叠合盆地构造热演化模拟方法研究——以江汉盆地为例   总被引：6，自引：4，他引：2       下载免费PDF全文

赵长煜  宋海斌  钱荣毅  宋洋  黄兴辉  陈林  田丽花 《地球物理学报》2010,53(1):128-137

基于地球动力学的构造-热演化方法是沉积盆地热史研究的重要方法之一.本文以江汉盆地宜随大剖面为例,采用平衡剖面方法对叠合盆地复杂、漫长的演化历史进行构造恢复,采用多期有限拉张-挤压应变速率法进行古热流反演,最后得到盆地的古地温场.由此,建立了构造恢复—盆地基底热流反演—岩石圈尺度温度结构—沉积盆地尺度温度结构的多期伸展、挤压模型的热模拟方法流程,实现了岩石圈尺度的热模拟与盆地尺度的热模拟相结合.  相似文献   

俯冲带耦合作用对苏门答腊地区应变场影响的三维数值模拟   总被引：2，自引：1，他引：1       下载免费PDF全文

戴黎明  李三忠  陶春辉  李西双  刘鑫  索艳慧  楼达 《地球物理学报》2010,53(8):1837-1851

采用有限元方法模拟了俯冲带耦合作用对巽他弧及其邻区的影响.根据模拟结果,对比GPS、地震和地质学观测数据,定量分析了苏门答腊及其周边地区的应变强度和主应变方向的分布特征,据此探讨了该区构造特征、地震发生模式与耦合面积之间的关系.模型由具有黏弹性性质的岩石圈和软流圈上地幔组成,其中岩石圈包括了大陆岩石圈和大洋岩石圈以及俯冲至上地幔中的俯冲板片.研究结果如下:(1) 通过对不同俯冲带耦合面积模拟,发现苏门答腊前弧伴随耦合面积的增加应变强度逐渐增大,而增大的应变强度又影响了其周边地区的应变分布特征,因此整个苏门答腊前弧呈现出明显的分段性,这与该区地震破裂模式有较好的对应.(2)苏门答腊北部地区主应变方向与南部相比存在一定的差异,该差异是俯冲带的俯冲方向、俯冲速度、俯冲形态以及不同区域间耦合面积共同作用的结果.(3)虽然苏门答腊2004年地震主震区处于弱耦合状态,但从本文模拟的结果中可以看到,在俯冲作用下该区依然存在垂直向下的位移,这为地震激发海啸提供了有利的构造环境.  相似文献   

Strain fields and foliation trajectories around pre-, syn-, and post-tectonic plutons in coaxially deformed terranes     

Nibir Mandal  Chandan Chakraborty 《Geological Journal》1990,25(1):19-33

This paper determines, using simple mathematical models, maps of strain fields and foliation trajectories in the neighbourhood of plutonic bodies intruded into a region before, during, and after a lateral compression. The analyses reveal contrasting features for the three cases, which may be useful in distinguishing pre-, syn-, and post-tectonic plutons in coaxially deformed terranes. The theoretically calibrated strain variation curve, along the regional shortening direction, around a pretectonic, rigid plutonic body shows a zone of strain increase (relative to the far-field strain), whereas that around a syntectonic pluton shows a zone of strain decrease along with a zone of strain increase. The foliations deflect outward from a pretectonic pluton, but they bend towards a syntectonic pluton. The analysis also reveals that syntectonic plutons are likely to be elliptical in plan with axial ratio directly dependent on the ratio of the pluton's stress to the tectonic stress. Tectonic foliations deflect away from post-tectonic plutons. However, the foliated area around a post-tectonic pluton is systematically divided into two sets of zones one characterized by foliations showing compressional features, the other showing extensional features.  相似文献   

马兰黄土的应力-应变本构方程   总被引：3，自引：0，他引：3  

何青峰  林斌  赵法锁  王雷 《工程地质学报》2007,15(1):71-76

依据马兰黄土的室内CU试验,运用土力学的相关理论,建议性地提出了马兰黄土的应力-应变本构方程。通过对不同围压下的试验结果(应变小于15%)与理论模型的拟合发现,二者吻合较好。另外,与以往的模型相比,本文的模型参数a和b只需通过一次常规三轴试验即可全部求得,具有参数少、容易确定的优点。  相似文献   

基于GNSS数据的三种应变计算方法在青藏高原东南缘地区的应用     

金阳  金红林  高原  黄星 《地震》2021,41(4):57-67

利用GNSS速度场求解应变率的方法存在多元化特征,可以区分为数学方法和物理方法.本文选取求解应变率的三种数学方法:最小二乘配置法、多尺度球面小波法、Gussian加权内插法,对1999-2019年青藏高原东南缘(97°E～106°E,21°N～30°N)GNSS速度场以及均匀GNSS速度场进行解算,探讨以上三种方法在该...  相似文献   

利用钻孔应变资料预报新疆伽师强震群   总被引：6，自引：0，他引：6       下载免费PDF全文

蒋靖祥  赖爱京  胡群  徐衍冈 《地震工程学报》1998,20(2):16-21

介绍了利用钻孔应变资料预报１９９７年新疆伽师强震群的基本情况,分析了钻孔应变异常的基本特点．伽师地震前距震中２５０ｋｍ的乌什钻孔应变趋势变化一反常态并且短临阶段的应变值出现突跳．  相似文献   

