内蒙古巴彦诺日公地区构造砾岩特征及其形成机制     

李新仁  贾利亚  陈志勇  苏宏伟  张志祥 《西北地质》2003,36(4):25-29

通过巴彦诺日公地区1／5万地质填图和重点解剖研究，认为原1／20万区调中所划下元古界阿拉善群大部分岩石组合可与内蒙古中部地区色尔腾山岩群进行对比，且祖宗毛道组三段实际上是一套构造砾岩。在研究该砾岩宏观和微观特征的基础上，认为其形成机制为伸展机制下的构造拆离。  相似文献   

New constraints to the geodynamic evolution of the southern sector of the Calabria–Peloritani Arc (Italy)Nouvelles données sur l'évolution géodynamique du secteur méridional de l'Arc Calabro-Péloritain (Italie)     

Glauco Bonardi  Paola de Capoa  Angelida Di Staso  Manuél Martı́n-Martı́n  Iván Martı́n-Rojas  Vincenzo Perrone  José Enrique Tent-Manclús 《Comptes Rendus Geoscience》2002,334(6):423-430

New studies have been carried out on the Tertiary of the Stilo Unit, the uppermost of the Calabria–Peloritani Arc southern sector, and the Stilo–Capo d'Orlando Formation, sealing the whole nappe stack. The Tertiary terrains linked to the Mesozoic cover of the Stilo Unit consist of the lowermost Oligocene Palizzi Formation and the Late Rupelian–Aquitanian Pignolo Formation. The possibility that they deposited before the emplacement of this unit as the highest tectonic sheet of the sector is suggested. The base of the Stilo–Capo d'Orlando Formation resulted of Burdigalian age in both type areas. This interpretation, together with the existing and new data, allows proposing an age close to the Aquitanian–Burdigalian boundary for the stacking of the whole Calabria–Peloritani Arc southern sector. To cite this article: G. Bonardi et al., C. R. Geoscience 334 (2002) 423–430.  相似文献   

松辽盆地第三系含砾砂岩、砂砾岩层的钻探取心技术   总被引：1，自引：0，他引：1       下载免费PDF全文

刘晓阳  段隆臣 《探矿工程》2002,(3):39-41

介绍了自行设计加工的2种取心钻具在松辽盆地第三系含砾砂岩，砂砾岩层的应用情况。生产试验结果表明，这2种钻具设计合理，制订的操作规程适当。  相似文献   

Upper Cretaceous deposits in the northwest of Saratov oblast,Part 1: Litho- and biostratigraphic analysis of the Vishnevoe section     

A. G. Olfer’ev  V. N. Beniamovski  V. S. Vishnevskaya  A. V. Ivanov  L. F. Kopaevich  E. M. Pervushov  V. B. Sel’tser  E. M. Tesakova  V. M. Kharitonov  E. A. Shcherbinina 《Stratigraphy and Geological Correlation》2007,15(6):610-655

The work is dedicated to multidisciplinary study of Upper Cretaceous deposits exposed at the day surface in a ravine near the village of Vishnevoe, the Petrovsk district of Saratov oblast. The exposed section includes deposits of the Bannovka, Mozzhevelovyi Ovrag, Mesino-Lapshinovka, Rybushka, Ardym, Lokh formations and of the Borisoglebsk sequence first distinguished in the Volga River basin. Age ranges of the formations studied are confirmed or defined more precisely (the Ardym and Lokh formations) based on fossil faunas of cephalopods, bivalves, radiolarians, planktonic and benthic foraminifers. The middle-upper Coniacian range of the Borisoglebsk sequence is substantiated. Distribution of brachiopods, sponges, radiolarians, ostracodes and calcareous nannoplankton in the section is established. Radiolarian assemblages are used to distinguish biostratigraphic subdivisions corresponding in rank to faunal beds. Based on nannofossil assemblages, zones and subzones of standard zonations after Perch-Nielsen (1985) and Burnett (1998) are established. Stratigraphic ranges of certain radiolarian, ostracode and calcareous nannoplankton taxa are verified.  相似文献   

Liquefaction evaluation discrepancies in tropical lagoonal soils     

Peter G. Nicholson 《Geotechnical and Geological Engineering》2006,24(5):1259-1269

Field penetration tests and shear wave velocity measurements are both established and accepted methods for evaluating liquefaction potential in soils. The results produced by the two methods are generally well correlated. However, recent studies have shown that when investigating tropical lagoonal deposits, the same accepted methods for evaluating liquefaction potential often produce significant discrepancies in results. This discrepancy is most apparent in saturated lagoonal deposits of calcareous gravelly sand (or sandy gravel), which tend to exhibit low penetration resistance values but relatively high shear wave velocities. These disparate test results can suggest different soil classifications under current building codes. Ambiguity in the code may allow for a potentially unconservative classification, which may in turn allow for the use and construction of less costly, lighter weight foundation systems than warranted. Equally as important, the potential for unconservative design as related to liquefaction appears to be high when shear wave velocity measurements are used as a basis for evaluation in these types of lagoonal deposits. Because of this, it is strongly recommended that caution should be excercised when determining seismic design parameters in these types of geologic environments. A hypothesis to explain the discrepancies in the results of evaluation methods and a suggested design protocol is proposed.  相似文献   

辽河西部凹陷沙三段浊积岩储层中钙质夹层研究   总被引：29，自引：0，他引：29  

林承焰  黄金柱 《沉积学报》1996,14(3):72-80

本文阐明了辽河西部凹陷高升、兴隆台、曙光和冷东四个地区沙三段浊积岩油气储层内的钙质夹层识别标志，定性、定量地揭示了它在剖面和平面上空间分布规律，探讨了它的成因机制，指出了钙质胶结作用和钙质夹层对储层性质与油气分布的重要影响。  相似文献   

