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171.
强震的孕育、发生涉及大尺度的地壳运动和构造形变的分布.中国大陆西部现今构造形变强烈,一些强烈活动的深大断裂的分布,把地壳分割成了若干活动地块.GPS观测获得的大范围的水平运动速度场分布具有较好的空间有序性和协调性.大区域水平相对运动和变形的协调与平衡,主要是通过一些大的断裂带(活动地块的边界带)的剧烈运动和变形来调整实现的.大区域的继承性构造运动决定了这些大的活动断裂带的相对运动与变形的性质及其空间分布趋势.强震前局部区域的相对运动和变形的异常是与大区域的地壳运动和整体变形相联系的.强震活动引起的调整总体上是维护大区域地壳运动和变形的协调与平衡的趋势.研究大断裂带构造变形的趋势背景和识别异常区段,是预测未来强震地点的重要途径.  相似文献   
172.
Introduction Both Sichuan and Yunnan are provinces with more earthquakes. Based on catalogue of strong earthquakes in China compiled by the Prediction Department of China Earthquake Administration, there are 639 M5.0 earthquakes during 26 B.C.~A.D. 2001. Among them, 475 are M=5.0~5.9 events, 124 are M=6.0~6.9 events, 39 are M=7.0~7.9 events, and one is M=8 event occurred in Sichuan and Yunnan area. Here is one of the areas where seismic activities are most active in China. Sichuan-Yun…  相似文献   
173.
应用周期-频度谱方法对黑龙江省数字地震台网资料进行处理,给出了矿震、电缆应力释放、震源车作业、火山地震等振动的周期-频度谱和链波指数,并对构造地震和爆破的链波指数进行了讨论。针对港震公司的数字地震记录格式编写了专门的处理程序,为数字地震台站开展周期-频度谱分析提供了有力的工具。  相似文献   
174.
黔西南下——中三叠统界线年龄   总被引:2,自引:3,他引:2  
下—中三叠统界线年龄的精确测定是进行区域地层年表和国际地层委员会全球标准年表研究中重要的组成部分。中国贵州望谟甘河桥剖面下—中三叠统地层为奥仑尼克阶—安尼阶界线层型的理想候选剖面 ,其临界层位的玻屑凝灰岩为下—中三叠统界线的岩性标志。应用高精度高灵敏度的二次离子探针质谱对玻屑凝灰岩中的锆石进行 U- Pb年代学分析 ,结果为 2 39.0± 2 .9Ma(2σ)。这是首次直接从界线层位准确测定的下—中三叠统界线的锆石 U - Pb同位素年龄。中国贵州望谟甘河桥剖面下—中三叠统界线剖面地层连续 ,牙形石分带清楚 ,临界层位发育区域上分布较为稳定的玻屑凝灰岩 ,是极好的区域等时标志层。这一剖面有望成为国际下—中三叠统界线层型剖面。  相似文献   
175.
The Cretaceous system of the Kuqa depression is a regional scale (second order) depositional sequence defined by parallel unconformities or minor angular unconformities. It can be divided into four third-order sequence sets, eleven third-order sequences and tens of fourth- and fifth-order sequences. It consists generally of a regional depositional cycle from transgression to regression and is composed of three sets of facies associations: alluvial-fluvial, braided river-deltaic and lacustrine-deltaic facies associations. They represent the lowstand, transgressive and highstand facies tracts within the second-order sequence. The tectonic subsidence curve reconstructed by backstripping technique revealed that the Cretaceous Kuqa depression underwent a subsidence history from early accelerated subsidence, middle rapid subsidence and final slower subsidence phases during the Cretaceous time, with the correspondent tectonic subsidence rates being 30-35 m/Ma, 40-45 m/Ma and 5-10 m/Ma obtained from northern foredeep. This is likely attributed to the foreland dynamic process from early thrust flexural subsidence to late stress relaxation and erosion rebound uplift. The entire sedimentary history and the development of the three facies tracts are a response to the basin subsidence process. The slower subsidence foreland gentle slope was a favorable setting for the formation of braided fluvial deltaic systems during the late period of the Cretaceous, which comprise the important sandstone reservoirs in the depression. Sediment records of impermanent marine transgression were discovered in the Cretaceous and the major marine horizons are correctable to the highstands of the global sea level during the period.  相似文献   
176.
