Ore-forming fluid characteristics and ore-forming materials source of the Tudimiaogou – Yindongshan lead-zinc polymetallic orefield, west Henan

1 Introduction The Tudimiaogou-Yindongshan lead-zinc polymetallic orefield is located in the Tudimiaogou-Weimoshi lead and zinc silver polymetallic metallogenic belt.The belt is an important part of southwestern Henan lead and zinc

Ore-forming Fluid Characteristics of the Saishitang Cu-polymetallic Deposit in Qinghai Province,China

Saishitang Cu-polymetallic deposit is located in the southeast section of Late Paleozoic arcfoid in the southeastern margin of Qaidam platform. Accoring to the geological process of the deposit, four mineralization episodes were identified： melt/fluid coexisting period （O）, skarn period （A）, first sulfide period （B） and second sulfide period （C）, and 10 stages were finally subdivided. Three types of inclusions were classified in seven stages, namely crystal bearing inclusions （type I）, aqueous inclusions （type Ⅱ） and pure liquid inclusions （type Ⅲ）. Type I and Ⅱ inclusions were observed in stage O1, having homogenization temperature from 252 to 431℃, and salinities ranging from 24.3% to 48.0%. Type I inclusion was present in stage A1, having homogenization temperature from 506 to 548℃, and salinities ranging from 39.4% to 44.6%. In stage B1, type Ⅱ and Ⅲ inclusions were observed, with homogenization temperature concentrating between 300-400℃, and salinities from 0.4% to 4.3%. Type II inclusions were present in stage B2, with homogenization temperature varying from 403 to 550℃. In stage C1, type I and II inclusion commonly coexisted, and constituted a boiling inclusion group, having homogenization temperatures at 187-463℃, and salinities in a range of 29.4%-46.8% and 2.2%-11.0%. Type II and III inclusions were developed in stage C2, having homogenization temperature at 124-350℃, and salinities ranging between 1.6% and 15.4%. In stage C3, type Ⅱ and Ⅲ inclusions were presented, with a homogenization temperature range of 164-360℃, and salinities varying from 4.0% to 11.0%. The results of micro-thermal analysis show that fluids are characterized by high temperature and high salinity in stage O1 and A1, and experienced slight decrease in temperature and dramatic decrease in salinity in stage B1 and B2. In stage C1, the salinity of fluid increased greatly and a further decrease of temperature and salinity occurred in stage C2 and C3. Fluids boiled in stage C1. With calculated pressure of 22 MPa from the trapping temperature of 284- 289℃, a mineralization depth of 2.2 km was inferred. Results of Laser Raman Spectroscopy show high density of H2_O, CH_4 and CO_2 were found as gas composition. H-O isotope study indicates the ore- forming fluids were the mixture of magmatic water and meteoric water. Physicochemical parameters of fluids show oxygen and sulfur fugacity experienced a decrease, and redox state is weakly reducing. Along with fluid evolution, oxidation has increased slightly. Comprehensive analysis shows that melt exsolution occurred during the formation of quartz diorite and that metal elements existed and migrated in the form of chlorine complex. Immiscible fluid separation and boiling widely occurred after addition of new fluids, bringing about dissociation of chlorine-complex, resulting in a great deal of copper precipitation. In conclusion, Saishitang deposit, controlled by regional tectonics, is formed by metasomatism between highly fractionated mineralization rock body and wall rock, and belongs to banded skarn Cu-polymetallic deposit.Abstract： Saishitang Cu-polymetallic deposit is located in the southeast section of Late Paleozoic arcfoid in the southeastern margin of Qaidam platform. Accoring to the geological process of the deposit, four mineralization episodes were identified： melt/fluid coexisting period （O）, skarn period （A）, first sulfide period （B） and second sulfide period （C）, and 10 stages were finally subdivided. Three types of inclusions were classified in seven stages, namely crystal bearing inclusions （type I）, aqueous inclusions （type Ⅱ） and pure liquid inclusions （type Ⅲ）. Type I and II inclusions were observed in stage O1, having homogenization temperature from 252 to 431℃, and salinities ranging from 24.3% to 48.0%. Type I inclusion was present in stage A1, having homogenization temperature from 506 to 548℃, and salinities ranging from 39.4% to 44.6%. In stage B1, type II and III inclusions were observed, with homogenization temperature concentrating between 300-400℃, and salinities from 0.4% to 4.3%. Type II inclusions were present in stage B2, with homogenization temperature varying from 403 to 550℃. In stage C1, type I and II inclusion commonly coexisted, and constituted a boiling inclusion group, having homogenization temperatures at 187-463℃, and salinities in a range of 29.4%-46.8% and 2.2%-11.0%. Type II and III inclusions were developed in stage C2, having homogenization temperature at 124-350℃, and salinities ranging between 1.6% and 15.4%. In stage C3, type II and Ⅲ inclusions were presented, with a homogenization temperature range of 164-360℃, and salinities varying from 4.0% to 11.0%. The results of micro-thermal analysis show that fluids are characterized by high temperature and high salinity in stage O1 and A1, and experienced slight decrease in temperature and dramatic decrease in salinity in stage B1 and B2. In stage C1, the salinity of fluid increased greatly and a further decrease of temperature and salinity occurred in stage C2 and C3. Fluids boiled in stage C1. With calculated pressure of 22 MPa from the trapping temperature of 284- 289℃, a mineralization depth of 2.2 km was inferred. Results of Laser Raman Spectroscopy show high density of H_2O, CH_4 and CO_2 were found as gas composition. H-O isotope study indicates the ore- forming fluids were the mixture of magmatic water and meteoric water. Physicochemical parameters of fluids show oxygen and sulfur fugacity experienced a decrease, and redox state is weakly reducing. Along with fluid evolution, oxidation has increased slightly. Comprehensive analysis shows that melt exsolution occurred during the formation of quartz diorite and that metal elements existed and migrated in the form of chlorine complex. Immiscible fluid separation and boiling widely occurred after addition of new fluids, bringing about dissociation of chlorine-complex, resulting in a great deal of copper precipitation. In conclusion, Saishitang deposit, controlled by regional tectonics, is formed by metasomatism between highly fractionated mineralization rock body and wall rock, and belongs to banded skarn Cu-polymetallic deposit.

