A close-interval sampler for collection of sediment pore waters for nutrient analyses     

John R. Montgomery  Mary T. Price  John Holt  Carl Zimmermann 《Estuaries and Coasts》1981,4(1):75-77

An in situ sediment pore water sampler is described. It can simultaneously and continuously sample at four discrete 1 cm levels at one location without disturbing the sediment or the sample. The sampler can maintain an anaerobic environment, and can be used over extended periods of time. Laboratory tests indicate 98 to 100 percent recoveries for ammonium, silicate, reactive phosphate, nitrate and nitrite. Vertical profiles for ammonium, reactive phosphate and silicate are shown from field studies.  相似文献   

Der Aufbau einer Registrieranlage zur Bestimmung des vertikalen Windprofiles     

Dr. O. Motschka  Dipl.-Ing. K. Zimmermann 《Theoretical and Applied Climatology》1972,20(3-4):345-352

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Bayesian approach to daily rainfall modelling to estimate monthly net infiltration using the Thornthwaite water budget and Curve Number methods     

E. Zimmermann 《Hydrogeology Journal》2006,14(5):648-656

The Thornthwaite and Mather water budget is a simple and frequently applicable tool to estimate surpluses of water, which are not stored in the soil profile. Combining it with the empiric CN-method of the US Soil Conservation Service (US-SCS), which is applied to daily rainfall records, it is possible to estimate the runoff, and this way, from the difference between surpluses and runoff, to estimate the net infiltration that would recharge a phreatic aquifer. In order to apply both methods during a sequence of years, it is necessary to predict the number of rain events per month, and the rainfall depth for each event. In this work, the author proposes a methodology based on the theorem of Bayes to estimate the number of occurrences of rainy events in a considered month conditioning the forecast to the monthly rainfall. In addition, an exponential distribution to generate rainfall depth knowing the monthly rainfall was done. Both algorithms were applied in four stations of the southern region of Santa Fe province (Argentina). More than 7,600 forecasts of rain occurrences and rainfall depths were compared with the observed records. Moreover, the runoff values estimated by means of the US-SCS method, using the observed rainfall and using rainfalls predicted with the algorithms were also compared. In both cases, the obtained results were also very satisfactory. The proposed methodologies allow the correct application of the balance of Thornthwaite and Mather together with the US-SCS method and a good forecast of monthly runoff and net infiltration.  相似文献   

Variability of dissolved reactive phosphate flux rates in nearshore estuarine sediments: Effects of groundwater flow   总被引：1，自引：0，他引：1  

Carl F. Zimmermann  John R. Montgomery  Paul R. Carlson 《Estuaries and Coasts》1985,8(2):228-236

Theoretical diffusive flux rates for dissolved reactive phosphate (DRP) were determined for sediments in a small area of the Indian River, Florida for the period March–May 1982. Flux rates from the sediment varied from 29 to 70 × 10^?6g per m² per day in seagrass associated sediments to 3–25 × 10^?6g per m² per day for an area devoid of seagrass. Simultaneous measurements of groundwater seepage velocities indicated greater velocities in seagrass associated sediments (1.03 × 10^?6m per sec) than an area devoid of grass (0.77 × 10^?6m per sec). Measured seepage flux accounted for more than 99% of the combined estimated diffusive and seepage flux of DRP for nearshore seagrass sediments. Also noted was an apparent direct relationship between tidal height, DRP and seepage velocity in nearshore sediments (25 m from shore) which further demonstrates the importance of hydrogeologic variables to these areas.  相似文献   

The interstellar band at λ 4430 Å and the abundance of interstellar iron,titanium, and molecular hydrogen     

H. Zimmermann 《Astrophysics and Space Science》1982,84(2):505-517

For the direction to a number of stars the depletion of interstellar gaseous iron and titanium as well as the relative abundance of molecular hydrogen and the strength of the interstellar band at 4430 Å were determined by different authors and can be found in the literature. In this paper it is shown that the difference (A _c-A_co) is a more reliable measurement of the column density of 4430 Å absorbers than the usually used central depth,A _c, because the positive valueA _co ofA _c forE(B-V)=0, i.e. the intercept with theA _c axis of a least-squares fit to the observedA _c vsE(B-V) data, is with a high probability not caused by an interstellar effect.There was no correlation found between the interstellar depletion of iron and titanium, respectively, and (A _c-A_co), whereas a tendency exists that with increasing relative molecular hydrogen abundance the number of 4430 Å absorbers per hydrogen atom decreases. If the carriers of the 4430 Å absorbers are interstellar grains, then these grains must be altered during the same process in which molecular hydrogen is built. The found correlation is also compatible with the assumption that the 4430 Å absorber is related to an interstellar gaseous species.  相似文献   

