班公湖—怒江构造带西段三叠纪—侏罗纪构造—沉积演化

班公湖－怒江构造带西段在大地构造位置上处于特提斯构造域东端，横跨班公湖－怒江断裂带。三叠纪－株罗纪期间，其构造－沉积演化经历了大陆初始裂谷（T）、原洋裂谷（J1）、残余弧后盆地（J2－J3）阶段。初始裂谷阶段的拉张是呈南断北超的半地堑式由东向西进行的，逐渐形成地堑式原洋裂谷盆地。中晚侏罗世，南部新特提斯洋壳开始北各俯冲,产生的区域挤压应力使原洋裂谷逐渐封闭，裂谷盆地的小洋壳表现出以南向俯冲为主的双向式腑冲，同时伴生区域热沉降，盆地具残余弧后盆地的性质。该阶段,羌南地区发育碳酸盐岩为主的稳定陆缘沉积，冈度斯－念青唐古拉板片北部则形成广泛南超的近源碎屑沉积。     

新疆东昆仑木孜塔格蛇绿混杂岩中发现富Nb玄武岩

富Nb 玄武岩以相对高的TiO2 含量、低的LILE/HFSE和LREE/HFSE比值以及(La/Nb)MN＜2为特征,是岛弧环境的典型产物。首次报道发现于新疆东昆仑木孜塔格蛇绿混杂岩中的富Nb玄武岩,并分析了它们的典型地球化学特征和构造环境,表明了它们形成在岛弧环境。     

河南省卢氏县桃花—石门金矿带地质特征及成矿规律

桃花－石门金矿带位于秦岭地槽区北秦岭纬向褶皱带的北端黑沟和瓦穴子断裂所夹持的前加里东褶皱带中。矿床类型为石英脉型，石英脉规模小，数量多，分布于瓦穴子断裂北侧。矿脉的产出受地层、构造控制、成矿与岩性、构造、岩浆活动，温度等关系密切。     

湘东北中生代基性岩脉岩石地球化学及构造意义

湘东北中生代发育以辉绿岩类和煌斑岩类为代表的基性岩脉,属陆内拉斑玄武岩系,部分煌斑岩属于碱性系列。岩石富集LREE,δEu负异常不明显,其形成主要受软流圈地幔部分熔融作用制约。煌斑岩类微量元素总体上具有洋岛玄武岩(OIB)岩浆源区特征,富集Nd、P、Cs而K、Rb、Sr、U、Th等富集程度不明显,Ta、Nb略有富集。辉绿岩类表现出Ta、Nb、Ti亏损,但LILE并不富集,反映地壳混染程度的增强。基性岩脉形成于陆内拉张带的构造环境,岩浆活动未受到中生代大洋板块俯冲的影响。基性岩脉在时、空及物质组成上与湘东南玄武质岩石基本一致,属于整个湘东南岩石圈拉张-减薄带的一部分。     

中国北方农牧交错带与非洲萨哈尔地带全新世环境变迁的比较研究

中国北方农牧交错带和非洲萨哈尔带均为处在季风尾闾带的干旱向半湿润气候过渡的地带。通过对比分析 ,发现两个地带自然地理环境及其全新世以来的环境演变等具有很大程度的相似性 ;自全新世以来 ,两个地带均出现过几乎同步的 8个千年尺度的冷暖、干湿旋回 ;在近百年的干湿变化方面都有 10～ 2 0a变化周期 ;在少雨期和多雨期的转变过程中非洲萨哈尔带较中国北方农牧交错带提前 5a以上。这一超前信息的存在 ,为中国北方农牧交错带的气候预测提供了一个重要的前兆因素。     

华北板块北缘活动带元古宙构造岩片

新的研究证实 ,华北板块北缘残存一条元古宙构造岩片堆集带 ,包括古元古代、中元古代、新元古代等多期构造岩片。并相伴有 180 0Ma±、140 0Ma±、10 0 0Ma±、6 5 0Ma±的花岗岩类的侵入活动和构造变质成矿等热事件的年代记录 ,并在华北板块北部金镶边带中保存了相一致的信息 ,揭示了它们是陆缘多期拼贴造山的产物。这为超大陆旋回 ,特别是元古宙两次超大陆的聚合与裂解及其构造演化过程的研究提供了良好的野外实验园地 ,并为元古宙、特别是古元古代大陆的增生及Rodinia超大陆在北半球的存在或构造响应提出新的课题。     

