Study on Epithermal Gold Mineralization System at Shwebontha Prospect,Monywa Copper-Gold Ore Field,Central Myanmar

The Shwebontha prospect area is situated in the Central Volcanic Belt,central Myanmar,where the well-known Sagaing Fault serves as its eastern boundary.This study aims to document key the mineralogy,host rock geochemistry and ore mineralizing fluids.The mineralization,hosted by Upper Oligocene to Middle Miocene rhyolites,displays a strong lithological control.Mineralization is characterized by gold-bearing silicified massive ore and chalcedonic quartz veins in which sulfides are clustered and disseminated not only in quartz gangue but also in rhyolite host rocks.The significant ore minerals in the mineralized veins include pyrite,sphalerite,galena,chalcopyrite,and gold.Common hydrothermal alterations such as silicic,argillic and propylitic alteration types are recognized.According to the fluid inclusion data and interpretation,ore mineralizing fluids in the research area are characterized by formation temperatures of 260-280℃ and salinity of 0.35-2.41%wt.NaCl eq.respectively.Mixing of hydrothermal fluids was generally considered to be an effective mechanism for ore transport and deposition.

Analysis of Mineralization System and Prediction of New-Type Ore Deposits

The discovery of new-type ore deposits, an important approach to guarantee the mineral resources supply in the 21st century, often brings about a gigantic increase in the mineral resources reserves. The analysis of mineralization system is of great importance to the discovery of new type ore deposits. ① The understanding of the relationship among various ore deposit types within a mineralization system in a region can help us to locate the unknown ore deposit types from the known ore deposit types, evidence that has been proved in the mineral prospecting history of ore belts in the middle and lower reaches of the Yangtze River, China. ② The understanding of the spatial structure of a mineralization system, especially of the vertical zonation, is helpful for the discovery of the concealed ore deposit types. ③ Clarifying the temporal structure of a mineralization system, including the iteration relationship between the mineral deposit types in the mineralization, leads to the location of the missing mineralization chains from the known mineralization chains (mineral deposit type), a method often proved to be effective in the magmatic hydrothermal mineralization system.④ Clarifying the factors restraining the diversity of mineral deposit types in mineralization system leads to the discovery of the potential of new type mineral deposits in relevant region. ⑤ Studying new mineralization setting and new ore forming processes leads to discovery of new type mineral deposit. More probabilities of discovery of new type mineral deposits are present in biogenic mineralization system, deep sea mineralization system, low temperature mineralization system, tectonic mineralization system and superimposed mineralization system.

Hydrodynamic Links between Shallow and Deep Mineralization Systems and Implications for Deep Mineral Exploration

Deep mineral exploration is increasingly important for finding new mineral resources but there are many uncertainties.Understanding the factors controlling the localization of mineralization at depth can reduce the risk in deep mineral exploration.One of the relatively poorly constrained but important factors is the hydrodynamics of mineralization.This paper reviews the principles of hydrodynamics of mineralization,especially the nature of relationships between mineralization and structures,and their applications to various types of mineralization systems in the context of hydrodynamic linkage between shallow and deep parts of the systems.Three categories of mineralization systems were examined,i.e.,magmatic-hydrothermal systems,structurally controlled hydrothermal systems with uncertain fluid sources,and hydrothermal systems associated with sedimentary basins.The implications for deep mineral exploration,including potentials for new mineral resources at depth,favorable locations for mineralization,as well as uncertainties,are discussed.

DBU-based CO2 absorption-mineralization system: Reaction process,feasibility and process intensification

Amine-based carbon dioxide(CO2)capture is still limited by high desorption energy consumption.Fixing CO2 into carbonate is a safer and more permanent method.In this work,calcium oxide(CaO)is introduced to perform chemical desorption instead of thermal desorption on 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU)aqueous solution after CO2 absorption.The X-ray diffraction(XRD)patterns of solid products show the formation of calcite calcium carbonate(CaCO3),which prove the feasibility of this method.The effects of reaction temperature,reaction time and Ca2+/CO32-molar ratios on the related reactions in CO2 absorption-mineralization process and CaCO3 precipitation are discussed,and purer CaCO3 is obtained by ultrasonic treatment.The CaCO3 content can be increased to 95.8%and the CO2 desorption ratio can achieve 80%by 30 min ultrasonic dispersion treatment under the conditions(40℃,180 min,Ca2+/CO32-molar ratio=1.0).After five cycles,DBU aqueous solution shows stable CO2 absorption and mineralization ability.Fourier transform infrared spectroscopy(FT-IR)spectra of the reaction process also indicate the regeneration of the solvent.Compared with thermal desorption,this process is exothermic,almost without no additional heat.

