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11.
对青海省祁连山永久冻土区天然气水合物DK一2钻孔的11件样品进行分析,通过微生物群落分析来探寻水合物层样品与非水合物层样品的差别。在11件样品中均发现了细菌16SrDNA,未检测到海洋天然气水合物地区常见的古菌16SrDNA、mc以（I,Ⅱ）、pmoA、mmoX和mxaF。分析得到的细菌16SrDNA分属5个门,包括变形杆菌门、放线菌门、拟杆菌门、厚壁菌门和异常球菌一栖热菌门,随着样品深度的增加,细菌多样性有降低的趋势。对非水合物层样品DK2—19和水合物层样品DK2—25进行细菌系统发育树分析,发现这2个样品群落结构相差较大。水合物层样品与非水合物层样品细菌群落对比后发现,水合物层样品中叫一变形杆菌的比例低于非水合物层样品中1一变形杆菌的比例,而Arthrobacter属多发现于非水合物层的样品中。 相似文献
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Most stochastic modelling techniques neglect the correlations among the raw un-differenced observations when forming the variance–covariance matrix of the Global Navigation Satellite System (GNSS) observations. Some methods were developed to model these correlations. One such method is the Minimum Norm Quadratic Unbiased Estimator (MINQUE). Studies have shown that MINQUE improves ambiguity resolution, and ultimately, the positioning solution in short baselines. However, its effect in cases of processing with longer baselines and on the estimation of zenith wet delay (ZWD) is somewhat unknown. In this paper, a comparison between the impact of neglecting the correlations among the observations using an elevation-angle-dependent model (EADM) and modelling the correlations using MINQUE on height determination and ZWD for medium and long baselines is carried out. The initial testing was carried out across two Australian GNSS stations with a medium-length baseline throughout a three-week campaign. The results showed that using MINQUE did not resolve the coordinate, height and wet delay components as accurately as the EADM. The results were further verified with two long-baseline campaigns whereby EADM was also able to provide better wet delay estimates. The coordinate results were, however, mixed. Overall, the study concluded that the inclusion of the correlations among the observations, in general, do not improve the resolution of the coordinate and wet delay estimates. 相似文献
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CHEN Wei‐Min HUANG Young‐Ching Yoshiyuki IIZUKA LO Ching‐Hua WU Hanquan SONG Shuguang YANG Jingsui XU Zhiqin YANG Houng‐Yi 《《地质学报》英文版》2002,76(1):44-62
After the integration of petrographic study, geothermobarometry and Gibbs method, the synthetic P-T paths for the rocks from different geological profiles in the North Qilian, China, have been derived. The composite P-T paths from different methods indicate that all the high-pressure rocks in the Qilian area recorded P-T paths with clockwise loops starting at the blueschist facies, later reaching peak metamorphism at the blueschist facies, eclogite fades or epidote-amphibolite facies and ending up with the greenschist facies. The incremental Ar-Ar dating shows that the plateau ages for the high-pressure rocks range from 410 to 443 Ma. The plateau ages could be used as a minimum age constraint for the subduction that resulted in the formation of these high-pressure rocks in the Qilian area. It is proposed that the late-stage decompressional and cooling P-T paths with ends at the greenschist facies for these high-pressure rocks probably reflect the uplift process which could occur after shifting the arc-t 相似文献
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Ching‐Hua LO Kieren T. HOWARD Sun‐Lin CHUNG Sebastien Meffre 《Meteoritics & planetary science》2002,37(11):1555-1562
Abstract— Three samples of Darwin Glass, an impact glass found in Tasmania, Australia at the edge of the Australasian tektite strewn field were dated using the 40Ar/39Ar single‐grain laser fusion technique, yielding isochron ages of 796–815 ka with an overall weighted mean of 816 ± 7 ka. These data are statistically indistinguishable from those recently reported for the Australasian tektites from Southeast Asia and Australia (761–816 ka; with a mean weighted age of 803 ± 3 ka). However, considering the compositional and textural differences and the disparity from the presumed impact crater area for Australasian tektites, Darwin Glass is more likely to have resulted from a distinct impact during the same period of time. 相似文献
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A MESO-β SCALE SIMULATION OF THE EFFECTS OF BOREAL FOREST ECOSYSTEM ON THE LOWER ATMOSPHERE* 
