沉积环境与影响矿井设计的顶板稳定性因素的探讨          下载免费PDF全文

葛宝勋  刘祖发 《沉积与特提斯地质》1990,10(4):35-40

煤层顶板的稳定性不仅是影响矿井开采技术条件中的一项主要内容,而且也是进行矿井设计与选择合理支护方法的基础。众所周知,由于顶板条件造成的冒顶事故是生产矿井中最常见、最容易发生的事故。据国内外有关事故的统计资料表明,因冒顶造成的井下伤亡事故常占各类事故之首。为了分析和预测煤层顶板的稳定性,重塑顶板形成时的沉积环境是一种有效的方法。在影响煤层顶板稳定性的诸因素中,顶板岩石的性质常起着主导作  相似文献   

镇江大力山中,下三叠统沉积特征及环境分析   总被引：2，自引：0，他引：2  

朱洪发  陈亚中 《矿物岩石》1990,10(3):58-66

镇江大力山中、下三叠统青龙组2段和3段发育的瘤体灰岩属盆地边缘斜坡环境,杂乱瘤体灰岩横向相变为盆地边缘斜坡滑塌重力流成因(深水)的泥晶砾屑灰岩;蠕粒灰岩则为台地前缘斜坡的浅水沉积环境,与浅水重力流的砾屑泥晶灰岩共生.  相似文献   

A TECHNIQUE TO RECOGNIZE AND ESTIMATE SEVERE STORM BY USING SINGLE DOPPLER WEATHER RADAR   总被引：1，自引：0，他引：1       下载免费PDF全文

Zhang Pengfei  Ge Runsheng  Liu Enqing 《Acta Meteorologica Sinica》1991,5(3):274-284

Using single Doppler weather radar echo information, this paper presents a technique for recognizing two-di-mensional flow field structure of the severe storm and estimating the divergence, the vorticity, and the intensityof wind shear line, and gives some examples.  相似文献   

新疆昆仑山乌斯腾塔格—喀拉米兰晚三叠世植物化石的首次发现   总被引：1，自引：0，他引：1  

李洁  甄保生  孙革 《新疆地质》1991,(1)

新疆昆仑山乌斯腾塔格—喀拉米兰地区晚三叠世植物群Drepanozamites nilssoni-Otozamites indosinensis-Thinnfeldia nordenskioldi-Glossophyllum sheisense等的首次发现,揭示了该地区中国南方型晚三叠世植物群的面貌.对研究新疆南部地区晚三叠世地层、中国地层区划及晚三叠世植物群地理分区、以及板块构造等均具有重要意义.  相似文献   

华南二叠-三叠系的成因地层序列及古特提斯海重建   总被引：10，自引：0，他引：10       下载免费PDF全文

夏文臣  葛立刚 《地球科学》1994,19(5):663-675

总结各类沉积盆地的沉积和地层格架，厘定出６类等时性地层界面和５个级别的成因地层单位，在分析地层界面性质和各类成因地层单位沉积构成的基础上，将华南二叠－三叠系划分为７个沉积幕、３个构造沉积幕和２个沉积盆地域、恢复了华南板块二叠－三叠纪的演化过程，论述了板块构造运动，海平面升降和源区侵蚀作用对各级成因地层单位的控制意义，证明了华南的古特提斯海经历了陆表海和伸展裂谷海两个演化阶段。  相似文献   

带电α卡找矿法及其特点     

华荣洲  葛静霞 《铀矿地质》1985,(2)

带电α卡找矿法是铀矿普查中继α卡找矿法后发展起来的一种测氡找矿法。文章介绍了带电α卡找矿法原理及其在铀矿床上的试验结果,带电α卡找矿法比自然α卡找矿法具有更高的测氡灵敏度,并且卡上α强度与杯中氡浓度有良好的线性关系。自从J·W·卡特等人提出用α卡法找铀矿后,近年来国内外均在进行这一方面的试验或用于找铀矿。我们根据氡的短寿子体在初始态呈正离子,可以被电场加速漂移的特点,试验了“带电α卡”找铀矿的方法。“带电α卡”即是将α卡带电,形成一电场。由于电场的作用,使α卡比正常条件下能吸附更多的氡短寿子体,使α卡上的α强度相对增高,从而提高了α卡的测氡灵敏度。我们将一般条件下金属薄膜对氡短寿子体的吸附称为“自然吸附”(此时的α卡称为“自然α卡”或“α卡”以区别于带电α卡)。将电场作用下金属薄膜对氡短寿子体的吸附称为“电场吸附”。显然有电场吸附作用叠加时将比纯自然吸附作用强。自1981年以来,我们对带电α卡找矿法的原理,装置,野外找矿方法及其效果等力面进行了试验研究。用带电α卡法找铀矿时,α卡用镀铝聚脂薄膜制成,将α卡挂在塑料杯(容器)中,加上负300伏电压。然后将整个装置倒置在测点探坑中(见图1)。六小时后取出α卡,用辐射仪测量卡上α强度,则卡上α强度将与测点的氡浓度有关。  相似文献   