Systemic modulation of skeletal mineralization by magnesium implant promoting fracture healing: Radiological exploration enhanced with PCA-based machine learning in a rat femoral model

The clinical application of magnesium(Mg)and its alloys for bone fractures has been well supported by in vitro and in vivo trials.However,there were studies indicating negative effects of high dose Mg intake and sustained local release of Mg ions on bone metabolism or repair,which should not be ignored when developing Mg-based implants.Thus,it remains necessary to assess the biological effects of Mg implants in animal models relevant to clinical treatment modalities.The primary purpose of this study was to validate the beneficial effects of intramedullary Mg implants on the healing outcome of femoral fractures in a modified rat model.In addition,the mineralization parameters at multiple anatomical sites were evaluated,to investigate their association with healing outcome and potential clinical applications.Compared to the control group without Mg implantation,postoperative imaging at week 12 demonstrated better healing outcomes in the Mg group,with more stable unions in 3D analysis and high-mineralized bridging in 2D evaluation.The bone tissue mineral density(TMD)was higher in the Mg group at the non-operated femur and lumbar vertebra,while no differences between groups were identified regarding the bone tissue volume(TV),TMD and bone mineral content(BMC)in humerus.In the surgical femur,the Mg group presented higher TMD,but lower TV and BMC in the distal metaphyseal region,as well as reduced BMC at the osteotomy site.Principal component analysis(PCA)-based machine learning revealed that by selecting clinically relevant parameters,radiological markers could be constructed for differentiation of healing outcomes,with better performance than 2D scoring.The study provides insights and preclinical evidence for the rational investigation of bioactive materials,the identification of potential adverse effects,and the promotion of diagnostic capabilities for fracture healing.

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.

Research progress of CO_(2) capture and mineralization based on natural minerals

Natural minerals,such as kaolinite,halloysite,montmorillonite,attapulgite,bentonite,sepiolite,forsterite,and wollastonite,have considerable potential for use in CO_(2) capture and mineralization due to their abundant reserves,low cost,excellent mechanical prop-erties,and chemical stability.Over the past decades,various methods,such as those involving heat,acid,alkali,organic amine,amino sil-ane,and ionic liquid,have been employed to enhance the CO_(2) capture performance of natural minerals to attain high specific surface area,a large number of pore structures,and rich active sites.Future research on CO_(2) capture by natural minerals will focus on the full utiliza-tion of the properties of natural minerals,adoption of suitable modification methods,and preparation of composite materials with high specific surface area and rich active sites.In addition,we provide a summary of the principle and technical route of direct and indirect mineralization of CO_(2) by natural minerals.This process uses minerals with high calcium and magnesium contents,such as forsterite(Mg_(2)SiO_(4)),serpentine[Mg_(3)Si_(2)O(OH)_(4)],and wollastonite(CaSiO_(3)).The research status of indirect mineralization of CO_(2) using hydro-chloric acid,acetic acid,molten salt,and ammonium salt as media is also introduced in detail.The recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO_(2) mineralization by natural minerals.

Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest communities.In the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 year.Sampling locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest communities.F.orientalis had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),P.nigra the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N turnover.Tannic acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

Trace element compositions of pyrite and stibnite:implications for the genesis of antimony mineralization in the Yangla Cu skarn deposit,Northwestern Yunnan,China

The Yangla Cu skarn deposit is located in the central part of the Jinshajiang Suture Zone,southwest China,with a total reserve of 150 Mt Cu@1.03%.The newly discovered antimony orebodies at the depth of Yangla are strictly controlled by the stratum,structure,and lithology,which are lenticular and vein-like within the marble fracture zone,which can provide a window into multistage miner-alization and ore genesis at Yangla.Mineralization can be divided into three types,Cu–Pb–Zn(skarn)pyrite,galena,and sphalerite,Cu(porphyry)chalcopyrite and pyrite,and Sb(hydrothermal)stibnite and pyrite.The mineral assem-blages were stibnite+pyrite+calcite+quartz±minor scheelite in antimony ores.This study presents quantitative measurements of the trace element compositions of pyrite and stibnite from the Yangla antimony ores.Analysis of pyrite with electron probe microanalysis(EPMA)showed enrichment in Co,Ni,Sb,As,and Mo,and deficit in its S and Fe contents when compared to the stoichiometric con-centrations of S and Fe in pyrite.The Sb-related pyrite may belong to sedimentary-reworked genesis and may be modi-fied by hydrothermalfluids,thereby presenting a certain dif-ference(i.e.,crystal morphology,texture,and chemical com-position)compared to the skarn and porphyry Cu-related pyrite in the Yangla Cu skarn deposit.Analysis of stibnite with EPMA and inductively coupled plasma-mass spectrom-etry showed enrichment in As,Pb,Sn,Pb,Cu,and Zn,and presented much higher Sb contents and slightly lower S con-tents when compared to the stoichiometric concentrations of Sb and S in stibnite.Statistical analysis of the stibnite trace elements showed correlations for the elemental pairs Cu–Pb,As–Sb,and Sn–Pb,and the coupled substitution equations Sb^(3+)↔Cu^(+)+Pb^(2+),Sb^(3+)↔As^(3+),and Sn^(2+)↔Pb^(2+)may be the major factors governed the incorporating Cu,Pb,As and Sn within the stibnite.Moreover,this study preliminary shows that the antimony mineralization may belong to a car-bonate replacement hydrothermal genesis at Yangla.

