Major and Trace Elements of Magnetite from the Qimantag Metallogenic Belt: Insights into Evolution of Ore–forming Fluids

Magnetite, as a genetic indicator of ores, has been studied in various deposits in the world. In this paper, we present textural and compositional data of magnetite from the Qimantag metallogenic belt of the Kunlun Orogenic Belt in China, to provide a better understanding of the formation mechanism and genesis of the metallogenic belt and to shed light on analytical protocols for the in situ chemical analysis of magnetite. Magnetite samples from various occurrences, including the ore–related granitoid pluton, mineralised endoskarn and vein–type iron ores hosted in marine carbonate intruded by the pluton, were examined using scanning electron microscopy and analysed for major and trace elements using electron microprobe and laser ablation–inductively coupled plasma–mass spectrometry. The field and microscope observation reveals that early–stage magnetite from the Hutouya and Kendekeke deposits occurs as massive or banded assemblages, whereas late–stage magnetite is disseminated or scattered in the ores. Early–stage magnetite contains high contents of Ti, V, Ga, Al and low in Mg and Mn. In contrast, late–stage magnetite is high in Mg, Mn and low in Ti, V, Ga, Al. Most magnetite grains from the Qimantag metallogenic belt deposits except the Kendekeke deposit plot in the " Skarn " field in the Ca+Al+Mn vs Ti+V diagram, far from typical magmatic Fe deposits such as the Damiao and Panzhihua deposits. According to the(Mg O+Mn O)–Ti O2–Al2O3 diagram, magnetite grains from the Kaerqueka and Galingge deposits and the No.7 ore body of the Hutouya deposit show typical characteristics of skarn magnetite, whereas magnetite grains from the Kendekeke deposit and the No.2 ore body of the Hutouya deposit show continuous elemental variation from magmatic type to skarn type. This compositional contrast indicates that chemical composition of magnetite is largely controlled by the compositions of magmatic fluids and host rocks of the ores that have reacted with the fluids. Moreover, a combination of petrography and magnetite geochemistry indicates that the formation of those ore deposits in the Qimantag metallogenic belt involved a magmatic–hydrothermal process.     

Re–Os geochronology of Cu and W–Mo deposits in the Balkhash metallogenic belt, Kazakhstan and its geological significance

The Central Asian metallogenic domain (CAMD) is a multi-core metallogenic system controlled by boundary strike-slip fault systems. The Balkhash metallogenic belt in Kazakhstan, in which occur many large and super-large porphyritic Cu–Mo deposits and some quartz vein- and greisen-type W–Mo deposits, is a well-known porphyritic Cu–Mo metallogenic belt in the CAMD. In this paper 11 molybdenite samples from the western segment of the Balkhash metallogenic belt are selected for Re–Os compositional analyses and Re–Os isotopic dating. Molybdenites from the Borly porphyry Cu deposit and the three quartz vein-greisen W–Mo deposits—East Kounrad, Akshatau and Zhanet—all have relatively high Re contents (2712–2772 μg/g for Borly and 2.267–31.50 μg/g for the other three W–Mo deposits), and lower common Os contents (0.670–2.696 ng/g for Borly and 0.0051–0.056 ng/g for the other three). The molybdenites from the Borly porphyry Cu–Mo deposit and the East Kounrad, Zhanet, and Akshatau quartz vein- and greisen-type W–Mo deposits give average model Re–Os ages of 315.9 Ma, 298.0 Ma, 295.0 Ma, and 289.3 Ma respectively. Meanwhile, molybdenites from the East Kounrad, Zhanet, and Akshatau W–Mo deposits give a Re–Os isochron age of 297.9 Ma, with an MSWD value of 0.97. Re–Os dating of the molybdenites indicates that Cu–W–Mo metallogenesis in the western Balkhash metallogenic belt occurred during Late Carboniferous to Early Permian (315.9–289.3 Ma), while the porphyry Cu–Mo deposits formed at 316 Ma, and the quartz vein-greisen W–Mo deposits formed at 298 Ma. The Re–Os model and isochron ages thus suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism took place during the late Hercynian movement. Compared to the Junggar-East Tianshan porphyry Cu metallogenic belt in northwestern China, the formation of the Cu–Mo metallogenesis in the Balkhash metallogenic belt occurred between that of the Tuwu-Yandong in East Tianshan and the Baogutu porphyry Cu deposits in West Junggar. Collectively, the large-scale Late Carboniferous porphyry Cu–Mo metallogenesis in the Central Asian metallogenic domain is related to Hercynian tectono-magmatic activities.     

