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241.
Dr. Ulrich Manze Dr. John C. Vogel Dr. Reinhard Streit Prof. Dr. Karl Brunnacker 《International Journal of Earth Sciences》1974,63(3):885-897
The ratio of oxygen and carbon isotopes is a criterion for the carbonate-genesis with distinct differences between marine, freshwater, soil and loess carbonates. In addition it becomes clear that there is a number of carbonate soils within the loess of the mediterranean region with distinguishable isotopic compositions. The components affecting the relation of the isotopes in these loesses and the intercalated soils are discussed. The carbonate-turnover during the sedimentation of the loess with carbonate-precipitation from remnant solutions seems to be of some importance. The relatively small participation of biogenic CO2 in the carbonate-turnover ist evident. 相似文献
242.
243.
Time series measurements from light vessel and coastal stations in the transition area of the Kattegat and the Baltic Sea are analyzed for the period August 1975 to March 1976. The data consist of daily sampled salinities from different depth levels and daily means of sea levels, surface current, and wind, respectively. The purpose of this paper is to examine the dynamics of the mass- and salt-transport during a major salt water inflow.The principal conclusions of this paper are that
相似文献
1) | the dynamics of the barotropic water exchange between the Kattegat and the Baltic Sea resembles that of a Helmholtz-resonator with a geostrophically controlled flow in the connecting channel; |
2) | the water exchange is forced by both the east component of the windstress over the North Sea and the windstress component in 30o true over the Baltic Sea; |
3) | the salinity in the upper layer of the Kattegat is governed by a permanent weak salt flux directed from the bottom to the surface layer and the outflow of less saline Baltic water into the upper layer of the Kattegat whereas the salinity of the Belt Sea is advected by the local currents along the main channel; |
4) | the most favorable conditions for a major salt inflow are initially a mean sea level of the Baltic lowered by about 30 cm followed by west winds steadily increasing over the following several ten days. Moreover, the hitherto used definition of a major salt water inflow is discussed and an improved definition is proposed. |
244.
Andreas Krein Holger Klinck Michael Eiden Wolfhard Symader Reinhard Bierl Lucien Hoffmann Laurent Pfister 《地球表面变化过程与地形》2008,33(1):152-163
This article deals with the following two questions. Are acoustic measurements in running waters appropriate for a highly resolved investigation of the bedload transport? Which characterizations of the bedload regarding mass and shape are possible via the acoustic signals? The signals were recorded by means of data recorders (Tascam Inc. DAP1 Portable Data Recorder) and hydrophones (International Transducer Corp. ITC‐4001 A). The ITC‐4001 is a shallow water omnidirectional transducer containing a flexural disc transducer utilizing Channelite‐5400 ceramics mounted in a rugged corrosion‐resistant housing. These hydrophones were screwed onto the bottom side of stainless steel plates, serving as a contact surface for the bedload in motion above them. After more than 100 series of tests in the laboratory, which indicated the basic relations between the dimension, shape and weight of the bedload and the resulting signal, field tests of the measuring system were conducted. By artificially produced flood waves in the small brooks Riverisbach, Olewiger Bach and by a winter flood wave in the River Moselle, it is possible to elaborate similar structures of the signal course of the bedload movement. The highest transport rates can be observed at the beginning of the increasing limbs and behind the peaks of the waves. At the beginning of the waves, the increasing transport power of the water and the loose material can be considered as the cause for this result. The high stream velocity behind the wave peaks explains the increase in the bedload transport so that material from the channel beds is unfastened and will be mobilized. The characterization of the bedload regarding the shape and mass is still limited regarding the field measurements and could be solved only for homogeneous grain sizes and single stones under laboratory conditions. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
245.
246.
The Sukari Gold Mine,Eastern Desert—Egypt: structural setting,mineralogy and fluid inclusion study 总被引:1,自引:0,他引:1
Hassan?M.?Helmy Reinhard?KaindlEmail author Harald?Fritz Jürgen?Loizenbauer 《Mineralium Deposita》2004,39(4):495-511
The Sukari gold mine (18.8 Mt @ 2.14 g/t Au) is located 15 km west of the Red Sea coast in the southern central Eastern Desert of Egypt. The vein-type deposit is hosted in Late Neoproterozoic granite that intruded island-arc and ophiolite rock assemblages. The vein-forming process is related to overall late Pan-African shear and extension tectonics. At Sukari, bulk NE–SW strike-slip deformation was accommodated by a local flower structure and extensional faults with veins that formed initially at conditions of about 300 °C and 1.5–2 kbar. Gold is associated with sulfides in quartz veins and in alteration zones. Pyrite and arsenopyrite dominate the sulfide ore beside minor sphalerite, chalcopyrite and galena. Gold occurs in three distinct positions: (1) anhedral grains (GI) at the contact between As-rich zones within the arsenian pyrite; (2) randomly distributed anhedral grains (GII) and along cracks in arsenian pyrite and arsenopyrite, and (3) large gold grains (GIII) interstitial to fine-grained pyrite and arsenopyrite. Fluid inclusion studies yield minimum vein-formation temperatures and pressures between 96 and 188 °C, 210 and 1,890 bar, respectively, which is in the range of epi- to mesothermal hydrothermal ore deposits. The structural evolution of the area suggests a long-term, cyclic process of repeated veining and leaching followed by sealing, initiated by the intrusion of granodiorite. This cyclic process explains the mineralogical features and is responsible for the predicted gold reserves of the Sukari deposits. A characteristic feature of the Sukari gold mineralization is the co-precipitation of gold and arsenic in pyrite and arsenopyrite.Editorial handling: H. Frimmel 相似文献
247.
