Preliminary analysis on roles of metal–organic compounds in the formation of invisible gold

The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen, closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit (Kazakhstan), related to post-collisional magmatic-hydrothermal origin. Gold mineralization of the deposit occurs mainly in the form of an “invisible” type of gold in the structures of arsenian pyrite and arsenopyrite, and the form of gold-organic compounds of pyrobitumen in carbonaceous-terrigenous sequences of Carboniferous formation. Microscopic and electron microscopic analysis, Raman and FT-Infrared analysis, mineralogical and three-step sequential extraction analysis (NH₂OH·HCl, H₂O_2, HNO₃ + HCl) has been carried out using 9 ore samples (from 3 different types of ores) for a comprehensive study of pyrobitumen and sulfide arsenic ores focusing mainly on organic matter. The sequentially extracted precious metal content of pyrobitumen reaches up to 7 ppm gold and other metals like Ag 4 ppm, Pt 31 ppb, and Pd 26 ppb, forming metal–organic compounds, while arsenic sulfide minerals incorporate 11 ppm gold, 39 ppm Ag, 0.49 ppm Pt. The enrichment of gold associating with organic matter and sulfide ore minerals was confirmed in this study. Organic matter was active in the migration of gold and the capture of gold by pyrobitumen. Moreover, the reductive organic matter agent released gold, most likely for the sulfide arsenic ore minerals. Pyrobitumen was a decisive factor in the concentration, transportation, and preservation of gold in the deposit.

     

Speciation studies of arsenic in the environment and in human

Arsenic is the 20th most abundant element in the Earth crust. Humans are exposed to naturally occurring and anthropogenic sources of arsenic compounds in the environment. A wide variety of adverse health effects have been attributed to chronic exposure to high levels of arsenic. More than two-dozen arsenic compounds （species） are present in the environment and in biological systems. The various arsenic species have dramatically different behavior and toxicity. This presentation briefly describes arsenic speciation analysis, human exposure to and metabolism of arsenic species. Environmental issues on arsenic in Canada are briefly discussed. These include （1） the arsenic waste left from previous gold mining and smelting activities; （2） the domestic use of wood treated with chromated copper arsenate; and （3） use of well water as the source of drinking water by approximately one third of the Canadian population.     

Preliminary Study on the PGE Geochemistry of the Permian Basalts in the Jinping Area

INTRODUCTIONIn comparison with studies on the geochemistryof the REE and trace elements of the Emeishan Per-mian basalts ,there has been onlyli mited research onthe platinum group elements ( PGE) . Preli minarystudies have been carried out on the PGE geochemis-try of the basalts in the Emeishan area ( QingyingPower Station profile) and Xinjie area (Zhang andLi ,1998) ,andinthe Shuicheng and Weining areasinGuizhou (Li et al .,2003) . There are no PGEanaly-sis data of the basaltsin…     

Preliminary Study of the Characteristics and Genesis of Arsenate Minerals in the Oxidized Zone of the Debao Skarn-Type Cu-Sn Ore Deposit in Guangxi

Through the study of the oxidized zone of the Debao skarn-type Cu-Sn deposit in Guangxi, the authorshave found 14 arsenate minerals, most of which are for the first time reported in China. They are mainly Cuarsenate minerals with subordinate Cu-Pb arsenate minerals and minor Fe-Pb-Ba varieties. Based on their paragenesis these minerals may be divided into the following series: (1) the clinoclasite-olivenite-cornwallite- cornubite- debaoite- copper silicarsenate association, (2) the scorodite- carminite- beudan-tite-bayldonite- duftite association, and (3) the scorodite-Ba-bearing pharmacosiderite- dussertite association. Arsenate minerals are formed generally in the oxidized zone of the sulfide-type deposits which lie in thewarm, humid and rainy torrid-subtropical zone with pH=6-8 and contain large amounts of arsenopyrite andcarbonate rocks.     

A Preliminary Study of the Gas Hydrate Stability Zone in the South China Sea

Based on the analysis of sea-bottom temperature and geothermal gradient, and by means of the phase boundary curve of gas hydrate and the sea-bottom temperature versus water depth curve in the South China Sea, this paper studies the temperature and pressure conditions for gas hydrate to keep stable. In a marine environment, methane hydrate keeps stable at water depths greater than 550 m in the South China Sea. Further, the thickness of the gas hydrate stability zone in the South China Sea was calculated by using the phase boundary curve and temperature-depth equations. The result shows that gas hydrate have a better perspective in the southeast of the Dongsha Islands, the northeast of the Xisha Islands and the north of the Nansha Islands for thicker stability zones.     