海水环境下巴氏芽孢杆菌驯化及钙质砂固化效果研究     

肖瑶  邓华锋  李建林  程雷  朱文羲 《岩土力学》2022,(2):395-404

为了提升微生物诱导碳酸盐沉淀(MICP)技术在海洋环境下对钙质砂的加固效果,在以往研究的基础上,设计进行了人工海水环境下巴氏芽孢杆菌多梯度人工驯化培养试验,并结合MICP固化钙质砂柱的力学试验和微细观结构分析,对巴氏芽孢杆菌的驯化效果进行了综合评价。结果表明:(1)海水环境下五梯度驯化后细菌的菌液浓度可达到淡水环境的97%以上,其与胶结液作用后碳酸盐的生成量较淡水环境下有一定幅度提高;(2)驯化后的巴氏芽孢杆菌具有很好的温度适应能力,在10～30℃温度下均有较好的MICP性能;(3)海水环境下加固的钙质砂柱无论是碳酸盐生成量还是无侧限抗压强度均较未驯化前高,尤其是五梯度驯化后的细菌,驯化后的细菌菌体变小,在海水环境生成的碳酸盐(碳酸钙和碳酸镁)晶体更小,更加致密,能更好地填充钙质砂颗粒的孔隙并胶结相邻的钙质砂颗粒,具有更优异的MICP性能。相关研究思路和方法可为MICP技术在海洋环境钙质砂地基加固方面的研究与应用提供参考。  相似文献   

水泥胶结钙质砂地层中单桩竖向承载特性试验研究     

柴源  牛勇  吕海波 《岩土力学》2022,43(8):2203-2212

钙质砂属于岩土工程中一种特殊的岩土材料,除具有颗粒形状不规则、易破碎等特征,还具有胶结性。针对钙质砂具有胶结性的地质现状,通过室内模型试验研究了胶结钙质砂地层中钢管桩的承载能力、沉降情况及其影响因素,同时与未胶结钙质砂中的桩基承载特性进行了对比。研究结果表明：与未胶结钙质砂中的钢管桩相比,胶结钙质砂的相对密实度对桩基承载力影响程度明显减弱,桩的承载形式依然表现为端承桩,随着钙质砂胶结程度的提升,桩端阻力承载占比越来越高;胶结程度较高的钙质砂地层中桩身侧摩阻力发挥存在异步过程,这是因为桩基沉降时桩身下部破坏砂层形成了更为紧密的新接触面,该接触面对桩身的径向膨胀更为敏感;胶结钙质砂中桩基 q_s-S_u 线没有出现明显的硬化阶段,与未胶结钙质砂地层中桩基的 q_s-S_u多段折线变化规律不同,胶结钙质砂地层中桩基的 q_s-S_u曲线更为接近双曲线线型。  相似文献   

MICP联合纤维加筋改性钙质砂的动力特性研究   总被引：1，自引：0，他引：1  

王瑞  泮晓华  唐朝生  吕超  王殿龙  董志浩  施斌 《岩土力学》2022,43(10):2643-2654

为了提高我国南海钙质砂地基的抗液化性能,提出利用微生物诱导碳酸钙沉积（MICP）技术联合纤维加筋技术对钙质砂进行改性处理。通过开展动三轴试验,对比分析了改性前后钙质砂试样的动应变、动孔压、应力−应变滞回曲线以及动弹性模量的发展规律和演化特征,并结合扫描电镜（SEM）试验探究了MICP和纤维加筋技术对钙质砂的联合改性机制。研究结果表明：（1）MICP技术可以明显改善钙质砂试样的抗变形与抗液化性能,相比于未胶结处理试样,仅MICP处理试样的动应变和动孔压分别降低了95.74% 和 92.46%;（2）纤维的掺入进一步提升了MICP的改性效果,相比于仅MICP处理试样,MICP和纤维加筋联合处理试样的动应变和动孔压分别降低了 74.32%和 74.18%;（3）MICP 和纤维加筋技术通过减轻试样在循环荷载作用下的循环活动强度和能量耗散、提高试样的动弹性模量和减小动弹性模量的衰减速率,从而实现试样抗变形与抗液化性能的显著提高;（4）SEM 试验分析结果表明,MICP 与纤维对钙质砂动力特性的改善具有协同作用。纤维的掺入为细菌提供了更多的附着场所,促进了碳酸钙晶体的生成量,该部分碳酸钙不仅增加了颗粒间的胶结强度,同时也将纤维固定在砂颗粒上增强了纤维网的约束作用。  相似文献   

西沙群岛西科1井第四纪钙藻及其生态功能   总被引：2，自引：0，他引：2       下载免费PDF全文

马兆亮  祝幼华  刘新宇  罗威  马瑞芳  徐守立 《地球科学》2015,40(4):718-724

对西沙群岛西科1井第四纪地层中的钙藻进行了初步研究, 共鉴定钙藻3科7属, 包括红藻门珊瑚藻科让氏藻属、蟹手藻属、珊瑚藻属、石枝藻属和石孔藻属, 以及绿藻门松藻科仙掌藻属和粗枝藻科伞轴藻属.通过对地层中钙藻形态功能的分析, 西科1井第四纪早期海水较深, 沉积环境为礁前相, 中期外礁坪和内礁坪交替沉积, 至晚期出现短时间的泻湖相之后沉积环境演变为礁后滩相.西科1井第四纪钙藻在造礁功能上主要体现在2个方面: (1)通过自身的钙化作用, 为生物礁的生长供应微小碳酸盐颗粒沉积物; (2)利用自身形成的节片结构和生物捆扎-粘结结构参与造礁.   相似文献