西准噶尔白碱滩二辉橄榄岩中两种辉石的出溶结构及其地质意义

克拉玛依白碱滩尖晶石二辉橄榄岩主要由橄榄石、单斜辉石、斜方辉石和尖晶石组成,橄榄石和斜方辉石均发生程度不等的蛇纹石化.单斜辉石一般很新鲜.单斜辉石和斜方辉石均发育出溶结构,出溶条纹或者平直或者发生舒缓的弯曲变形（即便是在发生弯曲的情况下也是完全平行的）.透辉石-普通辉石出溶体一般呈针状（直径一般为1μm,长度＞150μm）,顽火辉石出溶条纹直径一般为1～3μm（长度＞300μm）.斜方辉石主晶属于顽火辉石-易变辉石,单斜辉石主晶为透辉石（成分很均一）.地质温度压力估算表明,白碱滩二辉橄榄岩中辉石出溶结构发生的温度为700℃～1000℃、压力为2.0～2.7GPa,它们代表辉石出溶结构形成的最低PT条件.白碱滩二辉橄榄岩至少经历了三个演化阶段：原始辉石与尖晶石和橄榄石平衡共生（阶段Ⅰ,＞94km）;随着地幔上隆,原始辉石结构不稳定,分解并形成出溶结构（阶段Ⅱ,700℃～1000℃）,斜方辉石开始分解的深度为94km,单斜辉石开始分解的深度为78km;之后,蛇绿岩经历的侵位事件导致辉石发生塑性变形（阶段Ⅲ）.蛇绿岩侵位之前,地幔岩曾发生了＞50km的隆升,而且,在隆升过程中地幔岩没有发生明显部分熔融（地幔岩因此没有经历明显的岩浆抽提过程）.     

云南宾川-永胜-丽江地区低钛玄武岩和苦橄岩的岩石成因与源区性质

云南宾川-永胜-丽江地区是峨眉山玄武岩厚度最大、喷发最早的地区，最主要的岩石类型是低钛和高钛玄武岩，并有少量摘要云南宾川-永胜-丽江地区是峨眉山玄武岩厚度最大、喷发最早的地区，最主要的岩石类型是低钛和高钛玄武岩，并有少量的苦橄质玄武岩、苦橄岩和麦美奇岩。大部分火山岩的岩石化学组成属于拉斑玄武岩系列，少数低钛玄武岩属碱性玄武岩系列。它们不同程度地富集大离子亲石元素和轻稀土元素，相对亏损重稀土元素，稀土元素分馏明显，显著亏损相容元素（Co，V，Cr，Ni）。陆壳物质对低钛玄武岩浆的混染程度明显大于对苦橄质岩浆的影响程度。而且混染作用对于Sr同位素和大离子亲石元素的影响程度明显大于对Nd同位素和稀土元素的影响程度。Nd和Sr同位素证明，混染物主要是下地壳变质岩，也有少量上部陆壳物质。未受混染的样品具有适度亏损的Nd、Sr同位素组成。低钛玄武岩和苦橄岩类岩石是不同原生岩浆分异演化的产物。低钛玄武岩的原生岩浆是高镁拉斑玄武岩浆，原生苦橄质岩浆以EM-55为代表（MgO=16．56％）。此外，还有一种比EM-55更富镁的原生岩浆。高镁拉斑玄武岩浆分异过程中的主要分离结晶相／堆晶相是单斜辉石，并有少量斜长石。苦橄岩浆分异过程中的主要分离结晶相／堆晶相是橄榄石，并有少量单斜辉石。参考相关的实验岩石学成果，可以证明，地幔柱源区由两种岩石组成：一种是50％榴辉岩和50％橄榄岩反应形成的石榴石辉石岩，另一种是橄榄岩。在地幔柱绝热上升过程中，位于其轴部的石榴石辉石岩的熔融作用始于≈165km，主要的熔融作用发生于165～128km，持续到66km。熔融产物为苦橄岩浆。橄榄岩的部分熔融始于≈150km，持续到66km，熔融产物是比EM-55更富镁的岩浆。地幔柱头部的熔融作用始于≈100km，终止于66km，主要的熔融作用发生于尖晶石稳定域，熔融产物为低钛玄武岩浆。     