248.
Sedimentary Micro-facies and Macro Heterogeneity of Reservoir Beds in the Third Member of the Qingshankou Formation, Qian’an Area, Songliao Basin 总被引:2,自引:0,他引:2
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An analysis of drill cores and well logs shows that the main micro-facies of the third member sand bodies of the Qingshankou Formation in Qian’an are subaqueous distributary channel facies, sheet sand facies and subaqueous fan facies (olistostrome). Maps showing the distribution of these micro-facies together with inter-channel bay and prodelta mocro-facies are presented for different time-slices (lower, middle and upper parts of the Qingshankou Formation). These maps reveal the instability and change of sediment transport in the Baokang sedimentary system during the depositional period. Sediment transport was from the west in the early stage, from the south in the middle stage and from the northwest in the late stage. Values of thickness, porosity and permeability of the sand bodies in the third member of the Qingshankou Formation show that they have low to medium porosity and low permeability, and are characterized by serious reservoir heterogeneity. The joints between micro-facies and subaqueous fan micro-facies are characterized by the highest heterogeneity, the sheet sand and distal sand bar subfacies come next, and the heterogeneity of the subaqueous distributary channel sand bodies is relatively weak. 相似文献
249.
The role of horizontal resolution in simulating drivers of the global hydrological cycle 总被引:1,自引:1,他引:0
Marie-Estelle Demory Pier Luigi Vidale Malcolm J. Roberts Paul Berrisford Jane Strachan Reinhard Schiemann Matthew S. Mizielinski 《Climate Dynamics》2014,42(7-8):2201-2225
The role of atmospheric general circulation model (AGCM) horizontal resolution in representing the global energy budget and hydrological cycle is assessed, with the aim of improving the understanding of model uncertainties in simulating the hydrological cycle. We use two AGCMs from the UK Met Office Hadley Centre: HadGEM1-A at resolutions ranging from 270 to 60 km, and HadGEM3-A ranging from 135 to 25 km. The models exhibit a stable hydrological cycle, although too intense compared to reanalyses and observations. This over-intensity is explained by excess surface shortwave radiation, a common error in general circulation models (GCMs). This result is insensitive to resolution. However, as resolution is increased, precipitation decreases over the ocean and increases over the land. This is associated with an increase in atmospheric moisture transport from ocean to land, which changes the partitioning of moisture fluxes that contribute to precipitation over land from less local to more non-local moisture sources. The results start to converge at 60-km resolution, which underlines the excessive reliance of the mean hydrological cycle on physical parametrization (local unresolved processes) versus model dynamics (large-scale resolved processes) in coarser HadGEM1 and HadGEM3 GCMs. This finding may be valid for other GCMs, showing the necessity to analyze other chains of GCMs that may become available in the future with such a range of horizontal resolutions. Our finding supports the hypothesis that heterogeneity in model parametrization is one of the underlying causes of model disagreement in the Coupled Model Intercomparison Project (CMIP) exercises. 相似文献
250.
Jens Wendler Jens Köster Jens Götze Norbert Kasch Norbert Zisser Jonas Kley Dieter Pudlo Georg Nover Reinhard Gaupp 《International Journal of Earth Sciences》2012,101(1):159-176
Fracture-related bleaching of Lower Triassic Buntsandstein red beds of central Germany was related to significant carbonate
diagenesis and feldspar alteration caused by CO2-rich fluids. Using cathodoluminescence microscopy and spectroscopy combined with electron microprobe analysis and stable
carbon isotope study, two major fluid–mineral interactions were detected: (1) zoned, joint-filling calcites and zoned pore-filling
calcite cements, the latter replacing an earlier dolomite, were formed during bleaching. During the calcite formation and
dolomite–calcite transformation, iron was incorporated into the calcite cement crystal cores due to Fe availability from the
coeval bleaching. The dedolomitisation was ultimately associated with a volume increase. The related permeability decrease
implies a certain degree of sealing and increasing retention of CO2, and the volume increase offers a minor CO2 sink. Carbonate-rich sandstone, therefore, can provide advantages for underground CO2 storage especially when situated in the fringes of the reservoir. (2) Alkali-feldspar alteration due to the bleaching fluids
is reflected in cathodoluminescence spectra predominantly by the modulation of a brown luminescence emission peak (~620 nm).
This peak represents a newly discovered effect related to alkali-feldspar alteration not solely associated with bleaching.
Its modulation by the bleaching is interpreted to be due to Na depletion or a lattice defect in the Si–O bonds of the SiO4-tetrahedron. Alteration reflected by this luminescence feature has a destructive effect on the feldspars implying the possibility
of diminished rock integrity due to bleaching and, hence, CO2-rich fluids. Two further CL spectral changes related to bleaching occur, (a) decreased intensity between around 570 nm assigned
to Mn-depletion, and (b) increased amplitude and wavelength shift of the red (~680 nm) band. Converging evidence from carbonate
and feldspar diagenesis, stable carbon isotope data and analysis of fracture directions suggests that CO2 fluids contributed to a significant extent to the bleaching phenomena and alteration in the studied Buntsandstein strata. 相似文献