http://www.sciencedirect.com/science/article/pii/S167498711100079X

Lower Paleozoic rocks exposed in various regions of Egypt (south central Sinai, north Eastern Desert and southwest Western Desert), in addition to occurring in the subsurface such as north Western Desert and the Gulf of Suez. The Lower Paleozoic rocks in Egypt include surface and subsurface rock units of formational status. The surface rock units are the Taba, Araba and Naqus formations. The subsurface rock units include the Shifa, Kohla and Basur formations. The Infracambrian Taba Formation has been discovered recently in the outcrops of the south eastern Sinai in the Taba-Ras El-Naqab area. It is missing and/or not recognized in the subsurface. The Taba Formation consists mainly of reddish brown, unfossiliferous gravelly fine-to medium-grained sandstones cemented by kaolinite and have subordinate beds of paleosols. The Cambrian Araba Formation and its subsurface equivalent (the Shifa Formation) are essentially composed of reddish brown, fine-grained laminated sandstone and siltstone with abundant Skolithos and Cruziana sp. In contrast, the Ordovician-Silurian Naqus Formation and its subsurface equivalents (Kohla Formation and Basur Formation) are mainly composed of white, unfossiliferous, cross-bedded, medium- to coarse-grained sandstones with haphazardly distributed pebbles and cobbles. Sedimentological analysis indicates that the Araba Formation and its equivalents were deposited in a marginal-marine environment, whereas the Naqus Formation and its equivalents were laid down in a fluvio-glacial environment. Integrated stratigraphic and sedimentological studies of the Lower Paleozoic rocks permit reconstruction of the paleogeography of Egypt at that time. Egypt has been largely controlled since the Cambrian by the pre-existing structural framework of the pre-Phanerozoic basement rocks inherited from the Late Proterozoic Pan-African event. Additionally, sedimentation processes were controlled during Cambro-Ordovician times by tectonic movements, whereas glacio-eustatic control predominated during the Late Ordovician-Silurian Period. These studies suggest that most areas of Egypt were exposed lands with episodically transgression by epicontinental seas related to the paleo-Tethys. These lands formed a part of a stable subsiding shelf at the northern Gondwana margin.     

澳大利亚与元三古代海底喷气矿床伴生的电气石岩

在绿片岩、角闪岩和麻粒岩和变质岩层中，电气石岩和富电气石的沉积物与喷气矿化伴生，它们遭受了中等到强烈的变形，呈连续层状分布于褶皱构造附近，显示出诸如层理、递变层理、交错层理、层内滑动等沉积构造和拉裂构造。在高级变质作用区，它们显示变质结构，通常被再活化而成的石英－电气石脉所穿切。富电气石岩出现在由海底喷气而形成的Pb－Zn－Ag、Cu－Co、Cu－Bi、W、Sn、Au和稀土元素矿化的下部、内部及矿化之上，且在横向上与矿化同期的地层中。在一些地方，电气石岩没有上述矿化现象，也不与花岗质岩石相伴生。电气石的成分是黑电气石－镁电气石，虽反映了其全岩成分，但不能作为矿化的标志。虽然电气石是与花岗岩、交代岩、角砾岩简伴生的普通矿物，但本文描述的富电气石层为山硅电气石前身的变质作用产生的富硼硅质铁建造。它们是一种常见的喷气岩类型，并且常常出现在早－中元古代厚层的泥质变沉积岩和蒸发岩层序中。这就说明硼是由含硼的粘土的淋滤作用或由含硼酸盐的蒸发岩的淋滤作用产生的。     

俄罗斯油气钻采废弃物处理及其利用研究

生态安全和环境保护是世界各国都非常关心的问题。地质钻探和石油天然气钻采工作中产生大量废弃物,直接影响生态安全和环境保护,给经济建设和人民生活带来很大的负面影响。俄罗斯钻探工作者对此进行了研究,取得了一定效果。他们主要采用综合处理方法和磁化处理方法。利用这2种方法,废弃物不仅可以再生,而且还可以二次使用,有一定的创新和实际意义,值得引起我们的重视,建议对此进行研究与讨论。     

热电离质谱法测定贵州郑家洞石笋的铀系年代及其古气候意义

本文报道了用高精度热电离质谱（ＴＩＭＳ）法测定的贵州郑家洞ＡＺＪ－２号石笋的铀系年代。该石笋经历了三个速度不同的生长阶段，顶部９０ｃｍ及底部２１ｃｍ生长迅速，ＴＩＭＳ铀系法高分辨率年代结果仍不足以给出其确切的生长速率。精确建立碳氧同位素演化时间坐标的困难，应是从新生碳酸盐提取古气候演变信息的重要制约因素之一。ＡＺＪ－２的生长起止年代为距今１４．７￣１３．８万年，贵州在此期间可能处于温暖湿润的气候条     

