排序方式： 共有33条查询结果，搜索用时 375 毫秒
1.
Classification of artificial (man-made) ground 总被引：1，自引：0，他引：1
M. S. Rosenbaum A. A. McMillan J. H. Powell A. H. Cooper M. G. Culshaw K. J. Northmore 《Engineering Geology》2003,69(3-4):399-409
The legacy inherited from anthropogenic processes needs to be addressed in order to provide reliable and up-to-date ground information relevant to development and regeneration in the urban environment. The legacy includes voids as well as anthropogenic deposits (artificial ground). Their characteristics derive from former quarrying and mining activities industrial processes creating derelict ground, variably consolidated made ground, and contaminated groundwater and soils. All need to be systematically assessed to inform the planning process and provide the basis for engineering solutions. Site-specific investigation needs to be conducted on the back of good quality geoscientific data. This comes from ‘field’ survey, remotely sensed data interpretation, historical maps, soil geochemical sampling, and geotechnical investigation. Three-dimensional and, in the future, four dimensional, characterization of superficial deposits is required to reach an understanding of the potential spatial lithological variability of artificial ground and the geometry of important surfaces, i.e. the boundary conditions. The classification scheme for artificial ground outlined in this paper and adopted by the British Geological Survey, will help in achieving this understanding. 相似文献
2.
Richard L. Reynolds Joseph G. Rosenbaum Josh Rapp Michael W. Kerwin J. Platt Bradbury Steven Colman David Adam 《Journal of Paleolimnology》2004,31(2):217-233
Petrological and textural properties of lacustrine sediments from Upper Klamath Lake, Oregon, reflect changing input volumes of glacial flour and thus reveal a detailed glacial history for the southern Cascade Range between about 37 and 15 ka. Magnetic properties vary as a result of mixing different amounts of the highly magnetic, glacially generated detritus with less magnetic, more weathered detritus derived from unglaciated parts of the large catchment. Evidence that the magnetic properties record glacial flour input is based mainly on the strong correlation between bulk sediment particle size and parameters that measure the magnetite content and magnetic mineral freshness. High magnetization corresponds to relatively fine particle size and lower magnetization to coarser particle size. This relation is not found in the Buck Lake core in a nearby, unglaciated catchment. Angular silt-sized volcanic rock fragments containing unaltered magnetite dominate the magnetic fraction in the late Pleistocene sediments but are absent in younger, low magnetization sediments. The finer grained, highly magnetic sediments contain high proportions of planktic diatoms indicative of cold, oligotrophic limnic conditions. Sediment with lower magnetite content contains populations of diatoms indicative of warmer, eutrophic limnic conditions. During the latter part of oxygen isotope stage 3 (about 37–25 ka), the magnetic properties record millennial-scale variations in glacial-flour content. The input of glacial flour was uniformly high during the Last Glacial Maximum, between about 21 and 16 ka. At about 16 ka, magnetite input, both absolute and relative to hematite, decreased abruptly, reflecting a rapid decline in glacially derived detritus. The decrease in magnetite transport into the lake preceded declines in pollen from both grass and sagebrush. A more gradual decrease in heavy mineral content over this interval records sediment starvation with the growth of marshes at the margins of the lake and dilution of detrital material by biogenic silica and other organic matter. 相似文献
3.
H. S. Negga S. M. F. Sheppard J. M. Rosenbaum M. Cuney 《Contributions to Mineralogy and Petrology》1986,93(2):179-186
Late Hercynian U-bearing carbonate veins within the metamorphic complex of La Lauzière are characterized by two parageneses. The first is dominated by dolomite or ankerite and the second by calcite and pitchblende. Fluids trapped in the dolomites and ankerites at 350–400° C are saline waters (20 to 15 wt % eq. NaCl) with D –34 to –49. In the calcite they are less saline (17 to 8 wt % eq. NaCl) and trapped at 300–350° C with D –50 to –65. All fluids contain trace N2, CO2 and probably CH4. The carbonates have
13C –8 to –14. and derived their carbon from organic matter. Evolution of the physico-chemical conditions from dolomite (ankerite) to calcite deposition was progressive.H and O-isotope studies indicate the involvement of two externally derived fluids during vein development. A D-rich ( –35) low fO2, saline fluid is interpreted to have come from underlying sediments and entered the hotter overlying metamorphic slab and mixed with more oxidizing and less saline U bearing meteoric waters during regional uplift. This evidence for a sedimentary formation water source for the deep fluid implies that the metamorphic complex overthrusted sedimentary formations during the Late-Hercynian. 相似文献
4.
