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991.
碳同位素在海相碳酸盐岩研究中日益受到重视,成为重大地质事件识别与解释、地层划分与对比的重要手段之一.通过对巢湖地区楚歌岭剖面早三叠世地层碳同位素研究,显示Smithian\Spathian界线处碳同位素的快速正漂具有全球性特征,可以作为地层划分对比的良好标志;而且这一变化特征反映一次海洋生产力暴发事件,与海洋环境突变和灾后生物的复苏关系密切,为早三叠世海洋生态系统灾后重建过程的恢复提供了重要线索. 相似文献
992.
Tran Tuan Dung Bui Cong Que Nguyen Hong Phuong 《Russian Journal of Pacific Geology》2013,7(4):227-236
The South China Sea and adjacent areas is a large region with diversely complicated geological conditions. In spite of investigations carried out over the past many years, the marine geological structure in many places has remained poorly understood because of the deficient data, a thick seawater layer as well as of the sensitive areas among the countries in the region. In this paper, the authors study and apply a model-based methodology of the modeling and interpretation of the newest gravity data and others, which are 3D modeling, frequency filtering, horizontal gravity gradient and maximum horizontal gravity gradient, in order to determine clearly the basement structure. The basement features such as the main faults systems, uplift-depression zones and seafloor spreading axis, oceanic boundary in the region have been defined. The achieved results are checked by the seismic data available for the region. From the studied results, the authors have brought out some initial remarks on the structure and form of the basement in the South China Sea and adjacent areas. 相似文献
993.
Major element geochemistry of purple soils/rocks in the red Sichuan Basin, China: implications of their diagenesis and pedogenesis 总被引:1,自引:0,他引:1
Jing Du Youjin Luo Weihua Zhang Chang Xu Chaofu Wei 《Environmental Earth Sciences》2013,69(6):1831-1844
Major element compositions and chemical weathering features of the purple soils and their corresponding rocks in the Red Sichuan Basin, China were studied in this paper to infer the diagenetic features of the purple rocks and the pedogenetic features of the purple soils. The results showed that all of the rock and soil samples, except those from Yibin, have strongly similar major element compositions and the distribution patterns of their major element compositions are similar to those of the upper continental crust. Chemical index of alteration, chemical index of weathering and Na2O/K2O indicate that the purple soils and rocks have similar chemical weathering intensities, whereas the Al2O3–CaO* + Na2O–K2O (A–CN–K) relationship, suggests that chemical weathering was strong during diagenesis of the purple rocks, but weak during pedogenesis of the purple soils. Variations in major element compositions of the purplish rock samples, except that from Yibin, do not primarily reflect differences in compositions of the sediment source, sediment recycling and potassium metasomatism, and therefore the effects of chemical weathering on the major element compositions were mainly dependent on climate condition and the residence time of material exposed to chemical weathering. Chemical weathering of the purple rocks reached only moderate degrees under the general influence of warm and humid climate during Jurassic and Cretaceous. Warmer and more humid climate conditions partly resulted in stronger chemical weathering of rocks in the southern region of the basin than in the central and western region, whereas shorter residence time of material in upslope position partly resulted in weaker chemical weathering of rocks in the eastern region than in the central and western region. The same climate and stable tectonic setting led to comparable chemical weathering intensities of rocks in the Ziliujing and Jiaguan Formations. Gradually colder and dryer climate from Early Jurassic to Middle Jurassic then to Late Jurassic and shorter residence time in tectonically active setting of Middle Jurassic and late Late Jurassic resulted in the following order of chemical weathering intensity of the purple Jurassic rocks: Ziliujing Formation ? Shaximiao Formation ≈ Suining Formation > Penglaizhen Formation. 相似文献
994.
995.
