An Integrated Laboratory Method to Measure and Verify Directional Hydraulic Conductivity in Fine‐to‐Medium Sandy Sediments          下载免费PDF全文

Jialiang Cai  Thomas Taute  Enrico Hamann  Michael Schneider 《Ground water》2015,53(1):140-150

The constant‐head permeameter test (CHPT) is widely used in sandy samples as a standard method in the laboratory to investigate hydraulic conductivity (K). However, it neither can be used to consistently determine directional hydraulic conductivity (DHC) nor guarantee the comparability of measured K values of samples with different sizes. Therefore, this paper proposes an integrated laboratory method, called modified CHPT (MCHPT), for the efficient determination and verification of consistent DHC values in fine‐to‐medium sandy sediments, based on a new methodological framework. A precise and standardized procedure for preparing the experimental setup of MCHPT was conducted, based on the integrated experimental setup of CHPT and tracer tests. Moreover, a formula was yielded for the time‐optimized sample saturation control. In comparison with grain size‐based methods, the validity of consistent K_h and K_v values determined by MCHPT was convincing.  相似文献   

The Triassic of Monte San Giorgio in the World Heritage List of UNESCO: An opportunity for science, the local people and tourism     

Markus Felber  Heinz Furrer  Andrea Tintori 《Eclogae Geologicae Helvetiae》2004,97(1):1-2

No abstract.  .  相似文献   

Editors’ Message     

Clifford?VossEmail author  Perry?Olcott  Robert?Schneider 《Hydrogeology Journal》2004,12(1):1-2

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Carbon,sulfur, oxygen and strontium isotope records,organic geochemistry and biostratigraphy across the Permian/Triassic boundary in Abadeh,Iran   总被引：6，自引：0，他引：6  

Christoph?KorteEmail author  Heinz?W.?Kozur  Michael?M.?Joachimski  Harald?Strauss  Ján?Veizer  Lorenz?Schwark 《International Journal of Earth Sciences》2004,93(4):565-581

Pelagic deposits at Abadeh represent a complete biostratigraphic record across the Permian/Triassic boundary (PTB). The presumed water depth during deposition of these sediments was between 60 and 90 m. Similar to other Permian/Triassic boundary sections, the succession at Abadeh is characterised by a negative carbon isotope shift of approximately 4. The values start to decrease in the lower C. changxingensis - C. deflecta s.l. Zone, reach –0.12 (V-PDB) in the uppermost Permian just below the PTB, remain low to the early I. isarcica Zone (–0.32) and increase subsequently in the upper I. isarcica Zone. For the time interval of the PTB negative carbon isotope excursion, between the C. iranica and the I. isarcica Zones, no correlation exists between the ¹³C_carb and the ¹⁸O_carb. The above observations argue against the conclusion of Heydari et al. (2001) that the carbon isotope event at the P/T transition is an alteration artefact and not a global signal. The decrease in ¹³C_carb is accompanied by a ~5 (and potentially up to 10) increase in ³⁴S_SSS. Together, these features are thought to reflect a complex global event, notably the development of widespread anoxic oceans with anoxic bottom layers rising onto the shelves. For the carbon isotope drop, other factors, such as the collapse of ocean primary productivity may also have played a role. The ⁸⁷Sr/⁸⁶Sr ratios of Dzhulfian seawater show only a minor increase from 0.70705 to 0.70710, reaching 0.70720 in the Dorashamian. The increase becomes steeper in the Early Triassic reaching 0.70754 in the N. dieneri Zone. The rise of the strontium isotope values is thought to be related to enhanced continental weathering under humid climatic conditions in the uppermost Permian (C. meishanensis - H. praeparvus Zone) and the lack of a dense land vegetation in the Early Triassic, prior to the Spathian (Upper Olenekian).  相似文献   

<Emphasis Type="Italic">Hydrogeology Journal</Emphasis> in 2002     

Perry?OlcottEmail author  Robert?Schneider  Clifford?Voss 《Hydrogeology Journal》2003,11(1):1-2

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Transport of terrestrial organic carbon to the oceans by rivers: re-estimating flux- and burial rates   总被引：5，自引：0，他引：5  