Source Enrichment Control on the Scale of Magmatic-Hydrothermal W-Sn Mineralization:Insights from Triassic and Jurassic Magma Reservoirs in the Continental Crust,Xitian,South China

There are two factors,source composition and magmatic differentiation,potentially controlling W-Sn mineralization.Which one is more important is widely debated and may need to be determined for each individual deposit.The Xitian granite batholith located in South China is a natural laboratory for investigating the above problem.It consists essentially of two separate components,formed in the Triassic at ca.226 Ma and Jurassic at ca.152 Ma,respectively.The Triassic and Jurassic rocks are both composed of porphyritic and fine-grained phases.The latter resulted from highlydifferentiated porphyritic ones but they have similar textural characteristics and mineral assemblages,indicating that they reached a similar degree of crystal fractionation.Although both fine-grained phases are highly differentiated with elevated rare metal contents,economic W–Sn mineralization is rare in the Triassic granitoids and this can be attributed to less fertile source materials than their Jurassic counterparts,with a slightly more enriched isotopic signature and whole-rockεNd(226 Ma)of−10.4 to−9.2(2σ=0.2)compared withεNd(152 Ma)of−9.2 to−8.2(2σ=0.2)for the Jurassic rocks.The initial W-Sn enrichment was derived from the metasedimentary rocks and strongly enhanced by reworking of the continental crust,culminating in the Jurassic.

A review of in situ carbon mineralization in basalt

Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable option for long-term carbon storage.Basalt rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as carbonates.However,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage potential.Under different reaction conditions,the carbonation products and carbonation rates vary.Carbon mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt reservoirs.In this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively reviewed.The assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling factors.Changes in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also discussed.This study could provide insight into challenges as well as perspectives for future research.

Characteristics of Gold Mineralization at the Baguiomo Gold Panning Site, Koudougou Region, Burkina Faso, West Africa

The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1B deformation. The second phase of D2B deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization.

Lithostructural Control of the Gold Mineralization of the Douta Permit of African Star Resources (Kédougou-Kéniéba Inlier, Southeastern Senegal)

The Douta permit of African Star Resources/Thor Explorations, located in the southeast of Senegal, in the Kédougou-Kéniéba Inlier (western part of the West African Craton), is dominated to the East by metasedimentary formations such as greywackes, shales, graphitic shales, quartzites, cherts, claystones and breccias characteristic of the Dialé-Daléma basin. To the West, the mafic formations of the Mako volcanic belt are the most common. Metasedimentary rocks are associated with metavolcanosedimentary terms found at the contact zones between the two (2) Birimian groups. These different geological formations are cut by mafic dolerite and gabbro sills and/or dykes, as well as quartz and microgranite veins. The Douta gold project is crossed from North to South by the MTZ (Main Transcurrent Zone), generally oriented NE-SW and becoming N-S towards the North. The permit is characterized by several shear corridors. The rocks are affected by brittle, brittle-ductile to ductile deformations. The gold mineralization is hosted by a NE-trending shear corridor called the Makosa corridor (Makosa shear zone), therefore sub-parallel to the MTZ. It has a subvertical dip (75˚ to 85˚ to the NW). It is associated with a hydrothermal phase characterized by quartz-sericite-epidote-fine, disseminated pyrite and arsenopyrite ± albite ± chlorite paragenesis. These minerals testify to the existence of a low degree of metamorphism (greenschist facies, epizonal domain) in the area. However, metamorphism reaches amphibolite facies in some places, particularly in the vicinity of intrusive bodies, with the presence of hornblende (amphiboles) and plagioclase. The gold mineralization is mainly hosted by two (2) metasedimentary lithological units: meta-greywackes and shales.

