新疆东天山黄山岩体岩石地球化学特征与岩石成因

黄山岩体位于东天山北部的土墩-黄山-图拉尔根镁铁-超镁铁质岩带中段,受康古尔塔格-黄山韧性剪切带控制,主要由橄榄岩、橄榄二辉岩、辉石岩、辉长苏长岩、辉长岩以及辉长闪长岩组成.岩石化学组成属拉斑玄武岩系列,普遍富集大离子亲石元素(Rb,Ba,Sr),亏损高场强元素(Nb,Ta,Ti).岩体εNd(t)=+4.1～+9.2,除3件样品εSr(t)为+2.2,+12.5和+15.4,大部分εSr(t)=(-22.5～-4.5),Nd,Sr同位素组成基本属亏损型地幔特征;Pb同住素初始值(206Pb/204Pb)i=18.081～18.413,(207Pb/204Pb)i=15.441～15.513,(208Pb/204Pb)i=37.461 6～37.899,具有MORB亲和性.岩相学及岩石地球化学特征显示岩浆演化过程中主要发生了橄榄石、斜方辉石、单斜辉石和斜长石的分离结晶作用.岩浆演化晚期阶段发生了一定程度的同化混染作用,元素地球化学和Nd,Sr,Pb同位素体系证明,岩浆源区主体由软流圈地幔物质组成,同时也有一定量富集型岩石圈地幔组份加入.黄山岩体是岩石圈根部拆沉加热熔融和软流圈地幔上涌减压熔融的产物,这种地幔动力学机制应该对应于后碰撞伸展环境.     

郯庐断裂带晚中生代富碱侵入岩Nd、Sr、Pb同位素特征及源区性质探讨

郯庐断裂带是中国东部一条巨大的深大断裂带,它纵切华北克拉通、扬子克拉通、兴蒙-吉黑造山带和大别-苏鲁造山带四个大地构造单元,特别是在该断裂带出露许多晚中生代富碱侵入岩体,构成一条长达近2000km的富碱侵入岩带.本文是在前人研究基础上首次从大尺度对整个郯庐断裂带富碱侵入岩的Nd、Sr、Pb同位素做了比较系统深入的研究,发现四个大地构造单元的富碱侵入岩具有明显不同的Nd、Sr、Pb同位素特征,暗示四大构造单元富碱侵入岩的源区性质差别较大:兴蒙-吉黑造山带晚中生代富碱侵入岩源于和亏损地幔有成因联系的年青地壳(εNd(t)为ft.,平均值 2.25);华北克拉通、扬子克拉通和大别-苏鲁造山带三大构造单元晚中生代富碱侵入岩都主要源于EMI型富集地幔(εNd(t)均为负值).但是这三大构造单元岩石圈地幔富集程度差别较大.大别-苏鲁造山带岩石圈地幔相对富集程度最高(εNd(t)平均值为-17.06);华北克拉通次之(εNd(t)平均值为-10.03);扬子克拉通岩石圈地幔富集程度最低(εNd(t)平均值为-6.41).本文认为大别.苏鲁造山带岩石圈地幔相对最富集的原因可能是在早中生代扬子克拉通陆壳向华北克拉通深俯冲之后的折返过程中,因压力释放有利于熔/流体的形成、析出和向上交代并改造华北岩石圈地幔使之成为富集地幔.     

新疆阿奇山岩体LA-ICP-MS锆石U-Pb年龄、Sr—Nd—Pb同位素特征及其成因探讨

本文运用LA-ICP-MS锆石U-Pb定年法对新疆阿奇山岩体进行了测定,获得年龄为269.5±1.6 Ma～272.1±1.3 Ma,表明阿奇山岩体为晚二叠世。岩石的Sr、Nd、Pb同位素分析表明,该岩体有较低的锶同位素初始比值[n(~(87)Sr)/n(~(86)Sr)]_i(0.7044～0.7055)、正ε_(Nd)(t)值(0.48～3.66)及较为年轻的Nd同位素两阶段模式年龄t_(2DM)~C(741～1090 Ma),表明其源岩与亏损地幔有关,而在Pb同位素n(~(207)Pb)/n(~(204)Pb)—n(~(206)Pb)/n(~(204)Pb)构造模式演化图解中,又显示其物质来源与壳幔相互作用有关。综合岩体岩石地球化学特征、前人研究成果及该区大地构造背景,分析认为阿奇山岩体的形成是地幔柱活动背景下壳幔相互作用过程的产物。阿奇山岩体位于新疆北部,属于中亚造山带的一部分,在晚二叠世,整个新疆北部已经进入后造山阶段,且晚古生代时期板块俯冲已经结束。但后造山岩浆形成必然需要新的动力及热源,而幔源岩浆的底侵不仅可以为后造山岩浆活动提供热源,还提供了大量物源。因此在区域性伸展构造环境下,由于壳幔相互作用强烈,来自深部的地幔柱幔源岩浆底侵,带来的热源诱发较年轻的地壳物质部分熔融,同时有部分幔源物质的混染,从而使阿奇山岩体花岗岩物源具有地幔和地壳双重特征。     

