Discrete multifractals

The concept of multifractal modeling has been used intensively in various fields of science for characterizing measures with self- similarity. It has been shown that multifractal modeling provides powerful tools for characterizing patterns in the spatial distribution of geological quantities and objects. Existing multifractal models were proposed for the purpose of handling spatially intertwined fractals with continuous fractal spectrum f(α) (or continuous codimension function C(γ)). In this paper, these conventional multifractals are termed “continuous multifractals” whereas multifractals with discrete fractal dimensions are termed “discrete multifractals.” The properties of discrete multifractals are investigated. It is shown by various artificial examples and a case study of stratigraphy of Ocean Drilling Program (ODP) site 645 that spatially intertwined fractals/multifractals indeed can have discrete fractal dimensions. Histogram-and moment-based techniques are proposed for discrete multifractal modeling and illustrated using the artificial examples. The new concept of discrete multifractals and associated multifractal modeling yields not only techniques for characterizing multifractals with discrete fractal dimensions but it also provides insight into the relationships between fractals, bifractals, and multifractals.     

美国内华达Goldstrike矿区卡林型贝茨金矿同变形的富矿分带(续)

(接第 1期第 1 6页 )3　富矿分带与控制因素贝茨金矿中不同矿石矿物组合和蚀变类型的分布与构造背景、围岩岩石及在矿体中的位置有关。根据形态、矿物组成和地质背景可分出几种空间形式截然不同的矿石类型 ,彼此之间由废石或低含金量的岩石所分隔。富矿体的地球化学、矿物学、地质及冶金方面的分带在三维空间上是连续的。富矿体的形状和定位与 Peters向斜构造的特征 ,沉积岩的岩石组成以及闪长岩接触带的几何形态和厚度有关 (图 6 A,B)。根据对不同的矿石类型和围岩类型的研究结果 ,对不同的富矿体进行了分类和判别。 Pe-ters( 1 996 ,1 9…     

赣西卡林型金矿控矿条件及成矿模式

论述了赣西卡林型金矿与基底地层、地层层位、岩性、构造及岩浆岩的关系，金的迁移富集形成与条件，建立了赣西卡林型金矿的成矿模式。     

The giant Carlin gold province: a protracted interplay of orogenic, basinal, and hydrothermal processes above a lithospheric boundary

Northern Nevada hosts the only province that contains multiple world-class Carlin-type gold deposits. The first-order control on the uniqueness of this province is its anomalous far back-arc tectonic setting over the rifted North American paleocontinental margin that separates Precambrian from Phanerozoic subcontinental lithospheric mantle. Globally, most other significant gold provinces form in volcanic arcs and accreted terranes proximal to convergent margins. In northern Nevada, periodic reactivation of basement faults along this margin focused and amplified subsequent geological events. Early basement faults localized Devonian synsedimentary extension and normal faulting. These controlled the geometry of the Devonian sedimentary basin architecture and focused the discharge of basinal brines that deposited syngenetic gold along the basin margins. Inversion of these basins and faults during subsequent contraction produced the complex elongate structural culminations that characterize the anomalous mineral deposit “trends.” Subsequently, these features localized repeated episodes of shallow magmatic and hydrothermal activity that also deposited some gold. During a pulse of Eocene extension, these faults focused advection of Carlin-type fluids, which had the opportunity to leach gold from gold-enriched sequences and deposit it in reactive miogeoclinal host rocks below the hydrologic seal at the Roberts Mountain thrust contact. Hence, the vast endowment of the Carlin province resulted from the conjunction of spatially superposed events localized by long-lived basement structures in a highly anomalous tectonic setting, rather than by the sole operation of special magmatic or fluid-related processes. An important indicator of the longevity of this basement control is the superposition of different gold deposit types (e.g., Sedex, porphyry, Carlin-type, epithermal, and hot spring deposits) that formed repeatedly between the Devonian and Miocene time along the trends. Interestingly, the large Cretaceous Alaska–Yukon intrusion-related gold deposits (e.g., Fort Knox) are associated with the northern extension of the same lithospheric margin in the Selwyn basin, which experienced an analogous series of geologic events.     

