平面变胞机构及其结构分析

首先定义了变胞机构和变胞运动副的概念,提出了5种类型的变胞运动副,并对它们的特性和原理进行了详细的研究;通过变胞机构中自由度变化分析,提出了变胞机构中变胞运动链的概念,研究了变胞机构的结构组成原理和变胞机构的结构分解步骤,为变胞机构构态变换和机构的综合打下了坚实的基础.     

The geological characteristics of oceanic-type UHP metamorphic belts and their tectonic implications: Case studies from Southwest Tianshan and North Qaidam in NW China

The geological characteristics of ultrahigh-pressure （UHP） metamorphic belts formed by deep subduction of oceanic crust are summarized in this paper. Oceanic-type UHP metamorphic belt is characterized by its protolithlc assemblage of typical oceanic crust, the peak metamorphic temperature 〈600℃, P-T path undergoing blueschist facies during prograde and retrograde metamorphic evolution, reepectively, with low geothermal gradient of cold subduction. The further study of oceanic-type UHP metamorphic belt is very significant for constructing metamorphic reaction series of cold subduction zone, for understanding how aqueous fluids were transported into deep mantle and for classifying the types of UHP metamorphism in cold subduction zone. The uplift and exhumation mechanism of oceanic UHP metamorphic rocks is one of the most challenging problems in the study of UHP metamorphism, which is very important for understanding the geodynamic mechanism of solid Earth. As a traveler eubducted into the mantle depth end then uplifted to the surface, oceanic-type UHP metamorphic belts witness the bulk process from the subduction to exhumation and is an ideal target to study the geochemical behavior end cycling of elements in subduction zones. The tectonic evolution of one convergent orogenic belt can be usually divided into two stages of oceanic subduction and followed continental subduction and collision, and the two best-established examples of orogenic belts are Alpa and Himalaya. Therefore, the study of oceanic-type UHP metamorphic belt is the frontier of the current plate tectonic theory. As two case studies, the current status and existing problems of oceanic-type UHP metamorphic belts in Southwest Tianshan and North Qaidam, NW China, are reviewed in this paper.     

新疆若羌县赤石山变质核杂岩研究

新疆北山裂谷带西缘若羌县赤石山地区存在大型变质核杂岩构造。其下拆离盘为古元古界结晶基底杂岩 ,上拆离盘为中元古界白湖群变质岩系 ,滑脱拆离带为已变形的大型韧性正断层。核杂岩南、北侧发育上叠盆地 ,北侧形成“年轻”正断层及同构造期岩浆岩。变质核杂岩的形成与晚古生代北山陆内裂谷区域伸展有直接联系。该区变质核杂岩的首次厘定 ,对深化北山裂谷的研究具有重要意义     

镍基单晶高温合金磨削变质层工艺试验研究

为探究镍基单晶高温合金的磨削变质层工艺特性，采用单因素试验的方法，研究不同磨削参数及冷却条件对磨削变质层厚度的影响规律.结果表明，在镍基单晶高温合金DD5的磨削表面及亚表面存在一定厚度的磨削变质层.磨削变质层中的塑性变形层内γ相和γ′相发生剧烈扭曲变形且磨削变质层的硬度大于基体.不同磨削参数及冷却条件对磨削变质层厚度产生不同影响，随着砂轮线速度、磨削深度、工件进给速度的增加，磨削变质层厚度的变化分别表现为先减小后增大、不断增大、先增大后减小；在试验参数范围内，微量润滑(MQL)作为冷却条件可以降低相应的磨削变质层厚度，最多达到3.5μm.     

