A synthesis of iron deposits in the eastern Tianshan,NW China

The northern Xinjiang region is one of the most significant iron metallogenic provinces in China.Iron deposits are found mainly within three regions:the Altay,western Tianshan,and eastern Tianshan orogenic belts.Previous studies have elaborated on the genesis of Fe deposits in the Altay orogenic belt and western Tianshan.However,the geological characteristics and mineralization history of iron deposits in the eastern Tianshan are still poorly understood.In this paper I describe the geological characteristics of iron deposits in the eastern Tianshan,and discuss their genetic types as well as metallogenic-tectonic settings,Iron deposits are preferentially distributed in central and southern parts of the eastern Tianshan.The known iron deposits in the eastern Tianshan show characteristics of magmatic Fe-Ti-V(e.g.,Weiya and Niumaoquan),sedimentary-metamorphic type(e.g.,Tianhu),and iron skarn(e.g.,Hongyuntan).In addition to the abovementioned iron deposits,many iron deposits in the eastern Tianshan are hosted in submarine volcanic rocks with well-developed skarn mineral assemblages.Their geological characteristics and magnetite compositions suggest that they may belong to distal skarns.SIMS zircon U-Pb analyses suggest that the Fe-Ti oxide ores from Niumaoquan and Weiya deposits were formed at 307.7±1.3 Ma and 242.7±1.9 Ma,respectively.Combined with available isotopic age data,the timing of Fe mineralization in the eastern Tianshan can be divided into four broad intervals:Early Ordovician-Early Silurian(476-438 Ma),Carboniferous(335-303 Ma),Early Permian(295-282 Ma),and Triassic(ca.243 Ma).Each of these episodes corresponds to a period of subduction,post-collision,and intraplate tectonics during the Paleozoic and Mesozoic time.

New Geochronologic Evidence of Diabases and Their Metallogenic Relationship with the Makeng-Type Iron Deposits in Southwest Fujian, SE China

Objective The Makeng-type iron deposits are located in Late Paleozoic depression of southwest Fujian Province in the southeast edge of Cathaysia,which are famous for their huge scale and specific ore genesis.Previous studies mainly focus on the ore characteristics,metallogenic setting and the granites in the mining area,and there is still controversy on the ore genesis.Recent research

Characteristics of Zhangsanying-Tongshanzi aeromagnetic anomaly zone and prospecting potential of iron deposits in northern Hebei,China

Based on the latest high-precision aeromagnetic data,an aeromagnetic anomaly zone is identified at Zhangsanying--Tongshanzi in northern Hebei Province.By the potential field conversion processing,including the reduction to the pole,vertical derivative,upward continuation and residual anomaly,the authors analyzed the characteristics of three typical aeromagnetic anomalies in Zhangsanying--Tongshanzi aeromagnetic anomaly zone and their geological origin.The methods include the forward and inversion methods,such as 2.5D optimization fitting and Euler deconvolution.Moreover,combined with the geological outcrop,known iron deposits,ground magnetic survey and verification,the authors studied the relationship between the aeromagnetic anomalies and iron deposits.The result shows that the Zhangsanying--Tongshanzi aeromagnetic anomaly zone is composed of 10 large magnetic anomalies with high amplitude and clear boundary.The aeromagnetic anomalies are comparable and intrinsically related to the ground magnetic anomalies and IP anomalies,indicating that the anomalies are caused by magnetite deposits.It has good magnetite prospecting potential in the Zhangsanying--Tongshanzi aeromagnetic anomaly zone.

