敦煌三危山地区白垩纪OIB型基性岩墙的特征及地质意义

本文首次报道甘肃敦煌三危山地区早白垩世玄武质岩浆活动的记录。在三危山附近,基性岩墙侵入于敦煌群TTG和表壳岩大理岩和片岩中。全岩的K-Ar年龄为136.00±11.56Ma到99.11±6.35Ma,形成时代属于早白垩世。基性岩墙SiO₂含量变化范围较小,集中在47.95%~50.65%之间,以富TiO₂ (2.07%~2.35%,平均为2.21%)、MgO(6.03 %~6.51%,平均为6.32%)、贫K₂O(<1.29%),Na₂O>K₂O, Mg^#值中等且比较稳定(48.9~53.1,平均为51.7)为特征。基性岩相容元素含量相对较低,Ni含量变化相对较小,分布在112.7×10^-6~182.7×10^-6之间。而V含量变化较大,介于184×10^-6~267×10^-6之间,表明岩浆早期可能发生了一定的以橄榄石和单斜辉石为主的分离结晶作用。基性岩富集LREE((La/Yb)_N ＝3.97~4.66)和LILE,无Eu负异常,较高的Fe/Mn比值等,具有与洋岛玄武岩(OIB)相似的特征。微量元素比值等特征表明其来源与富集地幔关系密切,玄武质岩浆的形成可能与岩石圈的减薄和软流圈的上涌有关。     

藏南冈底斯岩基晚白垩世含紫苏辉石侵入岩的地球化学特征及其成因探讨

冈底斯岩基南缘自西向东，从楠木林到米林广泛出露一系列含暗色细粒包体的含紫苏辉石侵入岩。这一系列含紫苏辉石的侵入岩具有斜长石以及紫苏辉石的巨晶（>5mm），呈现出堆晶结构。锆石U-Pb定年表明，这一系列含紫苏辉石侵入岩的结晶年龄为97~77Ma，并不随侵位位置具有显著的经度上的变化。含紫苏辉石的基性岩具有高的Al₂O₃（17.3%~18.2%）含量，较高的MgO（3.9%~4.1%）含量，FeO^T含量在8.7%~9.0%之间；低的Cr（<14.8×10^-6）和Ni（<15.0×10^-6）含量，基本不具有Eu的异常，富集大离子亲石元素（LILE）和LREE，亏损高场强元素（HFSE）。含紫苏辉石的中-酸性岩具有高的Al₂O₃（14.9%~18.8%）含量，高的Mg^#值（>39.7）；变化较大的Cr（5.7×10^-6~260×10^-6）和Ni（10.2×10^-6~78.2×10^-6）含量，具有微弱-强烈的Eu的负异常，富集LILE和LREE，亏损HFSE。暗色细粒包体与含紫苏辉石基性岩相比具有相似的SiO₂含量，FeO^T（8.1%~9.0%）含量，稍高的MgO（4.7%~5.4%）含量，Al₂O₃（18.1%~19.4%）含量以及Mg^#值（51.0~52.6）；具有与含紫苏辉石基性岩相似的微量元素分布和稀土元素配分模式。这一系列含紫苏辉石的侵入岩具有较低的初始Sr同位素比值（⁸⁷Sr/⁸⁶Sr_（t）=0.7037~0.7044），较高并变化较大的ε_Nd（t）值（+3.7~+9.4）和ε_Hf（t）值（+9.9~+14.6）。这些特征共同说明，经流体+熔体交代的地幔楔中软流圈部分在俯冲流体存在的情况下发生部分熔融形成母岩浆，其母岩浆随后与俯冲板片熔体发生混合。在岩浆演化过程中经历了单斜辉石、斜方辉石以及斜长石的分离结晶并最终形成了冈底斯岩基南缘出露的含紫苏辉石侵入岩。暗色细粒包体可以代表母岩浆的早期堆晶，是岩浆淬火作用的产物。母岩浆中大量流体的存在，使其结晶顺序为单斜辉石-斜长石（紫苏辉石），随后的堆晶作用使得这一系列侵入岩得以赋存紫苏辉石。     

