作者通过对十几个典型金属矿床进行试验研究后,初步总结了各类金属矿床上方,有机烃气和汞气的常见模式,即不对称对偶双峰式、对称对偶双峰式、顶端单峰(或峰丛)式和双峰、单峰混合式。并从烃气和汞的运移通道、成矿期的热差效应、金属硫化物的氧化作用、氧化还原条件等方面剖析了这些异常模式的成因机制。

The search for petroleum has evolved into a highly sophisticated technology where today almost every scientific discipline known is being brought to bear upon the endeavour. Yet, the use of geochemical hydrocarbon exploration remains a peripheral exploration tool. The trend toward scientific integration has led the petroleum explorationist to the point of being a specialist. It would seem that our petroleum scientists have focussed their interests mainly on the investigation of principles and less on their ultimate purpose of discovering new and larger oil and gas reserves. So, it is not by chance, that leading geochemists have been speaking more and more freely of the necessity to integrate our tools of exploration and thereby do a better job. The theoretical basis for hydrocarbon geochemistry is complex, and, as with all exploration tools, the problems and difficulties of interpreting the data will never be completely eliminated. This article considers the importance of using the ΔC method in geochemical hydrocarbon exploration which has been employed successfully for over 40 years. The addition of carbon-isotope ratios and trace-element analysis to this method has added a new dimension to geochemical hydrocarbon exploration. The theoretical basis of the ΔC method has been presented earlier by the author and will only be touched upon briefly here. Very simply, the basis of all geochemical hydrocarbon exploration is based on the much debated premise that the lighter hydrocarbon gases and their components migrate vertically from a trap through the overlying sedimentary pile to the surface. Upon reaching the surface, through oxidation, they leave their signatures in one form or another that can be detected by physicochemical methods. These physicochemical signatures are discernable as “geochemical haloes”. From soil samples, collected from 2–3 m deep, what is measured is the result of absorption and adsorption by soil particles that are altered to CO 2 by oxidation and form a unique, stable, carbonate system with the surface and near-surface material. This is unlike other carbonate systems and when subjected to a differential thermal technique, dissociates into CO 2 surface material is cumulative and indicates where maximum hydrocarbon leakage has taken place over the life span of the material sampled. It is durable and unaffected by pressure and temperature variation or recent hydrocarbon contamination. Values are expressed in terms of millivolts which are proportional to the CO 2 given off by the dissociation of the carbonate system under standard conditions. Frequency curves are constructed for all values for the determination of significant contour levels above the normal geochemical background for mapping. After significant ΔC anomalies are located, they can be further verified by use of carbon-isotope ratios. As methane migrates to the surface from underlying hydrocarbon accumulations, there is a progressive selection or fractionation that causes enrichment of the carbon-13 isotope. The methane, thus reaching the near-surface, is isotopically lighter. When oxidized in accordance with the equation CH 4 + 2O 2 → 2H 2O + CO 2, the carbon having been converted to carbon dioxide, is taken up in the pore-filling carbonate cements that are found in the near-surface soils and sediments. High carbon dioxide values (ΔC) in the geochemical halo are related the δ 13C carbon-isotope ratios from underlying hydrocarbon accumulations. This is observed over fields containing hydrocarbon accumulations where δ 13C values in the pore-filling carbonate cements become increasingly negative (lighter) toward the crests of traps (i.e. exhibiting lower ΔC values). This indicates enrichment of 12C relative to the PDB standard. Whereas, positive values of δ 13C indicate depletion in 12C or enrichment in 13C (i.e. exhibiting higher ΔC values away from the crests of the traps). The observed ΔC anomalies and δ 13C anomalies leave an indelible pattern in the near-surface sediments and soils which are herein referred to as geochemical hydrocarbon haloes. Trace-element associations, that form organometallic compounds, are found “haloed” or concentrated over or around underlying hydrocarbon reservoirs. These associations seem to have occurred from vertically migrating methane that has acted as a “carrier” sweeping up the trace elements on the pathways to the surface. Vanadium, nickel, chromium, iron, cobalt, copper, manganese, strontium, barium are various trace element ratios seen to also halo and indicate subsurface hydrocarbon accumulations. An example presented from the Ocho-Juan Field, a producing reef field, located in Scurry and Fisher Counties, Texas shows that the combination of ΔC, δ 13C and trace-element analysis from near-surface soil sampling is a significant step forward in improving geochemical hydrocarbon exploration methods.