Geological settings and metallogenesis of high-grade iron deposits in China

The predominant types of high-grade iron deposits in China include skarn,sedimentary metamorphic(banded ironformation,BIF-type),continental/submarine volcanic-hosted and magmatic Fe-Ti-Voxide deposits.Based on a comprehensive review of current studies on these deposits,this paper suggests that the oxygen concentration in atmosphere played an important role for the formation of BIFs,whereas the tectonic setting and deep magmatic differentiation processes are more important for the other types.Notably,both high temperature and high pressure experiments and melt inclusion studies indicate that during the differentiation,high temperature magmas could develop iron-rich magma via liquid immiscibility but not pure oxide melt("iron ore magma").Fe-P melt could be generated directly by liquid immiscibility under hydrous and oxidized condition.The formation of high-grade iron deposits is mostly associated with the processes related to multiple stages of superimposition,e.g.,desiliconization and iron enrichment,removal of impurity,and remobilization and re-precipitation of iron.According to the temporal evolution,the high-grade iron deposit could be divided into multi-episode superimposition type(temporally discontinuous mineralization)and multi-stage superimposition type(temporally continuous mineralization).The former is represented by the sedimentary metamorphic iron deposit,and the latter includes those related to magmatic-hydrothermal fluids(e.g.,skarn,volcanic-hosted and magmatic types).

Iron Isotopes and Trace Element Compositions of Magnetite from the Submarine Volcanic-Hosted Iron Deposits in East Tianshan,NW China:New Insights into the Mineralization Processes

The Aqishan-Yamansu metallogenic belt(AYMB)in East Tianshan hosts abundant sub-marine volcanic-hosted iron deposits.Although there is agreement with the magmatic source of the ore-forming materials and the role of hydrothermal replacement in iron ore formation,the mineraliza-tion processes of these iron deposits remain uncertain.Three ore types are identified on the basis of the geological occurrences of minerals and the sequence of mineral in ores.The typeⅠores are characte-rized by magnetite,diopside,amphibole with a few pyrite,and chalcopyrite.The type II ores are mainly composed of magnetite,garnet,chlorite with a few pyrite,while the type III ores are mainly composed of magnetite,quartz,calcite with a few pyrite.In order to constrain the mineralization processes of these ore types,we performed iron isotopes and trace element compositions of magnetite from three typical iron deposits(Yamansu,Duotoushan and Luotuofeng).Trace element and Fe isotope investiga-tions of the three ore types reveal two major groups.The groupⅠconsists of analyses of the typeⅠandⅡores,with both showing a narrow range of positiveδ56Fe values(+0.08‰to+0.22‰for typeⅠores and+0.15‰ to+0.22‰ for typeⅡores)and plotting in the range of the ortho-magmatic field.In contrast,the group 2 is composed merely of the typeⅢores,showing a wider range of negativeδ56Fe values(-0.49‰ to-0.01‰),which is similar to the features of Fe-skarn magnetite.As shown in the binary dia-grams of magnetite trace elements and a fractionation of the Fe isotopes,different ore types were likely produced during gradually changing ore-forming stages from magmatic to hydrothermal.Collectively,the submarine volcanic-hosted iron deposits in the East Tianshan are likely the results of a continuous magmatic-hydrothermal mineralization process.

Chitosan—The Application of a Natural Polymer against Iron Hydroxide Deposition

As a consequence of mining, heavy metal ions can be exposed to the environment hence contaminate ground water and surface water amongst others. The natural polymer chitosan was proved to be an excellent adsorber material for the effective removal of iron and sulfate ions in batch as well as in column experiments. The adsorption behavior of iron ions, as well as sulfate ions was investigated by utilizing chitosan flakes as a natural adsorbent. The removal was studied using adsorbance measurements, SEM and SEM-EDX. The adsorption capacity of chitosan was determined at different times. The received adsorption capacities for iron ions were very promising with a maximum adsorption capacity of 85 mg/g and a rate of separation of 100%. The maximum adsorption capacity obtained for sulfate ions was 188.8 mg/g and a rate of 80%.

Extraction of altered minerals from Aster remote sensing data in Gongchangling iron deposit of Liaoning, China

The precision of Aster data is higher than that of Landsat series of multispectral remote sensing data,which can more accurately reveal the distribution of altered minerals.It plays an important role in prospecting,but it is rarely used in areas with complex terrain and high vegetation coverage.Based on this purpose,this study used Aster remote sensing data,and took Gongchangling iron deposit as a case study.It combined the mineral spectrum theory and the basic geologic data of the study area,using the model of principal component analysis(PCA)and color synthesis to extract abnormal altered minerals.The results show that the distribution of identified anomalies is basically consistent with the existing geological data in this study area,which provides a reliable reference for the mineral resources ex-ploration and delineation of mining areas.