阿尔泰塔尔浪地区斜长角闪岩和辉长岩的形成时代、地球化学特征和构造意义

阿尔泰塔尔浪地区出露一些斜长角闪岩和辉长岩.其中,斜长角闪岩为基性岩浆岩变质的产物,SiO2含量为45.42%～52.96%,具有较高的Al2O3（13.14%～17.92%）、Fe2OT3（9.08%～16.88%）和TiO2（0.82%～3.23%）含量.斜长角闪岩样品稀土元素曲线比较平坦,轻重稀土元素分馏不明显（Ia/YbN=1.53～1.79）,无明显的Nb和Ta亏损.通过野外产状及地球化学特征分析,认为该斜长角闪岩形成于海山的构造环境.辉长岩SiO2（46.96%～49.86%）含量稍低,TiO2（0.38%～1.89%）变化较大,并富Al2O3（15.0%～20.81%）、CaO（10.13%～11.60%）,具有中等至较高MgO含量（7.3%～8.3%）和相对较低的钾含量（K2O=0.34%～1.03%）,属亚碱性岩石系列（Na2O＞K2O）.辉长岩呈现两种稀土元素组成特征.一种轻重稀土分馏不明显,配分曲线比较平坦（La/YbN=1.10～1.67）,具有轻微的Eu正异常（δEu=1.03～1.10）;另一种轻重稀土元素分馏较明显（La/YbN=5.97～6.39）并具有正的Eu异常（δEu=1.31-1.44）,反映其形成过程中可能受到斜长石堆晶的影响.在微量元素蛛网图上,辉长岩具有明显的Ti、Nb和Ta负异常和Pb、Sr正异常,反映出明显的消减带岩浆特征.角闪石的40Ar-39Ar测年结果显示,辉长岩样品的坪年龄为266.9±6.1Ma,且年龄坪谱显示在其形成之后没有受到后期热事件的明显干扰,基本上反映了辉长岩的形成年龄.斜长角闪岩的40Ar-39Ar结果呈现出似马鞍型坪谱,其中最小的年龄坪（297.3±6.1Ma）可能反映了最近一期的变质事件,而且明显早于辉长岩的侵入.斜长角闪岩和辉长岩不同的形成时代和地球化学组成表明二者可能代表了两期不同的基性岩浆活动.斜长角闪岩所具有的板内和消减带的复合特征表明其原岩可能是洋壳在俯冲消减过程中增生的海山残片,而辉长岩所具有消减带特征显示在二叠纪时期阿尔泰地区仍存在受俯冲作用影响的地幔源区.阿尔泰二叠纪岩浆活动无论在岩浆属性还是规模上都与泥盆和石炭纪的岩浆活动存在巨大差异,表明这两个时期的构造背景存在较大不同,可能反映阿尔泰正处于某种构造转换机制的控制之下.     

闽东南基性岩脉成因及动力学背景研究：Sr-Nd同位素、元素地球化学

闽东南的海边斜闪煌斑岩脉和赤湖辉长岩脉分别形成于晚白垩世和古新世,为高钾钙碱性和钙碱性系列岩石,具有高Al、Na2O＞K2O的特征;岩浆演化过程中可能经历了以橄榄石、单斜辉石为主的结晶分异作用.海边和赤湖基性岩脉具有相对富集大离子亲石元素和轻稀土元素,亏损高强场元素特征,不相容元素蛛网图显示出大陆边缘弧的地球化学特征,以Nb、Ta、Ti负异常为特征;海边和赤湖明显富集轻稀土元素,（La/Yb）N分别为5.0～10.9和11.2～12.0.具有高Sr同位素初始值和低εNd（t）值,海边的（^87Sr/^86Sr）i：0.70577～0.707574,εNd（t）：-8.1～-1.8,赤湖的（^87Sr/^86Sr）i：0.70547～0.70552,εNd（t）：-0.2～0.6.根据Sr、Nd同位素、微量元素研究及野外地质观察,本区基性岩脉的岩浆在上升侵位过程中未发生地壳物质混染.通过Sr、Nd同位素和微量元素等研究,认为地幔源区的演化与古太平洋板块俯冲密切相关,俯冲流体交代地幔楔、消减洋壳携带的海洋与陆源沉积物参与地幔源区的混合,形成本区基性岩脉的富集地幔源区,大离子亲石元素和轻稀土元素特别富集是俯冲流体与沉积物共同参与源区演化的结果.海边和赤湖基性岩脉形成的构造背景属于活动大陆边缘弧,构造性质应为活动陆缘拉张带（或裂谷带）.晚白垩世和古新世,闽东南发生了地壳拉张事件,与中国东南部晚白垩世以来的地壳拉张期次是一致.     

青海省布青山早古生代末期埃达克岩的发现及其构造意义

在青藏高原北部阿尼玛卿蛇绿岩带布青山段首次发现了埃达克岩,它们多呈不规则岩脉状侵入于布青山地区北部早古生代蛇绿混杂岩中.其岩性为花岗-英云闪长岩,主矿物有斜长石、石英、黑云母、角闪石、少量钾长石和辉石;副矿物有榍石、磷灰石、锆石和磁铁矿等.属钙碱系列,具典型（Ⅰ类、O型、HSA）埃达克岩的地球化学特征,表现为：高SiO：（63.65%～71.59%）,高Al2O3（14.81%～16.11%）,高Na2O（4.68%～5.33%）和Na2O/K2O（1.48～3.08,平均2.39）,高Sr（444.08×10^-6～560.41×10^-6）和Sr/Y（50.8～105.3）,HREE强烈亏损,低Yb（0.38×10^-6～0.74×10^-6）,高La/Yb（44.93～90.97）,弱负Eu异常（δEu=0.74～0.90）,富集大离子亲石元素（LILE）,亏损高场强元素（HFSE）,Ba、Pb正异常而Nb、P负异常.获得布青山埃达克岩的锆石TIMS U-Pb年龄为402±24Ma.布青山埃达克岩熔体来自俯冲的昆祁秦洋壳（含海洋沉积物）在石榴石角闪岩相条件下部分熔融,主要残留相为石榴石（±角闪石）.布青山埃达克岩的发现指示早古生代末期洋壳（昆祁秦多岛洋的一部分）俯冲作用的存在,俯冲方向朝北（现在方位）,此前,俯冲带发生长时间的向洋迁移,早古生代末期俯冲带已后退到阿尼玛卿蛇绿混杂岩带以南;暗示典型埃达克岩也可以形成于洋壳俯冲晚期;提示阿尼玛卿蛇绿岩带可能有与典型埃达克岩有关的Au、Ag、Cu、Mo等热液和斑岩矿床.     