绿岩带构造演化中的一些悬而未决的疑难问题

从已收到的一批专题讨论会的摘要中可以看出尚存在一些悬而未决的疑难问题;这些疑问可以认为是以往专题讨论中一直存在着的焦点问题,现列举如下: 1.应该寻找一种对所有绿岩带来说统一的构造环境,还是绿岩带仅象征着一定范围的构造环境?如何加以识别?绿岩带是大面积造山带的一部分?绿岩带是外来的吗?我们又如何证明/反驳他们? 2.是否早太古绿岩带(如塞卢奎、巴伯顿、彼得斯堡、皮尔巴拉、依苏阿)不同于晚太古绿岩带?如果是这样,那么是从哪些方面来考虑的吗?在绿岩带内对于岩石类型的定量估计上几乎没有什么已汇编的资料:这是首要目标。此外,因为许多绿岩带都是     

Sr,Nd,Pb Isotope Geochemistry and Magma Evolution of the Potassic Volcanic Rocks,Wudalianchi,Northeast China

Wudalianchi volcanic rocks are the most typical Cenozoic potassic volcanic rocks in easten China.Compositional comparisons between whole rocks and glasses of various occurrences indicate that the magma tends to become rich in silica and alkalis as a result of crystal differentiation in the course of evolu-tion.They are unique in isotopic composition with more radiogenic Sr but less radiogenic Pb.^87Sr/^86Sr is higher and ^143Nd/^144Nd is lower than the undifferentiated global values.In comparison to continental pot-ash volcanic rocks,Pb isotopes are apparently lower.These various threads of evidence indicate that the rocks were derived from a primary enriched mantle which had not been subjected to reworking and shows no sign of incorporation of crustal material.The correlation between Pb and Sr suggests the regional heterogeneity in the upper mantle in terms of chemical composition.     

TECTONO-SEDIMENTARY EVOLUTION OF THE TERTIARY BASINS IN EASTERN TIBET: CONSTRAINING THE RAISING OF TIBETAN PLATEAU

TECTONO-SEDIMENTARY EVOLUTION OF THE TERTIARY BASINS IN EASTERN TIBET: CONSTRAINING THE RAISING OF TIBETAN PLATEAU1　YinA ,HarrisonTM .TheTectonicEvolutionofAsia[M] ..Cambridge :CambridgeUniversityPress,1996 .4 4 2～ 4 85. 2　SunH ,ZhengD .FormationevolutionanddevelopmentofTibetanPlateau[M ] .Guangzhou :GuangdongScienceandTechnologyPress,1998.73～ 2 30 . 3　ShiY ,LiJ,LiB .UpliftandEnvironmentalChangesofTibetanPlateauintheLateCen…     

Petrographic and SHRIMP Studies of Zircons fromthe Caledonian Xiongdian Eclogite, NorthwesternDabie Mountains

The Xiongdian eclogite occurring in the Sujiahe tectonic melange zone at Luoshan County, Henan Province, in the western Dabie Mountains, is typical high-pressure (HP)-ultrahigh-pressure (UHP) and medium-temperature eclogite. The occurrence, internal texture and surface characteristics of zircons in eclogite were studied rather systematically petrographically combined with the cathodoluminescence (CL) and scanning electron microscope (SEM) methods. Zircons are mainly hosted in garnet and other metamorphic minerals with sharp boundaries, have a multifaceted morphology and are homogeneous or exhibit a metamorphic growth texture in the interior, thus indicating that they are the product of metamorphism. SHRIMP analyses give zircon 206Pb/238U ages of 335 to 424 Ma and show a certain degree of radiogenic Pb loss; therefore it may be inferred that the age of 424? Ma represents the minimum age of a HP-UHP metamorphic age. From the above analyses coupled with previous Sm-Nd, 40Ar-39Ar, U-Pb and 207Pb/206Pb age d     

同位素指示的巴丹吉林沙漠南缘地下水补给来源

通过恢复巴丹吉林沙漠及其周边地区大气降水氚值，并结合区域稳定同位素组合特征，揭示了区域地下水氚年龄的多解性与地下水稳定同位素的温度效应。恢复的1963年核试验期氚高峰值达到2 100 TU，进入90年代平均为60 TU。1960年以来降水补给的地下水氚值都应大于15 TU，而1963年的高峰氚衰变至今应在200 TU左右。地下水实测氚值较低，表明由现代少量降水补给的地下水与大量的古水进行了混合。影响降水中δ18O和δ2H分布的主要影响因子是月平均空气温度，对δ18O与δ2H的影响权重分别占到59.9%和57.0%。巴丹吉林沙漠及其周边地区地下水较低的稳定同位素组成表明，其补给主要是晚更新世较冷环境下形成的，来源于东南部的雅布赖山区，部分浅层地下水接受现代降水与河流的补给。 