Deep electrical structure of the Sulu orogen and neighboring areas

Because of the discovery of ultrahigh pressure metamorphic (UHPM) belt beneath the Sulu (Jiangsu Province-Shandong Province) orogen, this area has become a focused subject of current geoscience, as it has a close relationship with the evolution of the orogen and the neighboring North China craton. Probing the deep structure beneath this area would be of great significance for the geological interpretation of this issue. In this study, we make an analysis of magnetotelluric (MT) data along a profile across the Sulu orogen to provide evidence of deep structure below this region. The profile begins in west from the North China block, extending in S129°E, across the Tan-Lu fault, Sulu UHPM zone, and Sulu high pressure metamorphic (HPM) zone, and terminates in the Yangtze block in east. We use the nonlinear conjugate gradient method and TE-TM combined mode to perform inversion and interpretation of the MT data, and obtain an electrical structure image above depth of 150 km along the profile. It shows that the structure can be divided into seven sections in lateral direction, between which the electric boundaries coincide well with the major faults, such as the Tan-Lu, Haizhou-Siyang, and Jiashan-Xiangshui faults. In vertical direction the electrical structure can be subdivided into six layers of different resistivities. It is noted that there exist high-conductivity areas in crust below the North China block and Yangtze block, while such a feature is not present beneath the Sulu orogen, which is very different from the Dabie orogen. It is also observed that a fairly continuous zone of relatively low-resistivity exists at depths of 50–90 km of the electrical structure image, which is presumably a weak zone in the uppermost mantle. Just below this low-resistivity zone are the relatively high- resistivity layer of the North China block, relatively low-resistivity layer of the Sulu orogen, and relatively high-resistivity layer of the Yangtze block, all in the shallow upper mantle, respectively. From the whole 2D electrical structure image, there is no abnormally low-resistivity layer in the shallow upper mantle beneath the Sulu orogen and neighboring areas, indicating that no hot asthenoshperic material associated with lithospheric thinning exists at present. Supported by National Natural Science Foundation of China (Grant No. 40534023) and Director Foundation of Institute of Geology, China Earthquake Administration (Grant No. DF-IGCEA-0608-2-16)     

中国大陆科学钻探（CCSD）主孔超高压变质岩副矿物锆石中的流体包裹体研究

中国大陆科学钻探工程主孔位于苏鲁超高压变质地体南部,钻孔穿过的超高压岩石主要有榴辉岩、正、副片麻岩、石榴橄榄岩、角闪岩,以及少量片岩和石英岩。锆石是超高压岩石中的常见副矿物,按成因可以分为原岩锆石、变质(增生)锆石和新生锆石。这三类锆石中普遍含有矿物包体和少量流体包裹体,它们记录了超高压岩石经历的进变质、超高压变质和退变质期间流体作用的信息。锆石中的流体包裹体具有以下特征:(1)原岩锆石核部常见原生H2O和H2O-CO2包裹体,H2O包裹体的组成和盐度变化较大;而沿原岩锆石裂隙有时还有次生H2O-CO2和(或)CO2包裹体;(2)在变质锆石或锆石的变质增生带(幔部或边部)仅偶尔发现与超高压矿物包体共生的H2O-CO2包裹体;(3)榴辉岩,特别是片麻岩可以含大量微粒新生锆石,其中偶尔可见低盐度的H2O±CO2包裹体;(4)锆石中流体包裹体的丰度与主岩氧同位素值存在一定相关性:即具有很低δ18O值的岩石所含锆石中流体包裹体特别丰富,而具有正常氧同位素组成的岩石中锆石很少或不合流体包裹体;结合原岩锆石、变质锆石和新生锆石中均有中低盐度的H2O和H2O-CO2包裹体存在,反映了在大陆深俯冲-折返过程中变质流体具有继承性。H2O和H2O-CO2包裹体的等容线全都从根据矿物温压计获得的变质峰期压力-温度区间下部通过,推测在进变质-超高压变质峰期捕获的流体包裹体随后受到了改造。在进变质-超高压变质和退变质期间变质流体的存在促进了原岩锆石不同程度地受到溶蚀、变质增生和变质锆石、新生锆石的形成。     

New technique to compute the geometrical elements of the eclipsing of W UMa-type

The aim of this paper is to present a general method for computation of the geometrical elements of totally eclipsing W UMa (close, or in actual contact) binary systems in the frequency-domain.This method has been done using a new technique (two minima with the improved values of the photometric perturbation effects). The results are compared with the results calculated by different methods, that have used the same observation references.The improved photometric perturbation terms have been discussed and its effects are computed for both (primary and secondary) minima.     

