安徽巢湖北部地区下三叠统和龙山组微生物岩及其意义          下载免费PDF全文

张利伟  洪天求  贾志海 《地质科学》2011,46(2):392-403

巢湖北部地区下三叠统和龙山组(Smithian亚阶中上段)含有特征明显的微生物岩.微生物岩包含微生物席和叠层石两种类型,其中最为丰富的类型是以蓝藻为主.该组微生物岩的普遍发育以及宏体化石组合的分布特征表明,和龙山组微生物岩可能是早三叠世生态环境开始改善、生物开始复苏的标志.微生物岩及微生物群落特征表明,该组很可能沉积于...  相似文献   

黄河三角洲现代泥质沉积物非构造裂缝空间展布研究   总被引：1，自引：0，他引：1  

成玮  周瑶琪  闫华 《沉积学报》2011,29(2):363-373

通过对黄河三角洲现代泥质沉积物非构造裂缝进行实地考察观测、室内数据处理、实验分析等,分别针对水下收缩裂缝、干燥裂缝和混合成因裂缝,研究其空间展布特征和规律,详细探讨了3种裂缝的定量分级、分形特征、平面及剖面生长特征等,并且建立了不同类型现代泥质沉积物非构造裂缝的形成模式.本研究对于建立不同种类泥质沉积物非构造裂缝系统的...  相似文献   

康家湾铅锌矿区ZK1122号孔裸孔钻探技术          下载免费PDF全文

刘炳志  王英 《探矿工程》2011,38(9):42-45

为确保实现康家湾矿区ZK1122号钻孔的全孔裸孔施工,在普通地层钻进时,使用了低固相泥浆,适当加入润滑剂,以减少摩擦阻力;在水敏性地层钻进时,使用了强抑制剂维护孔壁稳定;在应力异常地层钻进时,使用了加重泥浆;同时根据地层的不同和施工深度的不同,选用了不同的钻具组合,钻至深部地层时,选用了厚壁岩心管、长胎体的阶梯钻头,并增加了扩孔器和扶正器的数量,以保证深部钻探时的施工安全和施工效率。通过采取严格钻探规程和现场管理等一系列措施,完成了复杂地层条件下的深孔裸孔钻探施工任务,为今后在金属矿深部施工,特别是危机矿山＂攻深找盲＂项目提供了一种比较可行的钻探技术。  相似文献   

BW200型往复泵曲轴磨损原因分析及解决措施          下载免费PDF全文

周利文  李宗义  王安平  唐建 《探矿工程》2011,38(9):74-77

建立齿轮传动往复泵的曲柄连杆机构曲轴空间力系,对曲轴曲柄销轴进行受力分析。通过加装平衡条平衡旋转惯性力和改变进水管接口位置试验,找出了液力端进排水流道尺寸的改变是BW 200型泵的工作腔液体产生水击的原因,解决了泵温升高和曲轴曲柄销磨损问题。可用于齿轮传动往复泵的曲柄连杆机构曲轴受力分析和计算,解决泥浆泵的类似问题。  相似文献   

老挝巴勉岩金矿钻探施工实践          下载免费PDF全文

刘宪 《探矿工程》2011,38(12):18-21

境外钻探施工不但有施工技术方面的难题,更重要的是会遇到境外的施工环境、语言等诸多让人担忧让人却步的从未接触过的问题。介绍了在老挝巴勉岩金矿进行钻探施工遇到的各种难题及解决办法。  相似文献   

河口及近岸海域底边界层生物地球化学过程研究进展   总被引：1，自引：0，他引：1  

于志刚  姚鹏  甄毓  姚庆祯  米铁柱  陈洪涛 《海洋学报》2011,33(5):1-8

河口及近岸海域底边界层的生物地球化学过程在很大程度上影响着陆源物质的迁移转化及向海洋的输送通量,是陆海相互作用研究、海洋碳的"源、汇"研究以及氮、磷循环研究的关键。本文对河口及近岸海域底边界层生物地球化学过程研究进展进行了综述,重点介绍了底边界层中移动泥的特点和功能及微生物在其生物地球化学过程中的作用,并对今后的研究进行了展望。  相似文献   

Long-term changes in the production by estuarine macrobenthos affected by multiple stressors   总被引：1，自引：0，他引：1  