Characteristics of Gold and Its Mineralization Style in the Boulon Djounga Eastern Perimeter of Liptako Mining Company (Central Southwestern Niger)

The Boulon Djounga eastern perimeter is part of the Tiawa operating permit of the Société des Mines du Liptako (SML), located in the central southwestern part of Liptako (Niger). In this study, we used field data, Reverse Circulation (RC) surveys and chemical analyzes of gold to determine the characteristics of gold and its mineralization style. The eastern perimeter of Boulon Djounga is represented by a succession of metabasalts and metasediments both intersected by intrusions of quartz and dolerite dykes, and covered by sandstone and clayey rocks. Gold is present in low contents (0.00 - 0.30 ppm) in the sedimentary cover and in medium (0.30 - 1.00 ppm) or high contents (1.00 - 4.534 ppm) in the metasediments, and in the gray quartz veins and locally in the volcanics. It exists in a disseminated state or in a concentrated state in the surrounding areas in the form of discrete grains associated with sulphurous minerals (pyrite: FeS2, chalcopyrite: CuFeS2 or arsenopyrite: FeAsS). The presence of gold in the quartz veins, and the NE-SW and NW-SE orientations of the ore bodies suggest that the eastern Boulon Djounga gold mineralization would be established during a late magmatic extensive phase.

Ore-forming Fluid Systems and Mineralization in the Eastern Jiangnan Uplift in the Border Area of Anhui and Jiangxi Provinces, China

Obvious differences in mineralization characteristics exist between the southern and northern parts of the eastern part of the Jiangnan Uplift in northern Jiangxi Province and southern Anhui Province. The regional metallogeny is discussed, and the ore-forming fluid systems are classified in this article. It is proposed that the fluid ore-forming activities in the Jiangnan Uplift both in northern Jiangxi and southern Anhui have close relationships with the crust-mantle interaction and magmatic-tectonic activities. The types and scales of the mineralization on the both sides of the eastern Jiangnan Uplift were determined by fluid ore-forming systems and geological backgrounds.

Zircon U-Pb-Hf Isotopic Systematics and Geochemistry of the Granites in the Wurinitu Molybdenum Deposit, Inner Mongolia, China： Implications for Tectonic Setting and Genetic Type of Mineralization

The Wurinitu Mo deposit is one of the newly found molybdenum deposits in the southwestern part of the late Paleozoic–Mesozoic Erenhot–Dong-Ujimqin metallogenic belt （S-EDMB）, Inner Mongolia, China. In the present study, the mineralization age of the Wurinitu deposit is constrained to 137.3 ± 1.3 to 131.9 ± 1.5 Ma based on a combination of the laser ablation–inductively coupled plasma–mass spectrometry （LA–ICP–MS） zircon U–Pb dating of the mineralization related fine-grained monzonitic granite and the post-mineralization granite porphyry. The results of zircon Lu–Hf isotopes, combined with the geochemical characteristics of the granites in the S-EDMB, suggest that the Wurinitu Mo deposit was formed in an extensional environment in relation to the subduction of the Paleo-Pacific plate in late Mesozoic. The Wurinitu deposit shares similarities with the classical Climax-type porphyry molybdenum deposits in tectonic setting, mineral assemblages, and metal zonation.

Soil-nitrogen net mineralization increased after nearly six years of continuous nitrogen additions in a subtropical bamboo ecosystem

In order to understand the effects of increasing atmospheric nitrogen （N） deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the rainy region of SW China, near the western edge of Sichuan Basin. Four N treatment levels---control （no N added）, low- N （50 kg N ha-1 a-l）, medium-N （150 kg N ha-1 a-l）, and high-N （300 kg N ha-1 a-1）--were applied monthly in the P. amarus plantation starting in November 2007. In June 2012, we collected intact soil cores in the bamboo plantation and conducted a 30-day laboratory incubation experiment. The results showed that the soil N net miner- alization rate was 0.96 4- 0.10 mg N kg-1 day-1, under control treatment. N additions stimulated the soil N net mineralization, and the high-N treatment significantly increased the soil N net mineralization rate compared with the control. Moreover, the soil N net mineralization rate was significantly and positively correlated with the fine root biomass, the soil microbial biomass nitrogen content and the soil initial inorganic N content, respectively,whereas it was negatively correlated with the soil pH value. There were no significant relationships between the soil N net mineralization rate and the soil total nitrogen （TN） content and the soil total organic carbon content and the soil C/N ratio and the soil microbial biomass carbon con- tent, respectively. These results suggest that N additions would improve the mineral N availability in the topsoil of the P. amarus plantation through the effects of N additions on soil chemical and physical characteristics and fine-root biomass.

