煤层滑覆顶板水文地质工程地质特征

豫西诸煤田主采煤层二₁煤层顶板非原生顶板,而是滑动构造的滑覆体。其由下而上可分为断层带、破碎带、裂隙带。它的水文地质条件简单,但工程地质条件复杂。岩石破碎,力学强度指标较低,回采中顶板不易管理。按其稳定性可分为较稳定的、不稳定的和极不稳定的三类,且以后两类为主,对这些顶板管理的基本措施是:短工作面,控顶距,快速推进,及时放顶,正常循环,不放大炮。     

川滇菱形块体东边界地壳形变研究

根据地质资料和GPS资料。在断层分布密集的地区用模拟断层的位错替代多断层位错,建立了川滇菱形块体东边界的非震位错模型。利用GPS区域网资料．采用改进的蒙特卡罗法和遗传算法,联合反演了川滇菱形块体东边界的活动特性．得到如下认识：1）小江断裂是高应变积累闭锁区,鲜水河断裂次之,安宁河和则木河断裂应变积累程度最低。2）2001～2004年与1999～2001年相比．鲜水河北西段应变积累即锁定程度没有明显变化。南东段略有加强;安宁河略微减弱;则木河没有明显的变化;小江断裂各段的锁定程度均有显著的增强。3）各断裂的运动特点在空间上呈现出分段性。4）边界带的变形主要集中在川滇菱形块体一侧。     

Spatial and temporal variation of vegetation phenology and its response to climate changes in Qaidam Basin from 2000 to 2015

Based on TIMESAT 3.2 platform, MODIS NDVI data (2000–2015) of Qaidam Basin are fitted, and three main phenological parameters are extracted with the method of dynamic threshold, including the start of growth season (SGS), the end of growth season (EGS) and the length of growth season (LGS). The spatial and temporal variation of vegetation phenology and its response to climate changes are analyzed respectively. The conclusions are as follows: (1) SGS is mainly delayed as a whole. Areas delayed are more than the advanced in EGS, and EGS is a little delayed as a whole. LGS is generally shortened. (2) With the altitude rising, SGS is delayed, EGS is advanced, and LGS is shortened and phenophase appears a big variation below 3000 m and above 5000 m. (3) From 2000 to 2015, the temperature appears a slight increase along with a big fluctuation, and the precipitation increases evidently. (4) Response of phenophase to precipitation is not obvious in the low elevation humid regions, where SGS arrives early and EGS delays; while, in the upper part of the mountain regions, SGS delays and EGS advances with temperature rising, SGS arrives early and EGS delays with precipitation increasing.     

异地碳酸盐岩块体与碳酸盐岩重力流沉积研究及展望

异地碳酸盐岩块体是指已固结或半固结的、经过一定距离搬运再沉积而产于正常沉积地层中规模 较大的碳酸盐岩块,它和碳酸盐岩重力流沉积均属于再沉积碳酸盐岩。文章分析了岩崩、岩屑崩坍、海底滑坡、 滑塌和碎屑流沉积的过程,讨论了异地碳酸盐岩块体的沉积机制;归纳了异地碳酸盐岩块体形成的主要地质背 景,认为异地碳酸盐岩块体可见于活动大陆边缘、被动大陆边缘、海山和前陆盆地等地质环境中;着重介绍了 异地碳酸盐岩块体和碳酸盐岩重力流沉积的研究进展,即线源式的碳酸盐岩裙沉积和点源式的碳酸盐岩海底扇 沉积;最后,阐释了滑来岩块、滑塌堆积和碎屑流沉积的区别与联系,总结了孤立碳酸盐岩块体的搬运沉积机 制,对比区分了碳酸盐岩裙沉积和碳酸盐岩海底扇的沉积特征,认为它们在斜坡环境、沉积物类型和沉积特征 等方面存在诸多不同。     

Acoustic experimental study of two types of rock from the Tibetan Plateau under the condition of freeze-thaw cycles

Under the condition of freeze-thaw cycles, two types of rocks (granite and andesite), used as slope protection for the Qinghai-Tibet Railway, were tested according to the special climatic conditions in the Tibetan Plateau, and their various damage processes in appearance were carefully observed. Observation results show that damage of andesite was more serious than that of granite. Using an acoustic instrument, ultrasonic velocity was tested. The changing trends of velocity with the number of freeze-thaw cycles were analyzed, and the freeze-thaw cycle damaging the physical and mechanical properties of rocks can be seen. According to the changing trends of ultrasonic velocity with the number of freeze-thaw cycles, mechanical parameters of rocks, such as dynamic elasticity modulus, Poisson’s ratio, and dynamic bulk modulus were analyzed. It is found that they all have declining trends as the number of freeze-thaw cycles increases, and in particular, when the cycle number reaches a certain extent, the Poisson’s ratio of rocks begins to become negative.     