Indo–Chinese Magmatic Activity in the Duobaoshan District of Heilongjiang Province and Its Geological Significance

The Duobaoshan ore concentration area, located in Nenjiang County of Heilongjiang Province, is an important porphyry Cu-Mo ore concentration area in China, which is characterized by complex magmatic activities and multi–phase overprinting metallogenesis. On the basis of field geological observation, systematic sampling, in-lab analysis and the metallogenic regularity in the Xiang'an–Mongolian metallogenic belt, this work carried out high-precision dating and geochemical analysis on the Yuejin, 173-kilometer and Wolihedingzi rock bodies. These rock bodies are renamed monzonitic granite and their consistent age(238 Ma) show that they were formed not in Variscan but in Indosinian. Therefore, it is inferred that the ore spots formed in the potassium silicate and sericite alteration zones of the rock mass also belong to Indosinian. In addition, we collected granodiorite from the Tongshan mining pit, and its zircon age is 223.1±2.8 Ma and the Cu content of the sample is high. The Tongshan mineralization is inferred to undergo the superimposition of Indosinian diagenetic mineralization. The age of the granodiorite porphyry related to copper-molybdenum mineralization in the Xiaoduobaoshan area is 222.1±5.5 Ma, and the earlier age of granodiorite is 471.8±7.4 Ma, indicating that the initial magmatic activities belong to the Duobaoshan porphyry system in the Caledonian period. The geochemical characteristics of the Indosinian rock samples show continental arc features, with reference to tectonic-magmatic activities of the whole Daxing'anling area. We consider that the magmatic activities and mineralization of the Indosinian period are affected by the southward subduction of Okhotsk Ocean since Late Permian. By combining the mineralization rules of Daxinganling area and the structural systems of Duobaoshan ore concentration area, we divide two rock-mineralization belts in this area including the Yuejin–Duobaoshan–Tongshan belt and 173-kilometer–Xiaoduobaoshan–Wolihedingzi belt, which are distributed nearly parallel along the NW-trending fractures and show similar geotectonic settings and the timing of the magmatic activities. It is favorable for discovering porphyry Cu-Mo deposits in these two metallogenic belts, especially in the Yuejin, 173-kilometer and Wolihedingzi areas where less research work has been made.     

Geology and Geochemistry of the Shizitou Molybdenum Deposit,Jiangxi Province: Implications for Geodynamic Setting and Metallogenesis

The Shizitou molybdenum(Mo) deposit in Yongping, Jiangxi, is an important, recently discovered deposit in the eastern section of the Qin–Hang metallogenic belt. The Mo deposit is located in the outer contact zone between the porphyritic biotite granite and the Neoproterozoic migmatite, and present in the deep central part of the intrusion. Re–Os dating and S and Pb isotopic analysis have been conducted to assess the metallogenesis of the Shizitou Mo deposit. S, Pb and Re isotopes show that the ore–forming materials were derived from the porphyritic biotite granitic magma, which originated from the mixing of mantle and crust. Re–Os dating of molybdenite from the ores gives a model age from 156.9±2.2 to 158.5±2.4 Ma, with a weighted mean age of 158±1 Ma and an isochron age of 158.0±2.5 Ma. Geological and geochemical characteristics of the ore deposit and the related granitoids indicate that the Shizitou deposit is a Climax–type Mo deposit. Based on previous studies of the Qin–Hang metallogenic belt, two metallogenic events are believed to have occurred during 172–145 Ma and 137–132 Ma. These two metallogenic periods are consistent with the timing of two metallogenic peaks during the middle to late Jurassic and the Cretaceous in South China. These events represent responses to the partial back–arc extension associated with the subduction of the Izanagi plate beneath the Eurasian continent and the rapid northeastward movement of the subducting Izanagi plate.     

On Metallogenic Conditions and Regularities of the Lower and Middle Reaches of the Changjiang River

The paper deals with the metallogenic conditions and regularities of the region ol the lower-middle reachesof the Changjiang River in China. The complicated structural network with the Changjiang (Yangtse) deepfracture as its trunk is the leading rock-and ore-controlling structure of the metallogenic belt. Thehigh-potassium granodiorites of the first magmatic sequence of the Mesozoic Yangtse syntexis type and thesodium-rich diorites of the second sequence are genetically related to the copper ore series and the iron ore se-ries respectively. and occur respectively in the block-faulted and-folded uplift area and the down-faulted vol-canic basin as well as the transitional zone between the two. The ore-hosting horizons show specific associa-tions of rocks and often contain ore beds basically of stratabound nature.     