Ore-forming fluid characteristics and genesis of vein-type lead-zinc mineralization of Xiaohongshilazi deposit,Jilin Province, China

The Xiaohongshilazi mineral deposit in Jilin Province,China,is located in the accretion zone in the northern margin of the North China Block. The deposit contains two types of ore bodies: layered Pb-Zn ore bodies in volcanic rock and vein-hosted Pb-Zn ore bodies controlled by fractures. The vein Pb-Zn ore bodies are strictly controlled by tectonic fracture zones trending in S-N direction,which comprise sulfide veins or sulfidebearing quartz veins distributed along faults or structural fissures. The ores mainly appear mesh-vein and vein structures,and also show solid-solution separation and metasomatic textures. The metal minerals are mainly sphalerite,galena,and pyrite,etc. Wall-rock alteration includes mainly sericitization,chloritization,silicification and carbonatization,etc. Microscope observations and Raman spectroscopy analyses indicate that the oreforming fluid of the vein Pb-Zn ore bodies was mainly magmatic water with low temperature,low salinity,and a shallow depth of metallogenesis( ~ 1.5 km). Sulfur and lead isotope analyses indicate that the sulfide source is mainly formation sulfur or biogenic sulfur,which is similar to the sulfur source of hydrothermal deposit( negative( δ^(34) S values),while the main Pb source was the upper crust with some mantle input. This article argues that the vein Pb-Zn ore body of the Xiaohongshilazi deposit is a low-to medium-temperature hydrothermal vein type related to the formation of a shallow magma chamber.

Flow Field Characteristics of Multi-Trophic Artificial Reef Based on Computation Fluid Dynamics

On the basis of computational fluid dynamics,the flow field characteristics of multi-trophic artificial reefs,including the flow field distribution features of a single reef under three different velocities and the effect of spacing between reefs on flow scale and the flow state,were analyzed.Results indicate upwelling,slow flow,and eddy around a single reef.Maximum velocity,height,and volume of upwelling in front of a single reef were positively correlated with inflow velocity.The length and volume of slow flow increased with the increase in inflow velocity.Eddies were present both inside and backward,and vorticity was positively correlated with inflow velocity.Space between reefs had a minor influence on the maximum velocity and height of upwelling.With the increase in space from 0.5 L to 1.5 L(L is the reef lehgth),the length of slow flow in the front and back of the combined reefs increased slightly.When the space was 2.0 L,the length of the slow flow decreased.In four different spaces,eddies were present inside and at the back of each reef.The maximum vorticity was negatively correlated with space from 0.5 L to 1.5 L,but under 2.0 L space,the maximum vorticity was close to the vorticity of a single reef under the same inflow velocity.

