清镇陨石中顽火辉石的高分辨电镜研究

清镇陨石中顽火辉石的(010)取向结构象清楚地显示出单斜顽火辉石(CLEN)和顽火辉石(OREN)连生现象其特点说明它经历了急冷且受到很弱的后期热变质作用,同时,电子衍射和光学衍射及结构象均显示其中有27的长周期结构。     

天然顽火辉石的高分辨电镜观察

利用透射电镜研究了陨石和地幔岩中斜方辉石与斜顽辉石的多型转变:吉林陨石和清镇陨石顽火辉石中的斜顽辉石多型晶域宽度既有奇数倍也有偶数倍9A,双晶现象发育,出现频率高,是原顽火辉石转变而成。尖晶石和石榴子石二辉橄榄岩斜方辉石中的斜顽辉石仅具偶数倍9晶域宽度,未见双晶现象,出现频率低,是剪切应力作用下由斜方辉石转变而成。测量证实OREN向CLEN的相变按13.3°机制进行。在相应高温条件下,相变时应变率ε可能大于10~(-6)sec~(-1)。     

天然辉石中缺陷结构的观察

利用高分辨电子显微术研究了陨石和地幔岩中辉石的超微结构,观察并发现了多种畸变结构现象。清镇和吉林陨石顽火辉石中的斜顽辉石受冲击作用,SiO_3链发生弯曲甚至断裂并沿a轴方向错动36的距离,同时还有(100)扭转晶界形成,不同类型的SiO_3链相互转变形成了(001)90°和180°畴结构。单斜辉石中则有(100)层错和孪晶及其有关的缺陷。     

滑石瓷相变及老化机理的探讨

滑石在加热过程中,当由层状结构转变为单链状结构的辉石时,可有三个晶相:原顽辉石、顽辉石和斜顽辉石。而在正常的滑石瓷中本文认为是以原顽辉石为主晶相。滑石瓷的老化现象主要是由于原顽辉石向斜顽辉石转变的结果,在转变的过程中因体积的收缩而产生内应力以改造成瓷坯的粉化和开裂。本文研究了原顽辉石和斜顽辉石的晶体结     

缅甸玉石中的钠铬辉石,硬玉及其共生矿物的研究

提出缅甸各种玉石中硬玉及其共生矿物的物理、光学Ｘ坶数据。硬玉玉石为单矿物或多矿物结晶质集合体。在多矿物集合体中，硬玉与浅闪石、钠透闪石、透闪石、钠铬辉石和顽火辉石最紧密地共生。钠长硬玉基本上由钠铬辉石和含或有时不含闪石类或顽火辉石的铬铁矿／镁铬铁矿组成，但没有纯的硬玉。     

丁青和新喀里多尼亚玻安岩类的辉石及其超微结构

本文对西藏丁青玻安岩类深成岩的辉石和新喀里多尼亚玻安岩的斜顽辉石进行了矿物学工作及高分辨电镜观察。丁青斜方辉石堆晶岩辉石的超微结构包括:单斜辉石的(100)双晶、斜方辉石a/4平移畴结构及斜方辉石—单斜辉石相转变。玻安岩斜顽辉石典型超微结构是(100)双晶。由矿物的碎裂、错动以及斜方辉石—单斜辉石相变中只出现偶数倍单斜辉石等表明:矿物结晶及成岩过程中曾受应力作用、后者可能与岩石所处的构造位置有关。由辉石成分计算的地质温度表明,丁青堆晶斜方辉石岩的辉石是在高温下晶出、岩石固结温度是1013～1111℃,当它们在～1000℃下稳定时,斜方辉石出溶了单斜辉石片晶。将玻安岩斜顽辉石加热至1100℃后淬冷及按120℃/h速度冷却均未得到纯的斜顽辉石,可能斜顽辉石是原顽火辉石在应力环境中高温淬冷所成。     

清镇顽火辉石球粒陨石矿物成分及其成因意义

在球粒陨石群中顽火辉石球粒陨石具高度还原和独特的矿物学特征。顽火辉石球粒陨石几乎由纯的顽火辉石、金属(含有固溶体的硅)、硫化物及少量的斜长石、橄榄石和单斜辉石组成。硫化物矿物的组成相当复杂,普通球粒陨石(H、L及LL球粒陨石)的强亲石元素Ca、Cr、Ti、Mg、Mn、K在顽火辉石球粒陨石中呈硫化物相产出。最近我们在原有工作的     