B. Schlünz  R. R. Schneider 《International Journal of Earth Sciences》2000,88(4):599-606

 This study re-estimates one important component in the global carbon cycle: the modern global fluviatile organic carbon discharge- and burial rates. According to these results, approximately 430×10¹² g of terrestrial organic carbon are transported to the ocean in modern times. This amount is higher than the latest estimates but takes into account new data from Oceania not previously considered in global flux studies. However, only the minor amount of 10% or approximately 43×10¹² gC year^–1 is most likely buried in marine sediments. This amount is similar to the burial of marine organic carbon in the coastal ocean (55×10¹² gC year^–1). Adding both estimates gives approximately 100×10¹² gC year^–1, which is the value calculated by Berner (1982) for "terrestrial" deltaic-shelf sediments. However, the results in this study suggest that on a global scale the organic carbon content in coastal ocean sediments is not solely of terrestrial origin but a mixture of nearly equal amounts of marine and terrestrial organic carbon. The major part of the terrestrial organic carbon that enters the ocean by rivers (approximately 400×10¹² gC year^–1) seems to be either (a) remineralised in the ocean, whereas the mechanism by which the terrestrial organic carbon is oxidised in the ocean are unknown; or (b) is dispersed throughout the oceans and accumulates in pelagic sediments. Received: 9 November 1998 / Accepted: 25 May 1999  相似文献   

Kinetic equilibrium of nonlinear electromagnetic waves in electron-positron-ion magnetoplasmas     

F. B. Rizzato  R. S. Schneider  D. Dillenburg 《Astrophysics and Space Science》1989,152(2):181-190

The problem of a one-dimensional, nonlinear, circularly polarized wave in a collisionless plasma is solved for the case in which the group velocity of the localized wave is zero relative to the plasma frame.For an electron-positron plasma the ponderomotive potential is repulsive, and both small and large amplitude waves in the presence of reflected and transmitted particles is discussed.The inclusion of an external magnetic field such that the cyclotron frequency is smaller than the wave frequency does not alter qualitatively the results of the fieldless case, except for the fact that an electrostatic potential is generated.For the case in which the cyclotron frequency is larger than the wave frequency, the resulting potential is attractive, and it is shown that no localized waves can coexist with confined and transmitted particles. If, however, an ionic component is presnt in the electron-positron plasma, such as may be the case in pulsar magnetospheres, localized waves may again be possible.  相似文献   

A note of thanks     

M. I. El-Sabh  Y. Fujinawa  G. Schneider 《Natural Hazards》1989,1(4):401-401

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Zur Nomenklatur der Gesteine in Granulitfazies     

Heinz G. Scharbert 《Mineralogy and Petrology》1963,8(4):591-598

Ohne Zusammenfassung  相似文献   

Barbados: maturation,source rock potential and burial history within a Cenozoic accretionary complex     

D.K. Larue  J. Schoonmaker  R. Torrini  J. Lucas-Clark  M. Clark  R. Schneider 《Marine and Petroleum Geology》1985,2(2):96-110

A number of diagenetic properties were studied in sedimentary rocks exposed along a 25 km across-strike transect on Barbados, the crest of the Barbados accretionary complex. The island of Barbados consists of three structural levels: a lower (mostly Eocene or undated) basal complex composed of quartzose turbidites, hemipelagites and melange; an intermediate level (Eocene to Miocene) of nappes composed mostly of calcareous pelagite; and a Pleistocene coral cap. Diagenetic studies concentrated on the basal complex although preliminary data from the nappes are also presented. The following subjects were studied: (1) clay mineralogy (% illite interlayers in mixed-layer clays); (2) vitrinite reflectance; (3) organic type and maturation, by Rock-Eval pyrolysis; (4) thermal alteration index of spores and pollen; (5) dry bulk density; (6) silica mineralogy. Taken together, the data can be interpreted to indicate maximum temperatures attained during diagenesis of less than 80°C. Based on a uniform palaeogeothermal gradient of 15°C km^?1, and a temperature at the sediment/water interface of 10°C, maximum burial depths of basement complex rocks were about 2–5 km. Minimum possible burial depths are < 1 km. No across-strike changes in maturation are observed indicating that these trench-associated rocks were uplifted uniformly. Mudstones are typically rich in total organic carbon (> 1 %), and are immature. Organic matter was derived mostly from terrigenous or oxidized sources (type III kerogens), although some marine planktonic sources are indicated locally (type II kerogens). Organic matter is therefore primarily gas-prone.  相似文献