吉林东南部晚中生代中酸性火山作用成因的地球化学制约

详细的主、微量元素和Sr-Nd-Pb同位素研究结果显示,延吉地区晚中生代(早白垩世)中酸性火山岩具有岛弧型微量元素特征(富集轻稀土(LREE)、大离子亲石元素(LILE)和亏损高场强元素(HFSE)),和中等放射成因Sr、Pb及类似于硅质地球的Nd同位素组成(~(87)Sr/~(86)Sr(i)=0.70437～0.70525;~(206)Pb/~(204)Pb(i)=18.19～18.37,~(207)Pb/~(204)Pb(i)=15.54～15.57,~(208)Pb/~(204)Pb(i)=38.13～38.22;ε_(Nd)(t)=-2.75～+1.61)。其Sr-Nd-Pb同位素组成特征类似于区域同期基性火山岩和大兴安岭地区同时代火山岩。这些广泛分布于吉林南部的晚中生代中酸性火山岩是岩石圈地幔来源岩浆经分离结晶或地壳物质混染/AFC过程的产物。吉林省东南部晚中生代不同区域火山岩的Sr-Nd-Pb同位素对比结果显示,辽源-延吉与通化地区分属不同构造单元,其中辽源-延吉一带则为中亚造山带的东段,而通化地区为华北克拉通的一部分,夹皮沟-松江断裂可能是华北克拉通东北缘的边界。     

庐枞早白垩世火山岩的地球化学特征及其源区意义

从中生代到新生代,华北东部岩石圈地幔发生了减薄以及地球化学性质置换, 而扬子地块东部中生代岩石圈地幔也表现出类似的过程,对中生代火山岩的地球化学研究有助于了解这一变化过程以及发生置换时的时空关系。庐枞火山岩出露于扬子地块东部,为一套包括粗玄岩–玄武粗安岩–粗面岩的富碱橄榄安粗岩系。研究了双庙组基性火山岩,这些岩石富集Rb,K,Sr,Th和轻稀土元素,亏损高场强元素。(87Sr/86Sr)i = 0.7060~0.7063,εNd(t )=-3.9~-6.2,(206Pb/204Pb)i=17.788~18.125,(207Pb/204Pb)i= 15.511~15.546,(208Pb/204Pb)i =37.735~38.184。在喷出地表过程中,火山岩没有受到明显的地壳物质混染,因此元素和同位素组成反映了地幔源区的地球化学特征。 其地幔源区具有同位素富集特征,表明火山岩源区曾受到地壳物质的影响,是富集地幔部分熔融的产物,并经历明显的结晶分异作用。庐枞火山岩的岩浆成分和源区特征反映该地区在晚中生代岩石圈地幔的伸展和软流圈地幔上涌的演化过程。     

鲁东昆嵛山地区宫家辉长闪长岩成因：岩石地球化学、锆石U-Pb年代学与Hf同位素制约

宫家辉长闪长岩是鲁东昆嵛山地区出露面积最大的基性侵入体。锆石LA-ICP-MS U-Pb定年表明,其侵位于113±2Ma。高MgO含量(Mg~#高达56),Hf同位素组成位于华北克拉通地壳演化线之上,说明其地幔来源的特征。在地球化学特征上,富集K、Rb、Ba、Th、U等大离子亲石元素和轻稀土元素,亏损Nb、Ti、P等高场强元素;I_(Sr)为0.70745～0.70812,ε_(Nd)为～15.9～-12.0,Sr、Nd和Pb同位素组成[(~(206)Pb/~(204)Pb)_i=17.108～17.239]与胶东基性脉岩和胶莱盆地青山组火山岩相似;锆石Hf同位素组成比较均一,ε_(Hf)(t)平均值为-16.7,这些特征都暗示其来源于富集的华北岩石圈地幔。地球化学研究表明宫家辉长闪长岩经历了分离结晶作用,是胶东乃至中国东部岩石圈减薄的产物。     