遥感技术与其全球变化的研究

全球变化是当今地球科学研究的热点。具有全球观测能力的遥感技术成为全球变化研究的重要技术手段。本文对全球变化研究的主要内容进行了简要回顾 ,对遥感技术在全球变化研究当中的地位和作用进行了论述 ,并对一些新一代的传感器作了简要介绍 ,同时对我国遥感工作者在全球变化方面的一些工作作了介绍。     

S-A多重分形法在地球化学异常圈定中的对比应用—以甘肃文康地区为例

通过对甘肃省陇南文康地区的地质背景分析,采用区域1:5万水系沉积物测量的17种常量元素含量数据,分别运用传统统计学方法、S-A（能谱密度-累计面积）多重分形滤波法,确定成矿元素（以Au为例）异常下限值,圈定化探异常。结果表明,与传统方法相比,S-A多重分形法所圈定的异常面积小、数量多,传统统计法圈定的面积较大;两种方法圈定的异常展布方向基本一致,与研究区内已知的矿点吻合度高。本次研究认为S-A多重分形法所圈定的异常基本位于传统方法所圈定异常的内带之中,重点突出,与矿床空间位置对应关系较好,便于野外开展工作。同时在传统异常周边提取了部分低背景区的弱异常,这些弱异常可作为下一步找矿工作的新靶区。     

郯庐断裂带南段早白垩世镁铁质岩墙成因及其地质意义

地壳再循环物质交代岩石圈地幔形成不均质的地幔源区,其衍生的镁铁质岩浆岩为揭示地幔演化及壳—幔相互作用提供了重要信息。本文对郯庐断裂带内张八岭隆起南段肥东地区镁铁质岩中的锆石进行LA‑ICP‑MS定年,获得年龄集中在127~122 Ma。镁铁质岩样品中SiO₂含量为51.33%~54.01%,Mg^#值为52.6~70.0,并具有富钠、富碱(σ = 2.46~4.22)的特征,属于亚碱性和高钾钙碱性系列。镁铁质岩样品均富集大离子亲石元素(LILEs,如Ba、Pb、K),相对亏损高场强元素(HFSEs,包括Nb、Ta、Ti等),表现为弧型地球化学特征。锆石Hf‑O同位素研究获得极负的ε_Hf(t)值(-23.4~-21.2)和略高的δ¹⁸O值(5.49‰~6.01‰),与新元古代斜长角闪岩同位素组成显示出一致的演化趋势和相似的分布特征。因此,早白垩世镁铁质岩墙富集的同位素特征主要继承于新元古代(~800 Ma)岩石圈地幔;在郯庐断裂带伸展背景下,由古老岩石圈地幔发生减压熔融形成。

     

Timing of mineralization at the Shihu gold deposit in the middle segment of the Taihang Mountain,China

The Shihu gold deposit, located in the middle-south section of the core of the Fuping mantle branch structure, is hosted in the Archean Fuping Group and adjacent to the quartz diorite porphyrite. The gold deposit is the only large gold deposit with reserves of more than 30 tons gold discovered in western Hebei Province so far. In order to constrain the timing of mineralization of this ore deposit, this paper focuses on the isotopic dating of zircon and pyrite. Zircons in gold-bearing quartz veins are magmatic in origin and no hydrothermal zircon has been found in such quartz veins, indicating that zircons were derived from the wall rocks. U–Pb ages of zircons fall mainly in the two domains: 2492 ± 82 and 136 ± 4 Ma, respectively, indicative of the contribution of the Fuping-Group TTG gneiss and Yanshanian igneous rocks, respectively. The Re–Os isotopic compositions of pyrites in the gold-bearing quartz veins yield an isochron age of 127 ± 31 Ma. Combined with other dating results, we suggest that the main metallogenic age of the Shihu gold deposit is 120–127 Ma.