渝东南地区隐伏铝土矿物探勘查技术试验研究—以车盘矿区试验结果为例     

李华  艾斯卡尔  吾守艾力  李富  焦彦杰  王桥  周一敏 《地质学报》2013,87(3):384-392

全国矿产资源潜力评价研究表明渝东南地区有着丰富的铝土矿资源,在此开展隐伏铝土矿的物探勘查技术试验研究对今后勘查工作的展开具有重要的指导意义。文中首先在充分了解渝东南地区铝土矿的成矿规律及矿体特征的基础上,总结了该地区铝土矿的储存模式;然后根据其成矿规律和储存模式,结合前人的经验及区域物性差异,提出了使用电磁测深法来确定该区唯一含矿层位—梁山组地层的空间分布形态,以达到间接寻找隐伏铝土矿的方案。选取重庆武隆车盘矿区作为试验场地,在同一剖面上同时展开了可控源(人工场源)音频大地电磁测深法(CSAMT)和高频大地电磁测深法（EH4）两种方法的试验工作,介绍了数据采集及数据质量评价等,对两种电磁测深数据分别进行了人机交互的二维连续介质反演,并结合钻孔资料对两个反演的频率—视电阻率剖面进行了对比分析,最后结合区域地质构造背景勾画出物探成果推断图。  相似文献   

Chronologies of sedimentary changes in the south Bohai Sea,China: constraints from luminescence and radiocarbon dating   总被引：1，自引：0，他引：1  

Liang Yi  Zhongping Lai  Hongjun Yu  Xingyong Xu  Qiao Su  Jing Yao  Xulong Wang  Xuefa Shi 《Boreas: An International Journal of Quaternary Research》2013,42(2):267-284

The alternation of terrestrial and marine deposits is an indicator of past environmental and sea‐level changes. The age of deposition is usually dated by means of radiocarbon. However, radiocarbon dates of molluscan shells from coastal areas may be complicated by various sources of carbon, and problematic for deposits of 40–50 ka or older. Herein, we apply the Optically Stimulated Luminescence (OSL) dating method to date samples from terrestrial and marine/coastal sediments extracted from three cores in the south Bohai Sea, China. Multiple‐ and single‐aliquot regenerative‐dose procedures using OSL signals from fine‐silt (4–11 μm), coarse‐silt (38–63 μm) and fine‐sand (63–90 or 90–125 μm) quartz were employed to determine the equivalent dose (D _e). The results showed that: (i) OSL ages from quartz of different grain sizes and different protocols are consistent with each other; (ii) for Holocene samples, most of the radiocarbon dates agree well with OSL ages; (iii) for pre‐Holocene samples, radiocarbon dates cluster at 40–50 ¹⁴ C ka BP, whereas OSL ages are in stratigraphic order from 11 ka to 176 ka. Because of the self‐consistency of the quartz OSL ages, the stratigraphic agreement in the three cores, and the clustering of the radiocarbon dates, we suggest that the quartz OSL ages are more reliable with respect to dating the samples from the south Bohai Sea. Finally, the four marine strata identified in the south Bohai Sea are likely to have formed during the Holocene, Marine Isotopic Stage (MIS) 3–5, MIS 6 and probably MIS 7, respectively.  相似文献   

贵州丹寨地区南华系地层地球化学特征及其对古气候、古环境的意义          下载免费PDF全文

谯文浪  汪建国  陈武 《地质科学》2013,48(3):847-859

南华系是地球历史上最重要的成冰时期,为了示踪冰期前后的气候与环境的变化,本文通过对南华系细屑岩的化学成分分析,重塑南华系古气候、古环境的演化过程。分析结果显示铁丝坳组具有明显低的CIA指数以及低Ti/Al比值,说明该时期主要以寒冷干燥气候为主,化学风化程度低,物源供应和沉积速率相对较低,为冰期特征,隆里组和大塘坡组具有高的CIA指数以及相对较高的Ti/Al比值,表明该时期主要以温暖湿润气候为主,化学风化程度相对较高,物源供应和沉积速率相对较高,为间冰期特征。南沱组的CIA指数以及Ti/Al比值具有交替变化特征,说明南沱组沉积时期气候存在冷暖交替变化,反映了冰期与间冰期的相互转换特征。另外,在铁丝坳组顶部和大塘坡组的下部以及南沱组中上部,具有一定程度的正Eu异常,说明在南华系沉积时期,存在热液活动,而这种热液活动可能与冰期的消亡存在着成因联系。  相似文献   