Geochemical Characteristics and Sources of Ore-forming Fluids of the Mayuan Pb-Zn Deposit,Nanzheng,Shaanxi,China

The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%（NaCl equiv.）.The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_（fluid） values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰（SMOW）,and the δ^（18）O_（fluid）values calculated from δ^（18）O_（quartz） and δ^（18）O_（calcite） values range from 4.5‰ to 16.7‰（SMOW）.These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^（13）C_（CH4） values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰（PDB）,suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction（TSR） was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type（MVT） deposit.

Characteristics of Pegmatite-Related Fluids and Significance to Ore-Forming Processes in the Zhaxikang Pb-Zn-Sb Polymetallic Deposit,Tibet,China

The Zhaxikang Pb-Zn-Sb polymetallic deposit is one of the most important deposits in the newly recognized southern Tibet antimony-gold metallogenic belt.Compared to the porphyry deposits in the Gangdese belt,much less researches have addressed these deposits,and the genesis of the Zhaxikang deposit is still controversial.Based on field investigation,petrographic,microthermometric,Laser Raman Microprobe（LRM） and SEM/EDS analyses of fluid,melt-fluid,melt and solid inclusions in quartz and beryl from pegmatite,this paper documents the characteristics and the evolution of primary magmatic fluid which was genetically related to greisenization,pegmatitization,and silification in the area.The results show that the primary magmatic fluids were derived from unmixing between melt and fluid and underwent a phase separation process soon after the exsolution.The primary magmatic fluids are of low salinity,high temperature,and can be approximated by the H_2O-NaCl-CO_2 system.The presence of Mn-Fe carbonate in melt-fluid inclusions and a Zn-bearing mineral（gahnite） trapped in beryl and in inclusions from pegmatite indicates high Mn,Fe,and Zn concentrations in the parent magma and magmatic fluids,and implies a genetic link between pegmatite and Pb-Zn-Sb mineralization.High B and F concentrations in the parent magma largely lower the solidus of the magma and lead to late fluid exsolution,thus the primary magmatic fluids related to pegmatite have much lower temperature than those in most porphyry systems.Boiling of the primary magmatic fluids leads to high-salinity and high-temperature fluids which have high capacity to transport Pb,Zn and Sb.The decrease in temperature and mixing with fluids from other sources may have caused the precipitation of Pb-Zn-Sn（Au） minerals in the distal fault systems surrounding the causative intrusion.

Characteristics and evolution of ore-forming fluids of the Chongjiang copper deposit in the Gangdise porphyry copper belt, Tibet

Petrography, microthermometry, and scanning electron microscope/energy dispersive spectrometer （SEM/EDS） studies were performed on the fluid inclusions in the ore-beating quartz veins and quartz phenocrysts in the porphyry of the Chongjiang porphyry copper deposit. The analyses of the fluid inclusions indicate that the ore-forming fluids were exsolved from magma. They are near-saturated, supercritical, rich in volatile constituents, and have the capture temperature of 362-389℃ and salinities of 17.7wt%- 18.9wt% NaC1 eq. With the decreasing of temperature and pressure, the supercritical fluids were separated into a low salinity vapor phase and a high salinity liquid phase. During quartz-sericitization, the high salinity fluid boiled and separated into a low salinity vapor phase and a high salinity liquid phase. The high salinity inclusions that formed in the boiling process had daughter mineral melting temperatures higher than the homogenization temperatures of the vapor and liquid phases. The late fluids that are responsible for argillization are of lower temperature and salinity.

