早元古代滹沱群玄武岩Rb-Sr、Sm-Nd同位素体系初论

本文给出的滹沱群下亚群青石村组玄武岩Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ全岩等时线年龄为２０４５．８±１７和２３６９±３０Ｍａ（Ｚ），角门石４０Ａｒ－３９Ａｒ坪年龄和最高视年龄为１３６４±１９和１９３２±１９Ｍａ（１）；中亚群河边村组玄武岩Ｒｂ－Ｓｒ全岩等时线年龄图的投点呈完全离散状，Ｓｍ－Ｎｄ全岩等时线年龄为２３２２±３１Ｍａ（２），角门石４０Ａｒ－３９Ａｒ坪年龄和最高视年龄为１３６０和１７４２±１７Ｍａ（１）。根据上述Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ数据与已知青石村组、河边村组单颗粒锆石Ｕ－Ｐｂ法确定的成岩年龄２４５０±１０和２４００±２０Ｍａ（２）的明显差别，４０Ａｒ－３９Ａｒ均揭示为较典型受扰动的年龄谱和较发育的透人性构造、晚期岩脉等地质证据，认为Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ是重设的同位素体系。     

广西龙胜丹洲群细碧岩锆石U－Pb及Sm－Nd等时线年龄

用单颗粒锆石Ｕ－Ｐｂ及全岩、全岩－矿物Ｓｍ－Ｎｄ等时线法对广西龙胜丹洲群细碧岩进行了地质年代学研究。结晶锆石年龄为９７７±１０Ｍａ，代表细碧岩的形成时代；锆石Ｕ－Ｐｂ及全岩Ｓｍ－Ｎｄ等时线均反映出～０．６Ｇａ的一次后期事件年龄，很可能代表一次较大规模富ＣＯ２流体的热液蚀变作用时代，即本区受细碧岩层控的滑石矿的成矿年龄；细碧岩全岩矿物Ｓｍ－Ｎｄ内部等时线年龄为２０１±４０Ｍａ，代表了印支期岩浆热事件的时代。     

东秦岭陡岭群变质杂岩Sm-Nd、Rb-Sr、40Ar/39Ar、207Pb/206Pb年龄

本文用单颗粒锆石逐级蒸发２０７Ｐｂ／２０６Ｐｂ、ＳｍＮｄ、ＲｂＳｒ、４０Ａｒ／３９Ａｒ年代学方法对东秦岭陡岭群变质杂岩的形成时代、变质时期和构造归属进行了研究。结果表明：陡岭群变质杂岩形成于早元古代，年龄为２０００Ｍａ左右，在其形成后遭受了多期变质作用。片麻岩ＳｍＮｄ等时年龄１８７８±２５６Ｍａ（εＮｄ（ｔ）＝＋２．８±２．６）代表了ＳｍＮｄ同位素系统重新发生均一化作用的时间。主期变质作用发生在８３３±１７Ｍａ（角闪石４０Ａｒ／３９Ａｒ高温坪年龄）；另一期变质作用发生于４２２±１６Ｍａ（片麻岩Ｒｂ     

新疆阿尔曼太蛇绿岩时代的Nd—Sr同位素地质研究

本文通过测定采自新疆阿尔曼太兔子泉一带蛇绿岩的堆晶辉长岩、辉绿岩和安山玢岩，获得Ｓｍ－Ｎｄ等时年龄为５６１±４１Ｍａ，εＮｄ（ｔ）＝６．１，Ｒｂ－Ｓｒ等时年龄为３９２±１７Ｍａ，（８７Ｓｒ／８６Ｓｒ）ｉ＝０．７０４１，前者为蛇绿岩的形成时代，后者为蛇绿岩遭受后期变质作用的时间。札河坝－阿尔曼太蛇绿岩的形成环境可能是古亚洲洋向南俯冲引起的弧后盆地     

广西龙胜丹洲群细碧岩锆石U—Pb及Sm—Nd等时线年龄

用单颗粒锆石Ｕ－Ｐｂ及全岩、全岩－矿物Ｓｍ－Ｎｄ等时线法对广西龙胜丹洲群细碧岩进行了地质年代学研究。结晶锆石年龄为９７７±１０Ｍａ，代表细碧岩的形成时代；锆石Ｕ－Ｐｂ及全岩Ｓｍ－Ｎｄ等时线均反映出￣０．６Ｇａ的一次后期事件年龄，很可能代表一次较大规模富ＣＯ２流体的热液蚀变作用时代，即本区受细碧岩层控的滑石矿的成矿年龄；细碧岩全岩－矿物Ｓｍ－Ｎｄ内部等时线年龄为２０１±４０Ｍａ，代表了印支期岩浆热事     

内蒙古贺根山地区蛇绿岩稀土元素和Sm－Nd同位素研究

贺根山地区蛇绿岩各类岩石的稀土元素地球化学特征表明其为上地幔部分熔融、分异演化的产物，其Ｓｍ－Ｎｄ等时线年龄为４０３±２７Ｍａ，εＮｄ（Ｔ）＝＋８．７±０．６，结合蛇绿岩套上部玄武岩和变火山熔岩的岩石化学研究，可以确认蛇绿岩来源于大洋中脊亏损的上地慢。     