气体地球化学测量方法由于气体的强穿透性，可将大量的与深部矿化作用有关的物质携带到地表，可直接或间接指示各种地质成矿过程，而受到勘查地球化学的重视。经历数十年的发展之后，气体地球化学测量在测量指标、方法及影响因素研究方面都取得了长足进展。特别是近年来由于分析技术提高，使得很多超微含量的气体测定成为可能，一些新的气体测量方法相继提出，在寻找隐伏矿或盲矿方面获得了较好的效果。笔者对气体测量发展史、气体测量方法、指标及影响因素进行了简单总结，并重点介绍了一种新的气体测量技术（SDP）的测量原理、使用方法及应用实例。

Samples of ground drill cores from the southern part of the Santa Cruz porphyry copper deposit, Casa Grande, Arizona, were oxidized in simulated weathering experiments. The samples were also separated into various mineral fractions and analyzed for contents of metals and sulfide minerals. The principal sulfide mineral present was pyrite. Gases produced in the weathering experiments were measured by gas chromatography. Carbon dioxide, oxygen, carbonyl sulfide, sulfur dioxide and carbon disulfide were found in the gases; no hydrogen sulfide, organic sulfides, or mercaptans were detected. Oxygen concentration was very important for production of the volatiles measured; in general, oxygen concentration was more important to gas production than were metallic element content, sulfide mineral content, or mineral fraction (oxide or sulfide) of the sample. The various volatile species also appeared to be interactive; some of the volatiles measured may have been formed through gas reactions.

Several gaseous elements and compounds have been found to occur in anomalous concentrations in soil gas or air over mineral deposits. These gases or vapors include mercury, sulfur dioxide, carbon dioxide, hydrogen sulfide, fluorine, chlorine, bromine, and iodine. Ore deposits buried by as much as several hundred meters of barren or postmineral overburden have been detected, and buried faults, fractures, and zones of tectonic disturbance have been mapped by use of gas anomalies. Some gases are measured directly with sensitive instrumental methods while others are concentrated and analyzed by traditional analytical methods. Temperature, barometric pressure, and other meteorological parameters influence gas anomalies, although their effects are incompletely understood. Gas anomalies extend the usefulness of geochemical exploration in the search for buried ore deposits.

为研究壤中汞气与二氧化硫气体地球化学测量在干旱戈壁荒漠区隐伏铜镍矿的找矿效果,设计了对沙泉子隐伏铜镍矿壤中汞气与二氧化硫气体的地球化学剖面测量试验,取得了较好的结果。壤中汞气与二氧化硫气体在隐伏矿化体上方出现不同程度的异常特征,说明这两种方法在试验区对寻找隐伏铜镍矿有一定效果,为在干旱戈壁荒漠区找矿提供了新思路。

<p>本文在综合大量资料的基础上,总结了气体地球化学的发展历史,对有关综合气体测量在发展过程中出现的一些术语,阐述了一点浅见,介绍了综合气体测量的采样方法、理论依据,提出了综合气体测量的发展方向。</p>

Two Italian areas, characterized by different seismological histories, were investigated to enhance the basic knowledge of gas migration mechanisms during earthquakes. Sharp variations occur in the movement and concentration of some gaseous species due to the evolution of the local stress regime. The first area (Colpasquale) is located in the central Italian region of Marche and provided a good location to study gas migration in a seismically active region. The area was devastated by a sequence of shallow earthquakes over a 302month-long period (September–December, 1997). The occurrence of this catastrophic event, as well as the long duration of the “seismic sequence”, presented a unique opportunity to study gas migration in a zone undergoing active displacement. Soil gas surveys were performed 1 day, 1 week, 1 year and 2 years after the main shock (Ms 5.6) in the Colpasquale area. In particular, results highlight a change in the Rn distribution during the three monitoring years indicating a variation of gas migration that may be linked to the evolution of the stress regime.The second study area is located in the Campidano Graben (southern part of Sardinia Island). This area is characterized by seismic quiescence, displaying an almost complete lack of historical earthquakes and instrumentally recorded seismicity. The consistently low values observed for all analyzed gases suggest that the studied area is likely characterized by sealed, non-active faults that prevent significant gas migration. The comparison of data from both studied areas indicate that soil gas geochemistry is useful to locate tectonic discontinuities even when they intersect non-cohesive clastic rocks near the surface and thus are not visible (i.e., “blind faults”).