Scale Dependence of Hydraulic and Structural Parameters in the Crystalline Rock of the KTB     

G. Zimmermann  H. Burkhardt  L. Engelhard 《Pure and Applied Geophysics》2003,160(5-6):1067-1085

— Knowledge of rock properties controlling the fluid movement is a basic prerequisite to understand the dynamical processes and the temperature and stress regime of the upper crust. Fracture networks were investigated on different scales to obtain quantitative results of fracture geometry like fracture length, orientation and fracture frequencies. Due to the scale effect, these parameters differ in several orders of magnitude in dependence of the scale of investigation. On the microscopic scale, fluorescent thin sections from cores were analysed and permeability was estimated for 2-D hydraulic networks. On the macroscopic scale, fracture parameters were determined from images of structural borehole measurements. The vicinity of the drill site represents the megascopic scale, where seismic reflectors were assumed as active hydraulic structures for construction of a fracture network. Compiling the fracture densities from all investigated scales and taking into consideration only the networks above the percolation threshold, the fracture length distribution follows a power law with an exponent of ?1.9 ± 0.05. Besides the scale differences of the geometric parameters like fracture density and length and the hydraulic parameters like permeability, the connectivity of the networks seems to be a confining characteristic. This is quantitatively described by the percolation parameter and the mean number of intersections per fracture. When assuming a macroscopic hydraulic system at the percolation threshold for the KTB site, the macroscopic mean fracture length can be estimated to approximately 30 m. This stands in agreement with the hydraulic experiments on site.  相似文献   

橄榄石-尖晶石相转变流变学的实验研究   总被引：2，自引：0，他引：2  

赵永红  J.D.Lawlis  S.Karato  M.Zimmermann 《地球物理学报》2002,45(Z1):225-230

对(Mgx,Ni1-x)2GeO4系统中橄榄石-尖晶石两相混合物的流变性进行了实验研究.利用不同温压条件对混合物进行热压,得到的橄榄石和尖晶石的比例不同.温度为1 573K,试件的化学组成从x=0.95-0.70时,得到的两相材料从100%橄榄石到100%尖晶石.三轴压缩试件为圆柱状,直径8mm,两相混合物的平均颗粒尺寸为2.21-9.43μm.流变学试验在气体介质试验机中进行,围压为300MPa,温度为1 073-1 573K.试验分为常应力和常位移率两种,差应力σ1-σ3为45-320MPa,应变率在2.8×10-6-2.8×10-5s-1之间,将实验测得的混合物力学性质与两端材料的强度进行对比,发现两相多晶介质的强度介于两端材料的强度之间.当橄榄石到尖晶石的相变发生在变形过程中时,尖晶石比率的增加使得多晶材料的总体强度上升.  相似文献   

CO₂-Laser Extraction-Static Mass Spectrometry Analysis of Ultra-Low Concentrations of Nitrogen in Silicates     

Franck Humbert  Guy Libourel  Christian France-Lanord  Laurent Zimmermann  Bernard Marty 《Geostandards and Geoanalytical Research》2000,24(2):255-260

A new installation for the analysis of picomole quantities of nitrogen has been designed and constructed. It permits the simultaneous analysis of N and rare gases extracted from silicates by heating. The extraction procedure involves the use of a CO₂ laser as a heater, and the analysis is made by static mass spectrometry using a high sensitivity, high resolution mass spectrometer. Procedural blanks of 2 picomoles N₂ (60 picogram N) allow us to analyse routinely N in mg-sized samples such as mantle-derived and meteoritic minerals, and Lunar soil grains.  相似文献   

Neoproterozoic to Lower Palaeozoic successions of the Tandilia System in Argentina: implication for the palaeotectonic framework of southwest Gondwana     

Udo Zimmermann  Daniel G. Poir��  Luc��a G��mez Peral 《International Journal of Earth Sciences》2011,100(2-3):489-510