广东沿海地区基性岩脉地球化学及成因

广东沿海地区基性岩脉的成岩年龄是146~54 Ma,主要形成于白垩纪,次为侏罗纪和第三纪。可将工作区基性岩脉的形成时代分为5期：第一期146Ma,第二期138~132Ma,第三期112~105Ma,第四期99~82Ma,第五期75~54Ma。根据K₂O/Na₂O比值和K₂O含量,以及不相容元素分配模式的“Nb-Ta”异常,可以划分出两类基性岩脉。第一类K₂O/Na₂O比值<0.5和K₂O含量<1.3%,在微量元素MORB标准化图解中具有弱的“Nb-Ta”负异常。第二类K₂O/Na₂O比值>0.5和K₂O含量>1.3%,在微量元素MORB标准化图解中具有显著的“Nb-Ta”负异常。在K₂O-SiO₂图解中,第一类基性岩脉样品落入中钾岩石范围,第二类基性岩脉样品落入高钾岩石或钾玄岩范围。基性岩脉分布的重要特点是中钾基性岩脉分布于本区北部上地幔拗陷区,而高钾基性岩脉分布于本区南部地幔隆起区或斜坡区。两类基性岩脉有着不同的岩浆来源。在本区北部,软流圈物质入侵和熔蚀Ⅰ型富集地幔混合形成中钾基性岩脉,随着时代的由老至新和熔蚀作用的不断进行,岩浆中Ⅰ型富集地幔成分增加。晚期,岩浆活动向连平、新丰一带迁移。在本区南部,软流圈物质入侵并熔蚀Ⅱ型富集地幔,形成具有软流圈物质和Ⅱ型富集地幔混合特征的高钾基性岩脉。随着熔蚀作用的不断进行,岩浆中Ⅱ型富集地幔成分增加,晚期基性岩浆活动向三水裂谷、南澳裂谷迁移。     

西北天山京希-伊尔曼德金矿区狮子山次火山岩的年代学、地球化学特征及其地质、成矿意义

京希-伊尔曼德金矿位于西北天山吐拉苏盆地中,矿区出露晚古生代火山-沉积岩和狮子山次火山岩;狮子山次火山岩主要为安山玢岩、英安玢岩,侵位于火山-沉积岩底部的凝灰质砂岩、凝灰岩、流纹岩以及安山岩组合中。锆石SHRIMP U-Pb年代学研究表明,狮子山次火山岩的形成年龄为370.5±2.1Ma,略晚于围岩火山岩。狮子山次火山岩MgO、TiO₂、K₂O含量低,为低钾拉斑系列,稀土元素总量低（5.1×10^-6~8.8×10^-6）,轻稀土弱富集（（La/Yb）_N=2.7~3.8）,弱Eu正异常和Ce负异常,相对富集大离子亲石元素和Zr、Hf,亏损Nd,地球化学特征与围岩安山岩明显不同。具有亏损的Sr-Nd同位素特征,（⁸⁷Sr/⁸⁶Sr）_i=0.703185~0.703810,ε_Nd（t）=4.03~4.54。狮子山次火山岩形成于火山弧环境,是火山弧中少量拉斑系列岩石的代表,其岩浆源区为俯冲带流体交代的亏损地幔,地幔石榴石二辉橄榄岩经~5%部分熔融形成原始玄武质岩浆,玄武质岩浆经~20%的矿物分离结晶形成狮子山次火山岩,其形成环境以及演化过程非常有利于岩浆演化形成热液型金矿床,可能与京希-伊尔曼德金矿具有密切的成因联系。     

华北克拉通胶莱盆地马山地区早白垩世粗面英安岩岩石成因

伸展盆地、拉张断层以及伴生火山岩是华北克拉通中生代岩石圈减薄的地质响应，前两者通常源于中上地壳伸展活动，而后者则可能来自下地壳甚至地幔部分熔融。因此火山岩能够提供来自深部地壳、地幔及壳-幔相互作用的信息。胶莱盆地马山粗面英安岩成因及其与华北克拉通岩石圈减薄的关系仍存在争议。本文对马山粗面英安岩开展岩石学、全岩地球化学、LA-ICP-MS锆石U-Pb年代学以及Lu-Hf同位素研究，查明其SiO₂含量为65.73%~66.08%，K₂O含量为3.13%~4.03%，全碱含量为7.56%~8.15%，属于高钾钙碱性系列。锆石²⁰⁶Pb/²³⁸U年龄为119.3±1.6Ma，与胶莱盆地早白垩世伸展变形时间一致。ε_Hf（t）值为-24.6~-11.5，两阶段Hf模式年龄为2700~1200Ma，表明岩浆源区为改造的古老下地壳并混有富集地幔物质。岩石相对富集K和Sr等大离子亲石元素，亏损Nb、Ta和Ti等高场强元素，LREE/HREE比值较高，无明显的Eu负异常（δEu=0.94~1.02），表明岩浆可能源于下地壳的部分熔融，因此，马山粗面英安岩可能是富集地幔与部分熔融的下地壳相互混染的产物。研究认为早白垩世高角度俯冲的古太平洋板片大规模回撤，胶莱盆地快速伸展断陷伴随青山群火山岩喷发，随后演化形成张性火山盆地。     