Geochronology of minerrlization and tectonic setting of Baishidong skaro-type iron deposit in Helony aree of Yanbian,Jilin Province,NE China

The Baishidong iron deposit is the only skarn-type iron deposit discovered in the study area.According to mineral assemblage and paragenesis,the mineralization can be divided into four metallogenic stages:early garnet-diopside skarn stage,late magnetite-tremolite-epidote skarn stage,early quartz-pyrite-chalcopyrite stage and late quartz-calcite-pyrite stage.Through LA-ICP-MS zircon U-Pb dating of diorite,which is closely related to mineralization,the results show that the weighted average age is 164.6±1.4 Ma,which limits the mineralization time of Baishidong iron deposit during or slightly later than Middle Jurassic.The diorite rocks are rich in sodium(Na_(2)O/K_(2)O=1.24-1.76),aluminium(Al_(2)O_(3)=17.41%-18.76%),LREE and large-ion lithophile elements(Ba,K and Sr),depleted in HREE and high-field-strength elements(Y,Nb,Ta,P and Ti),and show strongly fractionated patterns(LREE/HREE=6.58-9.93),no apparent Eu anomalies(δEu=0.91-1.13),which shows similar characteristics to island arc or active continental margin arc magma.The zirconεHf(t)values range from-22.6 to 5.9,and the age of the two-stage model(t_(DM2))is 836-2633 Ma.Above data combined with the geochemical characteristics,it is indicated that the magma was a mixture of multiple sources,composed of ancient materials and newly formed crust.During the process of evolution and ascending of magma,separation and crystallization occurred,and a large amount of continental crust material was mixed at the same time.Combined with regional tectonic evolution,the formation of this deposit may be related to the westward subduction of the Paleo-Pacific Plate to the Eurasian Plate.

The Shaytor Apatite-Magnetite Deposit in the Kashmar-Kerman Tectonic Zone (Central Iran): A Kiruna-Type Iron Deposit

The Shaytor apatite-rich iron deposit is located in the Kashmar-Kerman tectonic zone in the central of the Iranian plat, which is an important polymetallic belt in Iran. The ore bodies are interbedded with the upper inferacaamberian calc-alkaline igneous rocks that show well-preserved porphyritic and volcaniclastic textures. The iron ores have massive, disseminated, and brecciated structures. Magnetite from the Shaytor deposit is low in Ti (TiO2 = up to 0.70 wt.%) and different ore types show similar rare earth element (REE) and trace element-normalized patterns with weak-to-moderate enrichment in light REE and negative Eu anomalies, indicating a common source and genesis. The similar REE patterns for the magnetite and volcanic basaltic host rocks suggest their close genetic linkage and support a magmatic origin for the deposit. The Shaytor deposit shows the typical characteristics of Kiruna-type deposits with regard to the mineral assemblages, ore texture and structure, and the apatite and magnetite geochemistry. We propose that the Kiruna-type Shaytor apatite-rich iron deposit was derived from Fe-P-rich melt through liquid immiscibility and the activity of hydrothermal fluids.

Investigation on Initial Stage of Electroless Deposition on Low Carbon Steel and Pure Iron

Initial process is influenced by substrate microstructure according to the study of initial stage of electroless plating on low carbon steel and pure iron. For low carbon steels, depositing on cementite is prior to that on ferrite, and for pure iron, the grain boundaries and some favourable grains are deposited more easily. The initial reactions of electroless depositing of Ni-P alloy have been tentatively

Quality Characteristics and Washability Treatment of Nickeliferous Iron Ore of Agios Athanasios Deposit (Kastoria, Greece)