Characteristics of the ore-forming fluid in the Huayuan Pb-Zn ore filed, Northwest of Hunan Province, China

1 Geological Setting The Huayuan Pb-Zn ore field in Xiangxi is located in the southeastern margin of the Yangtze block and the mid-segment of the West Hunan-West Hubei metallogenic belt.The exposed stratum are the lower

Geochemical Characteristics of the Ore-forming Fluids of the Haigou Gold Deposit, Jilin

The quartz in the Haigou gold deposit contains a great abundance of three-phase CO2-NaCl-H2O and two-phase CO2-rich inclusions, which are associated with two-phase NaCl-H2O ones. The ore-forming fluids, which were rich in CO2, are classified into two types with two different sources: the high-salinity CO2-rich NaCl-H2O fluid derived from magmatic hydrothermal solution, and the low-salinity NaCl-H2O fluid from ancient meteoric water. The optimum conditions for gold mineralization are 220-300℃ for the temperature, 4-20 MPa for the fluid static pressure, 1-3 km for the mineralization depth, 2-7 w (NaCl)/10-2 for the fluid salinity, and 0.644 g/cm3 for the total density. The fluid was in a critical or supercritical state at the initial stage of mineralization, and it boiled and was unmixed with CO2 and NaCl-H2O in the climax of mineralization, leading to the decomposition of Au-chlorine complexes and the bulk precipitation of Au.The type, association, homogenization temperature and composition (CO2/H2O value etc.) are the microscopic criteria for distinguishing the auriferous quartz vein from the barren quartz

Characteristics of Ore-forming Fluid of the Gaoshan Gold-Silver Deposit in the Longquan Area, Zhejiang Province and its Implications for the Ore Genesis

The Gaoshan gold-silver deposit, located between the Yuyao-Lishui Fault and Jiangshan- Shaoxing fault in Longquan Area, occurs in the Suichang-Longquan gold-silver polymetallic metallogenic belt. This study conducted an investigation for ore-forming fluids using microthermometry, D-O isotope and trace element. The results show that two types of fluid inclusions involved into the formation of the deposit are pure liquid phase and gas-liquid phase aqueous inclusions. The homogenization temperature and salinity of major mineralization phase ranges from 156~C to 236~C （average 200~C） and 0.35% to 8.68% （NaCleqv） （average 3.68%）, respectively, indicating that the ore-forming fluid is characteristic of low temperature and low salinity. The ore- forming pressure ranges between in 118.02 to 232.13＂105 pa, and it is estabmiated that the ore- forming depth ranges from 0.39 to 0.77 km, indicating it is a hypabyssal deposit in genesis. The low rare earth elements content in pyrites, widely developed fluorite in late ore-forming stage and lack of chlorargyrite （AgCI）, indicates that the ore-forming fluid is rich in F rather than CI. The ratios of Y/ Ho, Zr/Hf and Nb/Ta of between different samples have little difference, indicating that the later hydrothermal activities had no effects on the former hydrothermal fluid. The chondrite-normalized REE patterns of pyrites from country rocks and ore veins are basically identical, with the characteristics of light REE enrichment and negative Eu anomalies, implying that the ore-forming fluid was oxidative and derived partly from the country rocks. The JD and jlSo of fluid inclusions in quartz formed during the main metallogenic stage range from -105%o to -69 %0 and -6.01%o to -3.81%o, respectively. The D-O isotopic diagram shows that the metallogenic fluid is characterized by the mixing of formation water and meteoric water, without involvement of magmatic water. The geological and geochemical characteristics of the Gaoshan gold-silver deposit are similar to those of continental volcanic hydrothermal deposit, and could be assigned to the continental volcanic hydrothermal gold-silver deposit type.

Numerical simulation of inlet placement on sewage characteristics in the rounded square aquaculture tank with single inlet

