Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. B...Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.展开更多
Academician Dai Jinxing has long been engaged in natural gas geology and geochemical researches,and has made prominent contributions to the establishment and development of China’s theory of coal-derived gas.He has o...Academician Dai Jinxing has long been engaged in natural gas geology and geochemical researches,and has made prominent contributions to the establishment and development of China’s theory of coal-derived gas.He has opened up new areas of coal-derived gas exploration,natural gas formation theory and formation“ control conditions of large ” medium gas fields.展开更多
Conventional geochemical exploration for gold deposits has not always been very satisfactory, especially for buried and blind ones. New considerations and methodology in sampling, analysis and interpretation have been...Conventional geochemical exploration for gold deposits has not always been very satisfactory, especially for buried and blind ones. New considerations and methodology in sampling, analysis and interpretation have been developed in China during the past decade. Important considerations for unconventional gold exploration in this paper are that (1) gold is active in surface environments; (2) gold occurs not only as discrete grains, but also as ultrafine particles (submicron?to nanometer-sized particles of gold) and other complex forms; (3) regional low anomalies and superimposed anomalies over buried gold deposits are produced by ultrafine gold grains and other complex forms of gold. The methodology based on these considerations has been developed both in regional and in local geochemical exploration for gold. Examples of the preliminary application of these methods in two areas covered by transported overburden are given.展开更多
Based on the results of researches and applications for many years, it has been discovered that new methods and techniques for geochemical exploration of oil and gas such as δC, altered carbonate, Hg in absorption ph...Based on the results of researches and applications for many years, it has been discovered that new methods and techniques for geochemical exploration of oil and gas such as δC, altered carbonate, Hg in absorption phase, Ks, Fe2+, δ13C, fluorescence in two and three dimensions, and N2 and O2 in heat release can give full play in the following five fields: (1) optimization of the favourable target or hollow zones and structural zones in a region; (2) evaluation of oil traps and delineation of prospective oil and gas areas; (3) prediction of deep-seated oil-bearing horizons; (4) evaluation of the genesis of oil and gas geochemical anomalies and determination of the types of oil and gas accumulations; (5) forecast of the burial depths of oil and gas pools.展开更多
Interference in the data of geochemical hydrocarbon exploration is a large obstacle for anomaly recognition. The multiresolution analysis of wavelet analysis can extract the information at different scales so as to pr...Interference in the data of geochemical hydrocarbon exploration is a large obstacle for anomaly recognition. The multiresolution analysis of wavelet analysis can extract the information at different scales so as to provide a powerful tool for information analysis and processing. Based on the analysis of the geometric nature of hydrocarbon anomalies and background, Mallat wavelet and symmetric border treatment are selected and data pre-processing (logarithm-normalization) is established. This approach provide good results in Shandong and Inner Mongolia, China. It is demonstrated that this approach overcome the disadvantage of backgound variation in the window (interference in window), used in moving average, frame filtering and spatial and scaling modeling methods.展开更多
The greatest difficulties in recognizing geochemical hydrocarbon anomalies are: (1) how to objectively and accurately separate anomalies from background; (2) how to distinguish hydrocarbon pool related apical anomal...The greatest difficulties in recognizing geochemical hydrocarbon anomalies are: (1) how to objectively and accurately separate anomalies from background; (2) how to distinguish hydrocarbon pool related apical anomalies from lateral anomalies controlled by faults; and (3) how to eliminate interferences. These uncertainties are serious obstacles for the wide acceptance and use of geochemical techniques in hydrocarbon exploration. In this paper, the features of hydrocarbon anomalies were analyzed based on the micro migration mechanisms. In most cases, there are two anomalous populations or point groups, which are produced by two distinct mechanisms: (1) a population that directly reflects oil and gas fields, and (2) one that is related to structures such as faults. Statistical studies show that background anomalous populations and the boundaries between them can be described by the population means, prior probabilities, which are the proportions of population sizes, and covariance matrices, when background and anomalous populations have normal distributions. When this normality condition is met, a series of formulas can be derived. The method is designed on the basis of these allows: (1) univariate anomaly recognition, (2) elimination of interferences, (3) multivariate anomaly recognition, and (4) multivariate anomaly combination which depicts a more representative picture of morphology of the anomalous target than individual anomalies. The univariate and multivariate anomaly recognition can not only separate anomalies from background objectively, but also simultaneously distinguish the two types of anomalies objectively. This method was applied to the hydrocarbon data in Yangshuiwu region, Hebei Province. The interferences from regional variation of background were eliminated, and the interpretation uncertainty was reduced greatly as the anomalous populations were separated. The method was also used in Daxing region within the confines of Beijing City, and Aershan and Jiergalangtu regions in Inner Mongolia.展开更多
Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore ...Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.展开更多
20161965 Hao Chun(AE&E Geomicrobial Technologies Inc.,Beijing 102200,China);Meng Qingfen Microbial Geochemical Exploration and Research on Gas Hydrate in Sanlutian of Muli,Qinghai Province(Geoscience,ISSN1000-8527...20161965 Hao Chun(AE&E Geomicrobial Technologies Inc.,Beijing 102200,China);Meng Qingfen Microbial Geochemical Exploration and Research on Gas Hydrate in Sanlutian of Muli,Qinghai Province(Geoscience,ISSN1000-8527,CN11-2035/P,29(5),2015,p.1157-1163,5illus.,18refs.)Key words:gas hydrates,microbiological surveys,Qinghai展开更多
20162671 Chen Lizi(No.5 Gold Geological Party,CAPF,Xi’an 710100,China);Liu Mannian Geochemical Characteristics of Stream Sediments and Ore-Prospecting Orientation in Taxiu-Qushi’an Area at the Junction of Qinling an...20162671 Chen Lizi(No.5 Gold Geological Party,CAPF,Xi’an 710100,China);Liu Mannian Geochemical Characteristics of Stream Sediments and Ore-Prospecting Orientation in Taxiu-Qushi’an Area at the Junction of Qinling and Kunlun(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,39(5),2015,p.897-903,5illus.,展开更多
20180233 Liang Pengfei (Geophysical Exploration Party, Sichuan Bureau of Geology and Mineral Resources Development, Chengdu 610000, China) Liu Yang The Lead-Zinc Anomaly Characteristics and Resource Prediction in Y...20180233 Liang Pengfei (Geophysical Exploration Party, Sichuan Bureau of Geology and Mineral Resources Development, Chengdu 610000, China) Liu Yang The Lead-Zinc Anomaly Characteristics and Resource Prediction in Yanziyan, Jinping Area, Yunnan Province (Geophysical and Geochemical Exploration, ISSN1000-8918, CN11-1906/P, 41 (1), 2017, p. 65-70, 2 illus., 3 tables, 23 refs. ) Key words : leadzinc deposit, geochemical anomaly, resources extent, prognosis, Yunnan Province In Yanziyan target in Yunnan Province, 1 area of Jinping district : 25 000 soil survey led to the discovery of many element anomalies, including Pb, Zn, Ag, Cd, Hg, Sb, Cu, Cr. According to the oreforming geological background of the survey area, the authors delineated the target area. By anomaly inspection, the authors found industrial-grade lead and zinc mineralization. Based on prognosis of target area's mineral reserves, the authors consider that the target area may be a medium to large lead-zinc deposit with considerable ore-prospecting potential.展开更多
Stream sediment sampling is a significant tool in geochemical exploration. The stream sediment composition reflects the bedrock geology, overburden cover, and metalliferous mineralization. This research article focuse...Stream sediment sampling is a significant tool in geochemical exploration. The stream sediment composition reflects the bedrock geology, overburden cover, and metalliferous mineralization. This research article focuses on assessing selected trace element concentrations in stream sediments and interpreting their inter-element relationships using multivariate statistical methods. Tagadur Ranganathaswamy Gudda and its surroundings in the Nuggihalli schist belt of southern India have been investigated in the present work. The geology of the study area is complex, with a diverse range of litho units and evidence of strong structural deformation. The area is known for its mineralization potential for chromite, vanadiferous titanomagnetite, and sulfides. The topography of the region is characterized by an undulating terrain with a radial drainage pattern. Most part of the schist belt is soil covered except the Tagadur Ranganathaswamy Gudda area. For this study, a discrete stream sediment sampling method was adopted to collect the samples. Stream sediment samples were collected using a discrete sampling method and analyzed for trace elements using an ICP-AES spectrophotometer: Fe, Cr, Ti, V, Cu, Ni, Zn, Pb, Mn, Cd, and As have been analyzed. The analytical data were statistically treated using the SPSS software, including descriptive statistics, normalization of data using natural log transformation, and factor analysis with varimax rotation. The transformed data showed a log-normal distribution, indicating the presence of geochemical anomalies. The results of the study provide valuable insights into the geochemical processes and mineralization potential of the study area. The statistical analysis helps in understanding the inter-element relationships and identifying element groups and their implications on bedrock potential mineralization. Additionally, spatial analysis using inverse distance weighting interpolation provides information about the distribution of geochemical parameters across the study area. Overall, this research contributes to the understanding of stream sediment geochemistry and its application in mineral exploration. The findings have implications for future exploration efforts and can aid in the identification of potential ore deposits in the Nuggihalli schist belt and similar geological settings.展开更多
