Geochemical studies, mineralization and mineral potential of Tafresh area, the Iran-Markazi

The study area is part of the Urumieh–Dokhtar volcanic arc that a large part of its surface is covered by extrusive Igneous rocks(tuff,intermediate lavas and ignimbrites sheets),plutonic igneous(diorite and granodiorite)and semi-deep stones(dyke and sill).Studied samples are situated in calc-alkaline domain of magmatic series diagrams.Harker diagrams show the fractional crystallization of Clinopyroxene,amphibole,plagioclase,alkali feldspars and opaque minerals(ilmenite Titano-magnetite,ilmenite and rutile).In spider diagrams,light rare earth elements(LREE)are enriched compared to heavy rare earth elements(HREE),and HFS elements(Ti,Nb)show negative anomaly and LFS elements(Cs,K,Pb)show positive anomaly,showing that it is a distinct characteristic of subduction zones.Skarns of the area mainly are of exoskarns and are rich in plagioclase,microcline,amphibole,biotite and epidote.Skarn is enriched of iron,copper,molybdenum,vanadium,lead,zinc and silver.Deposits of barite in the area show characteristics of volcanic-sedimentary barites and are associated to ore-bearing hydrothermal solutions.Using satellite images and processing information,four areas with high mineral potential are identified in the area.

Cumulative gain and lift charts for model performance assessment in mineral potential mapping

Model performance assessment is a key procedure for mineral potential mapping, but the correspond-ing research achievements are seldom reported in literature. Cumulative gain and lift charts are well known in the data mining community specialized in marketing and sales applications and widely used in customer chum prediction for model performance assessment. In this paper, they are introduced into the field of mineral poten-tial mapping for model performance assessment. These two charts can be viewed as a graphic representation of the advantage of using a predictive model to choose mineral targets. A cumulative gain curve can represent how much a predictive model is superior to a random guess in mineral target prediction. A lift chart can express how much more likely the mineral targets predicted by a model are deposit-bearing ones than those by a random se-lection. As an illustration, the cumulative gain and lift charts are applied to measure the performance of weights of evidence, logistic regression,restricted Boltzmann machine, and multilayer perceptron in mineral potential mapping in the Altay district in northern Xinjiang in China. The results show that the cumulative gain and lift charts can visually reveal that the first three models perform well while the last one performs poorly. Thus, the cumulative gain and lift charts can serve as a graphic tool for model performance assessment in mineral potential mapping.

Petrogenesis, oxidation state and volatile content of Dongga tonalite in the Gangdese belt, Xizang: Implication for porphyry Cu mineralization

The Gangdese belt in Xizang has experienced both Jurassic subduction and Cenozoic continental collision processes, making it a globally renowned region for magmatic rocks and porphyry copper deposits. Numerous Jurassic intrusions have been identified in the belt. Apart from the quartz diorite porphyry in the large Xietongmen deposit, the Cu mineralization potential of other Jurassic intrusions in this belt remains unclear. This study presents zircon U–Pb dating and trace elements, apatite major and trace elements as well as published whole-rock geochemical and isotopic data of the Dongga tonalite in the central part of the Gangdese belt, aiming to reveal the petrogenesis, oxidation state, volatile content, and Cu mineralization potential of this intrusion. The Dongga tonalite has a zircon U–Pb age of 179.4 ± 0.9 Ma. It exhibits high whole-rock V/Sc values(8.76–14.6), relatively low apatite CeN/CeN*ratios(1.04–1.28), elevated zircon(Eu/Eu*)Nvalues(an average of 0.44), high Ce4+/Ce3+values(205–1896), and high ?FMQ values(1.3–3.7), collectively suggesting a high magmatic oxygen fugacity. The Dongga tonalite features amphibole phenocrysts, relatively high whole-rock Sr/Y ratios(20.3–58.9), and lower zircon Ti temperatures (502–740 ℃), reflecting a high magmatic water content. Estimation of magmatic sulfur content(0.002–0.024 wt%) based on apatite SO3contents indicates an enriched magma sulfur content. Combined with previous studies and the collected Sr–Nd–Hf isotopes, the Dongga tonalite is derived from juvenile lower crust related with subduction of the Neo-Tethys oceanic slab. When compared with Xietongmen orebearing porphyries, the Dongga tonalite exhibits remarkable similarities with the Xietongmen ore-bearing porphyries in terms of magma source, tectonic background, magmatic redox state, and volatile components, which indicates that the Dongga tonalite has a high porphyry Cu mineralization potential, and therefore, provides important guidance for the future mineralization exploration.