顽火辉石中Li同位素扩散与分馏

顽火辉石作为斜方辉石晶系的重要Mg端元矿物,是地球上地幔主要组成矿物之一。Li同位素作为重要的地幔地球化学示踪剂,在主要地幔矿物中(如橄榄石,辉石等)的扩散分馏相关性质的研究显得尤为重要。我们通过经典力学的方法,计算模拟了原子尺度下Li同位素在顽火辉石晶格以2种不同的迁移机制(填隙机制和取代空位机制)迁移的活化能和其在不同晶格位上不同温度条件下的分馏作用程度。计算结果表明,Li同位素易以填隙位机制在顽火辉石中迁移。重同位素~7Li会更多的进入晶格填隙位中,而6Li相对更多进入Mg位。温度是影响这种分馏作用的1个关键因素,相应的结果可用来解释地幔Li同位素组成特征及冷却条件下的同位素分馏等科学问题。     

海南福基田幔源辉石结构OH与氢氧同位素

采用IR光谱和质谱技术分析了海南福基田幔源巨晶和包体中辉石的结构羟基红外光谱和氢氧同位素。测试的所有巨晶普通辉石和包体中透辉石及顽火辉石均含结构OH,对比印证了国内外同类矿物的红外光谱特征。结构水质量分数分别是:普通辉石87×10-6~389×10-6;透辉石127×10-6~273×10-6;顽火辉石69×10-6~207×10-6。包体中结构水质量分数为1 811×10-6~5 377×10-6,平均为3 133×10-6。包体中辉石的氢氧同位素特征如下:透辉石的δ(D)为-123.17‰,顽火辉石的δ(D)为-132.04‰;透辉石的δ(18O)为5.96‰,顽火辉石的δ(18O)为5.60‰。实验和对比表明,辉石是海南福基田上地幔重要的"水储库",包体未受地壳成分污染,继承和保持了上地幔"富水贫氘"的特征。上述结果为该地区上地幔研究提供了结构水和氢氧同位素的基础资料。     

四川石棉蛇纹石猫眼热相变的Raman光谱和XRD研究

采用Raman光谱和X射线粉晶衍射(XRD)方法对四川蛇纹石猫眼的热相变过程和产物进行的研究表明,蛇纹石猫眼热相变的最终产物为镁橄榄石和顽火辉石。加热到500℃,蛇纹石猫眼的结构稳定;700℃,时,镁橄榄石的拉曼特征峰824cm^-1和854cm^-1出现,同时出现非晶质顽火辉石686cm^-1和341cm^-1附近的包络峰;800～900℃时,镁橄榄石的含量和结晶程度增强。晶质顽火辉石相出现,但强度较弱。1000℃时,镁橄榄石的含量明显降低。1100℃时,顽火辉石的含量和结晶程度显著增加。     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

NONMETALS DEPOSITS

正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.)     

MATHEMATICAL GEOLOGY

正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology,     

PROSPECTING EXPLORATION

正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.)     

STRUCTURAL GEOLOGY

正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se-     

STRUCTURAL GEOLOGY

正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with     

PALEOZOOLOGY

正20141609 Chen Guiying(College of Earth Sciences,Guilin University of Technology,Guilin 541004,China);Han Nairen New Materials of Stylophora from the Upper Cambrian of the Jingxi Area,Guangxi,South China(Acta Palaeontologica Sinica,ISSN0001-6616,CN32-1188Q,52(3),2013,p.288-293,2 illus.,12 refs.)Key words:Stylophora,Guangxi     

GEOPHYSICS

正20140634 Cao Lingmin(Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China);Xu Yi Finite Difference Tomography of the Crustal Velocity Structure in Tengchong,Yunnan Province(Chinese Journal of Geophysics,ISSN0001-5733,CN11-2074/P,56(4),2013,p.1159-1167,6illus.,35refs.,with English abstract)