西秦岭地区造山型与卡林型金矿床

西秦岭金矿床分为卡林型和造山型两类。卡林型金矿床麇集于南秦岭和松潘—甘孜造山带的东北部。三叠纪和早侏罗世的同构造花岗闪长岩广泛分布于西秦岭中部和南部、松潘—甘孜盆地以及扬子克拉通边缘。造山型脉状金矿床主要分布于西秦岭造山带中的脆韧性剪切带内。大部分粗粒金主要赋存在网格状石英细脉和角砾状围岩中的黄铁矿、磁黄铁矿、毒砂和少量贱金属硫化物中和以分散状分布在蚀变围岩中。同位素资料表明晚三叠世 -中侏罗世与扬子克拉通俯冲有关的作用控制了造山型金矿床的形成。     

甘肃文县地区阳山超大微细浸染型金矿床的成因与类型

含矿岩石为本区泥盆系的一套Au含量较高的炭-硅-泥质地层。其中发现大量含AS异常（含As约0．15％）的草莓状黄铁矿;矿体沿断裂带呈构造透镜体-扁豆体斜列等间距分布,产于断裂带中次级破碎带或顺层剪切带内;在早一中期阶段的矿化硫化物中,金以不可见金赋存于含As黄铁矿及毒砂中,含As黄铁矿发育增生环带,载金矿物主要沿片理化带呈微细浸染状分布;在中一晚期阶段的金属硫化物-石英碎裂脉体中,可见显微颗粒金;斜长花岗斑岩为地壳重熔型花岗岩．具多期次性：H、O、S同位素及流体包裹体资料表明,成矿流体以大气降水为主,岩浆水也参与成矿。由此可见,阳山金矿具沉积-岩浆叠加-构造及热液改造的多因复成特征,矿床属超大型卡林-类卡林复合型金矿床。     

秦岭卡林型金矿床金、砷地球化学探讨

讨论了秦岭卡林型金矿床中Ａｕ 、Ａｓ 的元素地球化学、矿物学特征。在含矿岩系中获得的Ａｕ、Ａｓ 等成矿元素初始含量较高,且主要集中在成岩黄铁矿中。在矿石样品中对含砷硫化物矿物的研究表明,Ａｕ 、Ａｓ 在矿物显微结构中具有强的正相关性。在大量金进入到硫化物结构之前,就已有［ＡｓＳ］３ － 的存在。在含砷硫化物矿物中,金多半以一种带电类型（Ａｕ３ ＋） 存在, 它很可能替代铁位置上的过剩砷, 以固溶体方式沉淀于硫化物矿物中。此时, 黄铁矿构成（Ａｕ３ ＋ ,Ｆｅ２ ＋）（［ＡｓＳ］３ － ［Ｓ２］２ － ）,毒砂构成（Ａｕ３ ＋ ,Ｆｅ２ ＋）（［ＡｓＳ］３ － ［ＡｓＳ］３ －） 。通过电子探针（ＥＭＰ） 和透射电镜（ＴＥＭ） 对秦岭卡林型金矿含砷硫化物矿物中金的赋存状态的研究表明,在金的成矿作用早期阶段, 金主要以固溶体形式优先富集于含砷黄铁矿和毒砂及砷黝铜矿之中,并且认为是以金的氧化和砷的还原的共沉淀方式发生的。在此之后的金成矿作用晚期阶段,由于热液蚀变和结晶作用程度的增高,寄主矿物耐熔性质相对降低,加之金本身的聚集能力,和因过量砷加入而造成的含砷硫化物矿物的晶格缺陷,致使已形成的固溶体金以“出溶”形式发生再分布,赋存于硫化物矿物晶粒     

Geological-Geochemical Characteristics of Carlin-and Carlin-Like-Type Gold Deposits in south Qinling Mountains

In this paper an intergrated geological and geochemical comparison is made of Carlintype and Carlin-like-type gold depostis in the region of South Qinling with their associated hydrothermal sedimentary lead-zinc pdposits,the Carlin-type deposits in the Yunnan-Guizhou-Guangxi gold triangle,China,the Carlin gold deposits,Carlin,western United States,and the Muruntau-type gold deposits in Uzbekistan.The comparative study indicates that the formation of these deposits has an intimate coupling relation with the mechanism of the tectonic movement of modern plates.Therefore,these deposits belong to those that were formed in the orogenic stage. They have the following similar characteristics:they are all sediment-hosted.occur in a tectonic environment of extensional rifting nature and show the characteristics of syngenetically modified mineralization.On the other hand,they alsso have noticeable differences:they are different in respect to their tectonic settings.association and structure of orogenic belts and complexity and strength of the modified mineralization.The regional tectonic evolution and extensive mineralization in orogenic belts are different expressions of the same continental dynamic process.     

滇东南老寨湾金矿床主微量元素迁移及稀土元素地球化学特征

老寨湾金矿床位于扬子地台西南缘与华夏地块结合部位的南盘江造山褶皱带文山—富宁断褶束西畴拱凹北缘。矿体主要赋存于下泥盆统坡松冲组下段(D_1ps~1)石英砂岩、石英岩,硅化石英细砂岩、石英细砂岩中。本文运用Gresens和Grant提出的蚀变岩成分、体积公式和C_i~0—C_i~A图解法,对老寨湾金矿床岩(矿)石形成过程中主要元素迁移规律进行了研究,结果表明:1)石英砂岩在硅化过程中,SiO_2和As被带入,Au被带出进入流体;在氧化矿形成过程中,SiO_2和Au被带入;而在黄铁矿化矿石形成过程中,As、Au、FeO和Fe_2O_3被带入,SiO_2被带出。2)矿区各类岩(矿)石稀土元素分布模式图均呈右倾型式,为轻稀土富集型;氧化型岩(矿)石、硅化型岩(矿)石和石英砂岩的稀土元素分布型式类似,均表现为负铕异常,无明显的铈异常。3)黄铁矿化型矿石稀土元素分布模式图中样品分为2类:沉积成因和热液成因;沉积成因黄铁矿化型矿石含金低,w(ΣREE)值高,表现为负铕异常;热液成因黄铁矿化型矿石含金较高,w(ΣREE)值低,表现为正铕异常。4)黄铁矿化型矿石w(ΣREE)值明显低于其它几类岩矿石,说明热液型黄铁矿化型矿石的形成可能与矿区辉绿岩脉相关,表现出了深源的特征。     

南秦岭卡林型—似卡林型金矿床综合地质地球化学特征

笔者将南秦岭卡林型－似卡林型金矿床与与其共生的热水沉积成因铅锌矿床，中国滇黔桂卡林型金矿床、卡林型金矿床命名地美国西部卡林金矿床、乌兹别克斯坦穆龙套型金矿床等进行了地质地球化学综合对比研究，可以发现，这些矿床的形成均与现代板块构造活动机制具有密切耦合关系，属于造山期成矿矿床，它们既具有相似特点：容矿建造属沉积岩型，沉积构造环境具有拉张裂陷性质，均显示同生一叠加改造两次成矿作用的特征；它们又具明显差别；所属大地构造背景不同，造山带组成及结构存在明显差别，叠加改造成矿作用表现的复杂和强烈程度差别较大，造山带区域构造演化与大规模成矿作用是同一大陆动力学过程的不同表现。     

Structures and Implications for Fluid Migration in the Jiadi Carlin‐Type Gold Deposit,Guizhou Province,Southwest China

The Jiadi gold deposit is a newly discovered Carlin‐type gold deposit in the Guizhou Province, Southwest China. This deposit is structurally controlled by a shallow fold–fault superimposed system along the Lianhuashan trend. Field geological investigations, structural analysis, and mathematical research are conducted to study its structures and hydrothermal fluid flow process. Geological investigations (i.e. sections, stope, and drill hole) indicate that the structures are dominated by NE‐trending folds, NWW‐trending folds, and faults. A trend‐surface analysis of the low interformational fracture zone suggests that the overall distribution of the Lianhuashan trend is controlled by the NE‐trending Lianhuashan anticline. Nearly all primary Carlin‐type gold deposits are distributed along the southeastern flank where the fold axis changes from NE to EW. Gold orebodies are hosted by the interformational fracture zones and primarily situated at the transitions from the high‐value areas to the low‐value areas of the interformational fracture zones. A stress analysis on the hydrothermal veins indicates that they are of tenso‐shear properties. The ore‐forming elements (Au, As, Sb, Hg, and Tl) of the hydrothermal veins from the interformational fracture zones and intrusive breccia body present strong positive anomalies compared with those from the adjacent wall rocks. According to the development patterns of the ore‐forming elements and hydrothermal veins, a migration process of the ore‐forming fluids is proposed: the deeply sourced ore‐forming fluids migrated vertically to shallow crust along an intrusive breccia body, subsequently flowed horizontally along the interformational fracture zones accompanied by gold precipitation in the early stage, and finally migrated outward along steep micro‐fractures during following stages.     

甘肃寨上卡林型金矿床地质特征与控矿因素

寨上金矿床产于南秦岭古生代裂陷海槽局限盆地上泥盆统含C、Ca质复理石建造中，矿床规模较大，品位低，成矿元素复杂；受特定岩相沉积环境的含矿地层和后期陆内造山脆-韧性叠加断裂及伴随的成矿流体的联合控制；是西秦岭近2年新发现的较典型的沉积岩容矿的卡林型金矿床；由含As黄铁矿、含As黄铁矿-毒砂、铜-金与锑-金矿石组成；含Au黄铁矿、毒砂具有特征的增生环带结构；矿化带、矿体成矿元素具有Au-As-Hg-Cu-Pb-Zn-Ba组合特点。     

贵州省贞丰县那郎金矿点地质特征及找矿远景

文章以那郎金矿点勘查成果资料为依据,通过对该矿床的矿点地质特征、矿体特征等进行分析研究,初步总结了本区成矿控矿条件,并提出了找矿远景区及找矿方法。     

Entropy in Markov chains and discrimination of cyclic patterns in lithologic successions