Mineral Potential Mapping for Tungsten Polymetallic Deposits in the Nanling Metallogenic Belt, South China

The Nanling belt in South China has considerable resources of tungsten polymetallic commodities and is one of the most important metallogenic belts in the world. Data-driven weights-of-evidence （WofE） and fuzzy logic models are used to evaluate the tungsten polymetallic potential of the Nanling belt. Initially, seven ore-controlling factors derived from multi-source geospatial datasets （e.g., geological, geochemical, and geophysical） are used for data integration in the two models. Two mineral potential maps are generated that efficiently predicate the locations of the deposits. The WofE map predicate 81% of the deposits within 13.6% of the study area, whereas the fuzzy logic map predicate 81.5% of the deposits within 13% of the area. The predictive maps are syntheses of spatial association rules, which provide better understanding of those factors that control the distribution of mineralization and trigger eventual exploration work in new areas. Subsequently, in order to evaluate the success rate accuracy, the receiver operating characteristic curves and area under the curves （AUCs） for the two potential maps are constructed. The results show that the AUCs for the WofE and fuzzy logic models are 0.775 7 and 0.840 6, respectively. The higher AUC value for the fuzzy logic model implies that it delineate a greater number of favorable areas compared with the WorE model. Overall, the capabilities of both models for correctly classifying areas with existing mineral deposits are satisfactory.

Nitrogen Mineralization Potentials of Upland Soils inCentral China

Nitrogen mineralization potentials of 15 soil samples were studied by the methods of soil asrobic incuba-tion, and the correlation between the potentials and the amounts of nitrogen taken up by rye grass (Lolium.multifiorum Lam.) in pot culture was calculated. The soils were collected from Hubei Province in Cen-tral China. Soil nitrogen mineralization potentials (N_O) were calculated and optimized by a quick-BASICprogram. N_O ranged from 60 mg kg￣(-1) to 340 mg kg￣(-1), which accounted for 9.1% to 34.6% of the totalnitrogen content. Among the examined soils, yellow-brown soil collected from Wuhan had the largest N_Oand brown-red soil from Xianning had the smallest one. The mineralization rate constants (k) ranged from0.00556 d￣(-1) to 0.01280 d￣(-1) , in average 0.00882 d￣(-1) . Chao soil from Wuhan had the greatest k while yellow-cinnamon soil from Zhaoyang had the smallest one. There were apparent differences between mineralizationparameters (N_O and k) optimized and non-optimized ones. Optimized N_O had a better correlation thannon-optimized N_O with the amount of nitrogen accumulated in the aerial parts of rye grass. N_O , N_O × k andN_t(accumulated mineralized nitrogen within time t) could be used as indexes of soil nitrogen supply. Amongthem N_t was the best, which was significantly correlated with the amounts of nitrogen accumulated in theaerial parts of rye grass harvested at three different times.

Analysis on Uranium Mineralization Potential of Late Yanshanian Granites in Sichuan of Sanjiang Area

The Sanjiang area is an important granite distribution area in China,except for South China,in which granites is complex and complete.Based on fully collecting date about it,this paper explores the significance of uranium

Geochemical Characteristics and Uranium Mineralization Potential of The Yanshanian Granite in The West of Yunnan Province

1 Introduction The Sanjiang metallogenic belt is one of the important nonferrous metal metallogenic belts in China,the potential resources of copper,lead,zinc,silver,gold and tin are huge(Zhengqian et al.,1993).In the west of Yunnan province has a lot of Yanshanian granite,according to 1:20 million test data,development of granite belt rich in radioactive minerals in the west of Yunnan

Fractal Principle of Mineral Deposit Size Forecasting and Its Implication for Gold Resource Potential Evaluation in China