Call in question and discussion: Are there sandwiched low-grade metamorphic slabs within UHP metamorphic rocks in the Dabieshan terrane

Some geologists reported their discovery of sandwiched low-grade metamorphic slabs within UHP metamorphic Complexes in Changpu, Yuexi County, Anhui Province. They also suggested that some coesite-bearing eclogites are igneous veins, which intruded low-grade metamorphic slabs and other related rocks. Moreover they further called in question to UHP metamorphic process and continental collision tectonism in the Dabieshan terrane. Based on our recent study, so-called low-grade metamorphic slabs are strongly deformed fabric, fine-grained and tectonic recrystallized mylonites and tectonites. Their protolith rocks are garnet-bearing orthogneiss, eclogite and marble, as well as a few amounts of strongly deformed acid and basic veins. Their metamorphic, geochemical and geochronological characteristics are also identical with UHPM rocks and regional country orthogneisses. Therefore we conclude that there are not low-grade metamorphic slabs sand wiched with UHP metamorphic rocks in the Dabieshan terrane.     

金沙江变质杂岩的岩石学特征及其地质意义

介绍了云南东川金沙江变质杂岩的地质背景，较详细地分析了变质杂岩的岩石学、岩石化学特征，鉴定出钠长黑云片岩、浅变质火山岩的原岩为细碧质凝灰岩，可与下元古界河口群变钠质火山岩系对比，是昆阳群地层的基底变质岩系，它的出露可能是地壳多层次伸展滑脱的结果，为进一步探讨该区的地质构造演化提供了事实基础．     

Genesis of zircon and its constraints on interpretation of U-Pb age

Zircon U-Pb dating is the most commonly used method for isotopic geochronology. However, it has been a difficult issue when relating zircon U-Pb ages to metamorphic conditions in complex metamorphic rocks. Much progress has been made in the past decade with respect to the genesis of zircon and its constraints on interpretation of U-Pb age. Three methods have been proposed to link zircon U-Pb age to metamorphic conditions: ( i ) internal structure; ( ii ) trace element feature; (iii) mineral inclusion composition. Magmatic zircon shows typical oscillatory zoning and/or sector zoning, whereas metamorphic zircon has internal structures such as no zoned, weakly zoned, cloudy zoned, sector zoned, planar zoned, and patched zoned ones. Zircons formed in different geological environments generally have characteristic internal structures. Magmatic zircons from different rock types have variable trace element abundances, with a general trend of increasing trace element abundances in zircons from ultramafic through mafic to granitic rocks. Zircons formed under different metamorphic conditions have different trace element characteristics that can be used to relate their formation to metamorphic conditions. It is an effective way to relate zircon growth to certain P-T conditions by studying the trace element partitioning between coexisting metamorphic zircon and garnet in high-grade metamorphic rocks containing both zircon and garnet. Primary mineral inclusions in zircon can also provide unambiguous constraints on its formation conditions. Therefore, interpretation of zircon U-Pb ages can be constrained by its internal structure, trace element composition, mineral inclusion and so on.     

Detachment within subducted continental crust and multi-slice successive exhumation of ultrahigh-pressure metamorphic rocks: Evidence from the Dabie-Sulu orogenic belt

Although tectonic models were presented for exhumation of ultrahigh-pressure （UHP） metamorphic rocks during the continental collision, there is increasing evidence for the decoupling between crustal slices at various depths within deeply subducted continental crust. This lends support to the multi-slice successive exhumation model of the UHP metamorphic rocks in the Dabie-Sulu orogen. The available evidence is summarized as follows： （1） the low-grade metamorphic slices, which have geotectonic affinity to the South China Block and part of them records the Triassic metamorphism, occur in the northern margin of the Dabie-Sulu UHP metamorphic zone, suggesting decoupling of the upper crust from the underlying basement during the initial stages of continental subduction; （2） the Dabie and Sulu HP to UHP metamorphic zones comprise several HP to UHP slices, which have an increased trend of metamorphic grade from south to north but a decreased trend of peak metamorphic ages correspondingly; and （3） the Chinese Continental Science Drilling （CCSD） project at Donghai in the Sulu orogen reveals that the UHP metamorphic zone is composed of several stacked slices, which display distinctive high and low radiogenic Pb from upper to lower parts in the profile, suggesting that these UHP crustal slices were derived from the subducted upper and middle crusts, respectively. Detachment surfaces within the deeply subducted crust may occur either along an ancient fault as a channel of fluid flow, which resulted in weakening of mechanic strength of the rocks adjacent to the fault due to fluid-rock interaction, or along the low-viscosity zones which resulted from variations of geotherms and lithospheric compositions at different depths. The multi-slice successive exhumation model is different from the traditional exhumation model of the UHP metamorphic rocks in that the latter assumes the detachment of the entire subducted continental crust from the underlying mantle lithosphere and its subsequent exhumation as a whol     