广西凭祥地区早二叠世的岩浆弧及其构造意义

广西凭祥地区有3种不同建造背景的二叠-三叠系，深水相的下二叠统呈一飞来峰推覆在台地型的石炭纪-早三叠世沉积和早-中三叠世浊积岩上，与前者共生的基性-超基性岩是古特提斯岩浆弧的记录，当时的被动大陆边缘在百色阳圩-田林八渡，说明洋壳向南西消减，早二叠世弧的原形成位置可能在越南境内，早-中三叠世的弧则已向北东迁移，在中越交界区形成图尔基式造山带。     

Ground deformation of the southern sector of the Aeolian islands volcanic arc from geodetic data

The deformation pattern and the dynamics of the southern sector of the Aeolian archipelago are investigated. A study on the ground deformation, measured over the last 20 years in the trilateration geodetic network between the islands of Vulcano and Lipari, has been conducted. Analysis of the relative displacements and the uniform strain tensor parameters, as well as the comparison between areal dilatation and the vertical variations deduced by precise levelling, allow distinguishing different phases associated both with the regional dynamics and the local volcanic context of the area. These phases, however, appear to be closely interrelated. The analysis of the deformation pattern allows to constrain the predominance of a roughly E–W trending extension and a N–S contraction at a regional scale. This regime is consistent with right-lateral movements along a NW–SE striking fault system.     

Geochronology of Gold Deposits and Its Implication for Metallogenesis in the Fengxian-Lixian Area, Qinling Orogenic Belt, China

Abstract: A series of super large‐scale and large‐scale Pb and Zn, and Au deposits are distributed in the Qinling orogenic belt, China. Gold deposits were generally ascribed to Carlin‐type originated from circular meteoric water. Visible and coarse‐grained gold (up to over 3mm in grain size) was recently identified in some gold deposits in the Fengxian‐Lixian area, Qinling. Au‐bearing quartz lodes related to magmatism were discovered in the Xiaogouli gold deposit. Two types of Au‐bearing quartz veins, i.e., NW‐trending quartz veins and NE‐trending quartz veins cutting strata are widely present in the Baguamiao gold deposit. Both are spatially associated with each other. The former is generally snake–like, S‐shape or zigzag, which was resulted from plastic deformation by ductile shearing, being generally cut by the latter. The latter is generally linear with widely developed bleaching alteration zones in its adjacent wall rocks, which symbolizes the superimposition of brittle deformation and filling and metasomatism of magmatic hydrothermal solution in ductile shear zones after uplifting of the shear zones near the surface. The NW‐trending quartz veins contain Au of lower than 3ppm. The NE‐trending quartz veins contain Au of more than 3 ppm, so that NE‐trending quartz veins and the adjoining altered rocks are important ores. The NW‐trending Au–bearing quartz vein was dated as 210.61.26 to 232.581.59 Ma by ⁴⁰Ar–³⁹Ar method, i.e., late Indosinian epoch (Triassic). The NE‐trending Au–bearing quartz vein was dated as 131.910.89 to 197.451.13 Ma by ⁴⁰Ar–³⁹Ar method, i.e., Yanshanian epoch (Jurassic). The ⁴⁰Ar–³⁹Ar age of the NW‐trending Au–bearing quartz veins represents the age of the ductile shear formation. The isotope data of the NE‐trending quartz veins indicate that gold mineralization was closely related to Indosinian and Yanshanian granite intrusives not only in time and space, but also in origin.     

Three Alkali-Rich Intrusive Rock Belts Newly Discovered in the Mt. Kunlun-Mt. Altun Region, Xinjiang, China

The newly discovered three alkali-rich intrusive rock belts in the Mt. Kunlun Mt.Altun region of southern Xinjiang are the Lapeiquan-Yitunbulak alkali-rich intrusive rock belt,the Gez-Taxkorgan alkali-rich intrusive rock belt and the Beilisai-Abulash alkali-rich intrusive rock belt. The former two belts were formed during the Yanshanian period, and the third one was formed during the Himalayan period, which is the youngest alkali-rich intrusive rock belt in China. The discovery of the alkali-rich intrusive rock belts is of great significance in shedding light on the history of tectono-magmatic activities in this region.