Mineralization distributions are very heterogeneous in nature. As large orsuperlarge mineral deposits are quite rare whether in time or in space, it is difficult to detectall the largest mineral deposits in a region in a limited period of time owing to the restriction oftechnology and exploration degrees-this is called 'not all discovered'. However, all discoveredlarge, especially superlarge, mineral deposits generally have a complete census in the geologicalliteratures. On the other hand, not all discovered small mineral deposits are recorded in thegeological literatures because for economic reasons people have not much interest in them-this iscalled 'not all recorded'. This practice often results in the observation truncations, that is, thedata points near the two ends in an observable population, which is obtained by fitting a power lawsize-frequency distribution to discovered mineral deposits in a given region, show concave-downdeparture from the correlation line fitted. The authors suggest that the size and number ofundiscovered deposits may be forecast by fitting a fractal size distribution to discovered mineraldeposit sizes between the upper and lower truncation observations and then extrapolating thescale-independent area to deposit sizes larger than the upper truncation limit. Based on thestatistical results obtained by the fractal size-frequency distributions of 394 discovered golddeposits with sizes greater than 2 t Au in China and 83 known gold deposits with sizes over 0.3 t Auin the Jiaodong area of China, the authors forecast according to the present commercial standardsfor gold ores that the total resources of undiscovered gold deposits ranging in tonnage from 50 to2000 t Au are more than 4500 tin China, and that in the Jiaodong area of China the total resourcesof potential gold deposits with sizes in the range of 30 to 650 t Au are about 700 t.

Geology, Mineral Deposit Model and Potential of the Suwar Cu-Ni Sulphide Prospect, Northwest Yemen

The Suwar Cu-Ni sulphide prospect is very highly regarded for its potential to host a major nickel-copper sulphide deposit in Republic of Yemen, a mineral resource lacking country. The ore-hosting intrusion is a lopolith about 6km long and lkm wide and more than 300m deep. There are two types of Cu-Ni mineralizations in the prospect: primary massive chalcopyrite+ pyrrhotite+ pentlandite controlled by gravitational and structural traps while the secondary Cu-Ni mineralization is coarse grained and occur as veins, veinlets, fracture fill, blebs or associated with coarse, re-crystallized carbonate in shear zones and faults. The deposit type of the prospect is believed to be the one associated with the ultramafic component of a large, broadly differentiated noritic, gabbroid intrusive. It is suggested that the prospect and adjacent area possibly contain a similar world class Ni-Cu deposits as that in Jinchuan, China.

Singularity theories and methods for characterizing mineralization processes and mapping geo-anomalies for mineral deposit prediction

In this paper, we show that geo-anomalies can be delineated for mineral deposit prediction according to singularity theories developed to characterize nonlinear mineralization processes. Associ- ating singularity and geo-anomalies makes it possible to quantitatively study geo-anomalies with modern nonlinear theories and methods. This paper introduces a newly developed singularity analysis of nonlinear mineralization processes and nonlinear methods for characterizing and mapping geo-anomalies for mineral deposit prediction. Mineral deposits, as the products of singular mineralization processes caused by geo-anomalies, can be characterized by means of fractal or multifractal models. It has been shown that singularity can characterize the degree of geo-abnormality, and this has been demonstrated to be useful for mapping anomalies of undiscovered mineral deposits. The study of mineralization and mineral deposits from a nonlinear process point of view is a new but promising research direction. This study emphasizes the relationships between geo-anomalies and singularity, including singular processes resulting in singularity and geo-anomalies, the characterization of singularity and geo-anomalies and the identification of geo-anomalies for mineral deposit prediction. The concepts and methods are demon- strated using a case study of Sn mineral deposit prediction in the Gejiu mineral district in Yunnan, China.

Gold Resources Potential Assessment in Eastern Kunlun Mountains of China Combining Weights-of-evidence Model with GIS Spatial Analysis Technique

Resources potential assessment is one of the fields in geosciences,which is able to take great advantage of GIS technology as a substitution of traditional working methods.The gold resources potential in the eastern Kunlun Mountains,Qinghai Province,China was assessed by combining weights-of-evidence model with GIS spatial analysis technique.All the data sets used in this paper were derived from an established multi-source geological spatial database,which contains geological,geophysical,geochemical and remote sensing data.Three multi-class variables,i.e.,structural intersection,Indosinian k-feldspar granite and regional fault,were used in proximity analysis to examine their spatial association with known gold deposits.A prospectivity map was produced by weights-of-evidence model based on seven binary evidential maps,all of which had passed a conditional independence test.The study area was divided into three target zones of high potential,moderate potential and low potential areas,among which high potential areas and moderate potential areas accounted for 20% of the total area and contained 32 of the 43 gold deposits.The results show that the gold resources potential assessment in the eastern Kunlun Mountains has a higher precision.

