平邑盆地古近纪官庄群沉积建造与膏岩富集规律          下载免费PDF全文

陈华国  赵艳杰  甘延景  安仰生 《山东国土资源》2008,24(5):30-33

平邑盆地是蒙山断裂多期次活动的产物，盆地内沉积了厚约1700多米的新生代古近纪官庄群杂色-红色碎屑岩建造。将官庄群沉积建造、剖面类型，结合含膏岩系的沉积特点，可以划分为3个不同级别的沉积韵律，它们分别反映出含膏岩系在时间和空间上的变化趋势。蒙山断裂及盆地内次级断裂的阶段性活动，使盆地表现为升降运动，下降时成矿物质聚集、保存，相对稳定期是膏岩形成的有利期。  相似文献   

皖东地区毛山金矿蚀变矿物特征及其地质意义   总被引：1，自引：1，他引：1  

方勤方  刘玉林等 《地质与勘探》2001,37(5):34-37

毛山金矿属于中小规模金矿山。通过对矿体两侧的黄铁绢英岩进行热分析与透射电镜观察研究以及对绢云母的热分析及其化学成分研究，认为水热蚀变、硅化及矿化程度均较高，成矿热液可能来自矿区南部和深部，该地区是寻找隐伏矿体的靶区。黄铁绢英岩中出现微细石膏，反映在成矿过程中可能出现过氧化阶段，是出现富矿的显示。进而提出乳白色石英脉中出现石膏晶体是寻找金矿化的新的找矿标志。  相似文献   

湖北大冶铁山矿床钠化蚀变与成矿关系的探讨   总被引：6，自引：0，他引：6  

杨峰华 《地质与勘探》2001,37(6):20-24

对于大冶铁矿内接触带钠化蚀变的岩石特征、钠质来源、动力机制、形成机理等作了比较系统的阐述。并着重指出了钠化蚀变是铁矿化的重要指示标志之一。  相似文献   

Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific   总被引：4，自引：0，他引：4  

Erwin Suess  Dirk Rickert 《中国科学D辑(英文版)》2004,47(3)

Hydrate Ridge is located at the second accretion-ary ridge along the Cascadia margin of Oregon in the eastern North Pacific (fig. 1). The Bottom Simulating Reflector (BSR) underlies the entire Hydrate Ridge[1]. The Ocean Drilling Program (ODP) in 1992 at Site 892 and the TECFLUX99 and 2000 showed that the gas hydrate occurs just beneath the thin sediment- covered surface and at the horizon of around 64 meter below seafloor (mbsf) on Hydrate Ridge[25]. The col-lision of the Juan de …  相似文献   

Effect of Cement Type on the Mechanical Behavior of a Gravely Sand   总被引：1，自引：0，他引：1  

S. M. Haeri  A. Hamidi  S. M. Hosseini  E. Asghari  D. G. Toll 《Geotechnical and Geological Engineering》2006,24(2):335-360

The behavior of a cemented gravely sand was studied using triaxial compression tests. Gypsum, Portland cement and lime were used as the cementing agents in sample preparation. The samples with different cement types were compared in equal cement contents. Three cement contents of 1.5%, 3.0% and 4.5% were selected for sample preparation. Drained and undrained triaxial compression tests were conducted in a range of confining pressures from 25 kPa to 500 kPa. Failure modes, shear strength, stress–strain behavior, volume and pore pressure changes were considered. The gypsum cement induced the highest brittleness in soil among three cement types while the Portland cement was found to be the most ductile cementing agent. In lower cement contents and lower confining pressures the soil cemented with Portland cement showed the highest shear strength. However, in the same range of cement content, the soil cemented with gypsum showed highest shear strength for highest tested confining stress. For higher cement contents the shear strength of soil cemented with Portland cement is higher than that for the two other cement types for the range of confining pressures tested in the present study. The samples cemented with lime had the least peak and ultimate shear strength and the highest pore pressure generation in undrained tests. Contrary to the soil cemented with lime, the brittleness of soil cemented with gypsum and Portland cement reduces in undrained condition. Finally it was found that the effect of cement type on the shear strength of cemented soils is more profound in drained condition compared to undrained state.  相似文献   

Hydrologic and geoenvironmental characterization of wetlands in quarries of the Vinalopó Mitjà (Alicante, Spain)     

