韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例，通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比，确定等比线斜率，探讨韧性变形对岩石体积和成分变异的影响。计算结果表明，在糜棱岩化过程中，糜棱岩化花岗岩体积亏损21％，花岗质糜棱岩体积亏损31％。质量平衡计算结果和等比线图表明，韧；陛剪切作用导致SiO2，流失量最大，A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失，显示出较强的活动性，MnO、P2O5、Sc位于等比线上或附近，表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的，不活动组分的变异是体．积亏损造成的。     

柴达木盆地北缘早古生代碰撞造山系统

柴达木盆地北缘在早古生代形成了一条碰撞造山带，该造山带结构保存较完整，可分辨出深俯冲板片、火山岛弧带、蛇绿杂岩带、岛弧深成岩带等组成单元。其中，俯冲板块主要由中元古代鱼卡河岩群和中新元古代花岗片麻岩构成，在寒武纪末-奥陶纪可能全部或部分俯冲到岩石圈深部，发生了高压-超高压变质作用。火山岛弧主要由中基性火山岩、细碎屑岩等组成，成岩时代为晚寒武世-奥陶纪。蛇绿杂岩带由超镁铁质岩、辉长岩、玄武岩和少量硅质岩组成，形成于弧后扩张脊构造背景，成岩时代为寒武纪-奥陶纪。岛弧深成岩成分变化较大，由闪长岩变化到花岗岩，成岩时代为奥陶纪。而造山带北侧的欧龙布鲁克微陆块则具有双层结构，由德令哈杂岩和达肯大坂岩群构成基底，盖层为全吉群。     

青藏高原北羌塘半岛湖新生代粗面玄武岩橄榄石电子探针和激光探针分析

利用电子探针和激光探针剥蚀系统（LA-ICP-MS），对北羌塘新第三纪粗面玄武岩中的橄榄石主元素和微量、稀土元素进行了系统分析。结果表明，本区橄榄石Fo平均为88，属贵橄榄石种属。相对富集Ni、Co和重稀土，而强烈亏损轻稀土及Rb、Sr、Ba、Zr等大离子亲石元素。其稀土元素配分型配分型式与粗面玄武岩全岩稀土配分型式呈互补状态。     

华北陆块北缘西段中元古代与裂谷作用有关的铁、稀土、多金属矿床特征及成因

华北陆块北缘西段狼山—白云鄂博裂谷系中元古代形成的大型多金属矿床 ,是我国重要的铁、稀土、铜、铅、锌矿产地。矿床为产于沉积岩中热水沉积型多金属矿床。其形成受地层、构造控制 ,与裂谷作用有着密切的关系。裂谷系内外分支的地质环境及矿床矿种不同 ,导致矿床特征及成因具有一定差异。白云鄂博铁、稀土矿床为钾、钠、磷等含量较高的热水沉积型 ,霍各乞铜、铅、锌多金属矿床为与中基性火山岩有关的过渡热水沉积型 ,东升庙和甲生盘等铅、锌多金属矿床为热水沉积型。文中将对上述矿床分别进行论述。     

宁夏回族自治区土地沙漠化研究

该文分析土地沙漠化的形成是不合理的人类经济活动和恶劣的自然环境相互作用的结果。人类不仅是促进土地沙漠化发生发展的主要动因 ,同时也是沙漠化的受害者。只有采取合理的符合生态原则的治理活动 ,诸如一系列政策保护与技术防治相结合的措施 ,才能实现土地沙漠化逆转     

Present land use and cover patterns and their development potential in North Ningxia

With the objectives to acquire the fundamental data of the territorial resource, understand the impacts of human activities on the land use and cover patterns and evaluate the potential of the future exploitation, an intensive land cover classification with an accuracy of 93% has been completed for North Ningxia by remote sensing technique based on the adoption of a combination method composed of texture training, maximum likelihood classification and post-processing such as re-allocation and aggregation. This classification result was incorporated with the contemporaneous socio-economic and meteorological data for cross-sectional regression modelling to reveal the spatial determinants of the land cover patterns and understand the human-environmental relationships. A tentative evaluation on the potential of soil exploitation in the near future was carried out in combination with our land use and cover change detection results aiming at supplying some useful references for the central and local governments in their sustainable land use planning.     