柯坪玄武岩的岩石学、地球化学、Nd、Sr、Pb同位素组成与岩石成因

柯坪玄武岩位于塔里木板块西缘,产于下二叠统库普库兹曼组和开派兹雷克组中。岩石化学组成以富集TFeO、TiO2、P2O5和SiO2不饱和为特征。大部分样品属碱性玄武岩系列,个别属拉斑玄武岩系列。它们的稀土元素和微量元素显示了板内拉张环境玄武岩的地球化学特征。εNd(t)=-1.73～-3．69,εSr(t)= 27．56～ 56．87,^206Pb／^204Pb=17．87～18．02,^207Pb／^204Pb=15．45～15．53,^208Pb／^204Pb=38．22～38．49。Nd、Sr、Pb同位素组成证明柯坪玄武岩源自于前寒武纪的富集型大陆岩石圈地幔。而且,这种情况在塔里木盆地及周缘地区十分发育的镁铁质岩浆岩中具有广泛的代表性。据此,可以将新疆南部和北部划分为两个明显不同的同位素地球化学省。南部省以富集型地幔的同位素组成为特征,而北部省以亏损型地幔的同位素组成为特征。分属于这两个省的古生代晚期阶段岩浆岩有可能不是同一个地质过程的产物。     

雷琼地区晚新生代玄武岩地球化学：EM2成分来源及大陆岩石圈地幔的贡献

对雷琼地区21个晚新生代玄武岩样品的主量、微量元素和Sr、Nd、Pb同位素分别用湿化学法、ICP-MS和MC-ICPMS进行了测定.这些玄武岩主要为石英拉斑玄武岩,其次为橄榄拉斑玄武岩和碱性玄武岩.大多数样品的微量元素和同位素成分与洋岛玄武岩(OIBs)相似,而且随着SiO_2不饱和度增加,不相容元素含量也增加.除R4-1可能受到地壳混染外,其他样品相对均一的Nd同位素(ε_(Nd)=2.5-6.0)以及变化明显但范围有限的Sr同位素(0.703106～0.704481),可能继承了地幔源区的特征.~(87)Sr/~(86)Sr与~(206)Pb/~(204)Pb的正相关和~(143)Nd/~(144)Nd与~(206)Pb/~(204)Pb的负相关特征暗示DM(软流圈地幔)与EM2(岩石圈地幔)的混合.地幔捕虏体的同位素特征暗示EM2成分不可能存在于尖晶石橄榄岩地幔,而La/Yb和Sm/Yb系统表明岩浆由石榴石橄榄岩部分熔融产生,这意味着EM2成分可能存在于石榴石橄榄岩地幔.雷琼地区玄武岩的地球化学变化可以用软流圈地幔为主的熔体加入不同比例石榴石橄榄岩地幔不同程度熔融产生的熔体来解释:碱性玄武岩和橄榄拉斑玄武岩是软流圈熔体与石榴石橄榄岩地幔较低程度(7%～9%)熔融体混合,而石英拉斑玄武岩是软流圈熔体与石榴石橄榄岩地幔较高程度(10%～20%)熔融体的混合.     

山东中侏罗世-早白垩世侵入岩的锆石Hf同位素组成及其意义

对山东中侏罗世-早白垩世侵入岩中锆石的原位Hf同位素分析显示,形成于晚太古代(上交点年龄～2.5Ga)的继承锆石具有正的ε_(Hf)(t)值( 8～ 1),Hf同位素模式年龄集中在2.6～2.8Ga,与辽宁古生代金伯利岩中基性下地壳捕虏体中锆石Hf组成和Hf模式年龄十分一致,Hf模式年龄也与研究区变质岩和花岗岩的全岩Nd模式年龄相同,因此,这些继承锆石来自于晚太古代由岩浆底侵形成的基性下地壳。新生锆石出现在继承锆石周围或者以独立颗粒出现,其U-Pb年龄为177Ma和132～126Ma,ε_(Hf)(t)值均为负值(-23～-1)。山东中生代侵入岩的形成与富集岩石圈地幔,亏损地幔和地壳三个端员之间的相互作用有关。其中根据来源于晚太古代下地壳的侏罗纪铜石二长花岗岩限定的研究区下地壳ε_(Hf)(t)平均值为-20,根据来源于富集岩石圈地幔的早白垩纪沂南辉长岩限定的富集地幔端员的ε_(Hf)(t)为-16。部分样品锆石ε_(Hf)(t)变化非常大(-20～-1),示踪了岩浆作用过程中亏损地幔物质的参与程度的逐渐增强。这种变化是华北晚中生代岩石圈大规模减薄作用的结果。     