Mercury vapor haloes in soil air have been identified over more than 70 exposed, blind, buried and buried-and-blind deposits seated from 1 to 640 m deep. The usefulness of the mercury vapor technique has been proven by discovery of new ore bodies at depths from 2 to 35 m. There is a close relation between primary (rock) and secondary (vapor) Hg haloes. One kind of halo gives birth to another and vice versa. The depth resolution of the method is due to vertical dimensions or primary haloes. The anomalous gaseous component substantially exceeds the natural background of mercury vapor in soil air permitting mercury vapor haloes to be identified above deep-seated deposits. The anomalous occluded component in overburden has lower concentrations of syngenetic mercury and, therefore, superimposed dispersion haloes of mercury are rarely identified above buried and buried-and-blind deposits when using whole-rock analysis. Deposits with no anomalous mercury source are not accompanied by occluded and vapor haloes.

This paper discusses the distribution of mercury in four kinds of uranium deposits and the form of the corresponding soil-gas mercury haloes. Uranium deposits can be divided into three levels according to their mercury contents. Carbonatite-type uranium deposits are often associated with high levels of mercury, which forms large, high-concentration and high-contrast soil-gas haloes in residual alluvium. Mercury concentration goes up with increasing sampling depths and has been used successfully to locate deep uranium orebodies around siliceous limestone-hosted uranium deposits.

拉水峡铜镍矿位于秦祁昆造山系西南缘日月山一化隆新元古代地块中部。赋矿地层为化隆岩群的一 套中高级变质岩系，岩性主要为黑云斜长片麻岩、角闪片岩。因矿区普遍被厚50—150m的古近系一新近系西宁群紫红色砂砾岩、粘土岩等岩层覆盖，采用常规 的矿产勘查方法很难发挥作用。近几年在该矿区通过1：5000地气汞气测量详查工作，共圈出地气汞气异常11处，初步认为Ⅰ号和Ⅷ号异常找矿意义最大。结 果表明利用地气汞气测量方法对寻找隐伏矿床有一定借鉴意义。

银坑矿田位于南岭东段，是赣南最重要的Au-Ag找矿勘查区，区内最主要的矿床类型为破碎带蚀变岩型。为了对银坑矿田进行深部找矿，采用地质-土壤-汞气综合剖面测量的方法，对比研究了土壤元素和深穿透汞气的异常特征。结果显示，矿田土壤中，Au、Ag元素富集明显，Pb、Zn元素次之；不同地层所对应的土壤表现出不同的元素富集，如上施组地层区Au、Ag、Pb、Zn异常明显，隐爆角砾岩区Au元素较富集。土壤中汞气测量结果表明，破碎带、矿体都表现出明显的异常，矿体表现出高值异常，其峰背比均值达13.4，汞气最高值达5680 ng/m³。根据异常特征，并对比地质信息及已有勘探成果，综合圈定出破碎带蚀变岩型银（金）铅锌多金属矿找矿远景区3处，隐爆角砾岩型金矿找矿远景区1处。

<p>通过在西天山高寒山区已知火山热液型铜矿点外围矿化剖面和冰雪水沉积、洪积厚层覆盖区激电异常上的壤中汞气测量试验,进而扩大到面积性测量,均取得了显著的地质效果。结果表明,壤中汞气测量在高寒条件下仍是一种快速、经济、有效的方法,具有推广价值。</p>

长江中下游地区矿产丰富,不少矿区为冲洪积物所覆盖。基于烃汞气体挥发性、穿透性强以及迁移距离远的特点,文章利用烃汞综合气体测量法针对冲洪积物覆盖的特殊景观区开展了探索性的找矿试验研究。通过对长江中下游地区烃汞背景值和不同矿床类型烃汞异常场的研究,以及典型矿床烃汞测量找矿的有效性试验,结合烃类组分微观结构对比分析等方面的研究,发现长江中下游地区大部分矿床在成矿过程中伴随形成烃类气体原生异常场,同时,地表冲洪积物中含有与深部矿床同源的烃类异常信息,初步显示了烃汞测量法在冲洪积物覆盖区应用于找矿是可行的。

The differences between the CO 2 and O 2 concentrations in soil air and atmospheric air have been measured where sulfide mineralization occurs beneath transported exotic overburden in semi-arid and arid areas of the USA, South West Africa (Namibia) and Saudi Arabia. These mineralizations are reflected near surface by anomalous levels of CO 2 and O 2 in soil air, whereas in most cases heavy-metal anomalies are absent. The normal background variability of CO 2 and O 2 in soil air falls with increasing aridity, and anomaly definition improves with increasing aridity. Thus soil air CO 2 and O 2 data are potentially useful in exploring for concealed mineralization, especially in regions with an arid climate or conspicuous dry season.

