748

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