柴北缘东段奥陶纪埃达克岩-富Nb玄武岩:对大陆深俯冲之前大洋俯冲及地壳增生的启示

在柴北缘东段识别出早古生代埃达克岩-富Nb玄武岩的火山岩组合。埃达克岩富Na₂O、贫K₂O，K₂O/Na₂O比值介于0.14~0.43之间；高Sr（614×10^-6~1043×10^-6），但亏损Y（3.26×10^-6~14.1×10^-6）和Yb（0.33×10^-6~1.46×10^-6），具有高的Sr/Y比值（44~282）；富集Sr、Ba等大离子亲石元素，亏损Nb、Ta、Ti等高场强元素及Cr、Ni、Co、V等相容元素。富Nb玄武岩富Na₂O、贫K₂O、高TiO₂，其Nb含量较高，介于16.9×10^-6~17.9×10^-6之间，具有高的Nb/Ta、Nb/U、（Nb/La）_N比值，同时富集高场强元素。埃达克岩锆石U-Pb定年得到453±4Ma和457±4Ma的结晶年龄。锆石ε_Hf（t）范围较大，介于3.40~13.23之间，对应的二阶段模式年龄t_DM2介于1059~566Ma之间，显示以新生物质为主的特征。综合研究表明柴北缘东段埃达克岩可能为岛弧环境下俯冲的南祁连大洋板片部分熔融的产物。板片来源的埃达克质熔体交代或与上覆地幔楔橄榄岩反应，导致被交代的地幔橄榄岩部分熔融而形成富Nb玄武质岩浆。柴北缘东段埃达克岩-富Nb玄武岩火山岩组合的厘定表明南祁连洋可能直到~455Ma之前并未完全闭合，同时表明俯冲大洋板片的部分熔融可能是柴北缘早古生代地壳增生的一种重要方式。     

华北克拉通基性岩墙成因模式：来自锆石U-Pb年龄、地球化学和Sr-Nd-Pb同位素证据

本研究共涉及来自太行山和郯庐断裂岩浆带的12组基性岩墙群,岩墙群具体出露于河北省、山西省、山东省和安徽省。研究中给出了新的锆石LA-ICP-MS U-Pb年龄、地球化学和Sr-Nd-Pb同位素基性岩墙测试数据。基性岩墙形成于128.1±1.2Ma与115.0±0.8Ma之间,且具有典型的辉绿结构。另外,基性岩墙富集轻稀土元素（LREE）、个别大离子亲石元素（如,Rb、Ba、Sr）、Pb和Th,亏损Nb、Ta和Ti,具有高的初始⁸⁷Sr/⁸⁶Sr比值（0.7056~0.7105）,负的ε_Nd（t）（-15.5~-12.4）、相对一致的初始Pb同位素比值（²⁰⁶Pb/²⁰⁴Pb=16.45~16.49、²⁰⁷Pb/²⁰⁴Pb=15.44~15.51、²⁰⁸Pb/²⁰⁴Pb=36.49~36.53）及较大的Nd模式年龄（t_DM2^Nd=1.82~2.69Ga）。研究结果表明,基性岩墙来自石榴石二辉橄榄岩地幔源区（类似EM1）一定程度的（1.0%~5.0%）部分熔融,岩浆侵位前经历了橄榄石、单斜辉石和角闪石的分离结晶作用,同时受到少量地壳混染的影响。目前,关于华北克拉通破坏和中生代岩浆作用的成因已有较多可能模式,本研究基性岩墙成因的新模式：古太平洋板块与华北克拉通的持续碰撞,导致华北克拉通岩石圈（地幔和地壳）加厚,并发生可能的榴辉岩化,并在一定时间发生拆沉作用。在新模式的制约下,导致了研究区中生代基性岩墙的产生和侵位。     

河南嵩县庙岭金矿区花岗斑岩锆石U-Pb年龄、岩石地球化学和Sr-Nd-Pb同位素特征

河南嵩县庙岭金矿区地处华北陆块南缘熊耳山-外方山地区,LA-ICP-MS锆石U-Pb定年结果表明,庙岭金矿区花岗斑岩的成岩年龄为157Ma左右。岩石地球化学数据显示岩石具有高硅,富钾、铝而贫钠,低铁、镁、钙的特征,SiO₂含量为75.06%～77.66%,全碱含量（Na₂O+K₂O）为7.05%～7.39%;稀土元素总量较低,ΣREE=25.74×10^-6～32.63×10^-6,轻重稀土元素分馏明显,LREE/HREE=6.74～9.53,Eu具有中等的负异常;微量元素富集Rb、K、Pb等大离子亲石元素和Th、U,亏损Nb、Ta、Ti等高场强元素和Ba、Sr。Pb同位素分析结果显示庙岭金矿区花岗斑岩的Pb主要来自于下地壳;全岩的（⁸⁷Sr/⁸⁶Sr）_i=0.706207～0.711774,εNd（t）值变化于-19.0～-17.8之间,t_DM2=2.39～2.49Ga。岩石地球化学和Sr-Nd-Pb同位素组成特征显示庙岭金矿区花岗斑岩的源区物质主要来自于古老下地壳,可能为太古宙太华群。     