Multiple-aged granitoids and related tungsten-tin mineralization in the Nanling Range, South China

The Nanling metallogenic belt in South China is characterized by well-developed tungsten-tin mineralization related to multi- ple-aged granitoids. This belt is one of the 5 key prospecting and exploration areas among the 19 important metallogenic tar- gets in China. Important progress has been made in recent years in understanding the Nanling granitoids and associated miner- alization, and this paper introduces the latest major findings as follows： （1） there exists a series of Caledonian, Indosinian, and Yanshanian W-Sn-bearing granites; （2） the Sn-bearing Yanshanian granites in the Nanling Range form an NE-SW trending aluminous A-type granite belt that stretches over 350 km. The granites typically belong to the magnetite series, and dioritic micro-granular enclaves with mingling features are very common; （3） the Early Yanshanian Sn- and W-bearing granites pos- sess different petrological and geochemical features to each other： most Sn-bearing granites are metaluminous to weakly per- aluminous biotite （hornblende） granites, with zircon tHe（t） values of ca. -2 to -8, whereas most W-bearing granites are peralu- minous two-mica granites or muscovite granites with CHf（t） values of ca. -8 to -12; （4） based on the petrology and geochemis- try of the W-Sn-bearing granites, mineralogical studies have shown that common minerals such as titanite, magnetite, and bio- tite may be used as indicators for discriminating the mineralizing potential of the Sn-bearing granites. Similarly, W-bearing minerals such as wolframite may indicate the mineralizing potential of the W-bearing granites. Future studies should be fo- cused on examining the internal relationships between the multiple-aged granites in composite bodies, the metallogenic pecu- liarities of multiple-aged W-Sn-bearing granites, the links between melt evolution and highly evolved ore-bearing felsic dykes, and the connections between granite domes and mineralization.

Swelling of clay minerals in ammonium leaching of weathered crust elution-deposited rare earth ores

The effect of hydrated radius, cation valence, pH and solution concentration on the zeta potential of clay minerals was investigated, and the relation between zeta potential of clay minerals and swelling was discussed in different leaching agents as well. The results show that the zeta potential of clay minerals decreases with the hydrated ionic radius increasing. It could be seen that the zeta potential of the clay minerals in AICl3 solution is positive,whereas that in NH4C1, KCl and MgCl2 solution is negative. And the zeta potential of clay minerals increases with the cation valence increasing. Moreover, the zeta potential of clay minerals decreases with the solution pH increasing,whereas that increases with the solution concentration increasing in different ammonium solutions. In addition,the swelling of clay minerals decreases while the zeta potential of clay minerals increasing in different ammonium solutions. The ability of compound ammonium to inhibit the swelling of clay minerals is lower than that of single ammonium solution.

Greenhouse Gas Emissions and Growth of Wheat Cultivated in Soil Amended with Digestate from Biogas Production

Digestate, the product obtained after anaerobic digestion of organic waste for biogas production, is rich in plant nutrients and might be used to fertilize crops. Wheat （Triticum spp. L.） was fertilized with digestate, urea, or left unfertilized and cultivated in the greenhouse for 120 d. Emissions of greenhouse gasses （carbon dioxide （CO2）, methane （CH4）, and nitrous oxide （N20）） were monitored and plant growth characteristics were determined at harvest. The digestate was characterized for heavy metals, pathogens, and C and N mineralization potential in an aerobic incubation experiment. No Salmonella spp., Shigella spp., or viable eggs of helminths were detected in the digested pig slurry, but the number of faecal coliforms was as high as 3.6 ~ 104 colony-forming units （CFU） g-1 dry digestate. The concentrations of heavy metals did not surpass the upper limits established by US Environmental Protection Agency （EPA）. After 28 d, 17% of the organic C （436 g kg-1 dry digestate） and 8% of the organic N （6.92 g kg-1 dry digestate） were mineralized. Emissions of CO2 and CH4 were not significantly affected by fertilization in the wheat-cultivated soil, but digestate significantly increased the cumulative N20 emission by 5 times compared to the urea-amended soil and 63 times compared to the uncultivated unfertilized soil. It could be concluded that digestate was nutrient rich and low in heavy metals and pathogens, and did not affect emissions of CH4 and CO2 when applied to a soil cultivated with wheat, but increased emission of N20. Key Words： biodigester, C and N mineralization potential, faecal coliform, heavy metal, pathogen, pig slurry