Migration characteristics of dense non-aqueous phase liquids (DNAPLs) in the subsurface can be expressed as a water–DNAPL two-phase system based on mainly the k–S–p relations, which describe the relations among relative permeability (k), degree of water saturation (S), and capillary pressure head (p). The aims of this research are to develop an experimental system with new type of probes, such as the electrical conductivity probe for measuring the degree of water saturation and the hydrophilic and hydrophobic tensiometer for measuring the pore water and DNAPL pressures, and also to estimate the results obtained from the developed experimental system. From these tests, the excellent k–S–p relations were obtained and the efficiency and validity of this developed experimental system have been confirmed in terms of the concept of the scaling coefficient calculated by interfacial tensions. 相似文献
Iron fertilization of nutrient-rich surface waters of the ocean is one possible way to help slow the rising levels of atmospheric
CO2 by sequestering it in the oceans via biological carbon export. Here, I use an ocean general circulation model to simulate
a patch of nutrient depletion in the subpolar northwest Pacific under various scenarios. Model results confirm that surface
fertilization is an inefficient way to sequester carbon from the atmosphere (Gnanadesikan et al., 2003), since only about 20% of the exported carbon comes initially from the atmosphere. Fertilization reduces future production
and thus CO2 uptake by utilizing nutrients that would otherwise be available later. Effectively, this can be considered as leakage when
compared to a control run. This “effective” leakage and the actual leakage of sequestered CO2 cause a significant, rapid decrease in carbon retention (only 30–45% retained after 10 years and less than 20% after 50 years).
This contrasts markedly with the almost 100% retention efficiency for the same duration using the same model, when carbon
is disposed directly into the northwest Pacific (Matsumoto and Mignone, 2005). As a consequence, the economic effectiveness
of patch fertilization is poor in two limiting cases of the future price path of carbon. Sequestered carbon in patch fertilization
is lost to the atmosphere at increasingly remote places as time passes, which would make monitoring exceedingly difficult.
If all organic carbon from one-time fertilization reached the ocean bottom and remineralized there, acidification would be
about −0.05 pH unit with O2 depletion about −20 μmol kg−1. These anomalies are probably too small to seriously threaten deep sea biota, but they are underestimated in the model because
of its large grid size. The results from this study offer little to advocate purposeful surface fertilization as a serious
means to address the anthropogenic carbon problem. 相似文献
Illite crystallinity, K–Ar dating of illite, and fission‐track dating of zircon are analyzed in the hanging wall (Sampodake unit) and footwall (Mikado unit) of a seismogenic out‐of‐sequence thrust (Nobeoka thrust) within the Shimanto accretionary complex of central Kyushu, southwest Japan. The obtained metamorphic temperatures, and timing of metamorphism and cooling, reveal the tectono‐metamorphic evolution of the complex, and related development of the Nobeoka thrust. Illite crystallinity data indicate that the Late Cretaceous Sampodake unit was metamorphosed at temperatures of around 300 to 310°C, while the Middle Eocene Mikado unit was metamorphosed at 260 to 300°C. Illite K–Ar ages and zircon fission‐track ages constrain the timing of metamorphism of the Sampodake unit to the early Middle Eocene (46 to 50 Ma, mean = 48 Ma). Metamorphism of the Mikado unit occurred no earlier than 40 Ma, which is the youngest depositional age of the unit. The Nobeoka thrust is inferred to have been active during about 40 to 48 Ma, as the Sampodake unit started its post metamorphic cooling after 48 Ma and was thrust over the Mikado unit at about 40 Ma along the Nobeoka thrust. These results indicate that the Nobeoka thrust was active for more than 10 million years. 相似文献
Thorium isotopes in the airborne dust collected at Tsukuba Science City in Japan from January 1981 to December 1982 show clear seasonal variations. Especially228Th in the airborne particles have a typical maximum cincentration between February and April, which is about an order of magnitude higher than during the remainder of the year. According to the result of size distribution of thorium isotope-bearing particles in the air, about 53% of228Th is associated with the particles less than 1.6 μm aerodynamic diameter. These results reveal that228Th in the airborne particles is present in fine soily matters originating from the East Asian deserts. 相似文献
This paper deals with a Lopingian (Late Permian) foraminiferal faunal succession of the Shifodong Formation in the Changning–Menglian Belt, West Yunnan, Southwest China, which has been geologically interpreted as one of the closed remnants in East Asia of the Paleo‐Tethys Ocean. The Shifodong Formation is the uppermost stratigraphic unit in thick Carboniferous–Permian carbonates of the belt. These carbonates rest upon bases consisting of oceanic island basalt and are widely accepted as having a Paleo‐Tethyan mid‐oceanic (seamount‐ or oceanic plateau‐top) origin. Sixteen taxa of fusuline foraminifers and 37 taxa of smaller (non‐fusuline) foraminifers are recognized from the type section of the Shifodong Formation located in the Gengma area of the northern part of the Changning–Menglian Belt. Based on their stratigraphic distribution, three fusuline zones can be established in this section: they are, in ascending order, the Codonofusiella cf. C. kwangsiana Zone, Palaeofusulina minima Zone, and Palaeofusulina sinensis Zone. These three biozones are respectively referable to the Wuchiapingian, early Changhsingian, and late Changhsingian, of which the Wuchiapingian is first recognized in this study in the Changning–Menglian mid‐oceanic carbonates. The present study clearly demonstrates that the foraminiferal fauna in a Paleo‐Tethyan pelagic shallow‐marine environment still maintained high faunal diversity throughout the almost entire Lopingian, although the very latest Permian fauna in the upper part of the Palaeofusulina sinensis Zone of the Shifodong section records a sudden decrease in both faunal diversity and abundance. Moreover, the Shifodong faunas are comparable in diversity with those observed in circum‐Tethyan shelves such as South China. The present Paleo‐Tethyan mid‐oceanic foraminiferal faunas are definitely more diversified than coeval mid‐oceanic Panthalassan faunas, which are typically represented by those from the Kamura Limestone in a Jurassic accretionary complex of Southwest Japan. It is suggestive that the Paleo‐Tethyan mid‐oceanic buildups presumably supplied a peculiarly hospitable habitat for foraminiferal faunal development in a pelagic paleo‐equatorial condition. 相似文献
A rich foraminiferal assemblage, consisting of abundant Aulotortus sinuosus and A. tumidus in association with Lamelliconus multispirus, Endoteba ex gr. controversa, E. ex gr. badouxi, Endotebanella kocaeliensis, Endotriada tyrrhenica, Endotriadella wirzi, Malayspirina fontainei, Ammobaculites rhaeticus, Diplotremina astrofimbriata, Agathammina austroalpina, and others, was found in the Doi Long Formation of the Triassic Lampang Group, Northern Thailand. These foraminifers suggest that the formation is referable to the Carnian (early Late Triassic), which is consistent with the age estimated by ammonoids. In microfacies, peloidal grainstone, bioclastic grainstone, sponge-microbial boundstone, and oolitic grainstone were recognized in the Doi Long Formation. Based on microfacies, three depositional facies, the lagoon facies, reef facies, and shoal facies, are recognized in this formation. These lines of evidence are suggestive that the Doi Long Formation was deposited in a reef or bank setting rather than a ramp setting. 相似文献