新疆清水泉一带成矿地质特征及金铜矿找矿前景

清水泉一带位于新疆东准噶尔卡拉麦里成矿带西段,近年来,新发现铜矿床1处,铜矿点2处,金矿(化)脉6条,显示出良好的成矿潜力。在前人研究基础上,系统总结清水泉一带成矿地质背景,分析清水泉一带物化探和遥感异常特征。推断清水泉一带分布的主要地层与带内发现的金铜矿床赋矿地层一致;物探特征显示清水泉一带重力梯度值与深大断裂大体吻合;化探资料显示多处金铜矿的异常与带内金铜矿化带分布吻合;遥感资料异常提取结果与化探、构造特征在空间上的展布基本一致。在此基础上分析清水泉一带成矿地质特征,总结找矿模型,以期为资源潜力评价工作提供借鉴和参考。     

西藏许如错地区洁居纳卓组碎屑锆石U-Pb年龄及其地质意义

在西藏许如错地区新识别出的洁居纳卓组为一套固结—半固结的粗碎屑岩建造。为探讨该地层的沉积时代和沉积物源,对1个砂岩样品进行了碎屑锆石U-Pb年代学分析。获得了4组有效年龄:10.1~17.2Ma、41.7~72.2 Ma、77.9~87.8Ma、463~1610Ma。结合岩石组合特征、ESR测试结果和区域年龄资料,认为洁居纳卓组可能形成于上新世。物源分析结果显示,许如错以南的查孜及附近地区的林子宗群、布嘎寺组火山岩是洁居纳卓组沉积物质的主要来源,古新世—中新世的侵入岩和晚古生代地层也为其提供了少量的沉积物质。洁居纳卓组发育于许如错南北向地堑盆地之内,是上新世高原隆升在冈底斯地区的沉积响应,是青藏高原局部构造差异隆升的结果。     

黔南独山上泥盆统层序-海平面变化和成岩层序地层研究

贵州独山的上泥盆统由碳酸盐缓坡和碳酸盐台地两种沉积类型组成,包括13种沉积相和25种微相类型.它们构筑了6个层序,其中3个Ⅰ型层序和3个Ⅱ型层序.与6个层序对应的6个三级海平面升降旋回的速度、幅度和频率显示了不同的特征,第1和第2个旋回呈高幅、低频速进和高频缓退特征.第3个旋回为高幅、高频速进和高频缓退.第4个旋回为低幅、高频的中速进-退特征.第5、6个旋回具中、高幅高频缓进和低频速退特征.本文最后对不同沉积体系域和两种层序界面的成岩特征进行了探讨.     

Sedimentary characteristics of the Jurassic Zhiluo Formation and uranium deposits in Zhiluo-Diantou area,southern Ordos Basin

Diantou uranium deposits and multiple uranium mineralization sites have been discovered in the sandstones in the lower member of the Jurassic Zhiluo Formation in the southern Ordos Basin. However, the study on the sedimentary facies of the Zhiluo Formation, which restricts the prospecting work of sandstone-type uranium deposits. Based on the outcrop measurements and drilling core cataloging, and combined with the geological drilling data of petroleum, coal, and nuclear industry, we have elaborated the sedimentary characteristics of the Zhiluo Formation in the Fuxian area. We have also combined uranium source, structure, post-alteration and other factors to explore the relationship between sedimentary faces and uranium metallogenic conditions in the study area. The study found that in the lower member of the Jurassic Zhiluo Formation, the thickness of the sand body is 30-65 m and sand ratio is 0.6-0.75. It is gravel and sandy braided river deposit. In the upper member of the Jurassic Zhiluo Formation, the thickness of the sand body is 10-38 m, and the sand ratio is 0.15-0.45 and is a meandering river deposit. The study area is located at the center of the lake basin and sedimentary facies is coastal shallow lacustrine in the upper member of the Jurassic Zhiluo Formation. Sedimentary environment, sedimentary facies, the intersection of braided river channels, sand body thickness, sediment particle size and mudstone interlayer play an important role in controlling uranium mineralization. The exploration of uranium deposits in the northern part of the deposit should focus on the intersection or bifurcation of the braided river channel in the lower part of the Zhiluo Formation. The charcoal- and pyrite-bearing sandstone of channel bar can be used as a prospecting indicator for uranium mineralization.     

华南泥盆纪海平面变化节律及圈层耦合关系

在加里东不整合面之上的华南纪盆系中,可识别出20个正层序和相对应的海平面变化旋回,其中下泥盆统9个,中泥盆统5.5个,上泥盆统5.5个。它们可归并为4个正层序组,最大海泛面分别位于sulcatus带(D_1~2),perbonus带(D_1~3),中、上varcus带(D_2~2)和gigas带(D_3~1)。对埃姆斯期和吉维期4个海平面变化的瞬间状态,进行了瞬时古地理再造。华南泥盆纪海平面变化节律可分为三类:自节律;全球性他节律、区域性他节律;耦合节律,它们分别发育于法门期;布拉格期、艾费尔期;洛赫科夫期、埃姆斯期、吉维期、弗拉斯期和法门期/弗拉斯期之交(F/F)事件期。处于相对干暖和宁静期的布拉格期和艾费尔期全球性他节律海平面变化的原因,难以用冰川和构造机制解释,可能与海洋盆地容积或地球体积的脉动膨缩有关。F/F事件期的耦合节律海平面变化是地内外因素、圈层协同行为和耦合效应的灵敏标志。     