To improve the self-cleaning ability of aquaculture tank and the efficiency of circulating water,physical and numerical experiments were conducted on the influence of inlet structure on sewage discharge in a rounded square aquaculture tank with a single inlet.Based on the physical model of the tank,analysis of how inlet structure adjustment affects sewage discharge efficiency and flow field characteristics was conducted to provide suitable flow field conditions for sinkable solid particle discharge.In addition,an internal flow field simulation was conducted using the RNG k-εturbulence model in hydraulic drive mode.Then a solid-fluid multiphase model was created to investigate how the inlet structure affects sewage collection in the rounded square aquaculture tank with single inlet and outlet.The finding revealed that the impact of inlet structure is considerably affecting sewage collection.The conditions of C/B=0.07-0.11(the ratio of horizontal distance between the center of the inlet pipe and the tank wall(C)to length of the tank(B))andα=25°(αis the angle between the direction of the jet and the tangential direction of the arc angle)resulted in optimal sewage collection,which is similar to the flow field experiment in the rounded square aquaculture tank with single inlet and outlet.An excellent correlation was revealed between sewage collection and fluid circulation stability in the aquaculture tank.The present study provided a reference for design and optimization of circulating aquaculture tanks in aquaculture industry.

Unveil the Redox Evolution of Ore-forming Fluids using Sulfur Isotope:A Case Study of the Zhengguang Intermediate Sulfidation Epithermal Au-Zn Deposit,NE China

Oxygen fugacity(fO_(2))is a key intensity variable during the entire magmatic-hydrothermal mineralization courses.The redox state and its variations between different stages of the ore-forming fluids of intermediate sulfidation epithermal deposits are rarely deciphered due to the lack of appropriate approaches to determine fO_(2)of the fluids.Here,we reported theδ^(34)S of the sulfides from three different stages(stageⅠ,Ⅱ,Ⅲ)of Zhengguang,an Early Ordovician Au-rich intermediate sulfidation(IS)epithermal deposit,to decipher the redox evolution of the ore-forming fluids.The increasingδ^(34)S values from stageⅠpyrite(pyl,average-2.6‰)through py2(average-1.9‰)to py3(average-0.2‰)indicates a decrease of the oxygen fugacity of the ore-forming fluids.A compilation ofδ^(34)S values of sulfides from two subtypes of IS deposits(Au-rich and Ag-rich)from NE China shows that theδ^(34)S values of sulfides from Au-rich IS deposits are systematically lighter than those of Ag-rich IS Ag-Pb-Zn deposit,indicating the ore-forming fluids of the former are more oxidized than the latter.We highlight that sulfur isotopic composition of hypogene sulfides is an efficacious proxy to fingerprint the oxygen fugacity fluctuations of epithermal deposits and could potentially be used to distinguish the subtypes of IS deposits.

Characteristics and mechanism of smart fluid for sweep-controlling during CO_(2) flooding

A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly capabilities,and the tertiary amine group serves as the response component.The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO_(2)/oil were studied,followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO_(2).The temperature and salt resistance of the smart fluid and the aggregates were evaluated,and their feasibility and effectiveness in sweep-controlling during the CO_(2)flooding were confirmed.This research reveals:(1)Thickened aggregates could be assembled since the smart fluid interacted with CO_(2).When the mass fraction of the smart fluid ranged from 0.05%to 2.50%,the thickening ratio changed from 9 to 246,with viscosity reaching 13 to 3100 mPas.As a result,the sweep efficiency in low-permeability core models could be increased in our experiments.(2)When the smart fluid(0.5%to 1.0%)was exposed to simulated oil,the oil/fluid interfacial tension decreased to the level of 1×10^(-2)mN/m.Furthermore,the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%.As a result,the smart fluid could maintain low oil/fluid interfacial tension,and would not be thickened after oil exposure.(3)When the smart fluid interacted with CO_(2),the aggregates showed self-healing properties in terms of shear-thinning,static-thickening,and structural integrity after several shear-static cycles.Therefore,this fluid is safe to be placed in deep reservoirs.(4)The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.

Geochemical characteristics of temperature and pressure of Paleozoic reservoir fluid inclusions in Xuanjing region, Lower Yangtze area