利用地震矩张量反演汾渭断裂系现今运动学特征          下载免费PDF全文

王卫东  张兴忠  王平 《地震工程学报》1998,20(1):81-84

探讨了利用地震矩张量反演断裂形变带运动学参数的方法,将其应用于汾渭断裂带现今运动学特征的研究．结果表明,汾渭断裂带的运动呈Ｎ２２°Ｗ方向拉伸,Ｎ６８°Ｅ方向压缩．其平均拉伸位移速率为０．１５ｍｍ／ａ．  相似文献   

Superposition of replacements in the mafic granulites of the Jijal complex of the Kohistan arc, northern Pakistan: dehydration and rehydration within deep arc crust     

Hiroshi Yamamoto  Takashi Yoshino 《Lithos》1998,43(4):219-234

A deep-level crustal section of the Cretaceous Kohistan arc is exposed in the northern part of the Jijal complex. The occurrence of mafic to ultramafic granulite-facies rocks exhibits the nature and metamorphic evolution of the lower crust. Mafic granulites are divided into two rock types: two-pyroxene granulite (orthopyroxene+clinopyroxene+plagioclase±quartz [1]); and garnet–clinopyroxene granulite (garnet+clinopyroxene+plagioclase+quartz [2]). Two-pyroxene granulite occurs in the northeastern part of the Jijal complex as a relict host rock of garnet–clinopyroxene granulite, where the orthopyroxene-rich host is transected by elongated patches and bands of garnet–clinopyroxene granulite. Garnet–clinopyroxene granulite, together with two-pyroxene granulite, has been partly replaced by amphibolite (hornblende±garnet+plagioclase+quartz [3]). The garnet-bearing assemblage [2] is expressed by a compression–dehydration reaction: hornblende+orthopyroxene+plagioclase=garnet+clinopyroxene+quartz+H₂O↑. Subsequent amphibolitization to form the assemblage [3] is expressed by two hydration reactions: garnet+clinopyroxene+plagioclase+H₂O=hornblende+quartz and plagioclase+hornblende+H₂O=zoisite+chlorite+quartz. The mafic granulites include pod- and lens-shaped bodies of ultramafic granulites which consist of garnet hornblendite (garnet+hornblende+clinopyroxene [4]) associated with garnet clinopyroxenite, garnetite, and hornblendite. Field relation and comparisons in modal–chemical compositions between the mafic and ultramafic granulites indicate that the ultramafic granulites were originally intrusive rocks which dissected the protoliths of the mafic granulites and then have been metamorphosed simultaneously with the formation of garnet–clinopyroxene granulite. The results combined with isotopic ages reported elsewhere give the following tectonic constraints: (1) crustal thickening through the development of the Kohistan arc and the subsequent Kohistan–Asia collision caused the high-pressure granulite-facies metamorphism in the Jijal complex; (2) local amphibolitization of the mafic granulites occurred after the collision.  相似文献   

影响水泥土波速的因素     

孟杰武  桂林等 《上海国土资源》1998,(1):40-45

从水泥掺入比、养护龄期、含水量和土质四个方面,结合实测结果和试验结果分别分析了这些因素对水泥土波速的影响,对于改进工程检测有一定意义。  相似文献   

Rift propagation at craton margin.: Distribution of faulting and volcanism in the North Tanzanian Divergence (East Africa) during Neogene times   总被引：1，自引：0，他引：1  

B. Le Gall  P. Nonnotte  J. Rolet  M. Benoit  H. Guillou  M. Mousseau-Nonnotte  J. Albaric  J. Deverchre 《Tectonophysics》2008,448(1-4):1-19

A revised kinematic model is proposed for the Neogene tectono-magmatic development of the North Tanzanian Divergence where the axial valley in S Kenya splits southwards into a wide diverging pattern of block faulting in association with the disappearance of volcanism. Propagation of rifting along the S Kenya proto-rift during the last 8 Ma is first assumed to have operated by linkage of discrete magmatic cells as far S as the Ngorongoro–Kilimanjaro transverse volcanic belt that follows the margin of cratonic blocks in N Tanzania. Strain is believed to have nucleated throughout the thermally-weakened lithosphere in the transverse volcanic belt that might have later linked the S Kenya and N Tanzania rift segments with marked structural changes along-strike. The North Tanzanian Divergence is now regarded as a two-armed rift pattern involving: (1) a wide domain of tilted fault blocks to the W (Mbulu) that encompasses the Eyasi and Manyara fault systems, in direct continuation with the Natron northern trough. The reactivation of basement fabrics in the cold and intact Precambrian lithosphere in the Mbulu domain resulted in an oblique rift pattern that contrasts with the orthogonal extension that prevailed in the Magadi–Natron trough above a more attenuated lithosphere. (2) To the E, the Pangani horst-like range is thought to be a younger (< 1 Ma) structure that formed in response to the relocation of extension S of the Kilimanjaro magmatic center. A significant contrast in the mechanical behaviour of the stretched lithosphere in the North Tanzanian diverging rift is assumed to have occurred on both sides of the Masai cratonic block with a mid-crustal decoupling level to the W where asymmetrical fault-basin patterns are dominant (Magadi–Natron and Mbulu), whereas a component of dynamical uplift is suspected to have caused the topographic elevation of the Pangani range in relation with possible far-travelled mantle melts produced at depth further N.  相似文献