THE PERMIAN SYSTEM OF THE NUJIANG—LANCANGJIANG—JINSHAJIANG AREA, SOUTHWESTERN CHINA

THE PERMIAN SYSTEM OF THE NUJIANG—LANCANGJIANG—JINSHAJIANG AREA, SOUTHWESTERN CHINA     

西澳大利亚伊尔冈地块东部金矿田省太古宙地壳的演化

对西澳大利亚东部金矿田省太古宙花岗岩—绿岩地壳发展的几个不同模式作了系统的阐述。由于缺少以下几个方面资料,引起了许多争论: 1)绿岩和花岗岩的连续出露。 2)具有充分的区域的综合性多学科研究。 3)在对岩套研究中,用几种同位素方法进行补充的地质年代和岩石成因方面的研究。 4)标准地区的详细地球物理资料。     

星叶石族矿物红外光谱研究

在新测定的星叶石晶体结构资料的基础上,对星叶石矿物进行了详细和红外光谱研究,对比了单斜及三斜星叶石的红光谱特征,并对星叶石中工外吸收振动的归属问题进行了讨论。     

华南地区栖霞组“菊花石”假象与海泡石矿成因关系探讨

根据对华南地区二叠系栖霞组内菊花石假象的成因研究,结合对该组内燧石结核,菊花石内正延性玉髓和海泡石形成时代关系的现状关系的观察,认为华南地区栖霞组内的海泡石形成于早期成岩作用过程中,与该组内燧石结核和菊花石假象内的正延性玉髓同期形成,其成因既与高盐度的沉积环境或高盐度的成岩环境条件无关,也与热液活动无关。     

Geochemical Characteristics and Genesis of Late Cretaceous to Paleogene Basalts in the Tuyon Basin, South Tianshan Mountains

1. Introduction The Tianshan Mountains is a typical intercontinental orogenic belt in the world. From late Carboniferous to Permian, the old Tianshan formed during the tectonic amalgamation of the Tarim block, Tianshan block and Siberia craton (Carroll et al, 1990). Mid-Cenozoic basalts are widely distributed in both the Tuyon basin of southwest Tianshan and its western part of Tianshan in Jierjisi in late Cretaceous-Paleogene period, which indicates the activation of the old Tianshan.…     

中国西部元古代蓝片岩带——世界上保存最好的前寒武纪蓝片岩

阿克苏附近所发现的元古界阿克苏群为一完整的蓝片岩-绿片岩系列,我们通过野外调查肯定了这一认识,并认为它是高压-温相的变质块体,长40km,宽约2.5km.该变质岩由强烈片理化的绿泥石-黑硬绿泥石石墨片岩、黑硬绿泥石-多硅白云母片岩、绿片岩、蓝片岩及少量石英岩、变铁质岩组成.原岩包活泥质岩、砂岩、基性玻屑凝灰岩、块状熔岩、枕状熔岩及少量深海沉积物.蓝片岩的矿物组合:青铝闪石-绿帘石-绿泥石-钠长石-石英-阳起石.阿克苏群为世界上真正的前震旦纪蓝片岩之一,其变质年龄至少有800Ma.     

土水势、未冻水含量和温度

从热力学观点来看,土水体系中的水分迁移是由于该体系中的水处于不平衡状态引起的。这种不平衡状态是由许多力,包括物理、物理化学、力学和水分迁移期间产生的其它过程综合作用的结果。 除重力水之外,土中各种水都受到土矿物颗粒表面能的作用,或者说受到毛细力和吸附力的作用。     

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。