We present a combined 3-D geoelectric and seismic tomography study conducted on the large Åknes rockslide in western Norway. Movements on the slope are strongly influenced by water infiltration, such that the hydrogeological regime is considered as a critical factor affecting the slope stability. The aim of our combined geophysical study was to identify and visualize the main shallow tension fractures and to determine their effect on hydraulic processes by comparing the geophysical results with information from borehole logging and tracer tests. To resolve the complex subsurface conditions of the highly fractured rock mass, a three-dimensional set-up was chosen for our seismic survey. To map the water distribution within the rock mass, a pattern of nine intersecting 2-D geoelectric profiles covered the complete unstable slope. Six of them that crossed the seismic survey area were considered as a single data set in a 3-D inversion. For both methods, smoothing-constraint inversion algorithms were used, and the forward calculations and parameterizations were based on unstructured triangular meshes. A pair of parallel shallow low-velocity anomalies (< 1400 m/s) observed in the final seismic tomogram was immediately underlain by two anomalies with resistivities <13 kΩm in the resistivity tomogram. In combination with borehole logging results, the low-velocity and resistivity anomalies could be associated with the drained and water-filled part of the tension fractures, respectively. There were indications from impeller flowmeter measurements and tracer tests that such tension fractures intersected several other water-filled fractures and were responsible for distinct changes of the main groundwater flow paths. 相似文献
The effects of F, B2O3 and P2O5 on the H2O solubility in a haplogranite liquid (36 wt. % SiO2, 39 wt. % NaAlSi3O8, 25 wt. % KAlSi3O8) have been determined at 0.5, 1, 2, and 3 kb and 800, 850, and 900°C. The H2O solubility increases with increasing F and B content of the melt. The H2O solubility increase in more important at high pressure (2 and 3 kb) than at low pressure (0.5 kb). At 2 kb and 800°C, the H2O solubility increases from 5.94 to 8.22 wt. % H2O with increasing F content in the melt from 0 to 4.55 wt. %, corresponding to a linear H2O solubility increase of 0.53 mol H2O/mol F. With addition of 4.35 wt. % B2O3, the H2O solubility increases up to 6.86 wt. % H2O at 2 kb and 800°C, corresponding to a linear increase of 1.05 mol H2O/mol B2O3. The results allow to define the individual effects of fluorine and boron on H2O solubility in haplogranitic melts with compositions close to that of H2O-saturated thermal minima (at 0.5–3 kb). Although P has a dramatic effect on the phase relations in the haplogranite system, its effect on the H2O solubility was found to be negligible in natural melt compositions. The concominant increase in H2O solubility and F can not be interpreted on the basis of the available spectroscopic data (existence of hydrated aluminofluoride complexes or not). In contrast, hydrated borates or more probably boroxol complexes have been demonstrated in B-bearing hydrous melts. 相似文献
The paper discusses the role of all parties involved in the debate about environmental standards, their relationships in an ideal situation, the weaknesses today and how these weaknesses could be corrected. The question of who should set the environmental standards is an important element on the way to this ideal situation. It is considered necessary that all parties, industry, consumers, government regulations and the green lobby, should contribute to the development of better environmental standards. 相似文献
The central trough of the Bolivian Altiplano is occupied by two wide salt crusts: the salar of Uyuni, which is probably the largest salt pan in the world (10,000 km2) and the salar of Coipasa (2,500 km2). Both crusts are essentially made of porous halite filled with an interstitial brine very rich in Li, K, Mg, B (up to 4.7 g/l Li, 4.3 g/l B, 30 g/l K and 75 g/l Mg). Lithium reserves are the highest known in the world, around 9 × 106 tons. Potassium, magnesium and boron reserves in brines are also important (around 194 × 106 tons K, 8 × 106 tons B and 211 × 106 tons Mg).
The crusts are the remnant of saline Lake Tauca (13,000–10,000 yr BP). Its salinity was estimated approximately at 80 g/l. Its paleochemistry was derived in two ways: (1) by dissolving the present amounts of all chemical components in the former lake volume, and (2) by simulating the evaporation of the major inflows to the basin. The resulting chemical compositions are quite different. The dissolution-derived one is 5 to 50 times less concentrated in Li, K, Mg, B than the evaporation-simulated ones. However all compositions present the same Na and Cl contents. This suggests either a removal of bittern salts or an enrichment of the former lake water in Na and Cl.