The Agios Athanasios ore deposit is located within the wider area of Ieropigi in Kastoria, Greece. The specific ore deposit is developed in form of layers between ophiolites and Tertiary molassic conglomerates. The main mineralogical components are hematite, goethite, quartz, and secondarily, garnierite, lizardite, saponite, willemzeite and sepiolite, while scarcers are chromite, calcite and nepouite. Nickel is mainly found in garnierite, willemzeite and nepouite, which in coexistence with quartz are the main components in the binder material of the ore. For the mineral processing gravimetric and magnetic separations are used in the size of fractions -8 + 4 mm, -4 + 1 mm, -1 + 0.250 mm and -0.250 + 0.063 mm. The chemical and mineralogical analysis in combination with microscopic examination showed that mineral processing by gravimetric separation gave the most satisfactory results for the size fraction -1 + 0.250 mm.

In-situ LA-ICP-MS trace element and oxygen isotope signatures of magnetite from the Yamansu deposit,NW China,and their significance

The Yamansu iron deposit is hosted in submarine volcanic rocks in the Aqishan–Yamansu belt of Eastern Tianshan,NW China.A geological cross-section for the Carboniferous strata in the ore district shows that ore bodies in the Yamansu deposit are hosted in andesitic crystal tuff of the third cycle of the Carboniferous Yamansu Formation.This indicates an association between mineralization and volcanism.The orebodies are strata bound and lensoid and generally share the occurrence state of the host rocks.Magnetite mineralization mainly occurs asbreccia ores,ores in the mineralized volcanic rocks,massive ores,and sulfide-rich ores according to their structures and sequences of formation.Trace element compositions of magnetite from various types of ores were determined by LA-ICP-MS.The dataset indicates thatdifferent types of magnetite havedistinct trace element contents correlated to their formation environments.Magnetite crystals from breccia ores have high Ti,Ni,V,Cr,and Co and low Si,Al,Ca,and Mg contents,indicating crystallization from a volcanic magmatic eruption,which is consistent with field evidence of coexisting altered volcanic breccia.Magnetite crystals from ores in the mineralized volcanic rocks have moderate Ti,Ni,V,Cr,and Co contents.In contrast,magnetite from massive ores and sulfide-rich ores have low concentrations of Ti,Cr,Ni,and V,high concentrations of Si,Al,Ca,and Mg,and evidence of hydrothermal magnetite.In-situ magnetite compositions imply a magmatic-hydrothermal process.Although d18 O values for magnetite grains from Yamansu vary(?1.3 to?7.0%),they all plot in the range field of volcanic iron deposits,and they also record a magmatic-hydrothermal process.The compositions of Yamansu magnetites are interpreted as controlled mainly by temperature,fluid,host rock buffering,oxygen fugacity,and sulfur fugacity.The metallogenic conditions of the Yamansu deposit changed from high temperature and low oxygen fugacity to low temperature and high oxygen fugacity.However,more fluid-rock reactions and higher sulfur fugacity were involved during the deposition of massive ores and sulfiderich ores.

The Paleozoic Huoshenmiao iron skarn deposit in the Tongbai area of North Qinling Orogen,China:Insights from garnet U-Pb dating and geological constraints