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～2.5 Ga）的继承锆石具有正的εHf（t）值（＋8～＋1）,Hf同位素模式年龄集中在2.6～2.8 Ga,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177 Ma和132～126 Ma,εHf（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εHf（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εHf（t）为-16.部分样品锆石εHf（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.     

月球探测的进展与我国的月球探测

月球探测是我国航天活动发展的必然选择，将成为我国航天事业的第 三个里程碑，自20世纪60—70年代的第一次月球探测高潮后，迎来了“重返月球”的又一次 月球探 测热潮，以开发利用月球上丰富的核聚变燃料氦3、矿产和空间环境资源等为最终目标。 我国已经具备了进行月球探测的技术能力，首期工程的科学目标包括获取月球表面三维影像\\r 、分析月球表面有用元素含量和物质类型的分布特点、探测月壤厚度和探测地月空间环境 。     

Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool

Chang’E-4 landed in the South Pole-Aitken (SPA) basin, providing a unique chance to probe the composition of the lunar interior. Its landing site is located on ejecta strips in Von Kármán crater that possibly originate from the neighboring Finsen crater. A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations. In situ spectra of the regolith have peak band positions at 1 and 2 μm, similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper, which confirms that the regolith''s composition of the landing area is mostly similar to that of Finsen ejecta. The rock spectrum shows similar band peak positions, but stronger absorptions, suggesting relatively fresh exposure. The rock may consist of 38.1 ± 5.4% low-Ca pyroxene, 13.9 ± 5.1% olivine and 48.0 ± 3.1% plagioclase, referred to as olivine-norite. The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle, but representative of the lunar lower crust. Alternatively, the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials. This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool, indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model [Icarus 2012; 220: 730–43].     

Isotopic evidence for volatile replenishment of the Moon during the Late Accretion

The traditional view of a dry, volatile-poor Moon has been challenged by the identification of water and other volatiles in lunar samples, but the volatile budget delivery time(s), source(s) and temporal evolution remain poorly constrained. Here we show that hydrogen and chlorine isotopic ratios in lunar apatite changed significantly during the Late Accretion (LA, 4.1–3.8 billion years ago). During this period, deuterium/hydrogen ratios in the Moon changed from initial carbonaceous-chondrite-like values to values consistent with an influx of ordinary-chondrite-like material and pre-LA elevated δ³⁷Cl values drop towards lower chondrite-like values. Inferred pre-LA lunar interior water contents are significantly lower than pristine values suggesting degassing, followed by an increase during the LA. These trends are consistent with dynamic models of solar-system evolution, suggesting that the Moon''s (and Earth''s) initial volatiles were replenished ∼0.5 Ga after their formation, with their final budgets reflecting a mixture of sources and delivery times.     

绕月探测工程科学应用研究进展

我国月球探测工程分为“绕、落、回”三期实施。其中一期即绕月探测工程,其主要科学探测任务是对月球开展全球性、整体性和综合性的科学探测．包括以下4项科学目标：获取月球表面三维立体影像;分析月球表面元素含量和物质类型的分布特点;探测月壤特性;探测地月空间环境。在这4个科学目标中以全月球数字地图和三维立体影像图的获取为重点目标,结合物质成分探测、月壤特性探测和空间环境探测的成果,既与国际月球探测的发展趋势接轨,又有自己的创新特色。本文将主要介绍中科院在绕月探测工程中主要获得的科学研究成果。     

深空探测科技制高点上的新焦点：月球水资源

深空探测已经成为科技竞争的制高点。中国探月工程用20年的时间圆满完成“绕、落、回”并升级形成“勘、建、用”的新构想;同时,世界各国的月球探测发展已呈现出常态化和商业化的趋向。月球水资源的探测研究利用引发了各国和航天机构之间的广泛兴趣和激烈竞赛,成为科技制高点上的新焦点。月球水能够帮助揭示地月系统乃至太阳系形成演化的关键过程,是行星科学研究的前沿和学科建设的重要着力点;月球水资源的开发能够为未来的深空探测任务提供燃料和保障人类在月球上长期生存,是各国各机构扩展深化国际合作、共同利用地外资源造福人类的必然选择。文章结合月球水资源的探测研究现状和未来发展趋势,分析我国深空探测工程和行星科学学科发展的机遇与挑战,立足我国国情提出抢占科技制高点的对策与建议。     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.