The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion,volatilization,upward migration,and loss of gas in the strata.As a result,a low...The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion,volatilization,upward migration,and loss of gas in the strata.As a result,a low-concentration gas field will be formed in the strata above geothermal reservoirs.Geothermal reservoirs could in turn heat formation water and increase the solubility of soluble inorganic salts in the surrounding rocks and the total dissolved solids(TDS)content in the formation water.Since water can strongly wet and permeate strata,the dissolved inorganic salts migrate into upper strata along with water,giving rise to the formation of a high-concentration inorganic salt field in the strata above geothermal reservoirs.A higher geothermal reservoir temperature corresponds to more significant characteristics mentioned above.Therefore,a medium-to-high temperature geothermal system has a surface geochemical anomaly pattern of high inorganic salt concentrations and low gas concentrations(also referred to as the high-salt and low-gas pattern).This pattern is applied to the surface geochemical exploration of the two geothermal fields in Guangdong Province,i.e.,the Huangshadong geothermal field in Huizhou City and the Xinzhou geothermal field in Yangjiang City,revealing low-concentration gas fields above both.The application results also show that the exposed thermal spring water in both geological fields has higher concentration of dissolved inorganic salt than the surface water and nearby seawater,forming high-amplitude anomalies on the surface above geothermal reservoirs.These characteristics,as well as the measured temperature at known geothermal wells,verify the validity of the high-salt and low-gas pattern of medium-to-high temperature geothermal systems proposed in this study.Moreover,the high-salt and low-gas pattern proposed predicts three favorable medium-to-high temperature geothermal zones in the surface geochemical exploration of the Shiba Basin near the Huangshadong geothermal field.展开更多
1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D ma...Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D map. The scheme of regional geochemical division includes non supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.展开更多
A suite of elements(Ag,Au,Ba,Bi,Cd,Co,Cr,Cu,Ga,Hf,Hg,Mn,Mo,Ni,Pb,Rb,Sb,Se, Sr,Te and Zn),total organic carbon(TOC)and pH were analyzed in stream sediment and tailing samples from Um Shashoba area,in order to evalu...A suite of elements(Ag,Au,Ba,Bi,Cd,Co,Cr,Cu,Ga,Hf,Hg,Mn,Mo,Ni,Pb,Rb,Sb,Se, Sr,Te and Zn),total organic carbon(TOC)and pH were analyzed in stream sediment and tailing samples from Um Shashoba area,in order to evaluate Au placer and the sediments being impacted by old mining activities.Analytical results were examined using statistical,graphical and mapping methods.In spite of the results revealing that Au and most of the elements in sediments were in general significantly lower than those in tailing,Au was concentrated in the NE and SW parts forming Au placer.It is remarkably a close association of Au with Hg and Sb;both are useful as pathfinder elements for Au placers.Values of pH could not control a fate of analyzed elements,whereas TOC and Mn oxides and hydroxides could uptake some elements Au,Ba,Co,Cr,Hg,Ni,and Sr.The results also indicated that the sediments were contaminated by anthropogenic factors causing moderate,strong to very strong pollution with respect to Bi,Se and Te,respectively.Additionally,geogenic factors could also contribute elemental enrichment to the drainage system and cause significant toxicity level.展开更多
Hydrothermal plumes released from the eruption of sea floor hydrothermal fluids contain large amounts of oreforming materials. They precipitate within certain distances from the hydrothermal vent. Six surficial sedime...Hydrothermal plumes released from the eruption of sea floor hydrothermal fluids contain large amounts of oreforming materials. They precipitate within certain distances from the hydrothermal vent. Six surficial sediment samples from the Southwest Indian Ridge(SWIR) were analyzed by a portable X-ray fluorescence(PXRF) analyzer on board to find a favorable method fast and efficient enough for sea floor sulfide sediment geochemical exploration. These sediments were sampled near, at a moderate distance from, or far away from hydrothermal vents. The results demonstrate that the PXRF is effective in determining the enrichment characteristics of the oreforming elements in the calcareous sediments from the mid-ocean ridge. Sediment samples(〉40 mesh) have high levels of elemental copper, zinc, iron, and manganese, and levels of these elements in sediments finer than 40 mesh are lower and relatively stable. This may be due to relatively high levels of basalt debris/glass in the coarse sediments, which are consistent with the results obtained by microscopic observation. The results also show clear zoning of elements copper, zinc, arsenic, iron, and manganese in the surficial sediments around the hydrothermal vent. Sediments near the vent show relatively high content of the ore-forming elements and either high ratios of copper to iron content and zinc to iron content or high ratios of copper to manganese content and zinc to manganese content. These findings show that the content of the ore-forming elements in the sediments around hydrothermal vents are mainly influenced by the distance of sediments to the vent, rather than grain size. In this way, the PXRF analysis of surface sediment geochemistry is found to satisfy the requirements of recognition geochemical anomaly in mid-ocean ridge sediments. Sediments with diameters finer than 40 mesh should be used as analytical samples in the geochemical exploration for hydrothermal vents on mid-oceanic ridges. The results concerning copper, zinc, arsenic, iron, and manganese and their ratio features can be used as indicators in sediment geochemical exploration of seafloor sulfides.展开更多