一种似然蜕变关系动态发现工具设计

蜕变测试技术认为,测试中成功的测试用例可为构造蜕变关系提供有价值的信息,而似然蜕变关系的动态发现方法是根据已经成功运行的测试数据来发现蜕变关系的启发信息,基于一种似然蜕变关系发现算法的基本框架,进一步具体设计和实现算法,且开发相应的工具,实验表明该算法的可行性及工具的实用性.     

辽西太古代“建平变质杂岩”的变质作用演化

“建平变质杂岩”是辽宁省西部太古代的最下部的地体,它由连续性很差的表壳岩、TTG岩石及其它深成侵入岩构成。基本岩石类型有镁铁质岩石(包括角闪岩、辉石岩、斜长角闪岩等)、麻粒岩、紫苏花岗岩、片麻岩及少量的超镁铁质岩和磁铁石英岩。常见且主要的矿物相是斜方辉石、单斜辉石、石榴石、角闪石、斜长石和石英。岩相学研究确定了指示变质作用不同阶段的三个变质反应的存在,并且它们与推测的矿物相的转化关系吻合,结合地质温压的限定,本文得出了本区太古代末期的强烈的变质热事件的反时针的P-T-t演化轨迹,并推测出此变质热事件与大量的岩浆增聚密切相关。     

太行山缺水地区变质岩裂隙水水文地质特征及其电性响应-以阜平县为例

太行山缺水地区变质岩裂隙水水文地质特征与其电性响应之间关系的研究是长期困扰地质学者的一个大难题。根据区域地质资料,进行了阜平县变质岩地区水文地质研究,查明了该地区的地层、地质构造和变质岩裂隙水的赋存规律。在此基础上,采用音频大地电场法、放射性法、音频大地电磁法和激电法对比研究了变质岩裂隙水水文地质特征的电性响应;并布置地质钻孔验证了水文地质特征与电性响应之间的对应程度。结果表明,阜平县变质岩裂隙水地区水文地质特征与其电性响应之间具有明显的一一对应关系。     

桃林铅锌矿断裂变质带的地质特征研究

详细的野外观察和室内研究表明,桃林断裂变质带中存在有糜棱岩和碎裂岩两个系列的断裂变质岩,并具分带性,说明该带经历了韧性和脆性两个不同机制的变形阶段。笔者认为该断裂变质带早期为一韧性剪切带,晚期叠加了脆性断层。     

Zircon U/Pb ages for gniess from Qianshan, Anhui

Zircon U/Pb ages were measured for Qianshan gneiss at the ultrahigh pressure metamorphic (UHPM) complex in the Southern Dabie Terrain (SDT). According to morphology, Th and U contents of eight fractions of zircon and data distribution on the discordia, it is indicated that they should be treated as metamorphic overgrowth mixing zircons, in which the cores mainly are magmatic and the outers were metamorphic. The intercept ages show that the gneiss underwent UHPM. There is no direct correlation for zircon between morphological feature and genesis.     

坝基各向异性岩石力学特性试验研究

为了掌握坝基层理面发育变质凝灰岩的力学特性,对垂直和平行于层理面方向的变质凝灰岩试样进行了三轴压缩试验.基于试验结果,得到了不同围压下垂直和平行于层理面的变质凝灰岩强度和变形参数,研究了其强度和变形特性的各向异性特征,最后分析了三轴压缩状态下试样的破坏形式及机制.研究结果表明,变质凝灰岩强度和变形特性与层理面方位角关系密切,垂直和平行于层理面方向的强度和变形参数表现出显著的各向异性特征,并随围压呈一定规律的变化.     