M. Dolbeth  P.G. Cardoso  T.F. Grilo  M.D. Bordalo  D. Raffaelli  M.A. Pardal 《Estuarine, Coastal and Shelf Science》2011

The macrobenthic production of an estuarine system was evaluated over a 14-year study period in a seagrass bed and in a sandflat. Over this period, the estuary suffered severe eutrophication and extreme weather events with important impacts on the community, impairing system functioning and ultimately the goods and services provided by the estuary (decline in the seagrass bed, decreased community production and/or a boost in the production by opportunist species, such as Hydrobia ulvae). Following the anthropogenic impacts, management measures were introduced which allowed a gradual recovery of the seagrass bed and a new macrobenthic community structure manifested by production increases of slow-growing species, such as Scrobicularia plana and Hediste diversicolor. There was a gradual re-orientation of energy into population biomass instead of population density but this was not translated into higher community production, mainly due to the decreased production of opportunist species (H. ulvae and several polychaetes). Several weather extreme events occurred during this post-mitigation phase - floods, heatwaves and droughts, all of which had negative impacts on macrobenthic dynamics and production. The heatwaves led to the greatest decreases in macrobenthic production, mainly due to S. plana perhaps associated with its physiological intolerance of higher temperatures. The prolonged drought that followed the heatwaves maintained low levels of production by S. plana and H. ulvae. With climate change, the frequency and intensity of extreme weather events are likely to increase worldwide so that the recovery of impacted/disturbed systems from impacts such as eutrophication may be seriously affected by these additional stressors, compromising attempts to improve the ecological quality of estuarine ecosystems.  相似文献   

Laboratory testing of mathematical models for high-concentration fluid mud turbidity currents   总被引：1，自引：0，他引：1  

M.R. Chowdhury 《Ocean Engineering》2011,38(1):256-270

The propagation characteristics of fluid mud turbidity currents were investigated experimentally and theoretically. Parameterizations for propagation phase transition times from slumping to self-similar and self-similar to viscous phases are proposed. Predictive capabilities of different mathematical models that fall into three different modeling approaches (force-balance, box, shallow water) were evaluated for fluid mud turbidity current propagation using our experimental observations. For the slumping and self-similar phases, the box and force-balance models showed superior predictive capabilities than the one-layer shallow water models with deep ambient condition. Fluid mud turbidity currents have a non-Newtonian rheology and their transition and propagation characteristics in the viscous phase differ vastly from the Newtonian currents. We derived and presented a viscous force-balance expression for the propagation of a non-Newtonian power-law fluid current. We then experimentally evaluated the predictive capability of this force-balance and the viscous shallow water model by Di Federico et al. (2006). Both models' predictions are observed to be in notably good agreement with the experimental data. The results of this study are expected to be useful for preliminary swift calculations of the fluid mud turbidity current propagation characteristics as well as in deciding whether more detailed calculations at the expense of complexity are required.  相似文献   

上海民防工程建设与地下空间开发利用     

姚荷孙 《上海国土资源》2011,32(2):95-98

基于上海城市灾害特点与发展趋势的初步分析,提出充分利用地下空间资源、加强民防工程建设的建议,以有助于进一步提高上海防灾抗灾减灾综合能力。结合上海特殊的地质条件,分析了地下空间民防工程建设中的主要问题及其防治对策,以期提高城市土地综合利用效率,并有效保障城市安全与可持续发展。  相似文献   

南海北部白云凹陷-东沙岛西南海区的浅地层探测与深水沉积特点   总被引：1，自引：0，他引：1  

阎贫  王彦林  郑红波 《热带海洋学报》2011,30(2)

采用新引进的海洋深水浅层剖面仪,从珠江口外陆架进入白云凹陷-东沙岛西南海区中陆坡区,进行了浅地层探测,获得了高分辨率反射记录.分析发现,白云凹陷上陆坡段沉积连续性较好,海底反射强度侧向变化平缓,显示了比较均一的沉积底质和微弱的海底水动力条件;在白云凹陷-东沙岛西南海区中陆坡区,海底滑坡严重,局部存在强烈的、平行陆坡的海底洋流冲蚀,海底地形崎岖不平,反射强度侧向变化大,表明海底底质不均匀,海底水动力强.浅地层记录还显示中陆坡海底山丘有海底气体泄露现象,结合常规反射地震识别的海底泥底辟特征,确定海底山丘为泥火山.气体泄露和海底反射振幅的变化代表了海底浅层聚有丰富的气体以及嗜甲烷生物链活动的钙化,因而推断该区不仅是油气的聚集区,也是水合物的聚集带.  相似文献