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161.
162.
印度与欧亚大陆碰撞构造变形数值分析 总被引:8,自引:0,他引:8
在全面考虑了大陆构造变形三重非线性特征的基础上,用动态有限元法研究了藏东对印度与欧亚大陆碰撞作用的大变形响应。数值模拟结果显示了明显的纵向收缩变形,变形主轴多具有顺时针转动的趋势,但横向位移在总体上并不显著。其最大值正位于红河和鲜水河断裂之间,这一结果论证了印度板块对欧亚大陆的碰撞可能是川滇菱形块体向南东运动的动力来源。红河、鲜水河、昆仑及阿尔金活断层在碰撞作用下发生了顺时针的旋转变形;而且,计算结果模拟出了红河断裂由左旋变为右旋,另3条断裂始终左旋的运动特征 相似文献
163.
大灰厂跨断层形变资料的地震信息识别 总被引:1,自引:0,他引:1
利用具有明显物理意义的断层蠕动模型在充分考虑可能存在的干扰因素影响的基础上,对大灰石台跨断层地形变资料在1989年大同地震前后出现的较大幅度变化进行了异常属性分析。结果表明,这个时期的异常变化尽管叠加有一定的降雨影响,但蠕动模型计算得出的地表变化理论值与实际变化有一定程度的符合,显示出在区域应力场作用下,八宝山断层局部地段在大同地震前后可能存在着与区域应力场应力增强及应力调理有关的构造活动。 相似文献
164.
165.
论中国含油气区的构造环境性质、分区及其成油气专属性 总被引:13,自引:0,他引:13
在前中生代,形成了华北、扬子和塔里木等较大的海相及海陆交互相含油气区(盆地),构造格架呈南北分异。经海西-印支运动,形成统一的中国大陆板块,且整体构造格架演变为东西分异。根据盆地结构、构造变形样式、岩浆活动、地温场、壳幔结构及壳幔连通程度等方面的特征,论述了中、新生代中国含油气区的大地构造环境性质与含油气特征。据此划分出 4个具有不同构造环境性质的含油气区:①东部裂谷伸展区,其西带为华夏裂谷系,以产下第三系和白垩系原油为主,东带为大陆架裂谷系,以产下第三系煤型气为主;②中部克拉通构造稳定区,以产古生界天然气为主;③西北构造反转区,含油气层系较多,油气成因类型也多样;④特提斯碰撞-走滑区,构造变形复杂,部分地区具有较好的油气资源前景。进一步讨论了油气形成的"构造环境专属性"问题。 相似文献
166.
T. Wang H. Guo D. R. Blake Y. H. Kwok I. J. Simpson Y. S. Li 《Journal of Atmospheric Chemistry》2005,52(3):295-317
We present a 16-month record of ozone (O3), carbon monoxide (CO), total reactive nitrogen (NOy), sulphur dioxide (SO2), methane (CH4), C2 – C8 non-methane hydrocarbons (NMHCs), C1 – C2 halocarbons, and dimethyl sulfide (DMS) measured at a southern China coastal site. The study aimed to establish/update seasonal
profiles of chemically active trace gases and pollution tracers in subtropical Asia and to characterize the composition of
the `background' atmosphere over the South China Sea (SCS) and of pollution outflow from the industrialized Pearl River Delta
(PRD) region and southern China. Most of the measured trace gases of anthropogenic origin exhibited a winter maximum and a
summer minimum, while O3 showed a maximum in autumn which is in contrast to the seasonal behavior of O3 in rural eastern China and in many mid-latitude remote locations in the western Pacific. The data were segregated into two
groups representing the SCS background air and the outflow of regional continental pollution (PRD plus southern China), based
on CO mixing ratios and meteorological conditions. NMHCs and halocarbon data were further analyzed to examine the relationships
between their variability and atmospheric lifetime and to elucidate the extent of atmospheric processing in the sampled air
parcels. The trace gas variability (S) versus lifetime (τ) relationship, defined by the power law, Slnx = Aτ− b, (where X is the trace gas mixing ratio) gives a fit parameter A of 1.39 and exponent b of 0.42 for SCS air, and A of 2.86 and b of 0.31 for the regional continental air masses. An examination of ln[n-butane]/ln[ethane] versus ln[propane]/ln[ethane] indicates that their relative abundance was dominated by mixing as opposed
to photochemistry in both SCS and regional outflow air masses. The very low ratios of ethyne/CO, propane/ethane and toluene/benzene
suggest that the SCS air mass has undergone intense atmospheric processing since these gases were released into the atmosphere.