Zircon SHRIMP geochronology of the Xinkailing-Kele complex in the northwestern Lesser Xing＇an Range, and its geological implications

Located in the eastern portion of the Xing'an-Mongolian Orogenic Belt (XMOB), the Xinkailing-Kele complex has previously been considered to be Precambrian metamorphic rocks, mainly according to its relatively high metamorphic grade. Our filed observation, however, revealed that the complex is composed mainly of metamorphic rocks (Kele complex), tectono-schists ("Xinkailing Group"), and granitoids (Xinkailing granitic complex). Dating on these rocks using advanced SHRIMP zircon U-Pb technique indicates that: (1) Biotite-plagioclase gneiss from the Kele complex has a protolith age of 337±7 Ma (2σ) and a metamorphic age of 216±3 Ma (2σ); (2) the tectono-schist of the "Xinkailing Group" gave a magmatic age of 292±6 Ma (2σ), indicative of felsic volcanic protolith of the schist formed in late Paleozoic time; and (3) the Menluhedingzi and Lengchuan granites of the Xinkailing granitic complex were emplaced at 167±4 (2σ) and 164±4 Ma (2σ), respectively. These results suggest that the Xinkailing-Kele complex is not Precambrian metamorphic rocks and the so-called Precambrian "Nenji-ang Block" does essentially not exist. In combination with regional geological data, we propose that the Kele metamorphic complex is likely related to a collisional tectonism that took place in Triassic time, as indicted by its metamorphic age of 216±3 Ma. The Xinkailing granitic complex was em-placed along the collisional zone during Mid-Jurassic time, likely in a post-orogenic or anorogenic setting.     

Mineralogical evidence for continental deep subduction

Diamond is an index mineral to prove ultrahigh pressure (UHP) metamorphic conditions because it is only stable at the pressures above 3.3 GPa. Its occurrence in eclogite-facies metamorphic rocks suggests plate subduction to depths over 120 km assuming the normal gradient of lithostatic pressure. Because UHP eclogites are the metamorphic products of basaltic rocks, the occurrence of diamond in the eclogites demonstrates a complete geodynamic cycle in that mafic crustal rocks were subducted t…     

The large-scale ductile shear zone in Kuda, western Kunlun

A set of metamorphic suites, previously known as the Precambrian metamorphic basement in Kuda, western Kunlun has been determined as a large nappe ductile shear zone which develops penetrative foliation, oriented stretching lineation, various but consistent kinematic indicators of thrusting from north to south. The microstructure and the supermicrostructure also display the ductile deformation characteristics, and the paleotectonic differential stress is obtained. The metamorphic age is 426–451 Ma dated by⁴⁰Ar/³⁹Ar method. According to tectonic background, it is a product of early Paleozoic accretionary wedge orogenesis in western Kunlun.     

Metamorphic Algorithm of Self-reconfigurable Modular Robotic System

Introduction Aself reconfigurableroboticsystemconsistsofman simpleidenticalmechatronicmodules.Thesemodulesca connectanddisconnectfromonetoanothertochangethe overalltopology.Thesystemcanautonomouslyandynamicallyadaptitsshapetosuittheneedsofthetask hand,e.g.manipulation,locomotion,andcreationo staticstructures.Thegeneralphilosophyofsel reconfigurableroboticsystemistosimplifythedesignanreducemanufacturingcostandenhancefunctionalityan versatilitythroughalargernumberofidenticalmodules.I addition…     

Zircon isotopic ages from magnetite quartzites of the Jianping metamorphic complex, western Liaoning Province

Using the zircon Pb evaporation method and high precise ion microprobe analyses, zircon isotopic ages in supracrustal magnetite quartzites from Jianping metamorphic complex have been obtained. The results show that the deposition of the supracrustal rocks occurred around 2 552–2 520 Ma and the peak of granulite facies metamorphism reached at about 2 487 Ma; about (1 806±16) Ma, i.e. Mid-Proterozoic, the other possible metamorphic event with relatively low intensity happened in the study area. It is speculated that a likely tectonic setting where the Jianping metamorphic complex formed is an active continental margin that is involved in continental collision and crustal thickening shortly after its formation.