东南极拉斯曼丘陵镁铁质麻粒岩的变质作用演化   总被引：5，自引：4，他引：1  

周信  仝来喜  刘小汉  王彦斌  陈义兵 《岩石学报》2014,30(6):1731-1747

拉斯曼丘陵（Larsemann Hills）位于东南极普里兹构造带的中部,研究该区麻粒岩的变质作用演化对于理解普里兹带的构造属性至关重要。通过对该区含石榴石镁铁质麻粒岩转石详细的岩相学观察表明,峰期前进变质阶段矿物组合（M1）由角闪石+斜方辉石+单斜辉石+斜长石+黑云母+钛铁矿±石英±磁铁矿组成,其峰期矿物组合（M2）为石榴石+斜方辉石+单斜辉石+角闪石+钛铁矿±磁铁矿±石英,而代表后期与降压有关的叠加变质组合（M3）为斜方辉石+斜长石+单斜辉石+黑云母+钛铁矿±磁铁矿。矿物化学分析,结果显示其中石榴子石和斜方辉石具有弱的成分环带特征。利用THERMOCALC软件在NCFMASHTO体系下对该麻粒岩进行了详细的热力学模拟,结合传统温压计和平均温压计算结果,得出不同阶段温压条件分别为650~750℃/5.5~6.5kb （M1）,850~950℃/8~8.5kb （M2）,800~900℃/5.5~7.5kb （M3）。其变质作用演化为典型的峰期后近等温减压的（ITD）顺时针P-T轨迹。通过区域上镁铁质麻粒岩的对比分析,我们认为该镁铁质麻粒岩可能来源拉斯曼丘陵基岩露头。结合已有的年代学资料,表明该镁铁质麻粒岩的峰期变质事件可能对应于晚元古代格林威尔期构造事件,而后期退变质作用与早古生代的泛非期构造事件有关,意味着泛非期普里兹带可能是陆内造山带。  相似文献   

Jump conditions and dynamic surface tension at permeable interfaces such as the inner core boundary     

《Comptes Rendus Geoscience》2014,346(5-6):110-118

We consider a fluid crossing a zone of rapid density change, so thin that it can be considered as a density jump interface. In this case, the normal velocity undergoes a jump. For a Newtonian viscous fluid with low Reynolds number (creeping flow) that keeps its rheological properties within the interface, we show that this implies that the traction cannot be continuous across the density jump because the tangential stress is singular. The appropriate jump conditions are established by using the calculus of distributions, taking into account the curvature of the interface as well as the density and viscosity changes. Independently of any intrinsic surface tension, a dynamic surface tension appears and turns out to be proportional to the mass transfer across the interface and to a coefficient related to the variations of density and viscosity within the interface. Explicit solutions are exhibited to illustrate the importance of these new jump conditions. The example of the Earth's inner core crystallisation is questioned.  相似文献   

Properties of iron alloys under the Earth's core conditions     

《Comptes Rendus Geoscience》2014,346(5-6):130-139

The Earth's core is constituted of iron and nickel alloyed with lighter elements. In view of their affinity with the metallic phase, their relative high abundance in the solar system and their moderate volatility, a list of potential light elements have been established, including sulfur, silicon and oxygen. We will review the effects of these elements on different aspects of Fe–X high pressure phase diagrams under Earth's core conditions, such as melting temperature depression, solid–liquid partitioning during crystallization, and crystalline structure of the solid phases. Once extrapolated to the inner–outer core boundary, these petrological properties can be used to constrain the Earth's core properties.  相似文献   

The ammonia-water system at high pressures: Implications for the methane of Titan     

O. Grasset  J. Pargamin 《Planetary and Space Science》2005,53(4):371-384

  相似文献   

干涉雷达在DEM测量中的精度影响及处理方法   总被引：1，自引：0，他引：1  

郭泾平  彭军  向茂生 《测绘学院学报》1998,(3)

干涉合成孔径雷达 (INSAR)为数字高程模型 (DEM)测量提供了一种新的手段。它具有同时获取三维信息、测量范围广、空间和高程分辨率高等优点。文中首先扼要介绍了干涉雷达的原理 ,然后重点讨论几个影响测量精度的因素及其处理方法 ,如相关、运动补偿、配准、相位展开等。  相似文献   

1997年9月三水3.7和4.4级地震特征初析     

王正尚  康英 《华南地震》1998,18(1):125-129

对１９９７年９月２３日和２６日两次三水有感地震的特征进行了初步分析,认为这两次地震具有震前和震后地震活动水平低、面波发育和低震级高烈度等特性;震区的主压应力为北北西方向,两震的受力方向基本一致,但断层面解明显不同。  相似文献   

淮河流域洪涝变化吸引子维数研究   总被引：15，自引：1，他引：14  

周寅康  包浩生 《地理科学》1998,18(4):362-367

淮河流域洪涝序列的功率谱表现出了较好的混沌谱特征,这是序列呈分形结构的内在原因。洪涝序列及其不同平滑序列的关联维数表明,序列平滑程度越大,关联维数越小,关联维数反映了序列所在系统的层次,是系统结构复杂性的重要量度,是 系统建模所需独立变量的控制参数。要恰当地描述淮河流域洪涝发生系数,需构造至少５个状态变量的动力学系统。  相似文献   

LiMn_2O_4的溶胶─凝胶─酯化法合成及性能Ⅱ　立方尖晶石的形成及其形貌     

尉继英  孙长敏  高海春 《盐湖研究》1998,(1)

以溶胶-凝胶-酯化法在220℃即可得到纯相的LixMn2O4（0.762＜x＜1.139）尖晶石粉体材料。它在880℃时发生立方相向四方相的转变：900℃－1000℃间,四方相渐变为正交相LiMnO2,过程中有Li2MnO3生成。应用SEM、TEM观测了材料的粘度及形貌,其粒度10－40nm,粒子间极易团聚成为1-206μm的团块。以BET法测其比表面为3.6m2／g。  相似文献   

察尔汗盐湖盐田渗漏及其工程地质条件分析     

王石军 《化工矿产地质》1998,20(4):301-307

１９８１年以来对察尔汗盐湖三次渗漏试验结果表明,盐田渗漏是盐田土层与外界条件综合作用的结果,在盐田建设和生产管理过程中,应结合不同地点的土层特性、工程地质条件和其它有关条件,采取不同的处理措施。  相似文献   

Group Time Delay in the Reflection of P-Polarized Electromagnetic Plane Waves at a Stratigraphic Interface     

Fu-Ping Liu  Rui-Zhong Li  Jin-yao Li  Hui-Guo Chen  Chang-Chun Yang 《Mathematical Geosciences》2008,40(7):813-829

The group time delay (GTD) formulae of quasi-total reflection of inhomogeneous P-polarized electromagnetic waves (P-PEW, whose electric field parallels to the plane of incidence), caused by the Goos–Hänchen effect, is derived by the phase shift of the wave. A numerical example where the frequency equals to 1 GHz is given. The curves of calculating results show that there are three discontinuous points at the critical angle of phase shift vector, the critical angle of attenuation vector and 90^○. When the angle of incidence is equal to one of these three angles, the GTD will become infinite, and the electromagnetic wave will propagate along the interface. The GTD will be very large, when the angle of incidence is close to one of these three angles. The results indicate that there is an important relationship between the two critical angles and the conductivity and permittivity of the two strata, and that the GTD has an important relationship with the angle of incidence. These results can be used to determine the lithology of the strata and to delimit the interfaces of strata more effectively. It is suggested that this research may prove useful in electromagnetic logging analysis and, perhaps, in the design of logging instruments.  相似文献