Soil samples were collected over the North Silver Bell porphyry copper deposit near Tucson, Arizona. Volatile elements and compounds in gases derived from the soils and metallic elements in the soils were analyzed in order: (1) to see which volatile constituents of the soils might be indicative of the ore body or the alteration zones; and (2) to distinguish the ore and alteration zones by comparison of trace elements in the soil. Plots of analytical data on trace elements in soils indicated a typical distribution pattern for metals around a porphyry copper deposit, with copper, molybdenum, and arsenic concentrations higher over the ore body, and zinc, lead, and silver concentrations higher over the alteration zones. Higher than average concentrations of helium, carbon disulfide, and sulfur dioxide adsorbed on soils were found over the ore body, whereas higher concentrations of carbon dioxide and carbonyl sulfide were found over the alteration zones.

正 气体地球化学法是勘查地球化学的一个重要分支。近十多年来,该法发展迅速、成果丰硕,实践证明它是地质找矿中的一种新技术。气体地球化学勘查是以测量与矿 床在成因上及空间上有联系的某些气体元素或化合物的异常进行找矿。有些元素和化合物在地壳中呈气态迁移是很普遍的现象,在各种地质成矿过

正 使用土壤气体地球化学勘探法有时能发现一些深部矿体。但是,在某些情况下,这种方法并不成功,如在矿体埋藏很深或者取样线横切湿地或者矿体和主岩之间硫化物含量的对比度偏低时,都会导致失败。本文根据在美国和两德几个野外现场的调查研究,讨论了这些失败的原因和进一步研究时应注意的问题。

黄金洞金矿因长期采掘,面临资源接替问题.根据矿区地质概况、成矿机制、成矿 规律、成矿模式等内容,对黄金洞金矿深部成矿规律进行了分析研究,得出本矿区金矿的 成矿规律属于区域变质热液型,并对黄金洞金矿的找矿进行了预测,在矿区内确定了 3 个 级别共11 个找矿靶区,为黄金洞金矿的找矿问题指明了方向,为解决矿山资源接替带来 了新的希望.

在现代新构造学和成矿地质理论的指导下,以前人工作的研究为基础,重点对区内赋矿地层、矿脉特征、成矿条件及构造成矿方面做了深入的分析。提出了本区冷家溪群是矿源层,并且成矿物质不仅仅来自于围岩,还有一部分来自于地壳深部岩浆侵入;控制金矿田的是近EW向的3条区域韧性推覆剪切带,控制金矿体的是一些低次序在剪切带基础上的扩容断裂构造;金矿成矿与剪切变形存在密切的时空关系,长时间的强烈的剪切变形,不仅使矿体和围岩强烈变形,而且促使了成矿元素的高度富集;黄金洞金矿田矿脉主要分布在韧性剪切带上,因此今后主要工作在于寻找东西向的韧性剪切带。

黄金洞金矿床位于湘东北,赋存于中元古界冷家溪群浅变质碎屑岩中,并具有资源储量大、金品位高、伴生元素丰富等典型特征.在前人研究的基础上,对黄金洞金矿床的硫、铅同位素、流体包裹体特征和成矿时代展开了系统研究.研究结果表明：成矿物质具有地层和深部岩浆的混合来源特征;成矿流体属中低温、中低盐度的K-Na-Ca2-Mg-F-Cl-SO4体系,来源于深部岩浆和大气降水的混合;矿床成矿具有2个主成矿期,分别为加里东期和燕山期.

黄金洞金矿床是位于江南古陆造山带中段的大型金矿床，具有金矿资源储量大、品位高、共伴生元素多等特点。矿石微量元素和稀土元素分析结果显示：微量元素具有Li、Co、Cu、Rb、Cs、Tl、Th富集，而Cr、Ni、Sr、Cd、Ta、U、Zr亏损，大离子亲石元素Rb富集，Sr亏损，高场强元素Th富集，Nb亏损；稀土元素具有轻稀土富集，重稀土亏损，球粒陨石标准化配分曲线均为右倾型式的特征。由此表明，黄金洞金矿床成矿物质具有多来源性，应为壳幔混合来源。

黄金洞金矿田的成矿特主要来源于含矿地层，矿体赋存于近东西向的断裂中，并具多阶段成矿及主要成矿阶段叠加富集之特点。根据该矿田金矿的成矿特征及成矿规律，本文指出在其北部地域具有良好的找金前景。

湘东北是一个重要的脉型金矿成矿区，区内脉金矿都产于冷家溪群变质岩系虽，其成矿构造主要是与剪相相关的各级断裂构造，控制金矿田的主要是三条近东西向的区域韧性剪切带；控制矿体定位的含矿构造形态复杂多样，可总结出六种主要的基本含矿构造样式，这些含矿构造都剪切扩容构造。