梵净山地区镁铁质-超镁铁质侵入岩特征及其意义

梵净山地区中元古代地层发育,侵位于其中的镁铁质—超镁铁质岩的岩类齐全、旋回性好,厚度大,是中国南方研究该幔源岩的良好地区,特别对探讨Rodinia超大陆的演化具有重要的科学意义。     

A comparative study of different model families for the constitutive simulation of viscous clays

The simulation of the viscous behavior of some clays is of high importance in many geotechnical problems. The literature offers a vast amount of constitutive models able to simulate the rate dependence observed on these materials. Although most of these models are calibrated to very similar experimental observations and share similar definitions of material parameters, some discrepancies of their response have been detected, which are related to their mathematical formulations. In this work, the causes of these discrepancies are carefully studied. To that end, four different model families are analyzed, namely, nonstationary flow surface (NSFS) models, viscoplasticity with overstress function (OVP), viscoplasticity with Norton's power law (NVP), and visco-hypoplasticity (VHP). For the sake of a fair comparison, single constitutive models using the same set of material parameters, and following other requirements, are developed for each model family. Numerical implementations of the four resulting models are performed. Their response at different tests are carefully analyzed through simulation examples and direct examination of their constitutive equations. The set includes some basic tests at isotropic stress states and others as responses envelopes, undrained creep rupture, and an oedometer test with loading, unloading-reloading, creep, and relaxation. The article is concluded with some remarks about the observed discrepancies of these model families.     

德江县大元萤石矿床地质特征及控矿因素

德江县大元萤石矿床位于务川汞矿带金鸡岭背斜的南东翼,矿体(脉)赋存于寒武系下统清虚洞组第一段白云质灰岩中,产出层位独特,矿物组合简单,矿石质量尤佳。经初步研究认为,萤石矿床的形成与地下低温热卤水的活动有关,并严格受张性断裂、岩相古地理和地层岩石组合的综合控制,具有明显的层控特征,其成矿时代归属燕山期。     

由滞回曲线的形态特征分析冻结黏土的动力特性

利用滞回曲线研究冻结黏土的动力学特性。结果表明,当土体温度为-0.5 ℃～-4 ℃、荷载频率为1～10 Hz时,随温度的降低和动荷载振动频率的增加,冻结黏土的刚度逐渐增大,黏滞性、细观损伤程度、塑性变形和能量耗散能力逐渐减小,当土中温度低于-4 ℃或荷载频率高于10 Hz时,土的动力特性变化不明显;随动应力幅值的增大,刚度逐渐减小,黏滞性、细观损伤程度、塑性变形和能量耗散能力逐渐增大;相同动应力幅值下,刚度、黏滞性、细观损伤程度、塑性变形和能量耗散能力受温度影响最大,围压影响最小,频率影响居中;试验温度、频率和围压三因素对冻结黏土的细观损伤程度和塑性变形能力影响程度最大,对黏滞性和耗能能力的影响程度基本相同,位于第二,对刚度的影响程度最小。     

新疆哈密黄山杂岩体岩浆动力学计算及成岩模式

本文通过岩浆粘度、密度、不混溶分离速度及岩浆沿裂隙上升速度等的计算,论证了黄山杂岩体第二侵入期岩浆发生液态不混溶的流体动力学条件,从而推断存在一个次级岩浆房,并认为这个次级岩浆房为液态不混溶分离提供了稳定空间。在此基础上,结合地幔中硫化物的分布特点和地幔岩块底辟上升模式,提出了第二侵入期岩浆的形成演化模式。     

阿尔金采石沟金铜多金属矿床地质地球化学特片及找矿前景分析

采石沟金铜多金属矿是受火山机构控制的火山-次火山岩型矿床,地表及浅部以金矿化为主,而深部则以含金的铜多金属矿床为主,具有寻找大型金及铜多金属的找矿潜力。     

Segmentation of complex geophysical structures with well data

In many problems of geophysical interest, when trying to segment images (i.e., to locate interfaces between different regions on the images), one has to deal with data that exhibit very complex structures. This occurs, for instance, when describing complex geophysical images (with layers, faults,...); in that case, segmentation is very difficult. Moreover, the segmentation process requires to take into account well data to interpolate, which implies integrating interpolation condition in the mathematical model.More precisely, let be a given bounded image function, where Ω is an open and bounded domain that belongs to . Let be a finite set of given points (well data). The aim is to find a contour Γ⊂Ω such that Γ is an object boundary interpolating the points from S. To do that, we combine the ideas of the geodesic active contour (Caselles et al., Int. J. Comput. Vision 22-1:61-87, 1997) and of interpolation of points (Zhao et al., Comput. Vis. Image Understand. 80:295-314, 1986) in a Level Set approach developed by Osher and Sethian (J. Comput. Phys. 79:12-49, 1988). We present modelling of the proposed method. Both theoretical results (viscosity solution) and numerical results (on a velocity model for a real seismic line) are given.     

湖南郴州荷花坪锡多金属矿床地质特征

分析总结区内地层、构造、岩浆岩与矿床的关系,矿区有利赋矿层位为中泥盆统棋梓桥组底部不纯灰岩,NE向成矿构造发育,燕山期花岗质岩浆活动强烈,成矿地质条件非常有利。将荷花坪锡多金属矿床类型分为矽卡岩—锡石硫化物型、破碎带蚀变岩型、蚀变花岗斑岩型三种,其中泥盆统棋梓桥组底部不纯灰岩中的似层状矽卡岩—锡石硫化物型矿床规模巨大,找矿前景非常可观。     

青海阿尔金采石沟金-铜多金属矿床地质特征及成因分析

阿尔金采石沟金-铜多金属矿是受火山机构控制的火山一次火山岩型矿床，产于火山一次火山岩岩体周边环状、放射状断裂构造中，矿体形态以脉状为主。地表及浅部以金矿化为主，而深部则以含金的铜多金属矿床为主，具有大型金及铜多金属的找矿潜力。文章就采石沟金矿地质特征及成因作初步探讨。     

利用自然伽马能谱确定地层岩性的方法

地层中的放射性核素Th、U和K的分布规律,与岩石的岩性、矿物成分、成岩环境和地下水活动有关。本文根据三肇地区27口探井的646个取心岩样的自然伽马能谱和室内分析出的岩性,通过自然伽马能谱数据库管理系统,给出Th-U交会图和Th-K交会图,从而找出自然伽马能谐与岩性的关系。