甜水海地块寒武纪安山岩的地球化学和年代学研究:对西昆仑-喀喇昆仑造山带原特提斯洋演化的启示

甜水海地块作为西昆仑-喀喇昆仑造山带重要的组成部分，夹持于麻扎-康西瓦板块缝合带和洪山湖-乔尔天山板块缝合带之间，其构造属性的探讨对认知西昆仑地区早古生代地质演化具有重要的科学意义。笔者在甜水海地块中部麻扎地区通过野外填图新发现并厘定出一套火山岩-沉积岩组合，主要由安山岩、英安岩、流纹岩及其火山碎屑岩和少量沉积岩组成；与安山岩互层产出的英安岩和流纹岩锆石U-Pb年龄为519~513Ma，表明这套火山-沉积地层形成于中寒武世。该火山岩套的地球化学特征为：安山岩SiO₂含量为57.0%~67.2%，具有高MgO（1.91%~7.17%）含量和Mg^#值（39.1~65.3，平均值为55.0），较高Cr（31.0×10^-6~190×10^-6）和Ni（12.2×10^-6~121×10^-6）含量，低FeO^T/MgO比值（1.12~3.26），低Al₂O₃（13.7%~17.3%）和K₂O（1.12%~5.52%）含量的特征，属于低铁钙碱系列高镁安山岩-镁安山岩；英安岩较安山岩SiO₂含量高（63.8%~71.8%），具有相似的Al₂O₃（13.4%~15.4%）含量，低MgO（0.28%~1.19%）含量和Mg^#值（9.98~36.5，平均值为25.3），低Cr（11.5×10^-6~25.2×10^-6）和Ni（4.33×10^-6~11.8×10^-6）含量，高FeO^T/MgO比值（3.64~18.9）和K₂O（4.84%~9.27%）含量的特征，属于高钾钙碱性系列。安山岩和英安岩总体表现出右倾轻稀土富集分配模式，富集Rb、Ba、K、Th等大离子亲石元素，亏损Nb、Ta、Ti高场强元素，具有典型的岛弧岩浆岩特征。野外调查表明，安山岩与英安岩在空间上相邻，呈互层产出，且它们都出露于中寒武系地层中，暗示了二者在成因上紧密相联。岩石地球化学特征指示了安山岩和英安岩可能源于富集地幔楔不同比例的部分熔融作用，所产生的岩浆在上升过程中又遭受了不同比例的地壳混染。推测麻扎地区寒武纪火山岩形成于原特提斯洋向南俯冲消减机制下的岛弧构造环境，同时结合区域资料，认为在寒武纪甜水海地块存在两期岩浆作用，在早寒武系末期（~520Ma）原特提斯洋发生双向俯冲，甜水海地块北缘转化为活动大陆边缘。     

华北板块北缘中段早中二叠世的构造属性：来自花岗岩类锆石U-Pb年代学及地球化学的制约

内蒙古温都尔庙南-铁沙盖黑云角闪石英闪长岩和角闪黑云花岗闪长岩位于华北板块北缘中段晚古生代构造岩浆活动带中;锆石LA-ICP-MS U-Pb定年结果显示,其形成时代分别为271.8±2.4Ma,271.4±1.3Ma、268.7±1.3Ma。主量元素SiO₂含量61.42%~71.73%,K₂O含量3.10%~5.11%,K₂O/Na₂O值介于0.93~1.96之间,Mg^#值介于42.54~49.93之间,A/CNK为0.90~1.03;副矿物为锆石、磷灰石和磁铁矿,属亚碱性高钾钙碱性系列、I型花岗岩类;富集轻稀土(LREEs)、大离子亲石元素(LILEs,Cs、Rb、K、Ba、Th和U),亏损重稀土元素(HREEs)及高场强元素(HFSEs,Nb、Ta和Ti),弱Eu负异常(δEu=0.55~0.95),形成于活动大陆边缘弧环境,是上地壳部分熔融的产物。黑云角闪石英闪长岩和角闪黑云花岗闪长岩中发育大量暗色微粒包体(黑云闪长岩),包体可能是岩石圈地幔部分熔融的产物,相对于寄主岩石贫Si、K富Fe、Mg、Ca、Ti、大离子亲石元素(LILEs,Rb、Cs、Sr和U)和高场强元素(HFSEs,Nb、Ta、Zr、Hf)。本文花岗岩类的侵位反映了早中二叠世古亚洲洋俯冲于华北板块北缘之下及岩浆混合作用的岩浆事件。     

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。     

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.     

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。     

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.     

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.     

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″.     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.