浙江中生代浅成热液金银成矿作用的耗散结构模型     

胡永和  王建国  朱兴盛 《浙江国土资源》2001,17(2):17-26

浙江中生代主要浅成热液金银矿床在蚀变-矿化过程中的一些物理化学特征参数(如T、P、St和ρ等)呈非线性的变化关系,其控制变量是P、T和PH值.推断条带(或环带)状构造的矿脉(石)是由减压沸腾作用造成的.据Drummond等(1985)沸腾的模拟计算和研究表明,[H+]浓度是决定沸腾热液中的Au、Ag等成矿元素命运的主要因素.因此,可以[H+]浓度(状态变量)作为序参量来反映成矿溶液中Au、Ag浓度的变化趋势;并建立其自组织过程的动力学方程与开放沸腾热液系统Au、Ag沉淀的耗散结构模型.  相似文献   

广西平桂地区观赏石简介     

陈志强  刘志乾 《南方国土资源》1993,(2)

广西平桂地区观赏石资源丰富。本文简介该区观赏石的常见品种及其特点、成因类型、分布规律、质量评价及开发前景。  相似文献   

桂东南那卜地区古生代变质岩系的构造演化序列     

覃小锋  李锦诚 《南方国土资源》2001,14(2):7-13

桂东南那卜地区古生代变质岩系 ,主要由花岗质岩石 (宁潭超单元 )和古生界组成。岩石构造变形强烈 ,构造形迹复杂 ,根据不同尺度上观察到的各种构造要素的几何学、运动学、构造应力场以及相互叠加关系等特征 ,可将其组成不同的构造组合 (群落 )。依据各构造组合之间的相互关系、同位素年龄 ,并结合相应的变质事件和岩浆活动事件等 ,建立起 2个旋回和 4个世代的构造变形序列。并初步探讨了古生代变质岩系的构造演化过程。  相似文献   

A Generalized Backward Euler algorithm for the numerical integration of an isotropic hardening elastoplastic model for mechanical and chemical degradation of bonded geomaterials     

Claudio Tamagnini  Riccardo Castellanza  Roberto Nova 《国际地质力学数值与分析法杂志》2002,26(10):963-1004

An extended version of the classical Generalized Backward Euler (GBE) algorithm is proposed for the numerical integration of a three‐invariant isotropic‐hardening elastoplastic model for cemented soils or weak rocks undergoing mechanical and non‐mechanical degradation processes. The restriction to isotropy allows to formulate the return mapping algorithm in the space of principal elastic strains. In this way, an efficient and robust integration scheme is developed which can be applied to relatively complex yield surface and plastic potential functions. Moreover, the proposed algorithm can be linearized in closed form, thus allowing for quadratic convergence in the global Newton iteration. A series of numerical experiments are performed to illustrate the accuracy and convergence properties of the algorithm. Selected results from a finite element analysis of a circular footing on a soft rock layer undergoing chemical weathering are then presented to illustrate the algorithm performance at the boundary value problem level. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

卢氏西虎岭黄铁矿床围岩蚀变特征及其找矿意义     

阎五成 《河南国土资源》1996,(2)

文章通过对西虎岭黄铁矿床围岩蚀变的研究认为，围岩蚀变大致可分为６种基本蚀变类型，５个蚀变阶段，３个蚀变带。各蚀变带以矿体为中心对称分布，各带之间呈渐变过渡关系。同时认为矿床成因类型属中低温热液充填型，并指出围岩蚀变的找矿意义。  相似文献   

地震属性分析在块碳酸盐岩储层研究中的应用   总被引：2，自引：0，他引：2  

马伯林 《安徽地质》2007,17(1):40-45

通过对也门1区块地层特征及电测资料的分析,从目的层段精细层位标定入手,确定属性提取的时窗大小,沿层提取1区块西北部盐上、盐下两套碳酸盐岩储集层地震属性.综合应用地震属性技术研究碳酸盐储层的剖面和平面分布特征,预测碳酸盐储层"孔-洞-缝"发育区.  相似文献   

刘店煤矿岩浆侵入与煤质特征初探   总被引：1，自引：0，他引：1  

陈富勇 《安徽地质》2007,17(1):34-36

岩浆侵入是煤矿常见的构造现象之一,岩浆侵入后对煤层与煤质的影响也十分明显,岩浆侵入不仅破坏了煤层的原生结构、厚度、构造,还改变了煤质.本文依据刘店煤矿的勘探资料,对淮北矿业集团公司筹建矿井--刘店煤矿的岩浆侵入与煤质特征进行了探讨,以期为刘店煤矿的生产提供有益的帮助.  相似文献   