The Chemical Composition of Global Subducting Sediments and Its Geological Significance     

Renjie Zhao  Quanshu Yan  Haitao Zhang  Yili Guan  Zhenmin Ge  Long Yuan  Shishuai Yan 《地球科学进展》1986,35(8):789-803

Subducted sediments play an important role in crust-mantle interaction and deep mantle processes, especially for subduction zone magmatism and mantle geochemistry. The current rate of Global Subducting Sediments (GLOSS) is 0.5~0.7 km³/a. The GLOSS are composed of terrigenous material(76 wt.%), calcium carbonate(7 wt.%), opal(10 wt.%) and mineral-bound H₂O⁺(7 wt.%). The chemical compositions of GLOSS are similar to those of upper continental crust which is mainly controlled by the terrigenous materials, and yet the materials formed by marine processes will dilute the terrigenous materials. The components of subducted sediments are different among trenches. In the accretionary margin, the components of subducted sediments are similar to those of the upper crust, while in the non-accretionary margin the components are terrigenous materials plus those produced by marine processes. During subduction, subducted sediments will released fluids, melt or supercritical fluid to affect island arc/back-arc basin magmatism by means of aqueous fluid or sediment melt. In addition, a part of subducted sediments, together with underlying altered oceanic crust/lithosphere, recycle into the mantle and contribute to the mantle heterogeneity. Geochemical tracers indicate that subducted sediments play variable contributions to the magmatic processes in different tectonic setting. Thus, subducted sediments play an important role in two relatively independent dynamics systems (plate tectonics and mantle plume), as well as related mantle evolution models. As a result, by accurately calculating the compositions of subduction sediments and using various geochemical indicators, we can further limit the input and output fluxes of various elements or isotopes, and then obtain more accurately residual subducted components, which can provide us some important clues for geodynamic process.  相似文献   

吉林省太古宙TTG岩类固结的温度压力条件     

孙德有  周永胜 《吉林地质》1995,14(2):57-63

吉林省太古宙ＴＴＧ岩类型成于变质上壳岩系麻粒岩相变质作用晚期阶段。详细的岩相学研究表明，ＴＴＧ岩类中存在岩浆结晶的绿帘石，角闪石和黑云母等。绿帘石的出现标志了一定的压条件。  相似文献   

吉林南部太古宙英云闪长质片麻岩类的特征及成因     

孙德有  葛文春  吴福元  周永胜 《吉林大学学报(地球科学版)》1995,(4)

吉林南部太古宙英云闪长质片麻岩类主要由石英闪长质、英云闪长质、花岗闪长质和奥长花岗质片麻岩组成。地质学、岩相学、地球化学研究表明，它们是同源岩浆通过结晶分异作用形成的，最主要的分离矿物相是角闪石和斜长石。岩浆来源于下地壳角闪质岩石的部分熔融作用。  相似文献   

Magnetostratieraphy of the Red Beds in the Hengyang Basin     

Hsu Vindell  A.Baksi 《《地质学报》英文版》1995,69(2)

This paper discusses the Cretaceous-Tertiary magnetic polarity sequence of the the Hengyang Basin on the basis of magnetostratigraphic study. The age of each stratigraphic unit has been determined with the magnetic polarity time scale combined with 39Ar/40Ar dating, thus providing evidence for determining the geological ages of different formations. The authors assign the age of the Dongjing Formation of the Hengyang Basin to Early Cretaceous, the Shenhuangshan Formation to Early-Late Cretaceous, the Daijiaping Formation to Late Cretaceous, and the Dongtang and Xialiushi formations to Palaeocene.  相似文献