安徽碧溪岭含柯石英榴辉岩的U－Pb与~（40）Ar／~（39）年代学研究

安徽大别、苏北和山东胶南是世界上第三个发现含柯石英榴辉岩的地区。在关于苏鲁皖超高压变质带大地构造背景的学术讨论中，其时代问题成为当前争论的焦点。本文用锆石Ｕ－Ｐｂ法得到碧溪岭榴辉岩体谐和图上交点年龄２７７４．５±２４Ｍａ以及ｔ（~（２０７）Ｐｂ／~（２０６）Ｔｂ）平均表面年龄２６６２Ｍａ，提供了榴辉岩的原岩和超高压变质作用可能形成于晚太古代的信息；并用多硅白云母Ａｒ－Ａｒ法测得６６１．７±１３Ｍａ的退变质年龄，也表明本区榴辉岩可能是前寒武纪的产物；此外，还测得围岩大别群斜长片麻岩中的白云母以及榴辉岩中晚期交代的普通角闪石的Ａｒ－Ａｒ等时线年龄分别为１９２．５５±３．８５和２３０．７０±４．６１Ｍａ，代表后榴辉岩（ｐｏｓｔｅｃｌｏｇｉｔｅ）的印支期区域动力变质作用改造年龄。笔者对已报道的榴辉岩Ｓｍ－Ｎｄ年龄的地质意义进行了讨论，并指出了含石榴子石Ｓｍ－Ｎｄ矿物等时线定年法潜在的弊端。     

江西德兴西湾钠长花岗岩的激光质谱~(40)Ar/~(39)Ar等时年龄

对采自江西德兴西湾钠长花岗岩的样品进行了激光质谱４０Ａｒ／３９Ａｒ年龄测定,得到等时年龄为（９２７９±１８６）Ｍａ。该年龄代表了赣东北蛇绿岩套中浅色侵入体部分的钠长花岗岩冷却到３５０℃左右时的结晶年龄,把它作为该蛇绿岩套形成时代的上限。结合近年来已经发表的有关该区蛇绿岩套的ＳｍＮｄ、ＵＰｂ和４０Ａｒ／３９Ａｒ同位素年龄数据,本文就该蛇绿岩套的形成年龄和构造侵位年龄进行了讨论。     

皖南和赣东北蛇绿岩成因及其构造意义：元素和Sm－Nd同位素制约

本文对扬子块体南缘构造侵位于板溪群（及相应地层）的皖南和赣东北晚元古代蛇绿岩进行了系统的元素和Ｓｍ－Ｎｄ同位素地球化学研究，结果表明两套蛇绿岩具有类似的元素地球化学特征，即二者的火山岩元素地球化学特征均类似于形成于弧后盆地构造环境的拉斑玄武岩。但是，两套蛇绿岩的Ｎｄ同位素组成明显不同。赣东北蛇绿岩具有相当均一的高εＮｄ（Ｔ）值（＋５．５±１．２），表明来源于一较亏损的上地幔源区，并且没有受到明显的较成熟地壳物质的混染。相反，皖南蛇绿岩的εＮｄ（Ｔ）值低，并有较大的变化范围（＋４．５──１．０），并和Ｓｍ／Ｎｄ、Ｎｄ、ＭｇＯ、ＳｉＯ２呈明显的二元混合相关关系，表明蛇绿岩是由亏损幔源岩浆（初始εＮｄ（Ｔ）≈＋５．５）在结晶分异过程中与地壳组分（初始εＮｄ（Ｔ）≈－１）混合形成的。皖南和赣东北蛇绿岩的Ｎｄ同位素和元素地球化学特征以及该地区的同时代花岗岩和火山岩的时空分布特征，可以用华南和扬子元古宙陆－弧－陆碰撞模式来解释。大约在１．０Ｇａ前，扬子和华南块体之间存在一多岛弧洋盆。大陆边缘岛弧和大洋岛弧在扬子块体南缘发育演化。皖南和赣东北蛇绿岩就是在大陆边缘盆地和弧间盆地演化过程中形成的洋壳构造侵位的碎片。该地区Ｉ型     

早元古代滹沱群玄武岩Rb—Sr,Sm—Nd同位素体系初论

本文给出了的滹沱群下亚群青石村组玄武岩Ｒｂ－Ｓｒ、Ｓｍ－Ｎｄ全岩等时线年龄为２０４５．８±１７和２３６９±３０Ｍａ（２σ），角闪石＾４０Ａｒ＾－＾３９Ａｒ坪年龄和最高视年龄为１３６４±１９和１９３２±１９Ｍａ（１σ）；中亚群河边村组玄武岩Ｒｂ－Ｓｒ全岩等时线年龄图的投点呈完全离散状。     

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)