藏北申扎一带下奥陶统拉塞组的发现及意义

吉林省地质调查院在进行1：25万《多巴区幅》区域地质调查时，在西藏北部申扎县一带首次发现一套富含北方珠角石动物群Armenoceras sp.,Wutinoceras sp.,Discoactinoceras multiplerum Kobayashi,Adaomsoceras sp.,Sactoceras sp.,Ordosoceras sp.,Oncoceratida,Ormoceratidae,? Curtoceras sp.,Ormoceras sp.,Liulinoceras sp.,Deiroceras cf.globsom Zholt et Shen及腕足类、牙形刺、苔藓虫、海百合茎等化石的海相碳酸盐岩地层。该地层的岩石组合特征及生物群面貌与区内已知的地层存在明显的差异，其地质时代也明显早于区内已知的其它古生代地层，故建立下奥陶统拉塞组。     

青海北祁连区中三叠世孢粉的发现及其意义

祁连县俄博乡土圈沟、大擦汗沟、柯柯里等剖面的粉砂岩、砂质页岩、泥质页岩岩层之中，首次发现丰富的孢粉化石，计39属74种(其中包括1新种)，疑源类8属9种。推出Verrucosisporites(8．6％)-Triadispora(2％)-Trematosphaeridium(7．2％)的孢粉组合。该孢粉组合面貌应归于中三叠世Anisian期。它的发现为该套地层的进一步研究与合理归属提供了最新成果。     

An Mw based earthquake Catalogue for central, northern and northwestern Europe using a hierarchy of magnitude conversions

Data from 25 local catalogues and 30special studies of earthquakes in central,northern and northwestern Europe have beenincorporated into a Databank. The dataprocessing includes discriminating eventtypes, eliminating fake events and dupletsand converting different magnitudes andintensities to M_w if this is not givenby the original source. The magnitudeconversion is a key task of the study andimplies establishment of regressionequations where no local relations exist.The Catalogue contains tectonic events fromthe Databank within the area44°N–72°N,25°W–32°E and the time period1300–1993. The lower magnitude level forthe Catalogue entries is setat M_w == 3.50. The area covered by thedifferent catalogues are associated withpolygons. Within each polygon only datafrom one or a small number of the localcatalogues, supplemented by data fromspecial studies, enter the Catalogue. Ifthere are two or more such catalogues orstudies providing a solution for an event,a priority algorithm selects one entry forthe Catalogue. Then M_w is calculatedfrom one of the magnitude types, or frommacroseismic data, given by the selectedentry according to another priority scheme.The origin time, location, M_w magnitude and reference are specified for eachentry of the Catalogue. So is theepicentral intensity, I₀, if providedby the original source. Following thesecriteria, a total of about 5,000earthquakes constitute the Catalogue.Although originally derived for the purposeof seismic hazard calculation within GSHAP,the Catalogue provides a data base for manytypes of seismicity and seismic hazardstudies.     

东天山北麓2000多年以来的森林线与环境变化

依据吉木萨尔县泉子街乡桦树窝子和小西沟两个剖面进行高时间分辨率的孢粉分析，结合剖面岩性特征分析、历史文献记录和碳屑鉴定，揭示了天山北麓最近2000多年以来的环境变化。2000aB．P．以前，该地植被为荒漠草原；2000-1300aB．P．(50a B．C．-650A．D．)，植被为草原植被，其中1750—1400aB．P．(200—550A．D．)，植被为有少量森林的草原植被，当时气候状况较今凉湿，适宜云杉生长，使得云杉林带下移，幅度可达250m左右。当时的年均气温较今低1℃而降水量较高，是新疆历史上一个相对冷湿的环境；约1300—450a B．P．(650—1500A．D．)，植被为荒漠草原；4．50aB．P．年以来，植被为荒漠草原—草原。