The most probable interpretation is that Lake Tauca redissolved a salt crust akin to that existing today. Several older lakes have been detected on the Altiplano. Nevertheless, such an explanation only pushes the problem back. It is likely that the anomaly was transferred from one lake to an other. Three hypotheses may be put forward: (1) bittern seepage through bottom sediments, (2) uptake of the missing components by minerals, and (3) leaching of ancient evaporites from the catchment area at the beginning of the lacustrine history of the basin. The excess halite could have been recycled from lake to lake. This latter process seems to be the most effective to explain the large excess of Na and Cl over the bittern solutes — Li, K, Mg and B. The occurrence of almost pure Na/1bCl saline springs flowing out from a gypsum diapir in the northern Altiplano gives substantial support to this hypothesis. 相似文献
Results of laboratory feeding experiments suggest that oyster (Crassostrea virginica) larvae select small phytoplanktonic organisms (<10 μm) over larger-celled forms from natural estuarine assemblages, but that little selection occurs within the small phytoplankton fraction. Laboratory-reared larvae grazed each of five small-celled phytoplankton groups enumerated (coccoids, centrate diatoms, pennate diatoms, dinoflagellates, and flagellates) at rates proportional to phytoplankton group densities in controls (no larvae added). Larval grazing rates (number of cells removed per larva per hour) were inversely proportional to both larval density and experimental duration. 相似文献
Formation of methoxy (CH3O) radicals in the reaction (1) CH3O2+NOCH3O+NO2 at 298 K has been observed directly using time resolved LIF. The branching ratio % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqOXdyMaae% 4qaiaabIeadaWgaaWcbaGaae4maaqabaGccaqGpbGaaeiiaiaabIca% ieqacaWF9aGaa8hiaiaa-nbicaWFGaGaeuiLdqKaai4waiaaboeaca% qGibWaaSbaaSqaaiaabodaaeqaaOGaae4taiaac2facaWFVaGaeuiL% dqKaai4waiaaboeacaqGibWaaSbaaSqaaiaabodaaeqaaOGaae4tam% aaBaaaleaacaqGYaaabeaakiaac2facaqGPaaaaa!4E31!\[\phi {\rm{CH}}_{\rm{3}} {\rm{O (}} = -- \Delta [{\rm{CH}}_{\rm{3}} {\rm{O}}]/\Delta [{\rm{CH}}_{\rm{3}} {\rm{O}}_{\rm{2}} ]{\rm{)}}\] has been determined by quantitative cw-UV-laser absorption at 257 nm of CH3O2 and CH3ONO, the product of the consecutive methoxy trapping reaction (2) % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4qaiaabI% eadaWgaaWcbaGaae4maaqabaGccaqGpbacbeGaa83kaiaa-bcaieaa% caGFobGaa43taiaa+bcacaGFOaGaa83kaiaa+1eacaGFPaGaa4hiai% abgkziUkaabccacaqGdbGaaeisamaaBaaaleaacaqGZaaabeaakiaa% b+eacaqGGaGaaeOtaiaab+eacaqGGaGaa4hkaiaa-TcacaGFnbGaa4% xkaiaa+5cacaGFGaGaa4hiaiabeA8aMnaaBaaajqwaacqaaiaaboea% caqGibWaaSbaaKazcaiabaGaae4maaqabaqcKfaGaiaab+eaaSqaba% aaaa!55AC!\[{\rm{CH}}_{\rm{3}} {\rm{O}} + NO ( + M) \to {\rm{ CH}}_{\rm{3}} {\rm{O NO }}( + M). \phi _{{\rm{CH}}_{\rm{3}} {\rm{O}}} \] is found to be (1.0±0.2). The rate constant k1 is (7±2) 10-12 cm3/molecule · s in good agreement with previous results. 相似文献
Patterns of inter-well correlations in map view can yield insight into the architecture of an area such as a petroleum reservoir. Preferred directions of fluid communications, discontinuities, and structural or depositional “grain” of an area often can be identified. In coherence mapping, large numbers of wells are compared in pairs, using a similarity coefficient. Sliding cross-correlation techniques of sections can be used to adjust for some normal stratigraphic inconsistencies. The calculated parameters are mapped as vector spider plots for each well, or as link-lines between well pairs with line thickness proportional to the strength of correlation. The resulting maps display areas of coherence and lines of discontinuities which can be interpreted according to the geologic style of the region. The method works best for areas with relatively great density of wells and uniform distribution. The database should contain logs digitized over the interval of interest and at least one stratigraphic marker. A pilot study of a carbonate reservoir with some 150 wells provided useful suggestions for reinterpretation of the field in terms of steeply dipping clinoforms of basin margin deposits. 相似文献
An optical method is discussed for the determination of the line average of the vertical temperature gradient, which is subsequently used for the calculation of the scaling temperature and of the sensible heat flux. The method requires conventional surveying instrumentation only, and the measurements are carried out easily. The attainable accuracy is estimated as 10% or better. Observations are also possible during night or light-wind conditions. In a field experiment, results from this optical method were compared with measurements taken with a conventional covariance eddy-flux instrument. Excellent agreement between both methods was found. 相似文献