E. Dunworth E.-R. Neumann J. Rosenbaum 《Contributions to Mineralogy and Petrology》2001,140(6):701-719
The Skien lavas, which form the earliest phase of basaltic magmatism within the Permo-Carboniferous Oslo Rift, contain multiple generations of clinopyroxene which exhibit strong petrological and geochemical disequilibrium. Three principal core compositions have been identified: (1) low-jadeite, high-Mg, Cr-diopside cores (CrMgDi) with strongly depleted trace-element signatures, which are believed to be xenocrystic in origin; (2) Mg-rich, Cr-poor diopside cores (MgDi) with moderately depleted trace-element signatures which probably represent early cognate growth; and (3) more dominant, low-Mg, phenocrystic diopside cores (PhenDi). Several samples contain CrMgDi or MgDi cores which have been subjected to resorption and partial re-equilibration with their host melts, indicative of extensive disequilibrium and magma mixing. These three core types are overgrown by trace-element-enriched Ti-augite, which also forms megacrysts and late-stage lava groundmass. Calculated Ti-augite/melt partition coefficients show clinopyroxene compatibility of the M-HREE, Zr, Hf and Y. The LILE, Sr, and Nb remain incompatible. )Sr300 and )Nd300 of Ti-augite overgrowths, phenocrystic diopside, and MgDi diopside cores show that intrasample isotopic disequilibrium existed when the host basalts were erupted. All epsilon values lie within the range of data previously published for the Skien lavas. Detailed examination of the chemical, isotopic and textural disequilibrium features seen in these lavas has enabled us to place constraints upon the magmatic evolution of this basalt suite, ranging from xenocryst incorporation to cognate multistage pyroxene growth, as well as identifying clear evidence of magma mixing and possible crustal contamination. 相似文献
5.
6.
S. Bauer H. Class M. Ebert V. Feeser H. G?tze A. Holzheid O. Kolditz Sabine Rosenbaum W. Rabbel D. Sch?fer A. Dahmke 《Environmental Earth Sciences》2012,67(2):351-367
Capture and geological sequestration of CO2 from large industrial sources is considered a measure for reducing anthropogenic emissions of CO2 and thus mitigating climate change. One of the main storage options proposed are deep saline formations, as they provide the largest potential storage capacities among the geologic options. A thorough assessment of this type of storage site therefore is required. The CO2-MoPa project aims at contributing to the dimensioning of CO2 storage projects and to evaluating monitoring methods for CO2 injection by an integrated approach. For this, virtual, but realistic test sites are designed geometrically and fully parameterized. Numerical process models are developed and then used to simulate the effects of a CO2 injection into the virtual test sites. Because the parameterization of the virtual sites is known completely, investigation as well as monitoring methods can be closely examined and evaluated by comparing the virtual monitoring result with the simulation. To this end, the monitoring or investigation method is also simulated, and the (virtual) measurements are recorded and evaluated like real data. Application to a synthetic site typical for the north German basin showed that pressure response has to be evaluated taking into account the layered structure of the storage system. Microgravimetric measurements are found to be promising for detecting the CO2 phase distribution. A combination of seismic and geoelectric measurements can be used to constrain the CO2 phase distribution for the anticline system used in the synthetic site. 相似文献
7.
Studies of magnetic properties enable reconstruction of environmental conditions that affected magnetic minerals incorporated in sediments from Upper Klamath Lake. Analyses of stream sediment samples from throughout the catchment of Upper Klamath Lake show that alteration of Fe-oxide minerals during subaerial chemical weathering of basic volcanic rocks has significantly changed magnetic properties of surficial deposits. Titanomagnetite, which is abundant both as phenocrysts and as microcrystals in fresh volcanic rocks, is progressively destroyed during weathering. Because fine-grained magnetite is readily altered due to large surface-to-volume ratios, weathering causes an increase in average magnetic grain size as well as reduction in the quantity of titanomagnetite both absolutely and relative to hematite. Hydrodynamic mineralogical sorting also produces differences in magnetic properties among rock and mineral grains of differing sizes. Importantly, removal of coarse silicate and Fe-oxide grains by sorting concentrated extremely fine-grained magnetite in the resulting sediment. The effects of weathering and sorting of minerals cannot be completely separated. These processes combine to produce the magnetic properties of a non-glacial lithic component of Upper Klamath Lake sediments, which is characterized by relatively low magnetite content and coarse magnetic grain size. Hydrodynamic sorting alone causes significant differences between the magnetic properties of glacial flour in lake sediments and of fresh volcanic rocks in the catchment. In comparison to source volcanic rocks, glacial flour in the lake sediment is highly enriched in extremely fine-grained magnetite. 相似文献
8.
Steven M. Colman J. Platt Bradbury Joseph G. Rosenbaum 《Journal of Paleolimnology》2004,31(2):129-138
The subsiding Upper Klamath Lake Basin contains sediments that were continuously deposited in a shallow, freshwater lake for more than 40 000 years. Well dated by radiometric methods and containing volcanic ashes of known age, these sediments constitute a valuable paleoclimate record. Sediment constituents and properties that reflect past climatic conditions in the area include pollen, diatoms, sediment geochemistry, and sediment magnetic properties. Many of these proxy measurements are also useful for comparing natural conditions in the lake to conditions following human settlement. Because of its location, the paleoclimate record from Upper Klamath Lake is valuable for comparisons to offshore marine records and as part of latitudinal transects of paleoclimate records along the west coast of the Americas. 相似文献
9.
Attention is drawn to the importance of spatial aspects when adopting a modelling approach to predict the likely character of sediment. This requires an understanding of the processes controlling transport, deposition and remobilization, singly and in combination. The advantages of incorporating expert systems are examined alongside recently developed GIS techniques utilising multiple criteria and fuzzy sets. 相似文献
10.
P.?LuEmail author S.?Cai P.?Yang M.?S.?Rosenbaum 《Geotechnical and Geological Engineering》2005,23(2):131-139
The deterioration of weak rock subject to wetting impacts upon excavation and tunnelling for mine development. Based on a limited number of determinations at the XGZ Iron Mine, China, the Grey Prediction technique has been employed to assess susceptibility to deterioration. This has been compared to regression, suggesting that the Grey Prediction provides an effective approach where data are limited or inaccessible. 相似文献