In order to understand the geochemical characteristics of Paleozoic reservoir fluids in Xuanjing region,Lower Yangtze area,drilling core samples from Y and D wells were tested and analyzed to study the fluid inclusion types and composition.Pressure correction was undertaken to determine the temperature and pressure environment for inclusion formation,and the influence of fluid characteristics of the Upper Permian and Lower Triassic reservoirs on the preservation of shale gas was investigated.According to petrograph-ic observations,fluid inclusions are mainly brine and bitumen inclusions.Bitumen inclusions are mainly distributed in holes and fractures,and with smaller individuals.No visible fluorescence was observed,and the vitrinite reflectance is 3.39%–3.92%.This indicates that there had been oil and gas accumulation in the early stage of diagenesis in the study area,but due to the influence of magmatic hydrothermal solution,oil and gas underwent thermal metamorphism in the early stage,making liquid petroleum into solid bitumen.At present,oil and gas in the reservoir were largely formed in the late stage.During the continuous process in which shale was buried,light oil and gas were generated.Light oil and gas underwent magmatic and tectonic hydrothermal processes in some areas,resulting in high-temperature metamorphic cracking that formed dry gas.Moreover,nitrogen inclusions are found in fluid inclusions,forming metamorphic fluids caused by mag-matic hydrothermal activities.The study shows that Paleozoic reservoirs in Xuanjing area are characterized by self-generation and self-storage.Furthermore,the mechanism of shale gas accumulation is not only related to the buried hydrocarbon generation process of shale itself,but is also related to later magmatic activity and tectonic hydrothermal transformation.Therefore,preservation conditions are generally key factors of shale gas accumulation in this area.

Rare Earth Element Geochemistry Characteristics of Laowan Gold Deposit in Henan Province: Trace to Source of Ore-Forming Materials

The compositions of REE in quartz and pyrite from main mineralized stage of the Laowan gold deposit in Henan province and that of quartz from Laowan granite were determined by Inductively Coupled Plasma-Mass-Spectrometry （ICP-MS）. The REE of deposit ore of the Laowan gold deposit, wall-rock and Laowan granite also were studied to trace the source of metallogenic materials in Laowan gold deposit in detail. The range of ∑ REE in quartz and pyrite from gold deposit is 4.18 × 10^-6 - 30.91 × 10^-6, average of 13.39 × 10^-6, 6.68 × 10^-6 of the Laowan granite quartz, obviously lower to REE concentration of deposit, granite and wall-rock. The value of （La/ Yb）N and （La/Sm）N of ore minerals from the gold deposit is 13.23 and 4.17 respectively. The differences in REE parameters, such as δEu, δCe and diffusion degree in REE from light to heavy, among deposit ore minerals and granite mineral are weak. Especially, there are no differences between the chondrite-normalised REE curves of minerals from gold deposit and those of quartzs in Laowan granite, no similarity to wall-rock＇, which shows that ore-forming hydrothermal fluid mainly came from magma fluid resulting from the Laowan granite magma, metamorphic fluid in few. The results also show that REE characteristics of ore minerals in deposit are effective for disclosing oreforming fluid quality comparing with deposit ore＇REE compositions.

Geological characteristics and the origin of ore-forming materials of(Laozhaiwan gold deposit, Yunnan Province

"Golden triangle"area bordered on Yunnan-Guizhou-Guangxi was one of the most important Carlin-type gold deposits concentration areas.Deep understanding of Carlin-type gold deposits in Guizhou and Guangxi Province had reached through several decades studies,but geological environment was very complex in the southeastern Yunnan,and Carlin-type gold deposits produced in the southeastern Yunnan were different from that of America,few studies were taken there.Based on a large number of field work,studies on the geological characteristics combining with geochemistry characteristics were taken,and analysis the genesis of Laozhaiwan gold deposit.The types of alteration in Laozhaiwan gold deposit were mainly silicification and pyritization,and Gold grade was high when silicification and pyritization were both occurred.It could be caculated that fluid density(g/cm3)varied from 0.7 to 4.9,salinity varied from 0.76%to 0.95%and ore-forming pressure(Pa)varied from 1.81×105 to 49.96×105 according to fluid inclusion test results,showed that Laozhaiwan gold deposit was hypabyssal hydrothermal deposit in low temperature and low salinity.According to composition of fluid inclusion analysis,combining with H-O isotope,made theδD-δ18O figure,showed that the fluid of the deposit rooted in formation water and mixed with meteoric waters later.