Baseline geochemical studies in Australia with particular reference to geohealth studies in the Gawler Craton of South Australia

Geoscience Australia and the Cooperative Research Centre for Landscape Environments and Mineral Exploration, in collaboration with State agencies are conducting a series of pilot baseline geochemical surveys （BGS）. These aim to characterize regional geochemical patterns and contribute to what is presently a limited research direction in Australia. BGS can help （1） establish baselines to monitor future change; （2） target mineral exploration; （3） develop informed environmental policies; and （4） geomedical studies on plant and animal well being. In 2004-05, sampling at an average density of 1 sample per 1100 km^2, was conducted in the Gawler Craton, South Australia. In contrast to our pilot region in the Riverina of New South Wales and Victoria, the Gawler lacks well-developed drainage systems and is dominated by aeolian dunes in its western sector. One of the key aims of the Gawler study is to determine whether elemental excesses or deficiencies exist in the regolith and the implications of these for plant, animal and human health. Top （0-10 cm depth） and bottom （～55-90 cm depth） sediment samples were collected in the lower parts of 42 catchments. The compositions of the 〈75 um and 〈180 um fractions were analyzed using XRF （major and some trace elements）, ICP-MS （most trace elements） and ISE （F） methods. Preliminary results show that F, Cr and V are locally elevated above national and international guideline concentrations, raising concerns that these elements may pose potential health issues. Heavy mineral fractions （density 〉2.95） in 4 samples （3 sites） are dominated by iron oxides, spinels, rutile, zircon and barite. Some Cr and V may be related to heavy minerals such as spinels, limiting their bioavailability. Cu, Se and Zn are potentially deficient in parts of the region, but once identified in agricultural areas can easily be remedied through the application of suitable fertilizers.     

Clogging microstructures in the vadose zone—laboratory and field studies

Long-term water infiltration into porous media, like clastic deposits, causes colmatage (clogging), which is expressed by the decrease of permeability. It is caused by progressive filling of pore spaces with fine particles carried in suspension (mechanical colmatage) and minerals precipitated from water (chemical colmatage or biochemical colmatage, when the process is affected by bacterial activity). Although this material is introduced into the sediment after deposition, it does not destroy the primary framework of it but it only coats grains and fills voids. This process results in some characteristic microstructures that are called ‘clogging microstructures’. The research included: (1) experiments on sands exposed to mechanical colmatage in laboratory conditions, which aimed to describe clogging microstructures and to examine the effects of grain size distribution on the rate and degree of clogging; (2) field and laboratory studies of deposits in which colmatage occurred in natural conditions in the infiltrating water intake ‘Dębina’ in Poznań, Poland. The main goal of the research was to identify post-depositional changes that took place in fluvial deposits affected by forced river water infiltration in the Warta River valley. Examples are presented of clogging microstructures formed in deposits affected by colmatage in the laboratory and in natural conditions.

The place of ecological–geophysical studies in the system of urban ecology

According to the forecasts of the World Health Organization, 70% of the world’s population will have lived in large and small cities by 2050. This means that more than two-thirds of the planet’s population will become a part of new natural-technical formation, that is, geobiotechnoecosystems. Such ecosystems are characterized by profound changes in natural properties during active human impacts and by acquiring new qualities. The changes manifest themselves in all ecological functions of the terrestrial spheres: the atmosphere, the hydrosphere, and the lithosphere, including a change in the geophysical (energetic) potential as well. The presented material can be considered as a basis for the formation of Geophysical Urban Ecology, which is a new scientific and practical field.     

Geological Characteristics and REE Geochemistry of Sn—mineralized Granitoids in the Mt.Hengduanshan Region—A Preliminary Study

Studied in this paper are the mode of occurrence, petrology, petrochemistry, Sn abundance and REE geochemistry of Sn-mineralized granitoids in the Mt. Hengduanshan Region. The results show that the concentration of Sn increases with decreasing LREE but increasing HREE in the complex plutons associated with Sn mineralization. Generally, LREE< 150ppm, HREE> 50ppm, δEu = 0.01–0.14 and symmetrically “V” -shaped curves representing the REE patterns are the important indices of Sn enrichment and mineralization. This project was finantially supported by the National Natural Science Foundation of China.     

Gold in vegetation and soil — three case studies from the goldfields of southern Western Australia

Biogeochemistry has not been widely used as an exploration technique for Au in Western Australia because (1) sampling of soils and other surficial materials have been reasonably effective in finding new mineral deposits, and (2) it has been difficult to identify a consistent and regionally typical vegetation sample type. The potential of the technique has been tested at three sites in the goldfields of southern Western Australia. Vegetation and soil were analysed for Au from the Bounty (Mt Hope), Panglo and Zuleika Au deposits in the southern Yilgarn Craton. Gold concentrations in vegetation were generally lower at Panglo and Zuleika compared with Bounty, and probably reflect the depth to mineralization which is considerably greater at Panglo (40 m) and Zuleika (20 m) than at Bounty, where it is close to the surface. At Bounty, Au concentrations in dried vegetation varied from < 0.5 ppb in background areas to a maximum of 11 ppb (the highest for any area) over mineralization. In general, the association between Au concentrations in vegetation and mineralization is only weak although, at Zuleika, Maireana (bluebush) seemed a slightly better sample medium than soil for predicting the location of underlying mineralization.As the emphasis in exploration changes to more difficult terrains, the suitability of biogeochemistry needs to be re-examined. These preliminary results from Western Australia suggest that biogeochemistry may have some role to play in the search for deeply buried mineral deposits.     