青海省共和盆地周缘晚古生代镁铁质火山岩Sr-Nd-Pb同位素地球化学及其地质意义

青海省共和盆地周缘晚古生代镁铁质火山岩分属阿尼玛卿蛇绿混杂带,宗务隆构造带和苦海-赛什塘带。阿尼玛卿带正常洋中脊玄武岩(N-MORB)样品具有较高的~(87)Sr/~(86)Sr(t)比值(0.7066～0.7084)、高的ε_(Nd)(t)(12.2～12.8)和较低的~(206)Pb/~(204)Pb初始值(17.72～17.79)。这些同位素特征类似于秦岭勉略蛇绿岩带的N-MORB以及印度洋低~(206)Pb/~(204)Pb高~(143)Nd/~(144)Nd N-MORB。该带中的洋岛玄武岩(OIB)的~(87)Sr/~(86)Sr比值为0.7036～0.7044,ε_(Nd)(t)=4.4～4.8,~(206)Pb/~(204)Pb=17.45～17.62。其Sr和Nd同位素比值可与印度洋代表热点构造的洋岛玄武岩对比,但~(206)Pb/~(204)Pb低于印度洋的热点构造玄武岩,因此,具有类似印度洋低~(143)Nd/~(144)Nd比值MORB同位素特征。宗务隆构造带的N-MORB的Sr同位素比值在0.7041～0.7058,ε_(Nd)(t)=6.1～8.4,~(206)Pb/~(204)Pb=17.51～17.90,划归高~(143)Nd/~(144)Nd比值的N-MORB。苦海大陆裂谷玄武岩显示了高的~(87)Sr/~(86)Sr同位素比值(0.7115和0.7104)和低的ε_(Nd)(t)值(-1.7和-2.5),其~(206)Pb/~(204)Pb(17.64和17.46)与上述大洋玄武质岩石无显著区别。上述各岩类的同位素特征反映了它们生成的构造环境和陆壳组分混染的程度。阿尼玛卿带的N-MORB代表了典型的来自亏损地幔源区的洋中脊产物。与勉略带同类岩石可能来自同一源区。OIB可能属于热点构造成因的洋岛产物并与MORB一起构成了阿尼玛卿洋洋壳。宗务隆带MORB同样代表了主要源自相对亏损地幔的洋脊产物并指示宗务隆带曾开裂成洋。苦海大陆裂谷玄武岩极高的Sr和低的Nd同位素比值是陆壳物质组分的强烈印记,这与该类火山岩发育在前寒武纪基底之上不无关系。结合本区大洋玄武岩普遍低的Nb/U和Ce/Pb比值,推测它们可能源自EMII与DMM物质的交代混合。按照习惯的想法,明显的Dupal异常(△~(208)Pb/~(204)Pb值=46～103和△~(207)Pb/~(204)Pb值=4～18;大多样品~(87)Sr/~(86)Sr>0.704)指示这些岩石在空间上代表了来自南半球印度洋位置的古洋壳残余。但是,北半球愈来愈多的Dupal异常的发现有可能指示它们是类似现今东南亚多洋岛构造历经"汇聚式(focused)俯冲"的产物。此外,宗务隆带MORB的Dupal异常指示本区古特提斯域的北界较先前所定还要北推200km。     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.     

郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

塘口水电站坝基岩体透水性和渗漏问题分析

塘口水电站大坝基础座落在断层和裂隙较发育的龟裂纹灰岩上,岩体完整性差、透水性强,多年运行后,大坝灌浆廊道和排水廊道出现多处集中性漏水,为确保大坝安全和电站正常发电,根据渗漏性质和成因,采用对灌浆廊道补充帷幕灌浆,对排水廊道进行固结+帷幕+回填灌浆。通过灌浆处理后,效果良好,表明灌浆工程有效的将导致坝基渗漏的上下游的裂隙通道封闭,并顺利的经受了随后的汛期洪水考验,大坝安全得到保障。     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Calculation of the Inverse of the Covariance

In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix.     

某高速公路下伏煤矿采空区稳定性分析

在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。      

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

Artemia in the Salt Lakes of Russia:the Productivity of Populations,the Reserves of the Cysts and the Fisheries

正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the