The analysis of frequency-dependent characteristics for fluid detection: a physical model experiment

According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a high-frequency bright spot as the amplitude energy shifts. However, it is a low-frequency shadow for the Class III AVO reservoirs saturated with hydrocarbons. In this paper, we verified the high-frequency bright spot results of Chapman for the Class I AVO response using the frequency-dependent analysis of a physical model dataset. The physical model is designed as inter-bedded thin sand and shale based on real field geology parameters. We observed two datasets using fixed offset and 2D geometry with different fluid- saturated conditions. Spectral and time-frequency analyses methods are applied to the seismic datasets to describe the response characteristics for gas-, water-, and oil-saturation. The results of physical model dataset processing and analysis indicate that reflection wave tuning and fluid-related dispersion are the main seismic response characteristic mechanisms. Additionally, the gas saturation model can be distinguished from water and oil saturation for Class I AVO utilizing the frequency-dependent abnormal characteristic. The frequency-dependent characteristic analysis of the physical model dataset verified the different spectral response characteristics corresponding to the different fluid-saturated models. Therefore, by careful analysis of real field seismic data, we can obtain the abnormal spectral characteristics induced by the fluid variation and implement fluid detection using seismic data directly.

Alzheimer's disease with sleep insufficiency:a cross-sectional study on correlations among clinical characteristics,orexin,its receptors,and the bloodbrain barrier

Previous studies have shown that reduced sleep duration,sleep fragmentation,and decreased sleep quality in patients with Alzheimer's disease are related to dysfunction in orexin signaling.At the same time,blood-brain barrier disruption is considered an early biomarker of Alzheimer's disease.However,currently no report has examined how changes in orexin signaling relate to changes in the blood-brain barrier of patients who have Alzheimer's disease with sleep insufficiency.This cross-sectional study included 50 patients with Alzheimer's disease who received treatment in 2019 at Beijing Tiantan Hospital.Patients were divided into two groups:those with insufficient sleep(sleep duration≤6 hours,n=19,age 61.58±8.54 years,10 men)and those with normal sleep durations(sleep duration>6 hours,n=31,age 63.19±10.09 years,18 men).Demographic variables were collected to evaluate cognitive function,neuropsychiatric symptoms,and activities of daily living.The levels of orexin,its receptor proteins,and several blood-brain barrier factors were measured in cerebrospinal fluid.Sleep insufficiency was associated with impaired overall cognitive function that spanned multiple cognitive domains.Furthermore,levels of orexin and its receptors were upregulated in the cerebrospinal fluid,and the blood–brain barrier was destroyed.Both these events precipitated each other and accelerated the progression of Alzheimer's disease.These findings describe the clinical characteristics and potential mechanism underlying Alzheimer's disease accompanied by sleep deprivation.Inhibiting the upregulation of elements within the orexin system or preventing the breakdown of the blood-brain barrier could thus be targets for treating Alzheimer's disease.

In, Sn, Pb and Zn Contents and Their Relationships in Ore-forming Fluids from Some In-rich and In-poor Deposits in China

All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn deposit in Yunnan, and the Meng＇entaolegai Ag-Pb-Zn deposit in Inner Mongolia, the indium contents in ores range from 98×10^-6 to 236×10^-6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0.8781 and 0.7430, respectively. The indium contents from such Sn-poor deposits as the Fozichong Pb-Zn deposit in Guangxi and the Huanren Pb-Zn deposit in Liaoning are generally lower than 10×10^-6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore -forming fluids or the ore-forming conditions has actually caused the enrichment/depletion of indium in the deposits？ After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In-rich and In-poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore-forming fluids. The results show that the contents of lead and zinc in the ore-forming fluids of In-rich and -poor deposits are at the same level, and the lead contents range from 22×10^-6 to 81×10^-6 and zinc from 164×10^-6 to 309×10^-6, while the contents of indium and tin in the ore-forming fluids of In-rich deposits are far higher than those of Inpoor deposits, with a difference of 1-2 orders of magnitude. Indium and tin contents in ore-forming fluid of In-rich deposits are 1.9×10^-6-4.1×10^-6 and 7×10^-6-55×10^-6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore-forming fluid of In-poor deposits are 0.03×10^-6-0.09×10^-6 and 0.4×10^-6-2.0×10^-6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In-rich oreforming fluids are the material basis for the formation of In-rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium.

Numerical Modelling of Ore-forming Dynamics of Fractal Dispersive Fluid Systems

Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid-rock interaction. It changes components and physico-chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore-forming materials. (3) Gold ore-forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone.