Physics of ore formation

The physics of the ore formation process is discussed using three parageneses of gold, viz., quartz, carbon, and pyrite, as examples. It is inferred that paragenetic associations in ore deposits are formed on a physical basis under the influence of magnetic fields of nuclides and electrons.     

The physics of ore formation

Ore formation is considered in the paper. The consideration is based on the topology of chemical elements that was discovered by the authors in 2007 as a result of the study of the Fibonacci distribution of chemical elements. On thoroughly analyzing the physical background of ore formation, we have concluded that spin effects play the leading role in the formation of paragenetic assemblages. The nuclear properties of elements should be taken into account in elucidating this problem.     

Addressing ore formation and exploration

Common base and noble metals represent an important economic factor in the actual industrial development.For instance the world resources for copper are actually estimated for about the next 30 years only.The situation requires rethinking the way major ore deposits form,leading to new guides for exploration.The present paper briefly examines the processes leading to ore formation,in relation with granitic or granodioritic intrusions.It identifies the importance of metal enrichment during the magmatic stage.Within the magma chamber that forms porphyry intrusions,metals may incorporate to first formed crystals,becoming inert;concentrate into the residual melt of a mush;or segregate by diffusion into the exsolved magmatic volatile phase(MVP)into which they are transported and precipitated.A competition results between elements partitioning and diffusivity.Hence,a specific Peclet number for each metal(Cu,Au,Ag,Mo,W,Sn,and REE)controls the ratio between the diffusive and the advective flux.Metals diffusivity in the melt shows differential behavior relative to a threshold of about10 13 m2/s.Metals with slower diffusivity values(e.g.As)will not concentrate.Conversely,fast diffusive metals(Au,Ag,Cu)may rapidly incorporate the MVP,provided an adequate component(halogens or S)is attractive for metals.The chemistry of the MVP escaping the magma induces different alteration patterns.Their relative content in F,Cl or S,attested by the composition of biotites and apatites,links with the preferential content of metals in o re deposits,representing a valuable tool for exploration.Finally the model is replaced in a set of coupled mechanical-chemical instabilities,within a three phase material.     

Alteration products of melanterite from Nikitov mercury ore deposits

Siderotil, szomolnokite, and rhoinboclase appear to be the early products of the alteration, as a rule, in different ratios, depending on the environmental variables. The other secondary minerals develop only on large aggregates of melanterite, by crystallization from water which evaporates from the surface of such aggregates. -- V.P. Sokoloff     

矿床形成深度与深部成矿预测

摘要：阐述了不同类型内生矿床的成矿深度和金属沉淀的垂直范围。热液成矿作用的深度下限可以下降到10000～12000m。不同类型矿床的成矿深度范围与成矿时的具体地质构造特征有关,且有很大的变化空间。金属矿床的形成深度受成矿母岩岩浆侵位深度的约束,而岩浆侵位的深度又与岩浆中挥发组分的数量、流体释放的时间、成矿元素的矿物/熔体和溶液/熔体分配系数等因素有关。据此可以解释斑岩铜－（钼）、斑岩钼-(铜)和斑岩钨矿床形成深度的差异。地温梯度和多孔岩石的渗透率也与成矿深度有关。CO2等挥发组分的溶解度对压力非常敏感,因此流体包裹体地质压力计对于成矿深度的确定有重要的应用价值。在开展深部成矿预测和找矿时,探寻隐伏岩体顶上带或岩钟是寻找深部与花岗岩有关的多金属矿床的捷径之一。     

矿床形成深度与深部成矿预测

摘要：阐述了不同类型内生矿床的成矿深度和金属沉淀的垂直范围。热液成矿作用的深度下限可以下降到10000～12000m。不同类型矿床的成矿深度范围与成矿时的具体地质构造特征有关,且有很大的变化空间。金属矿床的形成深度受成矿母岩岩浆侵位深度的约束,而岩浆侵位的深度又与岩浆中挥发组分的数量、流体释放的时间、成矿元素的矿物/熔体和溶液/熔体分配系数等因素有关。据此可以解释斑岩铜－（钼）、斑岩钼-(铜)和斑岩钨矿床形成深度的差异。地温梯度和多孔岩石的渗透率也与成矿深度有关。CO2等挥发组分的溶解度对压力非常敏感,因此流体包裹体地质压力计对于成矿深度的确定有重要的应用价值。在开展深部成矿预测和找矿时,探寻隐伏岩体顶上带或岩钟是寻找深部与花岗岩有关的多金属矿床的捷径之一。     

矿床形成深度与深部成矿预测

阐述了不同类型内生矿床的成矿深度和金属沉淀的垂直范围。热液成矿作用的深度下限可以下降到10000～12000m。不同类型矿床的成矿深度范围与成矿时的具体地质构造特征有关,且有很大的变化空间。金属矿床的形成深度受成矿母岩岩浆侵位深度的约束,而岩浆侵位的深度又与岩浆中挥发组分的数量、流体释放的时间、成矿元素的矿物/熔体和溶液/熔体分配系数等因素有关。据此可以解释斑岩铜-(钼)、斑岩钼-(铜)和斑岩钨矿床形成深度的差异。地温梯度和多孔岩石的渗透率也与成矿深度有关。CO2等挥发组分的溶解度对压力非常敏感,因此流体包裹体地质压力计对于成矿深度的确定有重要的应用价值。在开展深部成矿预测和找矿时,探寻隐伏岩体顶上带或岩钟是寻找深部与花岗岩有关的多金属矿床的捷径之一。     

A case history of finding ore deposits by mercury gas survey

Low-temperature absorption mercury (LTAM) surveys and soil gas mercury (SGM) surveys were carried out in Hou Poaou Sn-Pb-Zn mine in Chao'an County, Guangdong Province, where widespread heavy overburden and carbonaceous shale made conventional geophysical and geochemical methods ineffective. Distinct LTAM and SGM anomalies were delineated over known ore lodes and their unknown extensions under heavy overburden, and new ore lodes were discovered. The transportation and transformation of Hg are discussed to explain the effectiveness of Hg surveys in such environments.     

Regularities of ore formation in mid-ocean ridges

The regularities of the concentration of ore matter in the mid-ocean ridges are considered, and the mechanisms of hydrothermal and cumulative treatment of the crust by ore elements are substantiated.     

Some aspects of ore formation in ultramafics

The relationship between petrogenesis and ore formation during the development of ultrabasics is discussed. It is emphasized that it is different for deep-seated pyrope peridotite and shallower spinel-enstatite peridotite facies. The influence of depth (pressure) on the composition of fluids which accompany ultrabasic magmatism is considered. It is inferred that the pressure is responsible for H₂O and CO₂ prevailing in fluid inclusions in diamonds. Regular compositional correlations are established for chrome-spinellids (chromites) and rock-forming chrome-spinellids, as well as general correlations between the compositions of chromite and sulphide mineralization and surrounding ultrabasics. These correlations indicate that liquid immiscibility was responsible for the separation of ore-forming magmas from ultramafic silicate melts of various compositions. The general specificity of orecontent in ultramafic complexes is explained by means of the hypothesis on basic-ultrabasic immiscibility in magmas under the influence of fluid components, with hydrogen and hydrogen sulphide playing an important role. Rhythmic layering in massifs is explained by repeated separation of the developed magmatic layers as well as by differentiation crystallization proceeding under the effect of temperature and magmatic composition gradients. Rhythmic layering reflects the departure of the magmatic systems from equilibrium on fast cooling, much in the same way as zoning in crystals.     

Supergene processes and uranium ore formation in the Ronneburg ore field,Germany

The Ordovician-Lower Carboniferous sequence of slightly metamorphosed gray carbonate-terrigenous rocks contains the Silurian black cherty shales enriched in carbon (6–9%), pyrite (6–7%), and uranium (∼30 ppm). The uranium ore is localized at the pinch-out of areal and linear zones of the Early Permian supergene (exogenic) oxidation of rocks expressed in reddening (hematitization). U, As, Sb, Cu, Ni, Mo, and Ag have been removed from the oxidized black shales and concentrated in the cementation zone in form of pitchblende and sulfides in wall-rock disseminations and veinlets largely hosted in carbonate-bearing rocks. In the Late Permian, during deposition of the upper Rotliegende and Zechstein, the fractures in the basement were filled with carbonates and sulfates; uranium was partly redeposited along with enrichment in Pb and Zn. Mesozoic and Cenozoic supergene processes altered uranium ore insignificantly.     

The speciation of mercury in hydrothermal systems,with applications to ore deposition

Hg in hydrothermal systems is generally thought to be transported as Hg-S complexes. However, the abundance of Hg⁰_vap, in geothermal emissions suggests that Hg⁰_eq, is present in the liquid phase of geothermal systems. Calculations for reducing fluids (HS^? dominant over SO⁼₄) in equilibrium with cinnabar indicate that Hg⁰_eq, can be quite abundant relative to other species at temperatures above 200°C. Increasing pH and temperature, and decreasing total S, ionic strength, and pO₂ all promote the abundance of Hg⁰_eq. When a vapor phase develops from a geothermal liquid, Hg partitions strongly into the vapor as Hg⁰_vap. Vapor transport at shallow level then results in the formation of Hg halos around shallow aquifers as well as in a flux of Hg to the atmosphere. Hg deposition may occur in response to mixing with oxidizing or acidic water, turning Hg⁰_eq, into Hg⁺⁺, with subsequent cinnabar precipitation. When pyrite is the stable Fe-sulfide, cinnabar solubility is at its lowest, so cinnabar + pyrite assemblages are common. Cinnabar + hematite ± pyrite can precipitate from more oxidized or S-poor water. Hg⁰_liq, can occur as a primary mineral, in coexistence with all common Fe-sulfides and oxides. Cinnabar ± Hg⁰_liq cannot coexist with pyrrhotite or magnetite at temperatures between 100° and 250°C. Evidence from Hg deposits indicates that many formed from dilute hydrothermal fluids in which Hg probably occurred as Hg⁰_eq. In S-rich systems, Hg may occur as Hg-S complexes, and in saline waters it can occur as Hg-Cl complexes.     

沉积环境有机质及在铀成矿中的作用研究

通过系统研究,将沉积环境有机质分为可确定或未确定的高相对分子质量有机物质、简单物质和腐殖质3个主要部分,一般称为非腐殖质和腐殖质2个部分.非腐殖质系指那些可被列入单独的化合物类别中的有机化合物,主要包括糖、脂类和氨基酸;腐殖质系指那些很难确定的不能再分成其他化合物的有机化合物,据其溶解性质和颜色特征,腐殖质分为黄腐酸、...     

金矿焙烧工艺生产处理液中汞测量不确定度的评定

本文针对原子荧光对金矿焙烧工艺生产中汞处理液的测定,找出了影响其测量不确定度的因素,建立了数学模型,计算出各不确定度的分量,求出合成标准不确定度及扩展不确定度。     

Recent iron ore formation in Lake Malawi,Africa

Nontronite, limonite (with opal) and vivianite are forming at present in the aereated, shallower parts (water depths <250 m) of Lake Malawi. They overlie diatomite or coarse grained clastic sediments. Our investigations indicate a precipitation of nontronite and limonite (and opal) at the sediment/oxic water interface from geothermal solutions rich in SiO₂ percolating through the sedimentary fill of the basin. Under reducing conditions and a pH less than 7 (as occurring in the deeper parts of our sediment cores) iron and manganese are leached and discharged into the lake. In the anoxic parts of the lake (water depth greater than 250 m) Fe³⁺- and Mn³⁺-hydroxide are precipitated within the lake's water in the mixing zone of the aerobic with the anaerobic water bodies. High dispersion and a strong supply of detrital material, however, prevent a stronger enrichment of the hydroxides in the sediment. The formation of vivianite can be explained by a dissolution of Ca-phosphate (fish debris) within the sediment and a re-deposition as Fe-phosphate in the uppermost sediment layers under reducing but slightly alkaline conditions. The results of our investigations on Recent iron formation in Lake Malawi offer an explanation for the genesis of certain sedimentary iron ores in the geological past. They indicate that a formation of iron-rich sediments — including the silicate facies — is not restricted to the marine environment.

---

Zusammenfassung Nontronit, Limonit (und Opal) sowie Vivianit werden an zahlreichen Stellen des südlichen Malawi-Sees in Wassertiefen bis 250 m (aerober Bereich) abgeschieden und bilden dort die jüngste sedimentäre Einheit über Diatomit oder grobklastischem Sediment. Es muß angenommen werden, daß die Bildung der Eisenmineralien aus geothermalen Lösungen erfolgt, die reich an gelöster Kieselsäure und Fe²⁺ (untergeordnet Mn²⁺) sind, wobei Eisen und Mangan aus dem Sediment selber stammen, da heiße Quellen außerhalb des Malawi-Sees diese Elemente nicht enthalten. Die Auslösung von Eisen und Mangan erfolgt durch saure Lösungen im reduzierenden Milieu unter Bedingungen, wie sie im tieferen Teil der Sediment-Kerne angetroffen wurden (pH bis 3,6!). Beim Zusammentreffen dieser Lösungen mit dem sauerstoffhaltigen, schwach alkalischen Wasser des Malawi-Sees kommt es zur Ausfällung von Nontronit oder — bei wahrscheinlich höherem Redox-Potential — von Limonit und Opal. Beim Austritt der Fe²⁺, Mn²⁺- und SiO₂-reichen Lösungen in den anaeroben Teil des Malawi-Sees (Wassertiefen größer als 250 m) unterbleibt zunächst eine Ausfällung. Erst in der Mischzone des anoxischen mit dem oxischen Wasserkörper können Fe³⁺- und Mn³⁺-Hydroxide ausgeschieden werden, die jedoch infolge hoher Dispergierung und starker Zufuhr von klastischem Material eine starke Verdünnung erfahren. Für die Vivianit-Bildung kann angenommen werden, daß ein in den Sedimenten häufig vorhandener Apatit-Anteil (Fischreste) durch die sauren Lösungen aufgelöst und in den obersten Sedimentschichten (reduzierendes Milieu, pH jedoch >7) zusammen mit Fe²⁺ der Lösung als Vivianit abgeschieden wird. Die vorliegenden Untersuchungen geben Hinweise auf die Bildung bestimmter fossiler sedimentärer Eisenerze und zeigen gleichzeitig, daß die Genese eisenreicher Sedimente — auch von silikatischem Fazies-Typ — nicht an den marinen Ablagerungsraum gebunden ist.

     

地球化学位场（以矿床生成场为例）

一、引言及符号进行物理作用的空间范围称为场。地球空间中某物质系某相中某组分进行扩散时受到了扩散作用力,呈该性质的地球空间范围称为地球化学位场或扩散作用力场。本文从上述观点出发,以单一组分组成的理想气体为模型,应用了作者建议的光子原理化学热力学方法,