The concept of Markov chains, applied to stratigraphic sections, is reliable in analyzing cyclic patterns in lithologic successions. Randomness in the occurrence of lithologies repeating in a succession is evaluated generally in terms of entropies which can be calculated for the Markov matrix equated with the succession. Two types of entropies pertain to every state; one is relevant to the Markov matrix expressing the upward transitions, and the other, relevant to the matrix expressing the downward transitions. The latter and the former with respect to a certain state, making an entropy set, correspond to the degree of randomness in its linking with the others which occur as the precursor and the successor, respectively. It is obvious that the entropy sets which are calculated for all state variables serve as a reliable criterion in the discrimination of cyclic pattern of the succession. We are able based on the entropy sets to classify the various patterns into asymmetric, symmetric, and random cycles, which are exhibited also in actual lithologic successions. The entropy sets are calculated for Markov matrices which have been reported from a number of areas in the world, and compared with the cyclic patterns supposed there. Entropy for the whole system of sedimentation also is introduced to discuss variability of the condition in the depositional processes.     

秦岭卡林型金矿床及相关问题探讨

鉴于目前对沉积岩型金矿、卡林型金矿概念和类型划分存在分岐,该文在对秦岭沉积岩区浸染状金矿研究基础上,主张将沉积岩为容矿岩石的金矿床划分为广义和狭义两类：沉积岩型金矿床是具有广义内涵的一类金矿,包容了从沉积－轻微改造,到沉积－强烈改造的一类热液金矿;可划分四种亚类：卡林型、变质细碎屑岩型、热水沉积岩型、脉状体型。卡林型金矿床是狭义内涵的金矿类型,属于沉积岩型金矿类型中的重要亚类;在区域金成矿密集区内,可构成卡林型矿床地球化学系列。建议不要将沉积岩型金矿和卡林型金矿相互代替使用或等同起来。秦岭沉积岩区卡林型金矿与美国卡林典型矿床有较好的类比性。矿床具有沉积－轻微改造的中—低温热液成因特征。     

锗、银、金大型超大型矿床的有机地球化学研究

锗、银、金大型超大型矿床的有机地球化学研究庄汉平（中国科学院地球化学研究所，贵阳５５０００２）关键词有机质—金属相互作用褐煤型超大型锗矿床黑色页岩型银钒矿床卡林型金矿床有机地球化学有机质—金属相互作用是有关超大型矿床基础理论研究的重要内容之一。在以往...     

鲁西地区绿岩带型金矿及其矿源层探讨

鲁西泰山岩群是我国典型的新太古代绿岩带,发育并保存了良好的科马提岩,对其地质认识已基本趋于一致,但对鲁西地区绿岩带型金矿的认识还不够深入和全面.以往仅对韧性剪切带型金矿有所了解,对绿岩带层控型金矿很少重视,对矿源层的理解也较为模糊,笼统地将泰山岩群作为后期各种金矿成矿的矿源层.本文对鲁西绿岩带韧性剪切带型和层控型金矿做了系统介绍,认为绿岩带层控型金矿具有原生层状特征和矿源层意义,受绿岩带某特定层位控制十分明显,是超基性岩—基性火山岩—碎屑沉积岩建造旋回过程中发展到一定阶段的产物.对鲁西地区金矿源层成生发育机制进行了探讨,认为绿岩带中金初始沉积矿化层位十分狭窄,厚度一般仅1至十几米,但横向分布较广泛,一般长达5～10 km以上,初始沉积金品位一般在10×10-9～0.5×10-6,其金质来源于海底火山喷流(热液和喷气)作用.阐述了金矿源层与条带状硅铁建造(BIF)往往密切伴生的成因联系,并与硅铁矿层一样,也具有多旋回性沉积特点.韧性剪切带型金矿受矿源层内在控制,产于矿源层内或附近.     

扬子地块西北缘及西南缘卡林型金矿的有机质地质地球化学

扬子地块西北缘，西南缘卡林型金矿床的有机碳含量为０．０５％－８．７３％。含金建造形成的环境不同，其改造成的金矿床的有机碳含量不同；矿化主岩的岩性不同，基有机碳的含量不同。由浊积岩型含金建筑改造成的卡林型金矿床，其干酪根属Ⅱ型酪根，原始有机母质属还原环境沉积的海相菌藻类生物演化成的腐泥型有机质。     

中国绿岩带金矿床的时空分布

绿岩带金矿床是在绿岩带形成和演化过程中形成的，在我国岩金矿产储量中占有很重要的地位。该类金矿床主要分布在华北地台的北缘和西南缘。金矿床的分布具有趋群性，成带性、受绿带层序、构造，岩浆作用，退变质带等多因素的控制。