Surface geochemical exploration for oil and gas is still in the empirical stage , despite 50 years has passed since the method was first proposed by Laubmeyer and Sokolov . A boom of its application is emerging in Chi...Surface geochemical exploration for oil and gas is still in the empirical stage , despite 50 years has passed since the method was first proposed by Laubmeyer and Sokolov . A boom of its application is emerging in China followed the depression during 60 - 70 's . However , before the method can be accepted by the industry as a routine technique , a relatively sound basis should be established . This paper presents several cases over known oil and gas fields and discusses the factors that effect the surface geochemical expression of underground oil pools .展开更多
Geochemical assessment was carried out at the Morendat East geothermal prospect by characterizing radon (22~Rn) and Carbondioxide (CO2) concentration levels from soil-gas survey. The primary aim was to locate perm...Geochemical assessment was carried out at the Morendat East geothermal prospect by characterizing radon (22~Rn) and Carbondioxide (CO2) concentration levels from soil-gas survey. The primary aim was to locate permeable zones and infer the presence of possible heat source linked to an active geothermal system. The secondary aim was to rank the prospect and facilitate its development by the private sector. This study focused on the distribution of Radon and Carbon dioxide concentration levels in the soil cover within Morendat East area located in Nakuru County. The area was considered as having potential for geothermal resource hence earmarked for study in the financial Year 2014/2015 by the Ministry of Energy and Petroleum. The location is characterized by scarcity of surface geothermal manifestations hence soil gas survey was considered appropriate for the study. Random sampling method was used and resulted in sampling 100 points in an area of about 90 km^2. CO2 concentration measurements were done using an Orsat gas sampling apparatus whereas ^220Rn gas concentrations were measured using a portable radon detector. The CO2 values ranged from 0-5.4% while the ^220Rn ranged from 0-2,834 counts per minute (cpm). Possible faults were inferred north of the prospect area due to the anomalously high levels of CO2 and ^220Rn recorded.展开更多
In this study,methods based on the distribution model(with and without personal opinion)were used for the separation of anomalous zones,which include two different methods of U-spatial statistics and mean plus values ...In this study,methods based on the distribution model(with and without personal opinion)were used for the separation of anomalous zones,which include two different methods of U-spatial statistics and mean plus values of standard deviation(X+nS).The primary purpose is to compare the results of these methods with each other.To increase the accuracy of comparison,regional geochemical data were used where occurrences and mineralization zones of epithermal gold have been introduced.The study area is part of the Hashtjin geological map,which is structurally part of the folded and thrust belt and part of the Alborz Tertiary magmatic complex.Samples were taken from secondary lithogeochemical environments.Au element data concerning epithermal gold reserves were used to investigate the efficacy of these two methods.In the U-spatial statistics method,and criteria were used to determine the threshold,and in the method,the element enrichment index of the region rock units was obtained with grouping these units.The anomalous areas were identified by,and criteria.Comparison of methods was made considering the position of discovered occurrences and the occurrences obtained from these methods,the flexibility of the methods in separating the anomalous zones,and the two-dimensional spatial correlation of the three elements As,Pb,and Ag with Au element.The ability of two methods to identify potential areas is acceptable.Among these methods,it seems the method with criteria has a high degree of flexibility in separating anomalous regions in the case of epithermal type gold deposits.展开更多
Fractal and multi-fractal content area method finds application in a wide variety of geological,geochemical and geophysical fields.In this study,the fractal content-gradient method was used on1:10,000 scale to deline...Fractal and multi-fractal content area method finds application in a wide variety of geological,geochemical and geophysical fields.In this study,the fractal content-gradient method was used on1:10,000 scale to delineate geochemical anomalies associated with copper mineralization.Analysis of geochemical data from the Yangla super large Cu-Pb-Zn polymetallic ore district using the fractal content-gradient method,combined with other geological data from this area,indicates that oreprospecting in the ore district should focus on Cu as the main metal and Pb-Zn and Au as the auxiliary metals.The types of deposits include(in chronological order) re-formed sedimentary exhalative(SEDEX),skarns,porphyries,and hydrothermal vein-type deposits.Three ore-prospecting targets are divided on a S-N basis:(1) the Qulong exploration area,in which the targets are porphyry-type Cu deposits;(2) the Zongya exploration area,where the targets are porphyry-type Cu and hydrothermal vein-type Cu-Pb polymetallic deposits;and(3) the Zarelongma exploration area,characterized mainly skarn-type "Yangla-style" massive sulfide Cu-Pb deposits.Our study demonstrates that the fractal content-gradient method is convenient,simple,rapid,and direct for delineating geochemical anomalies and for outlining potential exploration targets.展开更多
文摘Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.