R. Miralles  E. García-Sánchez  M. M. Jordán 《Environmental Geology》2006,50(7):1053-1059

This paper deals with the environmental characterization of the “Collao de Candela” enclave (Alicante, SE Spain), which in the early 1980s reported strong mining activity mainly due to the extraction of marls. The subsequent abandonment of such quarries produces floods in depressed areas that are constituted as pools. These anthropogenic wetlands are the object of this research. In order to characterize the geometry of the studied wetlands a bathymetry was carried out. Bathymetric data are very important for water managers tasked with assessing wetlands’ status. A chemical and mineralogical characterization has been carried out on the lithologies in the study area. A study was also conducted of the physical and chemical parameters of the waters contained in these pools during one hydrologic cycle. The climate of the zone, having elevated evapotranspiration measurements, favors a progressive concentration of salts in the pools consequence of runoff water washing, the evaporitic sediments as well as from elevated evaporation. The results obtained justify the environmental protection of these marl-gypsum mining quarries as potential wetlands.  相似文献   

嘉陵江合川水利枢纽建坝岩体主要地质问题研究   总被引：2，自引：1，他引：1  

杨先毅 《水文地质工程地质》1998,25(4):36-37,45

作者分析利用嘉陵江合川水利枢纽的勘探试验资料,阐明了建坝岩体中的石膏脉、层间剪切带、层间裂隙水等主要地质问题,并以以上地质缺陷进行了工程地质评价,提出了处理的建议。  相似文献   

石膏对白云岩溶解影响的实验模拟研究   总被引：25，自引：2，他引：25  

黄思静  杨俊杰 《沉积学报》1996,14(1):103-109

表生到埋藏成岩作用的温度与压力（４０-１３０℃、常压－３０ＭＰａ）条件下，含膏与不含膏白云岩的溶解实验证明:在表生与相对浅埋藏的温压条件（低于７５℃，２０ＭＰａ）下，石膏（或硬石膏）的存在可不同程度地加速白云岩的溶解，随着实验温度和压力的升高，石膏（或硬石膏）对白云岩溶解的这种积极作用逐渐降低。在相对深埋藏的温压条件（高于７５℃、２０ＭＰａ）下，石膏（或硬石膏）的存在显著阻止白云岩的溶解，随着实验温度和压力的继续升高，石膏（或硬石膏）对白云岩溶解的这种消极作用也逐渐增加。从实验的这种结果可以预测，在近地表条件下和埋藏成岩作用的早期阶段，由溶解作用造成的含膏白云岩地层的次生孔隙将比不含膏的白云岩地层更为发育，因而在经历了古风化作用的地层中，含膏白云岩层更易形成良好的储层；与之相反，在相对高温高压的深埋藏成岩阶段，不含膏的白云岩地层中将更容易因酸性水的溶解作用而形成次生孔隙。因而在非蒸发沉积环境中形成的白云岩体（如正常海沉积环境的灰岩中的白云岩透镜体）更易因深埋藏溶蚀作用而形成良好的储层。  相似文献   

Evaporite Dissolution Subsidence in the Historical City of Calatayud,Spain: Damage Appraisal and Prevention   总被引：6，自引：0，他引：6  

Gutiérrez  Francisco  Cooper  Anthony H. 《Natural Hazards》2002,25(3):259-288

Calatayud in NE Spain is an historically important city built on recent alluvial deposits underlain by gypsum and other soluble rocks. Since its foundation by the Muslims in 716 A.D., the city development has been strongly influenced by geohazards including flooding, subsidence and slope movements. Most of the flooding problems have been mitigated by diversion of the local drainage. However, dissolution of the evaporite bedrock in the urban areas continually causes subsidence and triggers rock-falls from the gypsum cliffs overlooking the city. Subsidence is also caused by the hydrocollapse of gypsiferous silt in the alluvial fan deposits. Building damage in the city was surveyed using a classification scheme developed originally to record damage in British coal mining areas. The Calatayud damage survey shows that the worst building subsidence is concentrated along the line of a buried channel that runs underneath the gypsiferous silt alluvial fan. Natural subsurface drainage causes the dissolution and subsidence, which is aggravated by leakage from water and sewage pipes. Some building damage has been exacerbated during reconstruction by incomplete piling leaving buildings partially unsupported. Mitigation measures include the control of water leakage by the installation of flexible service pipes. Careful construction techniques are needed for both conservation and new developments, especially when piled and minipiled foundations are used. Geomorphological mapping is cost-effective in helping to locate and avoid the zones of subsidence for future development.  相似文献   

Snowball morphology and SEM analysis of pedogenic gypsum, southern New Mexico, U.S.A.     

Brenda J. Buck  John G. Van Hoesen 《Journal of Arid Environments》2002,51(4):469

Late Quaternary soils in southern New Mexico support previous work that suggested pedogenic gypsum accumulates in successive stages as a function of time, similar to pedogenic carbonate. However, gypsum also occurs as small (0·5–1 mm), powdery spheres that we term snowball morphology. The snowball morphology represents one of the initial stages of pedogenic gypsum development. Scanning electron microscope analyses indicate that soil microorganisms and organic material may play a crucial role in the development of this morphology. However, no trends were found in the crystal habits of gypsum suggesting the snowball morphology forms in a dynamic environment.  相似文献