东昆仑造山带东段下中三叠统研究进展

东昆仑造山带东段下中三叠统包括下三叠统洪水川群和中三叠统闹仓坚沟组.根据实体化石和遗迹化石的研究, 结合区域上的岩性对比, 将洪水川群划分为3个岩性单元, 即底部砂砾岩段、中部灰岩夹砂岩段和上部砂板岩段, 属于下三叠统印度阶和奥伦尼克阶.闹仓坚沟组包括闹一段砂砾岩和闹二段砂板岩, 从中三叠统早安尼锡期延续到中安尼锡期.砂岩的常量元素分析结果表明, 大部分砂岩为杂砂岩, 属于复理石盆地的浊积岩范畴; 砂岩稀土元素的特征值接近于活动大陆边缘和大陆岛弧元素的参数值.      

Population distribution and urbanization on both sides of the Hu Huanyong Line: Answering the Premier’s question

In late November 2014, while attending a science exhibition on human settlement at the National Museum, Premier Li Keqiang posed a question to society and scientists regarding the Hu Huanyong Line, which the media subsequently dubbed “the Premier’s question”. This increased awareness and interest in the Hu Huanyong Line and launched a lively debate which provoked a variety of views. In an attempt to address the Premier’s question, this paper firstly reviews the origins of the Hu Huanyong Line, named after the famous population geographer who proposed it in 1935 as part of a wider debate on domestic overpopulation. Using demographic data from China’s first, fifth and sixth censuses, as well as the ArcGIS platform, we analyze the size, proportion and density of populations in the areas southeast and northwest of the Hu Huanyong Line, showing that urbanization and migration have not changed the pattern of population distribution observed by Hu Huanyong. Based on this, we suggest that the pattern of a dense population southeast of the line and sparse population northwest of the line will not fundamentally change for a relatively long time, nor will the situation of urban agglomerations being mainly found in the southeastern region. We also argue that climate and other physical geographic conditions determine that the Hu Huanyong Line shall remain in place. We believe that the question posed by Premier Li Keqiang is solvable, and that with positive policy guidance and rational spatial organization, the northwestern region can achieve more modernization and better quality urbanization, while the same is true for the central region.     

雅鲁藏布植被类型及与侵蚀类型的关系

雅鲁藏布流域发育高山垫状植被、干旱河谷植被、沙洲植被、亚热带植被和高山冰川植被等多种类型的植被,与各种侵蚀类型相互克制又相互适应。通过2年的野外调查和采样分析研究植被分布规律和与各种侵蚀的相互关系。峡谷亚热带植被的物种多样性、覆盖度和植被厚度都很高,水力和风力侵蚀完全被克制,但是重力侵蚀和泥石流侵蚀发育。高山垫状植被由...     

青海东昆仑东段塔妥地区小庙岩组变质岩LA-ICP-MS锆石U-Pb年龄及其地质意义

东昆仑地区小庙岩组的形成时代长期存在争议,且缺少精确的年代学证据。以东昆仑东段塔妥地区小庙岩组变质碎屑岩为研究对象,采用LA-ICP-MS锆石U-Pb同位素定年方法,探讨其形成时代。结果显示,锆石具有较宽的年龄谱(1551~2624Ma),可划分为2624~2603Ma、2501~2290Ma、2196~2036Ma和1921~1551Ma年龄组,最后一组可进一步划分为1921~1690Ma和1641~1551Ma两个亚组。其中1921~1690Ma代表了物源区强烈的变质岩浆热事件,具有最强峰值特征(峰值年龄为1783Ma),而2501~2290Ma代表了源区一次变质事件,并有少量2196~2036Ma年龄记录,个别2600Ma的碎屑锆石暗示东昆仑地区存在新太古代的陆核。1641~1551Ma(加权平均年龄为1597Ma)代表了小庙岩组发生变质的时间,而物源区最晚变质年龄为1690Ma,从而确定小庙岩组形成于1690~1597Ma,属中元古代。对比碎屑锆石年龄频谱和东昆仑地区较老变质基底记录的构造-热事件信息,小庙岩组主要沉积物源可能来自于古元古界白沙河岩组,而东昆仑与华北在古元古代末—中元古代早期构造事件的对比揭示,在这一时期二者具有相似的构造演化特征。     

大别山苏家河地区榴辉岩和大理岩的地球化学研究

对大别山西段苏家河地区熊店和杨冲低温榴辉岩及胡家湾榴闪岩进行了详细的氢、氧和锶、钕同位素以及稀土元素和矿物化学分析。熊店榴辉岩和胡家湾榴闪岩的全岩δ＾１８Ｏ值较高（８．８‰￣１１．２‰）,而杨冲榴辉岩的全岩δ＾１８Ｏ值较低（４．３‰）,它们的全岩δＤ值为－５５‰￣７５‰。结合锶、钕同位素和稀土元素组成特征,推测苏家河榴辉岩（榴闪岩）的原岩可能为岛弧玄武岩,变质前曾与海水在不同温度下进行过氢、氧同位