文摘Academician Dai Jinxing has long been engaged in natural gas geology and geochemical researches,and has made prominent contributions to the establishment and development of China’s theory of coal-derived gas.He has opened up new areas of coal-derived gas exploration,natural gas formation theory and formation“ control conditions of large ” medium gas fields.
基金This research represents a portion of the State Eighth Five-Year Plan Key ScienceTechnology Project "Unconventional Geochemical Exploration for Gold" supported by the State Science and Technology Commission of Chinathe National Gold Bureau of China
文摘Conventional geochemical exploration for gold deposits has not always been very satisfactory, especially for buried and blind ones. New considerations and methodology in sampling, analysis and interpretation have been developed in China during the past decade. Important considerations for unconventional gold exploration in this paper are that (1) gold is active in surface environments; (2) gold occurs not only as discrete grains, but also as ultrafine particles (submicron?to nanometer-sized particles of gold) and other complex forms; (3) regional low anomalies and superimposed anomalies over buried gold deposits are produced by ultrafine gold grains and other complex forms of gold. The methodology based on these considerations has been developed both in regional and in local geochemical exploration for gold. Examples of the preliminary application of these methods in two areas covered by transported overburden are given.
文摘Based on the results of researches and applications for many years, it has been discovered that new methods and techniques for geochemical exploration of oil and gas such as δC, altered carbonate, Hg in absorption phase, Ks, Fe2+, δ13C, fluorescence in two and three dimensions, and N2 and O2 in heat release can give full play in the following five fields: (1) optimization of the favourable target or hollow zones and structural zones in a region; (2) evaluation of oil traps and delineation of prospective oil and gas areas; (3) prediction of deep-seated oil-bearing horizons; (4) evaluation of the genesis of oil and gas geochemical anomalies and determination of the types of oil and gas accumulations; (5) forecast of the burial depths of oil and gas pools.
文摘Interference in the data of geochemical hydrocarbon exploration is a large obstacle for anomaly recognition. The multiresolution analysis of wavelet analysis can extract the information at different scales so as to provide a powerful tool for information analysis and processing. Based on the analysis of the geometric nature of hydrocarbon anomalies and background, Mallat wavelet and symmetric border treatment are selected and data pre-processing (logarithm-normalization) is established. This approach provide good results in Shandong and Inner Mongolia, China. It is demonstrated that this approach overcome the disadvantage of backgound variation in the window (interference in window), used in moving average, frame filtering and spatial and scaling modeling methods.
文摘The greatest difficulties in recognizing geochemical hydrocarbon anomalies are: (1) how to objectively and accurately separate anomalies from background; (2) how to distinguish hydrocarbon pool related apical anomalies from lateral anomalies controlled by faults; and (3) how to eliminate interferences. These uncertainties are serious obstacles for the wide acceptance and use of geochemical techniques in hydrocarbon exploration. In this paper, the features of hydrocarbon anomalies were analyzed based on the micro migration mechanisms. In most cases, there are two anomalous populations or point groups, which are produced by two distinct mechanisms: (1) a population that directly reflects oil and gas fields, and (2) one that is related to structures such as faults. Statistical studies show that background anomalous populations and the boundaries between them can be described by the population means, prior probabilities, which are the proportions of population sizes, and covariance matrices, when background and anomalous populations have normal distributions. When this normality condition is met, a series of formulas can be derived. The method is designed on the basis of these allows: (1) univariate anomaly recognition, (2) elimination of interferences, (3) multivariate anomaly recognition, and (4) multivariate anomaly combination which depicts a more representative picture of morphology of the anomalous target than individual anomalies. The univariate and multivariate anomaly recognition can not only separate anomalies from background objectively, but also simultaneously distinguish the two types of anomalies objectively. This method was applied to the hydrocarbon data in Yangshuiwu region, Hebei Province. The interferences from regional variation of background were eliminated, and the interpretation uncertainty was reduced greatly as the anomalous populations were separated. The method was also used in Daxing region within the confines of Beijing City, and Aershan and Jiergalangtu regions in Inner Mongolia.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCXZ-YW-JC103)contribution no.1866 from Guangzhou Institute of Geochemistry, Chinese Academy of Sciences
文摘Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.