Preliminary Investigation on the Causes of Odd Vibration of Buildings in Guilin City—a Study on the Resonance between Buildings and the Underlying Soil Layer

A residential building in Guilin City, China, underwent an up-and-down vibration with an amplitude of 2 cm. By eliminating several causes such as earthquake, wind and construction, in combination with the unique karst geological conditions of Guilin, it was inferred that the effect of turbulent karst water is the main contributor to the occurrence of this vibration. Therefore, a geophysical survey was undertaken on the vibration zone and its surroundings. The resutls suggest that the soil in the upper part of the karst grooves shows conspicuous traces of disturbance and the water content has low resistance. A comprehensive analysis indicates that there is a karst strong runoff zone beneath the area. According to the water level and water temperature data collected automatically by the instrument, it can be concluded that the groundwater level had changed significantly twice during this period, so it was determined that the denudation of groundwater strong runoff causes the overlying soil layer to collapse, forming a soil-water soft-flow material with mixed phase. Since the building in this area was supported by friction piles, the groundwater-soil soft-flow material with mixed phase has intense plasticity, and the up-and-down vibration resulted in the change of the friction piles, which caused the up-and-down vibration of the building structure.     

A Preliminary Study of the Solubility of Copper in Water Vapor at Elevated Temperatures and Pressures

INTRODUCTIONAs early as 1644 , Ren啨Descartes proposed thatsilver-,gold-,and lead-bearing veins were producedby the condensation of vapors emanating from theearth' s interior ( Williams-Jones et al ., 2002) . Butthe solubility of many metals is higher in liquid thanin vapor andtherefore the focus of research on hydro-thermal ore deposits was placed on hydrothermal sys-tems (Barnes ,1997) ,considering the fact that ore-forming elements may exist as complexes in hydro-thermal solutions . T…     

A Bright-Coloured Flower in the Field of Earth Sciences in China——in Celebration of the 70th Anniversary of the Publication of Acta Geologica Sinica

Acta Geologica Sinica (hereinafter referred to as the Acta) starting publication in 1922, is a quaterly academia periodical sponsored by the Geological Society of China (GSC). It has been one of the science and technology periodicals in China with the longest history.     

Infrared and Raman spectroscopy studies of the α–β phase transition in cristobalite

Infrared and Raman spectra of cristobalite are presented as a function of temperature through the phase transition. The modes are assigned and the assignments compared to those of earlier workers. The compatibility of modes at the G-point of the a-phase with the X and G-points of the ß-phase is given. In the transition region of ca. 500–550 K, smooth changes in intensity, frequency and linewidths are seen in many modes, indicative of coexistence of a- and ß-forms.     

The Cretaceous-Tertiary boundary in a sector of the south limb of the Miranda-Treviño synclinal: the first appearance of chelonia and archosauria in the Basque country

This paper presents a study of the Cretaceous-Tertiary boundary in the Miranda-Treviño Synclinorium (Basque-Cantabric basin) where two main sequences have been recognised; the lower is regressive and theupper one has a marked transgressive trend. They are separated by a low angled un-conformity which is indicative of the Maastrichtian-Danian boundary.The lower sequence (S1) indicates a clear transition between the shoreface and backshore sub-environments. Bone accumulations are located in the sandy sediments of the upper foreshore and backshore, associated with ferrugenous hardgrounds and gypsum efflorescences.The upper sequence (S2) indicates the beginning of a marine transgression. It is composed a dominantly carbonate-rich sediments and the fauna suggests a deposition in environmental conditions ranging from stenohaline, to littoral, and to a coastal lagoon and inner carbonaterich platform.In the lower sequence (Maastrichtian Unit S₁ U₃), the following herpetofauna have been identified; an eusuchian alligator, and two dinosaurs (an ornithopod and a sauropod). Several plates of chelonia have been identified as? Adocus sp.     