Linking gold mineralization to regional-scale drivers of mineral systems using in situ U-Pb geochronology and pyrite LA-ICP-MS element mapping

Proterozoic orogens commonly host a range of hydrothermal ores that form in diverse tectonic settings at different times. However, the link between mineralization and the regional-scale tectonothermal evolution of orogens is usually not well understood, especially in areas subject to multiple hydrothermal events.Regional-scale drivers for mineral systems vary between the different classes of hydrothermal ore, but all involve an energy source and a fluid pathway to focus mineralizing fluids into the upper crust. The Mount Olympus gold deposit in the Proterozoic Capricorn Orogen of Western Australia, was regarded as an orogenic gold deposit that formed at ca. 1738 Ma during the assembly of Proterozoic Australia. However,the trace element chemistry of the pyrite crystals closely resembles those of the Carlin deposits of Nevada,with rims that display solid solution gold accompanied by elevated As, Cu, Sb, Hg, and Tl, surrounding gold-poor cores. New SHRIMP UeP b dating of xenotime intergrown with auriferous pyrite and ore-stage alteration minerals provided a weighted mean^(207) Pb*/^(206) Pb* date of 1769 ± 5 Ma, interpreted as the age of gold mineralization. This was followed by two discrete episodes of hydrothermal alteration at 1727 ± 7 Ma and 1673 ± 8 Ma. The three ages are linked to multiple reactivation of the crustal-scale Nanjilgardy Fault during repeated episodes of intracratonic reworking. The regional-scale drivers for Carlin-like gold mineralization at Mount Olympus are related to a change in tectonic regime during the final stages of the intracratonic 1820 -1770 Ma Capricorn Orogeny. Our results suggest that substantial sized Carlin-like gold deposits can form in an intracratonic setting during regional-scale crustal reworking.

SIMULATION OF SOIL NITROGEN MINERALIZATION AND NITRIFICATION IN TWO NORTHERN HARDWOOD FOREST ECOSYSTEMS

A process-based, biological model is presented that simulates soil nitrogen (N) mineralization and nitrification in two northern hardwood forest ecosystems in the Upper Peninsula of Michigan. The soil system is divided into two compartments (forest floor and mineral soil) since quantity and quality of the organic substrate, and the important driving variables (temperature and moisture) for the model vary between these two compartments. The model focuses on the central position of microorganisms in the N mineralization and nitrification processes, and the use of multiplicative factors to account for the effect of temperature, moisture and carbon(C):N ratio on these processes.The model has been validated with data from two northern hardwood stands in the Upper Peninsula of Michigan. A close agreement between calculated and observed monthly means was obtained in both stands, especially for net N mineralization, which plays a very impormnt role in determining available N. The nitrification rates had relatively larger variation than the N mineralization rates, but the model adequately described the seasonal trends of the observed values. A simple sensitivity analysiwas performed to assess the response of the model to changes in important variables (temperature, moisture, organic N, and C:N ratio) between the two study sites. This analysis showed that increased temperature and higher organic N levels consistently increased N mineralization and nitrification in the both stands. The model's results were most sensitive to moisture changes in forest floor, but were not sensitive to moisture changes in the mineral soil. In contrast, C:N ratio was influential in the mineral soil, but did not have any effect in the forest floor.

Classification and mineralization of global lithium deposits and lithium extraction technologies for exogenetic lithium deposits

A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous novel lithium resources. Given the presence of varied classification criteria for lithium resources presently, this study further ascertained and classified the lithium resources according to their occurrence modes, obtaining 10 types and 5 subtypes of lithium deposits(resources) based on endogenetic and exogenetic factors. As indicated by surveys of Cenozoic exogenetic lithium deposits in China and abroad,the formation and distribution of the deposits are primarily determined by plate collision zones, their primary material sources are linked to the anatectic magmas in the deep oceanic crust, and they were formed primarily during the Miocene and Late Paleogene. The researchers ascertained that these deposits,especially those of the salt lake, geothermal, and volcanic deposit types, are formed by unique slightly acidic magmas, tend to migrate and accumulate toward low-lying areas, and display supernormal enrichment. However, the material sources of lithium deposits(resources) of the Neopaleozoic clay subtype and the deep brine type are yet to be further identified. Given the various types and complex origins of lithium deposits(resources), which were formed due to the interactions of multiple spheres, it is recommended that the mineralization of exogenetic lithium deposits(resources) be investigated by integrating tectono-geochemistry, paleoatmospheric circulation, and salinology. So far, industrialized lithium extraction is primarily achieved in lithium deposits of the salt lake, clay, and hard rock types. The lithium extraction employs different processes, with lithium extraction from salt lake-type lithium deposits proving the most energy-saving and cost-effective.