文摘20161965 Hao Chun(AE&E Geomicrobial Technologies Inc.,Beijing 102200,China);Meng Qingfen Microbial Geochemical Exploration and Research on Gas Hydrate in Sanlutian of Muli,Qinghai Province(Geoscience,ISSN1000-8527,CN11-2035/P,29(5),2015,p.1157-1163,5illus.,18refs.)Key words:gas hydrates,microbiological surveys,Qinghai
文摘20162671 Chen Lizi(No.5 Gold Geological Party,CAPF,Xi’an 710100,China);Liu Mannian Geochemical Characteristics of Stream Sediments and Ore-Prospecting Orientation in Taxiu-Qushi’an Area at the Junction of Qinling and Kunlun(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,39(5),2015,p.897-903,5illus.,
文摘20180233 Liang Pengfei (Geophysical Exploration Party, Sichuan Bureau of Geology and Mineral Resources Development, Chengdu 610000, China) Liu Yang The Lead-Zinc Anomaly Characteristics and Resource Prediction in Yanziyan, Jinping Area, Yunnan Province (Geophysical and Geochemical Exploration, ISSN1000-8918, CN11-1906/P, 41 (1), 2017, p. 65-70, 2 illus., 3 tables, 23 refs. ) Key words : leadzinc deposit, geochemical anomaly, resources extent, prognosis, Yunnan Province In Yanziyan target in Yunnan Province, 1 area of Jinping district : 25 000 soil survey led to the discovery of many element anomalies, including Pb, Zn, Ag, Cd, Hg, Sb, Cu, Cr. According to the oreforming geological background of the survey area, the authors delineated the target area. By anomaly inspection, the authors found industrial-grade lead and zinc mineralization. Based on prognosis of target area's mineral reserves, the authors consider that the target area may be a medium to large lead-zinc deposit with considerable ore-prospecting potential.
文摘Stream sediment sampling is a significant tool in geochemical exploration. The stream sediment composition reflects the bedrock geology, overburden cover, and metalliferous mineralization. This research article focuses on assessing selected trace element concentrations in stream sediments and interpreting their inter-element relationships using multivariate statistical methods. Tagadur Ranganathaswamy Gudda and its surroundings in the Nuggihalli schist belt of southern India have been investigated in the present work. The geology of the study area is complex, with a diverse range of litho units and evidence of strong structural deformation. The area is known for its mineralization potential for chromite, vanadiferous titanomagnetite, and sulfides. The topography of the region is characterized by an undulating terrain with a radial drainage pattern. Most part of the schist belt is soil covered except the Tagadur Ranganathaswamy Gudda area. For this study, a discrete stream sediment sampling method was adopted to collect the samples. Stream sediment samples were collected using a discrete sampling method and analyzed for trace elements using an ICP-AES spectrophotometer: Fe, Cr, Ti, V, Cu, Ni, Zn, Pb, Mn, Cd, and As have been analyzed. The analytical data were statistically treated using the SPSS software, including descriptive statistics, normalization of data using natural log transformation, and factor analysis with varimax rotation. The transformed data showed a log-normal distribution, indicating the presence of geochemical anomalies. The results of the study provide valuable insights into the geochemical processes and mineralization potential of the study area. The statistical analysis helps in understanding the inter-element relationships and identifying element groups and their implications on bedrock potential mineralization. Additionally, spatial analysis using inverse distance weighting interpolation provides information about the distribution of geochemical parameters across the study area. Overall, this research contributes to the understanding of stream sediment geochemistry and its application in mineral exploration. The findings have implications for future exploration efforts and can aid in the identification of potential ore deposits in the Nuggihalli schist belt and similar geological settings.
基金This study was funded by the project entitled Exploration Technology for Deep Geothermal Resources in Igneous Rock Areas in South China(2019YFC0604902),Chinathe Ministry of Science and Technology of China,China+1 种基金the project entitled Research and Application of Key Technologies for Geophysical and Geochemical Exploration of Deep Geothermal Resources in Southeastern China(P20041-2),Chinathe Science and Technology Department of SINOPEC,China.