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下载免费PDF全文 Based on the Intensive Field Campaign(IFC-1)data of Boreal Ecosystem-Atmosphere Study (BOREAS),a three-dimensional meso-β scale model is used to simulate the effect of boreal forests on the lower atmosphere.A fine horizontal resolution of 2 km×2 km is used in order to distinguish the vegetative heterogeneity in the boreal region.A total of 20×25 grid points cover the entire sub-modeling area in BOREAS' South Study Area(SSA).The ecosystem types and their coverage in each grid square are extracted from the North American Land Cover Characteristics Data Base (NALCCD) generated by the U.S.Geographical Survey (USGS) and the University of Nebraska-Lincoln(UNL).The topography of the study area is taken from the Digital Elevation Map(DEM)of USGS.The model outputs include the components of the energy balance budget within the canopy and at the ground,the turbulence parameters in the atmospheric boundary layer and the wind,temperature and humidity profiles extending up to a height of 1500 m.In addition to the fine time and spatial step,the unique feature of the present model is the incorporation of both dynamic and biological effects of the Boreal forest into the model parameterization scheme.The model resultscompare favorably with BOREAS' IFC-1 data in 1994 when the forest was in the luxuriant growing period. 相似文献
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Dating of the Karakorum Strike-slip Fault 总被引：6，自引：0，他引：6
ZHOU Yong XU Ronghu YAN Yuehu PAN Yusheng Tsanyao Frank YANG Wei LO WU Chunming Laboratory of Lithosphere Tectonic Evolution Institute of Geology Geophysics Chinese Academy of Sciences Beijing Department of Geology National Taiwan University Choushan Ro Taipei - TaiwanDepartment of Geology Chinese Culture University Hwa-kang Yang-Ming-Shan Taipei Taiwan Institute of Geology Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》2001,75(1):10-18
This paper mainly discusses the timing of the Karakorum strike-slip fault, and gives a brief introduction of its structures, offset, and deformational style. This fault strikes NNW-SSE. Asymmetrical folds, stretching lineation, S-C fabrics, feldspar and quartz σ-porphyroclasts, domino structure, shear cleavages and faults in the fault zone are products of tectonic movements. They all indicate a dextral slip sense of faulting. Mylonitic bands are widely developed along this fault. Phengite appears, indicating rather high deformational pressure. Geochronological data indicate that the Karakorum strike-slip faulting occurred from 6.88±0.36 to 8.75±0.25 Ma. The cumulative displacement from Muztag Ata to Muji is about 135 km. 相似文献
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Abstract: The Mesozoic potash‐rich volcanic rocks which hosted several gold or gold (copper) deposits are widely distributed around the Yishu deep fault zone, eastern China. Lithologically, these rocks include basaltic trachyandesite, trachyandesite, latite and trachyte, of which the trachyandesite and latite are the predominant rock types. Whole‐rock Rb‐Sr isochron ages and 40Ar‐39Ar plateau dates of them are 108.2 ? 119.6 Ma and 114.7 ? 124.3 Ma, respectively. Chemically, they are characterized by high and variable Al2O3 contents, high K2O+Na2O values, and high K2O/Na2O and Fe2O3/FeO ratios. The rocks also have enriched LILE and LREE concentrations, low HFSE abundance, and display extraordinary Sr‐Nd isotope signatures (ISr = 0.7084 ? 0.7125, εNd(t) = ‐9.43 ? ?18.07). Integrated geological and geochemical data suggest that they were formed in a continental‐arc setting and most likely originated from the partial melting of enriched mantle which was induced by source contamination of subducted continental crustal materials. Gold (copper) deposits in this district are closely related to Mesozoic volcanic‐subvolcanic magmatism. They are frequently located either at the margin or adjacent to the volcanic basins. Most of them are spatially associated with maar‐diatreme systems and/or flow‐dome complexes. The formations of two gold (copper) deposits, the Qibaoshan breccia pipe‐porphyry type Au‐Cu deposit and the Guilaizhuang tellurium‐gold type epithermal Au deposit, have been proved to be in close relation with potash‐rich magmatism. The genetic relations between potash‐rich magmatism and Cu‐Au mineralization is still quite unclear. Detailed review of the previous works demonstrates that the high contents of volatiles (such as H2O, CO2, S, F and Cl, especially F and Cl) and the high oxidation state of the potash‐rich magmas may be the main favorable factors for the formation of the Cu‐Au deposits. 相似文献