Compared to the results from other polluted rural sites and from urban areas, the large values of these species in the outflow
of PRD/southern China suggest source(s) emitting higher levels of ethyne, benzene, and toluene, relative to light alkanes.
These chemical characteristics could be unique indicators of anthropogenic emissions from southern China. 相似文献
167.
金沙江虎跳峡成因及形成时代探讨 总被引:2,自引:0,他引:2
虎跳峡是金沙江峡谷的典型代表,其成因及形成时代涉及金沙江-长江水系发育及其环境效应问题。文中分析研究了虎跳峡附近发育的夷平面、剥蚀面、阶地等区域性的层状地貌,并认为虎跳峡上下游河谷发育历史具有一致性;从地质构造上的分析表明,虎跳峡两侧的玉龙雪山、哈巴雪山为一相对完整的地块,不存在虎跳峡大断裂,因而虎跳峡峡谷是在区域地壳抬升、先成河深切作用下而形成的。根据相关盆地沉积物、玉龙雪山的冰川发育状况、前人在附近发现的哺乳动物化石等,初步认为虎跳峡峡谷形成于中更新世。 相似文献
168.
Automatic Interpretation of Magnetic Data Using Euler Deconvolution with Nonlinear Background 总被引:1,自引:0,他引:1
Pawan Dewangan T. Ramprasad M. V. Ramana M. Desa B. Shailaja 《Pure and Applied Geophysics》2007,164(11):2359-2372
The voluminous gravity and magnetic data sets demand automatic interpretation techniques like Naudy, Euler and Werner deconvolution.
Of these techniques, the Euler deconvolution has become a popular choice because the method assumes no particular geological
model. However, the conventional approach to solving Euler equation requires tentative values of the structural index preventing
it from being fully automatic and assumes a constant background that can be easily violated if the singular points are close
to each other. We propose a possible solution to these problems by simultaneously estimating the source location, depth and
structural index assuming nonlinear background. The Euler equation is solved in a nonlinear fashion using the optimization
technique like conjugate gradient. This technique is applied to a published synthetic data set where the magnetic anomalies
were modeled for a complex assemblage of simple magnetic bodies. The results for close by singular points are superior to
those obtained by assuming linear background. We also applied the technique to a magnetic data set collected along the western
continental margin of India. The results are in agreement with the regional magnetic interpretation and the bathymetric expressions. 相似文献
169.
The Khanaser Valley was geoelectrically thoroughly surveyed through a grid which consisted of twelve VES profiles. The tectonically-oriented
Pichgin and Habibullaev method was enhanced to be applicable in areas of rugged relief and topography. The enhanced profiles
were tectonically interpreted and subsurface structures within the Khanaser Valley were delineated. Accordingly, a tectonic
evolutional scenario of the valley was established and its hydrogeological characteristics were derived. An approach for groundwater
exploration in areas of prominent relief and topography in dry areas such as the Khanaser Valley was established and its validity
was estimated. 相似文献
170.
依据化探成果对东昆仑地质背景的讨论 总被引:2,自引:0,他引:2
在东昆仑地区 6 0 0 0 0多km2 的地域内 ,按照 4km2 的采样单元 ,共采集了 15 0 0 0多件水系沉积物样品。按照 16km2 的网格加工成 4 0 0 0多件组合样后 ,定量分析了 4 0种微量元素的含量。在对这些数据进行数学处理的基础上 ,利用斜交因子的分析结果 ,讨论了东昆仑地区的区域地层、断裂构造和中酸性岩浆岩的特征。根据区域地球化学成果 ,进一步明确了昆中、昆南断裂对本区地层和侵入岩分布的控制作用。基于元素区域地球化学背景的对比 ,提出了昆中断裂应向东延伸的证据 ,并指出了东大滩、布青山两个地区经历了相似的地质 地球化学作用 相似文献