全国第二次土地调查数据库利用以后,城市建设用地审批、大型的线状用地、土地复垦、矿山治理等工程的前期可研及预审工作等基本都以二调数据为基础数据。将正确的用地红线用ArcGis软件处理成面文件(.Shp),然后把处理后的.shp文件复制到二调数据库里的KCDJ层里。再使用农村土地调查专用软件导出各级用地面积汇总表。通过文中介绍的方法,可以实现快速、准确的制作指定范围的各种地类面积表。 相似文献
996.
【研究目的】碎屑流是深水环境沉积物搬运和分散的重要机制,其相关的砂岩储层是含油气盆地重要的勘探目标,然而,与经典浊流及浊积系统相比,对碎屑流主控型深水体系的发育规律目前仍知之甚少。【研究方法】本文基于岩心、测井及全三维地震资料,通过系统的岩心观察描述、测井及地震资料解释,对渤海湾盆地东营凹陷始新统沙三中亚段深水体系沉积过程及模式开展研究。【研究结果】结果表明,沙三中深水体系发育九种异地搬运岩相,可概括为四大成因类型,反映了块体及流体两种搬运过程。岩相定量统计表明,该深水体系主要由碎屑流沉积构成,浊流沉积很少,碎屑流中又以砂质碎屑流为主。重力流在搬运过程中经历了滑动、滑塌、砂质碎屑流、泥质碎屑流及浊流等5个阶段演变,发育5类主要的深水沉积单元,包括滑动体、滑塌体、碎屑流水道、碎屑流朵体及浊积薄层砂。从发育规模及储层物性上,砂质碎屑流水道、朵体及砂质滑动体构成了本区最重要的深水储层类型。【结论】认为沙三中时期充足的物源供给、三角洲前缘高沉积速率、断陷期频繁的断层活动以及较短的搬运距离是碎屑流主控型深水体系形成及演化的主控因素,最终基于沉积过程、沉积样式及盆地地貌特征综合建立了碎屑流主控型深水体系沉积模式。本研究将进一步丰富深水沉积理论,为陆相深水储层预测提供借鉴。 相似文献
997.
Xin-Fa Deng Cheng-Hong Luo Peng Jiang Ying-Ping Ding 《Astrophysics and Space Science》2013,347(1):183-191
Using two volume-limited samples above and below the value of $M_{r}^{ *}$ constructed from the Main galaxy sample of the Sloan Digital Sky Survey Data Release 8 (SDSS DR8), we investigate correlations between galaxy morphology and star formation rate (SFR), specific star formation rate (SSFR) and stellar mass at different environmental density levels. For each sample, three subsamples at both density extremes and at the median density are selected. We found that examining either of our two volume-limited Main samples leads to the same conclusion: at different environmental density levels, SFR, SSFR and stellar mass are strongly correlated with galaxy morphology, which shows that SFR, SSFR and stellar mass of a galaxy depend on its environment as well as its morphology. 相似文献
998.
HE Tianrong LI Ting Yang Ruidong LUO Guangjun LANG Xiaofang An Yanling YAN Haiyu 《中国地球化学学报》2013,32(1):104-109
In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations. 相似文献
999.
1000.
轨道尺度东亚夏季风的动力反演 总被引:2,自引:0,他引:2
为了探求太阳辐射和高纬地区温度对东亚夏季风的驱动机理,用动力反演的方法建立了东亚夏季风的动力方程,为东亚夏季风的驱动机制研究提供了一种新的方法.在轨道尺度上得到如下结论:东亚夏季风是由南极温度和太阳辐射量共同驱动的复杂非线性动力系统;太阳辐射是驱动东亚夏季风的最重要驱动力,驱动贡献至少达到67.57%,南极温度次之,其驱动贡献达到21.58%,格陵兰温度对东亚夏季风的驱动不起作用;太阳辐射量的增加,会驱使东亚夏季风增强;南极温度存在一个阈值,在阈值两侧,对东亚夏季风具有不同的驱动机制;东亚夏季风对太阳辐射驱动的响应,还部分地依赖于季风强度的背景值. 相似文献