文摘The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion,volatilization,upward migration,and loss of gas in the strata.As a result,a low-concentration gas field will be formed in the strata above geothermal reservoirs.Geothermal reservoirs could in turn heat formation water and increase the solubility of soluble inorganic salts in the surrounding rocks and the total dissolved solids(TDS)content in the formation water.Since water can strongly wet and permeate strata,the dissolved inorganic salts migrate into upper strata along with water,giving rise to the formation of a high-concentration inorganic salt field in the strata above geothermal reservoirs.A higher geothermal reservoir temperature corresponds to more significant characteristics mentioned above.Therefore,a medium-to-high temperature geothermal system has a surface geochemical anomaly pattern of high inorganic salt concentrations and low gas concentrations(also referred to as the high-salt and low-gas pattern).This pattern is applied to the surface geochemical exploration of the two geothermal fields in Guangdong Province,i.e.,the Huangshadong geothermal field in Huizhou City and the Xinzhou geothermal field in Yangjiang City,revealing low-concentration gas fields above both.The application results also show that the exposed thermal spring water in both geological fields has higher concentration of dissolved inorganic salt than the surface water and nearby seawater,forming high-amplitude anomalies on the surface above geothermal reservoirs.These characteristics,as well as the measured temperature at known geothermal wells,verify the validity of the high-salt and low-gas pattern of medium-to-high temperature geothermal systems proposed in this study.Moreover,the high-salt and low-gas pattern proposed predicts three favorable medium-to-high temperature geothermal zones in the surface geochemical exploration of the Shiba Basin near the Huangshadong geothermal field.
文摘1 Geological Background of Minerlization or Geologic Setting The northeast of Yunnan1 Pb-Zn-Ag-Ge polymetallic ore district is an important part of the southwestern margin of the Yangtze block Sichuan-Yunnan-Guizhou
文摘Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2 D map. The scheme of regional geochemical division includes non supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.
文摘A suite of elements(Ag,Au,Ba,Bi,Cd,Co,Cr,Cu,Ga,Hf,Hg,Mn,Mo,Ni,Pb,Rb,Sb,Se, Sr,Te and Zn),total organic carbon(TOC)and pH were analyzed in stream sediment and tailing samples from Um Shashoba area,in order to evaluate Au placer and the sediments being impacted by old mining activities.Analytical results were examined using statistical,graphical and mapping methods.In spite of the results revealing that Au and most of the elements in sediments were in general significantly lower than those in tailing,Au was concentrated in the NE and SW parts forming Au placer.It is remarkably a close association of Au with Hg and Sb;both are useful as pathfinder elements for Au placers.Values of pH could not control a fate of analyzed elements,whereas TOC and Mn oxides and hydroxides could uptake some elements Au,Ba,Co,Cr,Hg,Ni,and Sr.The results also indicated that the sediments were contaminated by anthropogenic factors causing moderate,strong to very strong pollution with respect to Bi,Se and Te,respectively.Additionally,geogenic factors could also contribute elemental enrichment to the drainage system and cause significant toxicity level.
基金The Open Fund of Key Laboratory of Marine Mineral Resources,Ministry of Land and Resources under contract No.KLMMR-2015-B-03the China Ocean Mineral Resources Research and Development Association Project under contract Nos DY125-11-R-01 and DY125-11-R-05the National Basic Research Program(973 program)of China under contract No.2012CB417305
文摘Hydrothermal plumes released from the eruption of sea floor hydrothermal fluids contain large amounts of oreforming materials. They precipitate within certain distances from the hydrothermal vent. Six surficial sediment samples from the Southwest Indian Ridge(SWIR) were analyzed by a portable X-ray fluorescence(PXRF) analyzer on board to find a favorable method fast and efficient enough for sea floor sulfide sediment geochemical exploration. These sediments were sampled near, at a moderate distance from, or far away from hydrothermal vents. The results demonstrate that the PXRF is effective in determining the enrichment characteristics of the oreforming elements in the calcareous sediments from the mid-ocean ridge. Sediment samples(〉40 mesh) have high levels of elemental copper, zinc, iron, and manganese, and levels of these elements in sediments finer than 40 mesh are lower and relatively stable. This may be due to relatively high levels of basalt debris/glass in the coarse sediments, which are consistent with the results obtained by microscopic observation. The results also show clear zoning of elements copper, zinc, arsenic, iron, and manganese in the surficial sediments around the hydrothermal vent. Sediments near the vent show relatively high content of the ore-forming elements and either high ratios of copper to iron content and zinc to iron content or high ratios of copper to manganese content and zinc to manganese content. These findings show that the content of the ore-forming elements in the sediments around hydrothermal vents are mainly influenced by the distance of sediments to the vent, rather than grain size. In this way, the PXRF analysis of surface sediment geochemistry is found to satisfy the requirements of recognition geochemical anomaly in mid-ocean ridge sediments. Sediments with diameters finer than 40 mesh should be used as analytical samples in the geochemical exploration for hydrothermal vents on mid-oceanic ridges. The results concerning copper, zinc, arsenic, iron, and manganese and their ratio features can be used as indicators in sediment geochemical exploration of seafloor sulfides.