面向自动综合的河系结构化模型研究   总被引：1，自引：0，他引：1  

翟仁键  薛本新 《测绘科学技术学报》2007,24(4):294-298,302

针对地图上河流的自动综合,建立了基于河段的河系结构化数据模型,该模型充分考虑了河段与河段、河段与面状水系要素之间的空间关系,以及河系河段的层次关系;建立了一种面向自动综合的河系结构化数据模型,模型包含了大量水系综合所需要的信息.基于上述数据模型,设计了一种方便快捷的河系结构化算法,该算法较好地克服了现有河系结构化算法只针对河流以及只适用于形态相对简单的河系的缺陷,较为全面地考虑了河系结构中出现的各种复杂问题,具有较强的实用性.  相似文献   

Trace element and Nd isotope analyses of apatite in granitoids and metamorphosed granitoids from the eastern Central Asian Orogenic Belt: Implications for petrogenesis and post-magmatic alteration     

《地学前缘(英文版)》2023,14(2):101517

We present in situ trace element and Nd isotopic data of apatites from metamorphosed and metasomatized (i.e., altered) and unaltered granitoids in the Songnen and Jiamusi massifs in the eastern Central Asian Orogenic Belt, with the aim of fingerprinting granitoid petrogenesis, including both the magmatic and post-magmatic evolution processes. Apatites from altered granitoids (AG) and unaltered granitoids (UG) are characterized by distinct textures and geochemical compositions. Apatites from AG have irregular rim overgrowths and complex internal textures, along with low contents of rare earth elements (REEs), suggesting the re-precipitation of apatite during epidote crystallization and/or leaching of REEs from apatite by metasomatic fluids. ε_Nd(t) values of the these apatites are decoupled from zircon ε_Hf(t) values for most samples, which can be attributed to the higher mobility of Nd as compared to Sm in certain fluids. Apatites from UG are of igneous origin based on their homogeneous or concentric zoned textures and coupled Nd-Hf isotopic compositions. Trace element variations in igneous apatite are controlled primarily by the geochemical composition of the parental melt, fractional crystallization of other REE-bearing minerals, and changes in partition coefficients. Sr contents and Eu/Eu* values of apatites from UG correlate with whole-rock Sr and SiO₂ contents, highlighting the effects of plagioclase fractionation during magma evolution. Apatites from UG can be subdivided into four groups based on REE contents. Group 1 apatites have REE patterns similar to the host granitoids, but are slightly enriched in middle REEs, reflecting the influence of the parental melt composition and REE partitioning. Group 2 apatites exhibit strong light REE depletions, whereas Group 3 apatites are depleted in middle and heavy REEs, indicative of the crystallization of epidote-group minerals and hornblende before and/or during apatite crystallization, respectively. Group 4 apatites are depleted in heavy REEs, but enriched in Sr, which are features of adakites. Some unusual geochemical features of the apatites, including the REE patterns, Sr contents, Eu anomalies, and Nd isotopic compositions, indicate that inherited apatites are likely to retain the geochemical features of their parental magmas, and thus provide a record of small-scale crustal assimilation during magma evolution that is not evident from the whole-rock geochemistry.  相似文献   

Late Jurassic Volcanism Deduced from Geochemical,Geochronological, and Sr-Nd-Hf Isotopic Composition Characteristics of the Nanyuan Formation,South China     

WANG Dongsheng  LI Jinwen  SHE Hongquan  WANG Kunming  YANG Junzhi  REN Chenghao 《《地质学报》英文版》2023,97(2):449-468

The Nanyuan Formation contains information related to the Mesozoic tectonic transformation. In this study, three representative profiles were surveyed from the Nanyuan Formation, and multiple analyses were conducted. Zircon U-Pb dating yielded their ages as approximately 158–146 Ma. The volcanic rocks are enriched in Rb, Th, U, K, and Pb and depleted in Nb, Ta, P, and Ti, implying their affinity for I-type granites. The ε_Nd(t) values(-8.3 to-6.0),(⁸⁷Sr/⁸⁶Sr)_...  相似文献