Fatigue Behavior of Granite Subjected to Cyclic Loading Under Triaxial Compression Condition     

Zhechao Wang  Shucai Li  Liping Qiao  Jiangang Zhao 《Rock Mechanics and Rock Engineering》2013,46(6):1603-1615

A series of laboratory tests were performed to examine the fatigue behavior of granite subjected to cyclic loading under triaxial compression condition. In these tests, the influences of volumetric change and residual strain on the deformation modulus of granite under triaxial cyclic compression were investigated. It is shown that the fatigue behavior of granite varies with the tendency for volumetric change in triaxial cyclic compression tests. In the stress–strain space, there are three domains for fatigue behavior of rock subjected to cyclic loading, namely the volumetric compaction, volumetric dilation with strain-hardening behavior, and volumetric dilation with strain-softening behavior domains. In the different domains, the microscopic mechanisms for rock deformation are different. It was also found that the stress level corresponding to the transition from volumetric compaction to volumetric dilation could be considered as the threshold for fatigue failure. The potential of fatigue deformation was compared with that of plastic deformation. The comparison shows that rocks exhibit higher resistances to volumetric deformation under cyclic loading than under plastic loading. The influence of residual strain on the fatigue behavior of rock was also investigated. It was found that the axial residual strain could be a better option to describe the fatigue behavior of rock than the loading cycle number. A constitutive model for the fatigue behavior of rock subjected to cyclic loading is proposed according to the test results and discussion. In the model, the axial residual strain is considered as an internal state variable. The influences of confining pressure and peak deviatoric stress on the deformation modulus are considered in a term named the equivalent stress. Comparison of test results with model predictions shows that the proposed model is capable of describing the prepeak fatigue behavior of rock subjected to cyclic loading.  相似文献   

GPS-derived crustal deformation in southwestern China     

X. Qiao  S. Yang  R. Du  Q. Wang  K. Tan  L. Guo 《Australian Journal of Earth Sciences》2013,60(4):521-529

The Sichuan – Yunnan region is divided into nine active secondary crustal blocks, based on several GPS repeat surveys at more than 200 GPS sites during the period 1999 – 2005. Velocities of the nine secondary blocks are calculated and analysed. The strain field within the area related to the 2004 Sumatra – Andaman earthquake event is also analysed. Results indicate that the crustal movement in the northern and western areas of the Sichuan – Yunnan region is stronger than that in the south and east. The horizontal velocities change from 19 – 20 mm/y in the northern and the central rhombic block to 11.7 mm/y in the southern rhombic block. The orientations of block motion vary from 99° in the north to 126 – 150° in the central area and 156 – 188° in the south, implying that the motion of the Sichuan – Yunnan rhombic block is dominated by a clockwise rotation. The velocity differences between blocks inside and outside the rhombic block are about 6.5 – 7.7 mm/y in the northern and central Sichuan – Yunnan region. The southeastward extrusion rate of the Tibetan Plateau shows a remarkable downtrend of up to 47% along the Xianshuihe Fault, suggesting an increase in strain accumulation and hence an area prone to strong earthquakes. The horizontal coseismic deformation caused by the Mw9.0 Sumatra – Andaman earthquake is <10 mm with a south-southeast orientation towards the earthquake epicentre. The dilatational strain rates from coseismic displacements reveal a possible interaction between the extrusion from the Tibet plateau interior and the underthrust effects from the Sumatra – Andaman earthquake.  相似文献   