文摘Surface geochemical exploration for oil and gas is still in the empirical stage , despite 50 years has passed since the method was first proposed by Laubmeyer and Sokolov . A boom of its application is emerging in China followed the depression during 60 - 70 's . However , before the method can be accepted by the industry as a routine technique , a relatively sound basis should be established . This paper presents several cases over known oil and gas fields and discusses the factors that effect the surface geochemical expression of underground oil pools .
文摘Geochemical assessment was carried out at the Morendat East geothermal prospect by characterizing radon (22~Rn) and Carbondioxide (CO2) concentration levels from soil-gas survey. The primary aim was to locate permeable zones and infer the presence of possible heat source linked to an active geothermal system. The secondary aim was to rank the prospect and facilitate its development by the private sector. This study focused on the distribution of Radon and Carbon dioxide concentration levels in the soil cover within Morendat East area located in Nakuru County. The area was considered as having potential for geothermal resource hence earmarked for study in the financial Year 2014/2015 by the Ministry of Energy and Petroleum. The location is characterized by scarcity of surface geothermal manifestations hence soil gas survey was considered appropriate for the study. Random sampling method was used and resulted in sampling 100 points in an area of about 90 km^2. CO2 concentration measurements were done using an Orsat gas sampling apparatus whereas ^220Rn gas concentrations were measured using a portable radon detector. The CO2 values ranged from 0-5.4% while the ^220Rn ranged from 0-2,834 counts per minute (cpm). Possible faults were inferred north of the prospect area due to the anomalously high levels of CO2 and ^220Rn recorded.
文摘In this study,methods based on the distribution model(with and without personal opinion)were used for the separation of anomalous zones,which include two different methods of U-spatial statistics and mean plus values of standard deviation(X+nS).The primary purpose is to compare the results of these methods with each other.To increase the accuracy of comparison,regional geochemical data were used where occurrences and mineralization zones of epithermal gold have been introduced.The study area is part of the Hashtjin geological map,which is structurally part of the folded and thrust belt and part of the Alborz Tertiary magmatic complex.Samples were taken from secondary lithogeochemical environments.Au element data concerning epithermal gold reserves were used to investigate the efficacy of these two methods.In the U-spatial statistics method,and criteria were used to determine the threshold,and in the method,the element enrichment index of the region rock units was obtained with grouping these units.The anomalous areas were identified by,and criteria.Comparison of methods was made considering the position of discovered occurrences and the occurrences obtained from these methods,the flexibility of the methods in separating the anomalous zones,and the two-dimensional spatial correlation of the three elements As,Pb,and Ag with Au element.The ability of two methods to identify potential areas is acceptable.Among these methods,it seems the method with criteria has a high degree of flexibility in separating anomalous regions in the case of epithermal type gold deposits.
基金supported by the fund"Metallogenic Geodynamic Background,Process and Quantitative Evaluation of Super Large Fe-Cu Polymetallic Deposits,Qinghai Qimantag Area"(Grant No.1212011220929)from Beijing Key Laboratory of Land Resources Information Research and Development,China University of Geosciences,Beijing
文摘Fractal and multi-fractal content area method finds application in a wide variety of geological,geochemical and geophysical fields.In this study,the fractal content-gradient method was used on1:10,000 scale to delineate geochemical anomalies associated with copper mineralization.Analysis of geochemical data from the Yangla super large Cu-Pb-Zn polymetallic ore district using the fractal content-gradient method,combined with other geological data from this area,indicates that oreprospecting in the ore district should focus on Cu as the main metal and Pb-Zn and Au as the auxiliary metals.The types of deposits include(in chronological order) re-formed sedimentary exhalative(SEDEX),skarns,porphyries,and hydrothermal vein-type deposits.Three ore-prospecting targets are divided on a S-N basis:(1) the Qulong exploration area,in which the targets are porphyry-type Cu deposits;(2) the Zongya exploration area,where the targets are porphyry-type Cu and hydrothermal vein-type Cu-Pb polymetallic deposits;and(3) the Zarelongma exploration area,characterized mainly skarn-type "Yangla-style" massive sulfide Cu-Pb deposits.Our study demonstrates that the fractal content-gradient method is convenient,simple,rapid,and direct for delineating geochemical anomalies and for outlining potential exploration targets.