The Qinling Orogen is a composite orogenic belt that can be subdivided into the North and South Qinling,broadly separated by the Shangdan suture zone.These two orogenic belts were generated by subduction-collisional processes in the Early Paleozoic and Late Triassic,respectively.During the Late Jurassic to Early Cretaceous,the eastern portion of the Qinling Orogen was tectonically reactivated due to westerly subduction of the Izanagi plate underneath the East China continental margin.The Qinling Orogen is well-endowed with numerous Au,Mo,Ag-Pb-Zn deposits that predominantly formed in the Late Triassic to Early Cretaceous,with rare Paleozoic varieties documented.In this study,we present garnet and zircon U-Pb dating results to show that the Huoshenmiao iron skarn deposit in the Tongbai area of North Qinling orogenic belt formed in the Early Silurian and is genetically related to subduction-related magmatism.The Huoshenmiao deposit consists of lenticular and stratiform orebodies that contain massive or densely disseminated magnetite variably associated with garnet,diopside,epidote,hornblende,and actinolite.Garnets from iron ores are andradite and grossular in composition(Ad_(83.1)Gr_(13.3)-Ad_(86.5)Gr_(10.2))and characterized by enrichment in light rare earth elements(ΣLREE=57.85-103.82 ppm)and depletion in heavy rare earth elements(ΣHREE=5.50-11.34 ppm),with significantly positive Eu and Ce anomalies(δEu of 1.09-1.89 andδCe of 1.39-1.69).These compositional signatures are distinctly different from those of garnets in the ore-hosting metamorphic rocks that are typically dominated by almandine,spessartine and grossular(Al_(47.4)Sp_(30.4)Gr_(13.8)-Al_(51.9)Sp_(24.8)Gr_(17.6)),depleted in LREE(0.14-0.69 ppm),enriched in HREE(95.68-841.60 ppm)and have pronounced negative Eu anomalies(δEu=0.24-0.51).In addition,garnets from iron ores of the Huoshenmiao deposit contain abundant daughter mineral-bearing,multiphase fluid inclusions,further confirming their hydrothermal origin.Two samples of those hydrothermal garnets yield U-Pb dates of 437±9 Ma and 437±10 Ma(2σ),revealing a Paleozoic mineralization event that has long been ignored and rarely documented.These garnet dates agree well with zircon U-Pb dates of 438±4 Ma to 436±3 Ma for a gabbroic diorite and 430±4 Ma for a granite intrusion in close proximity of the mine,supporting a possible genetic link between the iron mineralization and Early Silurian magmatism.The Paleozoic intrusions are enriched in large ion lithophile elements(LILEs:Ba,K,Sr)and LREEs,depleted in high field strength elements(HFSEs:Nb,Ta,P,Ti),have whole-rock(^(87)Sr/^(86)Sr)i,ε_(Nd)(t),and zirconεHf(t)values of 0.7039-0.7042,3.32-4.33,and 13.0-14.9,respectively.These geochemical and isotopic characteristics suggest that the Paleozoic intrusions were affiliated with arc magmatism triggered by subduction of the Shangdan oceanic plate in the Early Paleozoic.Recognition of the Silurian Huoshenmiao iron skarn deposit opens a new window for exploration of Paleozoic mineral resources in the Tongbai area and other portions of the North Qinling Orogen.

The Shilu Iron Ore Deposit in Hainan Province,South China:A Structurally and Hydrothermally Reworked and Re-Enriched Lake-Superior-Type BIF Iron Deposit

The Shilu iron ore deposit,located in the western Hainan Province,South China,is one of the most important iron-ore mining districts in China not only for its huge reserves of hematite-rich ores,but also for its potentially economic significance of associated metals of copper,cobalt,nickel,silver,lead and zinc,and of non-metals of dolomite,quartzite,barite,gypsum and sulfur.

Utility of susceptibility-weighted imaging in Parkinson’s disease and atypical Parkinsonian disorders

In the clinic,the diagnosis of Parkinson’s disease(PD)largely depends on clinicians’experience.When the diagnosis is made,approximately 80%of dopaminergic cells in the substantia nigra(SN)have been lost.Additionally,it is rather challenging to differentiate PD from atypical parkinsonian disorders(APD).Clinially-available 3T conventional MRI contributes little to solve these problems.The pathologic alterations of parkinsonism show abnormal brain iron deposition,and therefore susceptibility-weighted imaging(SWI),which is sensitive to iron concentration,has been applied to find iron-related lesions for the diagnosis and differentiation of PD in recent decades.Until now,the majority of research has revealed that in SWI the signal intensity changes in deep brain nuclei,such as the SN,the putamen(PUT),the globus pallidus(GP),the thalamus(TH),the red nucleus(RN)and the caudate nucleus(CN),thereby raising the possibility of early diagnosis and differentiation.Furthermore,the signal changes in SN,PUT and TH sub-regions may settle the issues with higher accuracy.In this article,we review the brain iron deposition of PD,MSA-P and PSP in SWI in the hope of exhibiting a profile of SWI features in PD,MSA and PSP and its clinical values.