The detailed characteristics of the Paleozoic strike-slip fault zones developed in the northern slope of Tazhong uplift are closely related to hydrocarbon explorations. In this study, five major strike-slip fault zones that cut through the Cambrian-Middle Devonian units are identified, by using 3D seismic data. Each of the strike-slip fault zones is characterized by two styles of deformation, namely deeper strike-slip faults and shallower en-echelon faults. By counting the reverse separation of the horizon along the deeper faults, activity intensity on the deeper strike-slip faults in the south is stronger than that on the northern ones. The angle between the strike of the shallower en-echelon normal faults and the principal displacement zone(PDZ) below them is likely to have a tendency to decrease slightly from the south to the north, which may indicate that activity intensity on the shallower southern en-echelon faults is stronger than that on the northern ones. Comparing the reverse separation along the deeper faults and the fault throw of the shallower faults, activity intensity of the Fault zone S1 is similar across different layers, while the activity intensity of the southern faults is larger than that of the northern ones. It is obvious that both the activity intensity of the same layer in different fault zones and different layers in the same fault zone have a macro characteristic in that the southern faults show stronger activity intensity than the northern ones. The Late Ordovician décollement layer developed in the Tazhong area and the peripheral tectonic events of the Tarim Basin have been considered two main factors in the differential deformation characteristics of the strike-slip fault zones in the northern slope of Tazhong uplift. They controlled the differences in the multi-level and multi-stage deformations of the strike-slip faults, respectively. In particular, peripheral tectonic events of the Tarim Basin were the dynamic source of the formatting and evolution of the strike-slip fault zones, and good candidates to accommodate the differential activity intensity of these faults. 相似文献
Based on the survey data of 250 farmers from the Multan district of Southern region of Punjab, Pakistan this study aims to empirically examine the determinants of access to agricultural credit. This study used the probit model to analyze the data. The results revealed that formal education, farm size, level of farm mechanization, farm revenue and landholding size positively and significantly influenced access to agricultural credit while the age of the farmer’s, distance, and off- farm income negatively and insignificantly influenced farmer’s accessibility to agricultural credit. The findings of the current study offer a policy guideline to streamline national policy on agricultural finance. This study also recommends that ZaraiTaraqiati Bank (ZTBL) and other Commercial Banks should improve their agricultural credit schemes to fulfil the diversified needs of small farm holders.
Research on the origin of eukaryotes often focuses on the exceptional preservation found in silicified Precambrian fossils. Nuclei like subcellular structures in well-preserved fossil becomes confusion and arguments, which focus on whether the partial degradation of prokaryotes produces artifacts that resemble a ‘nucleus’, or fossilized nuclei of eukaryotes. In order to understand the mechanisms of silicification and identify the fossilized subcellular and microstructures in rocks, a series of laboratory controlled experiments were performed for simulating the silicification process. The effects of different silica solutions in eukaryote fossilization were studied in our experiments by exposing onion skin cells (epidermis) to silica solutions. Onion skin provides a good experimental model because of its well characterized cellular structures which are easily observed. The designed experiments revealed that the possibility of onion cell preserved as a “fossil” with nuclear structures, the first week fossilization, or mineralization as rapid as 1 week is important. And the experiment also revealed interactions between silica and the onion skin cell wall surface functional groups were weak. The preservation of nuclei in the onion skin model was due to precipitation in highly supersaturated silica solutions rather than simply the high silica concentration. When the silica gel precipitates slowly at low supersaturation states, the nuclei were not well preserved, but the rapid precipitation at high supersaturated silica conditions preserved nuclear structures. A better understanding of the processes involved in onion skin fossilization will further contribute to issues concerning the silicification of other eukaryotic materials. 相似文献
