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901.
为了维护极地深部冰层取心钻探工作中钻孔的稳定,避免孔内事故的发生,冰层孔壁的水压致裂问题是亟待解决的重要科学问题之一。本文在深入分析国内外冰层钻探资料的基础上,结合冰盖动力学相关理论,计算得出了钻孔所在区域冰层的密度、温度及内部应力随深度的变化规律。在此基础上,结合油气资源勘探水力压裂技术与冰层钻进钻井液等相关理论,建立了合理的孔壁压差计算方法,深入探讨了适用于深部冰层钻探孔壁水压致裂机理。研制了冰层钻孔水压致裂模拟实验装置,可分析研究不同围压条件下冰样的脆性变形机理。结合我国Dome A深冰心钻探工程实际,提出钻孔可能发生水压致裂的深度区域及孔壁所需的起始裂纹长度判定,以期为后续的安全高效冰层钻进提供重要的理论依据。 相似文献
902.
903.
Zhao Wenyu Center of Material Research Analysis Wuhan University of Technology Wuhan Liu Rong Wang QinyanFaculty of Earth Sciences China University of Geosciences Wuhan Peng Changqi Zhang QingjieCenter of Material Research Anal 《中国地质大学学报(英文版)》2001,12(3)
INTRODUCTIONItisanacknowledgedfactthataragonite,ahigh pressurepolymorphofCaCO3 ,occurswidelyasanindexmineralofhigh pressureandlow temperaturemetamorphism (glaucophaneschistfacies)withinthegeodynamiccontextofsubduction obductionandcontinentalcollision (Liou… 相似文献
904.
905.
906.
By utilizing the magnetic interactions possessingC 3v symmetry, the author has deduced the general expressions for theg-factors, zero-field splitting and effective magnetic moment of the ground singlet orbital state in d3-complex. For ruby (Al2O3: Cr3+) the results are in good agreement with experiments: theoretical values:g ‖ =1.9835;g ⊥=1.9876; 2D=?0.3731 cm?1;μ ‖ =3.857β;μ ⊥=3.861β; experimental values:g ‖ =1.9840±0.006,g ⊥=1.9867±0.0006, 2D=?0.3831±0.0002 cm?1,μ=3.8?3.9β. 相似文献
907.
在攀西地区,自海西期以来出现两套与大陆裂谷作用有关的岩浆岩共生组合,即基性岩套与碱(酸)性岩套。与基性岩套有成因联系和紧密伴生的印支期碱性正长伟晶岩脉和碱性花岗伟晶岩脉等,普遍具稀有、稀土和铀钍矿化,有的已形成中小型铌钽矿床:碱(酸)性岩套以超基性碱性岩、碱性花岗岩为代表,并具与碱性花岗岩有关的稀有、稀土矿床和铀钍矿化。本文对上述碱性杂岩有关的成矿系列,划分了矿床成因类型,并对主要控制因素作了较为详细的探讨。 相似文献
908.
新疆贝勒库都克A型花岗岩锆石U-Pb年龄、地球化学及锡成矿 总被引:1,自引:0,他引:1
新疆东准噶尔卡拉麦里地区是一个重要的锡成矿带,分布有多种类型花岗岩。贝勒库都克岩体位于锡成矿带中部,由黑云母正长花岗岩和黑云母二长花岗岩组成。本文通过精确的LA-ICP-MS锆石U-Pb测年获得贝勒库都克含锡黑云母正长花岗岩年龄为283±2Ma,MSWD=0.14(95%置信度),时代属于早二叠世,这与东准噶尔后碰撞深成岩浆活动的范围(330~265Ma)相吻合。岩石地球化学研究表明,贝勒库都克岩体富硅(SiO2=75.25%~76.67%),低铝(Al2O3=11.91%~12.86%),贫镁(MgO=0.02%~0.18%)和钙(CaO=0.39%~0.89%),富碱(Na2O+K2O=8.08%~8.97%),K2O>Na2O,NK/A=0.86~0.95(平均0.92),A/NCK=0.97~1.02,富集Rb、K等大离子亲石元素及Zr、Hf等高场强元素,Ba,Nb,Sr强烈亏损,δEu=0.01~0.11,其FeOt/MgO(12.71~84.51,平均34.55)和10000Ga/A1(2.97~4.20)值大,HFSE元素(Zr+Nb+Ce+Y=191.8×10-6~353.3×10-6)含量高,明显不同于典型的I型和S型花岗岩,基本属于典型的铝质A型花岗岩。年代学和地球化学综合研究表明,贝勒库都克铝质A型花岗岩是壳幔混合成因,是准噶尔地区后碰撞幔源岩浆底侵作用导致大陆地壳垂向生长过程的记录者。贝勒库都克铝质A型花岗岩Sn的含量高(6.0×10-6~19.5×10-6,个别为80.0×10-6),铝质A型花岗岩是成矿热液的直接母体,而富Sn的流体相最终形成了贝勒库都克锡矿床,锡矿与铝质A型花岗岩是同期地质事件的产物。 相似文献
909.
The Yanshan thrust belt (YTB) is located at the northern edge of the North China plate. Because of the intense thicking and
subsequent delamination of the lithosphere in north China, geologists have been focused on the Late Mesozoic deformation in
the Yanshan belt. The Yanshan belt has been regarded as part of a stable craton from the Proterozoic to the early Mesozoic.
In this paper, the authors present that the Yanshan area was deformed during the early Mesozoic. This deformation could be
related to ocean basin closure along the northern margin of North China, or related to the collision between the north China
and Yangtze Plates along the Qinling-Dabie ultrahigh pressure belt. Three stages of early Mesozoic deformation are identified
in the eastern Yanshan at Lingyuan County. The first stage is characterized by westward thrusting (D1), the second stage comprises
a top-to-east thrust system (D2), and the third stage comprises extensional gravity-induced collapse and landsliding (D3).
The timing of these evens is constrained by both the crosscutting relationships of faults and the isotopic dating of volcanic
rocks and gravels. The D1 and D2 events took place in the Late Triassic and Early Jurassic, whereas D3 event occurred at the
end of the Middle Jurassic. The Dengzhangzi formation was deposited during the D1–D2 period and recorded a rapid uplift, erosion,
and deposition sequence. These early Mesozoic contractional deformations in the YTB were probably related to the closure of
ancient Asian ocean and ancient Qinling ocean. The later crustal extension was caused by gravitational collapse of the eastern
China plateau during early Mesozoic. 相似文献
910.
Shujun Peng Zhennan Zhang Jianye Mou Bing Zhao Zhiyuan Liu Jiading Wang 《国际地质力学数值与分析法杂志》2019,43(1):441-460
The improved element partition method (IEPM) is a newly developed fracture simulation approach. IEPM allows a fracture to run across an element without introducing extra degrees of freedom. It can also simulate any number of fractures in a prescribed mesh without remeshing. In this study, the IEPM is extended to hydraulic fracture simulation. First, the seepage and volumetric storage matrix of a cracked element are derived using virtual nodes (the intersection points of a crack with element edges). Subsequently, the fully coupled hydromechanical equation is derived for this cracked element. To eliminate the extra degrees of freedom (virtual nodal quantities), the water pressure and displacement of the virtual nodes are associated with their adjacent nodes through least squares interpolation. Finally, the fully coupled equation in terms of nodal quantities is obtained. The verification cases validate the method. By using this method, the field-scale hydraulic fracturing process is well simulated. The proposed approach is simple and efficient for field-scale hydraulic fracture simulation. 相似文献