Kela 2 Gas Field, with high formation pressure (74.35MPa), high pressure coefficient (2.022) and difficulty of potential test and evaluation, is the largest integrated proved dry gas reservoir in China so far and the principal source for West-East Gas Development Project. In order to correctly evaluate the elastic-plastic deformation of rocks caused by the pressure decline during production, some researches, as the experiment on reservoir sensitivity to stress of gas filed with abnormal high pressure, are made. By testing the rock mechanic properties, porosities and permeabilities at different temperature and pressure of 342 core samples from 5 wells in this area, the variations of petro-physical properties at changing pressure are analyzed, and the applicable inspection relationship is concluded. The average productivity curve with the reservoir sensitivity to stress is plotted on the basis of the research, integrated with the field-wide productivity equation. The knowledge lays a foundation for the gas well productivity evaluation in the field and the gas field development plan, and provides effective techniques and measures for basic research on the development of similar gas fields.  相似文献   
177.
Differential retardation of organic matter maturation by overpressure   总被引:2,自引:1,他引:2  
Thetraditionalhydrocarbongenerationmodeldoesnottakeintoaccounttheeffectofpressure[1].Astotheroleofpressureinorganicmattermaturationandpetroleumgeneration,threeconflictingopinionshaveeverbeenproposed:(1)Increasingpressurehasnodetectableeffectonorganic-mattermaturation[1,2];(2)increasingpressureenhanceshydrocarbon-thermaldestruction[3];(3)increasingpressuresignificantlyretardsorganic-mattermaturationandhydrocarbongeneration[4,5].Therearemorethan180overpressuredbasinsintheworld.Theroleofoverpress…  相似文献   
178.
三明市农业气候资源概况   总被引:2,自引:0,他引:2  
通过分析三明市光照、水分、热量的时空分布特征及其与农作物发育生长的关系 ,指出 :三明市的农业气候资源丰富 ,其中 10℃以上活动积温为 6 6 77 9~ 5 2 4 0 2℃年 ,降水量为 14 4 0~ 182 5mm ,主要分布在 3~ 9月 (约占全年降水量的 80 %~ 85 % ) ,且随纬度、海拔高度的增加而增加 ,太阳总辐射量为 5 5 1~ 6 13MJ/m2 ,年变化为单峰型 ,2月最小、7月最大。  相似文献   
179.
通过深层样化探异常与物探重力、航磁和遥感解译关系的研究,认为深层样元素异常是由隐伏构造指示元素Au、Hg,与重力负异常有关的酸性岩元素Sn、Be、F、Y,与航磁正异常有关的基性岩元素Fe、Co、Ni、V、Cr和与地层有关元素Cd、C、Tl四部分组成;解释了深层样元素异常的原因,开拓出区域化探与区域物探、遥感解译相结合的新路。  相似文献   
180.
Abstract. Primary fluid inclusions in quartz and carbonates from the Kanggur gold deposit are dominated by aqueous inclusions, with subsidiary CO2-H2O inclusions that have a constant range in CO2 content (10–20 vol %). Microthermometric results indicate that total homogenization temperatures have a wide but similar range for both aqueous inclusions (120 to 310C) and CO2-H2O inclusions (140 to 340C). Estimates of fluid salinity for CO2-H2O inclusions are quite restricted (5.9∼10.3 equiv. wt% NaCl), whereas aqueous inclusions show much wider salinity ranging from 2.2 to 15.6 equivalent wt %NaCl.
The 6D values of fluid inclusions in carbonates vary from -45 to -61 %, in well accord with the published δD values of fluid inclusions in quartz (-46 to -66 %). Most of the δ18O and δD values of the ore-forming fluids can be achieved by exchanged meteoric water after isotopic equilibration with wall rock by fluid/rock interaction at a low water/rock ratio. However, the exchanged meteoric water alone cannot explain the full range of δ18O and δD values, magmatic and/or meta-morphic water should also be involved. The wide salinity in aqueous inclusions may also result from mixing of meteoric water and magmatic and/or metamorphic water.  相似文献   
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