Geostatistical analysis on the spatial variation of radiogenic elements in the crystalline basement of Grenville Province in the southwestern Québec

Accurate assessment of deep geothermal resources remains a challenge from the practical point of view. Parameter uncertainties and partial knowledge of initial conditions limit the prediction of subsurface temperatures using a variety of thermal models strongly unreliable, and the temperature is highly dependent on the radiogenic heat production in the geological layers mainly affected by a number of factors including the concentrations of uranium, thorium and potassium, and rock density. In this paper, geostatistical methods were applied to investigate the spatial distribution of radiogenic elements (e.g., uranium, thorium, potassium) and their corresponding concentrations and radiogenic heat production. A representative region measuring 35 km?×?80 km in the southwestern Québec, and covering the domains of Portneuf-Mauricie, Morin Terrane and Parc des Laurentides in the Grenville Province was selected for this study because of its easy accessibility. Analysis results show that the concentrations of uranium, thorium and potassium for most rocks of the Grenville basement in the research region are in the range of 1–2 ppm, 3–10 ppm and 1–4%, respectively. Furthermore, 90% of the total samples analysed in this study show a uranium concentration of less than 3 ppm, 64% of the samples show a thorium concentration of less than 5 ppm, and 56% of the samples show a potassium concentration of less than 3%. This paper engaged both the ordinary kriging interpolation and sequential Gaussian simulation (SGS) methods to study the spatial distribution of radiogenic elements. Using density data for specific rocks, the distribution of radiogenic heat production in the study area of the southwestern Grenville Province was also simulated using the SGS method. Conclusively, results show that the difference between the minimum and the maximum value of radiogenic heat production is 30%, considering a significant proportion of heterogeneity in rock density.     

Avalanche cycles in Austria: an analysis of the major events in the last 50 years

During the last 50 years, an average of 30 persons per year was killed by avalanches in Austria. About one-third of all avalanche fatalities occurred as a result of so-called ‘catastrophic avalanches’. ‘Catastrophic avalanches’ are spontaneously released avalanches that affect villages and cause damage to property (buildings, roads and other infrastructure). The biggest avalanche events in Austria were in 1950/1951 (135 fatalities), in 1953/1954 (143 fatalities) and in February 1999, when 38 persons were killed in Galtür and Valzur. This article deals with an analysis of nine major avalanche cycles in the last 55 years. An avalanche cycle in this article is defined as 50 recorded avalanches of at least size 3 in two days and/or 5 persons killed in villages within two days. The basis of this study are the well-documented records from Fliri (1998), who analysed natural disasters in the western part of Austria and the Trentino, including floods, mudflows, earthquakes and avalanches. The meteorological data were taken from two relevant observation sites in the northern part of the Austrian Alps, from two sites in an intermediate and continental region, respectively and from one site in the southern part of the Austrian Alps. Atmospheric patterns were analysed by using weather charts for the relevant periods. Both the meteorological data and the weather charts were provided by the Central Institute for Meteorology and Geodynamics (ZAMG). It was found that there was a major cycle every 6 years (on average). Two-thirds of all investigated cycles were characterised by a continuous increase of snow depth over a period of at least three days. In only three periods (1975, 1986, 1988), daily extreme values could be observed. More than 40% of all the cycles occurred in January. In two-thirds, a north-westerly oriented frontal zone was responsible for the formation of a major cycle. The remaining cycles were released by low-pressure areas over Central Europe and the Mediterranean Sea, respectively.     

Chemical and physical studies of type 3 chondrites—VIII: Thermoluminescence and metamorphism in the CO chondrites

The thermoluminescence properties of nine CO chondrites have been measured. With the exception of Colony and Allan Hills A77307 (ALHA 77307), whose maximum induced TL emission is at approximately 350°C, CO chondrites exhibit two TL peaks, one at 124 ± 7°C (130°C peak) and one at 252 ± 7°C (250°C peak). The 130°C peak shows a 100-fold range in TL sensitivity (0.99 ± 0.21 for Isna to 0.010 ± 0.004 for Colony), and correlates with various metamorphism-related phenomena, such as silicate heterogeneity, metal composition and McSween's metamorphic subtypes. The peak at 250°C does not show these correlations and, Colony excepted, varies little throughout the class (0.3 to 0.07, Colony 0.018 ± 0.004). Mineral separation experiments, and a series of annealing experiments on Isna, suggest that the TL properties for CO chondrites reflect the presence of feldspar in two forms, (1) a form produced during metamorphism, and analogous to the dominant form of feldspar in type 3 ordinary chondrites, and (2) a primary, metamorphism-independent form, perhaps associated with the amoeboid inclusions. If this interpretation is correct, then the CO chondrites have not experienced temperatures above the order/disorder temperature for feldspar (500–600°C) and they cooled more slowly than comparable (i.e. type <3.5) type 3 ordinary chondrites. Colony and ALHA 77307 have atypical TL properties, including very low TL sensitivity, suggesting that phosphors other than feldspar are important. They have apparently experienced less metamorphism than the others, and may have also been aqueously altered.