The Cryogenian to Uppermost Ediacaran successions of the Tandilia System (Sierras Bayas Group and Cerro Negro Formation) in central-eastern Argentina is exceptional because of its unmetamorphosed and nearly undeformed character, its sediment provenance trend and the absence of any identified glacial deposit and the deposition of warm water carbonates. We decipher a dramatic change in the basin evolution from small-scale depositional areas during the Neoproterozoic to a larger basin related to an active continental margin throughout the Uppermost Ediacaran. The base of the succession is represented by immature detritus of alkaline composition (Villa Mónica Formation), but towards the top of this formation, the material is sorted and reworked, nonetheless still reflecting in its detritus the local rocks. The clastic deposition is interrupted by diagenetic overprinted dolomites. The unconformable overlying quartz-arenitic Ediacaran Cerro Largo Formation reworked the Cryogenian Villa Mónica Formation and contains mainly felsic granitic and metamorphic basement material of slightly wider variety, while the dominant alkaline geochemical signature in rocks of the Villa Mónica Formation disappears. Based on diagenetic, petrographic and sedimentological data, we can interpret the unconformity representing a longer time of erosion. The Cerro Largo Formation shows a transition to mudstones and the heterolithic facies of the Olavarría Formation. The top of the Sierras Bayas Group is represented by limestones (Loma Negra Formation), which are discordantly overlain by the Uppermost Ediacaran Cerro Negro Formation. The latter displays detrital material derived from a continental arc, mafic and felsic sources. Several arc-related geochemical proxies (Th/Sc?<?0.8; Zr/Sc?<?10; La/Sc?<?2; Ti/Zr?>?20) are recorded in the sediment detritus, as are syn-depositional pyroclastites. The absence of volcanic material in the underlying rocks allows proposing that the Cerro Negro Formation is related to an active continental margin fringing Gondwana (??Terra Australis Orogen??) as a retro-arc or retro-arc foreland basin.  相似文献   

Provenance and reconnaissance study of detrital zircons of the Palaeozoic Cape Supergroup in South Africa: revealing the interaction of the Kalahari and R��o de la Plata cratons     

Pieter H. Fourie  Udo Zimmermann  Nicolas J. Beukes  Thanusha Naidoo  Katsuro Kobayashi  Jan Kosler  Eizo Nakamura  Jenny Tait  Johannes N. Theron 《International Journal of Earth Sciences》2011,100(2-3):527-541

In order to facilitate the understanding of the geological evolution of the Kalahari Craton and its relation to South America, the provenance of the first large-scale cratonic cover sequence of the craton, namely the Ordovician to Carboniferous Cape Supergroup was studied through geochemical analyses of the siliciclastics, and age determinations of detrital zircon. The Cape Supergroup comprises mainly quartz-arenites and a Hirnantian tillite in the basal Table Mountain Group, subgreywackes and mudrocks in the overlying Bokkeveld Group, while siltstones, interbedded shales and quartz-arenites are typical for the Witteberg Group at the top of the Cape Supergroup. Palaeocurrent analyses indicate transport of sediment mainly from northerly directions, off the interior of the Kalahari Craton with subordinate transport from a westerly source in the southwestern part of the basin near Cape Town. Geochemical provenance data suggest mainly sources from passive to active continental margin settings. The reconnaissance study of detrital zircons reveals a major contribution of Mesoproterozoic sources throughout the basin, reflecting the dominance of the Namaqua-Natal Metamorphic Belt, situated immediately north of the preserved strata of Cape Supergroup, as a source with Archaean-aged zircons being extremely rare. We interpret the Namaqua-Natal Metamorphic Belt to have been a large morphological divide at the time of deposition of the Cape Supergroup that prevented input of detrital zircons from the interior early Archaean Kaapvaal cratonic block of the Kalahari Craton. Neoproterozoic and Cambrian zircons are abundant and reflect the basement geology of the outcrops of Cape strata. Exposures close to Cape Town must have received sediment from a cratonic fragment that was situated off the Kalahari Craton to the west and that has subsequently drifted away. This cratonic fragment predominantly supplied Meso- to Neoproterozoic, and Cambrian-aged zircon grains in addition to minor Silurian to Lower Devonian zircons and very rare Archaean (2.5?Ga) and late Palaeoproterozoic (1.8-2.0?Ga) ones. No Siluro-Devonian source has yet been identified on the Kalahari Craton, but there are indications for such a source in southern Patagonia. Palaeozoic successions in eastern Argentina carry a similar detrital zircon population to that found here, including evidence of a Silurian to Lower Devonian magmatic event. The Kalahari and Río de la Plata Cratons were thus in all likelihood in close proximity until at least the Carboniferous.  相似文献