Correct interpretation of zircon ages from high-grade metamorphic terrains poses a major challenge because of the differential response of the U–Pb system to metamorphism, and many aspects like pressure–temperature conditions, metamorphic mineral transformations and textural properties of the zircon crystals have to be explored. A large (c. 450?km2) coherent migmatite complex was recently discovered in the Bohemian Massif, Central European Variscides. Rocks from this complex are characterized by granulite- and amphibolite-facies mineral assemblages and, based on compositional and isotopic trends, are identified as the remnants of a magma body derived from mixing between tonalite and supracrustal rocks. Zircon crystals from the migmatites are exclusively large (200–400?μm) and yield 207Pb/206Pb evaporation ages between 342–328?Ma and single-grain zircon fractions analysed by U–Pb ID-TIMS method plot along the concordia curve between 342 and 325?Ma. High-resolution U–Pb SHRIMP analyses substantiate the existence of a resolvable age variability and yield older 206Pb/238U ages (342–330?Ma, weighted mean age?=?333.6?±?3.1?Ma) for inner zone domains without relict cores and younger 206Pb/238U ages (333–320?Ma, weighted mean age?=?326.0?±?2.8?Ma) for rim domains. Pre-metamorphic cores were identified only in one sample (206Pb/238U ages at 375.0?±?3.9, 420.3?±?4.4 and 426.2?±?4.4?Ma). Most zircon ages bracket the time span between granulite-facies metamorphism in the Bohemian Massif (~345?Ma) and the late-Variscan anatectic overprint (Bavarian phase, ~325?Ma). It is argued that pre-existing zircon was variously affected by these metamorphic events and that primary magmatic growth zones were replaced by secondary textures as a result of diffusion reaction processes and replacement of zircon by dissolution and recrystallization followed by new zircon rim growth. Collectively, the results show that the zircons equilibrated during high-grade metamorphism and record partial loss of radiogenic Pb during post-peak granulite events and new growth under subsequent anatectic conditions. 相似文献
A sample preparation method of total sulphur measurement of reactive mine tailings was optimized. The total sulphur was measured by inductively coupled plasma optical emission spectroscopy, and ultrasound technique was used for sample digestion. The optimization process was adopted by a combined approach of experimental design and response surface methodology. The digestion time, temperature and acid-oxidant combination (i.e. effect of H2O2 with a fixed amount of acid mixture) were investigated. A two-level and three-factor (23) full factorial design of experiment was applied to identify the most significant factors, and a central composite design was used to optimize the digestion procedure. KZK-1, a sericite schist, was selected as the certified reference material. The optimum methodology at 95 % confidence level (P < 0.05) was identified to be 10 min of digestion at 77 °C, with a solution of 1 ml HNO3:1 ml HCl:1.35 ml H2O2. This combination resulted in 100 % sulphur recovery. The investigated method was verified by X-ray diffraction analysis. The optimum digestion level was applied to a reactive mine tailings, which achieved satisfactory results with a percentage relative standard deviation < 3 %. 相似文献
The paper deals with unsteady inter-porosity flow modeling of underground fluid in a multiple media reservoir. Assuming spherical
vugs, symmetrically distributed pressure, negligible inter-porosity flow between matrix and vug systems and centrifugal flow
of the fluid from matrix blocks or vugs to fractures, and treating media directly connected with wellbore as the fracture
system, we establish and solve a model of unsteady inter-porosity flow for dual and triple porosity media reservoirs. We provide
simulated graphs of pressure and pressure derivative log-log type curves, and analyze the transient flow process and characteristics
of type curves affected by different parameters. The new type curves of unsteady inter-porosity flow modeling are evidently
different in shape and characteristics from those of pseudo-steady inter-porosity flow modeling. The location of dimensionless
pressure of unsteady inter-porosity is lower than that of pseudo-steady inter-porosity, which indicates that unsteady inter-porosity
flow accelerates an energy supplement during production. Qualitatively, the unsteady inter-porosity flow modeling reduces
the classical V-shaped response. We also estimated parameters from well test data in real applications using this model. 相似文献