Evolution of superhigh magnetic fields of magnetars     

Z. F. Gao  N. Wang  J. P. Yuan  L. Jiang  D. L. Song  E. L. Qiao 《Astrophysics and Space Science》2011,333(2):427-435

In this paper, we consider the effect of Landau levels on the decay of superhigh magnetic fields of magnetars. Applying ³ P ₂ anisotropic neutron superfluid theory yield a second-order differential equation for a superhigh magnetic field B and its evolutionary timescale t. The superhigh magnetic fields may evolve on timescales ∼(10⁶–10⁷) yrs for common magnetars. According to our model, the activity of a magnetar may originate from instability caused by the high electron Fermi energy.  相似文献   

A Research on the Gravitational Wave Radiation of OJ 287     

Sun Yu-Tao  Liu Jie-Ying  Liu Jin-zhong  Ai Yan-Li  Zhou Ming  Qiao Er-lin   《Chinese Astronomy and Astrophysics》2011,35(2):103

The research on quasar OJ 287 has lasted over 100 years. OJ 287 exhibits the phenomenon of periodic two-peak outbursts with the eruptive period of 12 years. Observations are rather well interpreted with the black hole binary model. In this model, the secondary black hole moves around the primary black hole and crashes against the accretion disk of the primary black hole, causing outbursts. This model reasonably explains the light curves of OJ 287 and correctly predicts the time of future outbursts. These indirectly justify the precessional effect of general relativity and the existence of gravitational waves. The massive black hole in the center of galaxy is an important kind of gravitational wave source. However, the number of the galaxies with precisely determined kinematical equations of inner components is quite small. The precise kinematic orbits of black holes are provided by the black hole binary model, so the radiation of gravitational waves can be studied on the basis of these kinematic orbits. Based on the existing work, the evolutionary relations of the radiation power and waveform of gravitational waves with time are first derived by using the post-Newtonian approximation method. According to the current progress of the detection equipment of gravitational waves, i.e., IPTA (International Pulsar Timing Array), the direct detection of gravitational waves from OJ 287 may be possible within the future decade.  相似文献   

Precise Positions of Triton in 2010-2014 based on Gaia-DR2     

Huiyan Zhang  Yong Yu  Dan Yan  Kai Tang  Rongchuan Qiao 《天文和天体物理学研究(英文版)》2022,(3):57-60

With unique orbital and physical characteristics,Triton is a very important target because it may contain information of the origin and evolution of the solar s...  相似文献   

Influence of Active Control Strategy on the Motion Compensation at the Truncated Point of Mooring Line     

Qiao  Dong-sheng  Yin  Li  Yan  Jun  Tang  Wei  Ning  De-zhi  Li  Bin-bin  Ou  Jin-ping 《中国海洋工程》2021,35(5):700-711

The maximum predicting error of the commonly used passive truncated mooring system method may reach 30% due to the difference of dynamic characteristics between the truncated and full-depth mooring line. In this paper, the experimental strategy called three-parameter (displacement, velocity and acceleration) active control method at the truncated point of mooring line is established to implement the synchronous equivalent of motion and force, and the realization of active truncated mooring system for model test is studied theoretically. The influences of three-parameter and one-parameter (displacement) active control strategies on the compensation effects are compared by numerical study. The results show that the established three-parameter active control method can feasibly realize the static and dynamic equivalent of truncated and full-depth mooring system, laying a good foundation for the following physical model test of active truncated mooring system.

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基于GA-BP神经网络的高铁线下工程沉降预测模型     

刘龙  张献州  喻巧  甄亚男 《测绘工程》2014,(5):58-61

结合遗传算法与BP神经网络模型,介绍GA-BP模型的基本原理,建立高速铁路线下工程遗传BP神经网络沉降预测模型,并探讨模型精度的影响因子。通过实例分析表明GA-BP模型具有预测精度高、收敛速度快的特性,进而验证GA-BP模型在高速铁路线下工程沉降预测评估中的科学实用性。  相似文献