专家系统在岩土工程中应用的评价

Expert system is a newly developed discipline. It has been widely used in various fields. This paper analyzes the properties of expert system and evaluates the expert system application in geotechnical engineering.     

活动断裂带内第四纪松散沉积物的变形类型

选择了一些典型活断层地质剖面 ,对经受了构造变动的第四纪松散沉积物进行了定向原状样品采集。通过室内样品固结、显微薄片制作和显微构造现象观察 ,从显微域里找到了第四纪松散沉积物变形的一些特点 ,并进行了分类。第四纪松散沉积物的变形类型有两种 :一种是破裂变形 ,主要表现为平行滑动条带、平直滑动界面、碎屑颗粒的破碎等 ;另一种是流动变形 ,主要表现为 :流动构造、碎砾旋转、粘土矿物的拖曳滑动等     

A Study of Sr, Nd and O Isotopes of the K-rich Melanocratic Dykes in the Late Mesozoic Gold Field in the Jiaodong Peninsula

Geologic, petrographic and petrochemical studies of the late Mesozoic K-rich melanocratic dykes, including lamprophyres, andesite porphyrites and dacite-porphyry in the gold field system in the Jiaodong Peninsula, China, have shown that these dykes are characterized by rich potassium and alkali but poor titanium. They belong to an ultra-high potassic, shoshonitic and high potassic calc-alkaline rock series. The parental magma has relatively high initial strontium ratios ((87Sr/86Sr)i=0.70895-0.71140) and low (143Nd/144Nd)i ratios (varying from 0.51135 to 0.51231); and its δ18OSMow. whole rock values vary from +5.8‰ to +10.6‰ with a mean of+7.1‰. These features suggest that the source region of the magma is an enriched mantle wedge transformed from a continental lithosphere mantle which has experienced metasomatism by mantle-derived fluids with H2O-dominated fluids that were provided during the underthrusting of an ocean crust. The initial magma was generated by low-degree partial melting of the enri     

关于“侵入岩谱系单位填图方法”有关问题的讨论

本文简单地阐述了岩浆作用的多样性，指出不能以同源岩浆演化一种岩浆作用方式来概括或代表所有的岩浆活动，通过对“侵入岩谱系单位填图方法”在实际应用中存在的一些问题的讨论，指出同源岩浆演化理论尚不完善，不能人为地夸大同源岩浆演化理论的作用，未经深入研究和试验不宜把这个方法应用于所有时代和任何构造背景的花岗岩类。     

近期华北地震大形势的统计分析

文章在３－５年较长时间尺度概率估计的前提下，力争对未来较短时期（１－２年）各区，带地震活动趋势进行定量分析，特别着重于地震总活动水平的比较及年量大震级的预测。     

Characteristics of Fault Gouge from the Northwest-Trending Faults in Western Shandong and Its Seismogeological Significance

A systematical study is made on the characteristics of fault gouge from NW-trending faults in western Shandong.The macroscopic features of the fault gouge zones were investigated.From the data on surface structure of quartz fragments from the fault gouge and its maturity,the relative age,the movement mode,the rupture pattern,and the activities of the NW-trending faults are determined.Moreover,their seismogeological significance and some problems in study of fault gouge are discussed.     

山东蓝宝石质量研究

分析了山东蓝宝石与世界及我国各产地蓝宝石的质量差异，指出山东蓝宝石是国内质量最高的蓝宝石，在世界所有玄武岩源岩类蓝宝石中占有重要地位，可与澳大利亚，柬埔寨，泰国蓝宝石媲美，章还剖析了包裹体，色带，熔蚀构造，裂纹对蓝宝石质量的影响，发现这4种因素一方面可通过影响蓝宝石的颜色，透明度，形状，大小，出成率等降低蓝宝石的等级，另一方面在某些特殊条件下，又可形成星光蓝宝石，魔彩蓝宝石，花色蓝宝石等稀有珍贵品种。