A Preliminary Review of the Metallogenic Regularity of Nickel Deposits in China

The nickel deposits mainly distributed in 19 provinces and autonomous regions in China are 339 ore deposits/occurrences, including 4 super large-scale deposits, 14 large-scale deposits, 26 middle-scale deposits, 75 small-scale deposits, and 220 mineralized occurrences. The prediction types of mineral resources of nickel deposits are magmatic type, marine sedimentary type and regolith type. The formation age is from the Neoarchean to the Cenozoic with two peaks in the Neoproterozoic and the late Paleozoic. The nickel deposits formed in the Neoproterozoic are located on the margin of the North China Block and Yangtze Block, and those formed in the late Paleozoic are mainly distributed in the Central Asian Orogenic Belt (CAOB), Emeishan and the Tarim Large Igneous Provinces (LIPs). Magmatic nickel deposits are mainly related with broken-up continental margin, post-collision extension of the orogenic belt and mantle plume. According to different tectonic backgrounds and main characteristics of magmatism, the Ni-Cu-Co-PGE metallogenic series types of ore deposits related with mantle-derived mafic-ultramafic rocks can be divided into 4 subtypes: (1) the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in the broken-up continental margin, (2) the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in mantle plume magmatism, (3) the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in the subduction of the orogenic belt, and (4) the Ni-Cu-Co-PGE metallogenic series subtype of ore deposits related with mantle-derived mafic-ultramafic rocks in post-collision extension of the orogenic belt. We have discussed in this paper the typical characteristics and metallogenic models for Neoproterozoic Ni-Cu-(PGE) deposits related with broken-up continental margin, Cambrian marine sedimentary Ni-Mo-V deposits related with black shale, early Permian Ni-Cu deposits related with post-collision extension of the orogenic belt, late Permian Ni-Cu-(PGE) deposits related with Large Igneous Provinces (LIPs), and Cenozoic Ni-Au deposits related with regolith. The broken-up continental margin, mantle plume and post-collision extension of the orogenic belt are important ore-forming geological backgrounds, and the discordogenic fault, mafic-ultramafic intrusion, high MgO primitive magma (high-MgO basaltic magma), deep magmatism, sulfur saturation and sulfide segregation are 6 important geological conditions for the magmatic nickel deposits.     

The Cu-Mo Mineralization of the Late Jurassic Porphyry in the Northern Great Xing’an Range: Constraints from Zircon U-Pb Ages of the Ore-Causative Granites

The Great Xing’an Range(GXAR)is one of the most important metallogenic belts in China.Previous study has shown that porphyry Cu-Mo deposit distributed in the northern Great Xing’an Range formed mainly in two stages:(1)Early Ordovician,such as Duobaoshan and Tongshan deposits(Liu et al.,2017);2)Triassic-Early Jurassic,including Wunugetushan,Taipingchuan and Badaguan deposits(Tang et al.,2016).In recent years,two potential porphyry Cu-Mo deposits,Huoluotai and Xiaokele,were discovered in the Erguna Block,northern GXAR(Figs.1a–b).However,the ore formation ages and regional metallogenic regularity are ambiguous due to the lack of isotopic ages.Two zircon U-Pb ages from the ore-causative granites were reported in this paper,with the aims to constrain the metallogenic ages and provide evidence for study of the regional metallogenic regularity and ore prospect prediction.     

Features of Minerogenic Series Related to Continental VolcanicRocks in the Southeastern Coastal Area of China-A Case Study of the Daiyunshan-ShiniushanVolcanic Depression in Fujian

The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in Ch     

Magmatic Evolution and Mineralization of Porphyry Copper-Gold Deposits in the Duolong Ore Concentration Area, Tibet

<正>The Bangong Lake-Nujiang River metallogenic belt is located between the Qiangtang Block and Lhasa Block,and the Duolong ore concentration area is located in the western section of the Bangong Lake-Nujiang River metallogenic belt.Till now,several large and super large copper-gold deposits,such as Duobuza,Bolong,     

The First Discovery of Colusite in the Tiegelongnan Supper‐large Cu (Au,Ag) Deposit and Significance for the Genesis of the Deposit

正Objective The Tiegelongnan deposit,located at Duolong ore district in western part of Bangong Co.-Nujiang metallogenic belt,is the first super-large Cu(Au,Ag)deposit with typical features of high-sulfidation epithermal mineralization.The colusite was found in the deposit for     

Message from the Editor‐in‐Chief

<正>Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact     

Message from the Editor‐in‐Chief

<正>Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact     

Message from the Editor‐in‐Chief

<正>Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact     

Message from the Editor‐in‐Chief

<正>Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact factor varying between 1.58 and 2.15 from year to year.It is co-published by the Geological Society of     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagslhip journal of the Geological Society of China,it has become more and nmore influcntial in earth scicences in China and beyond.The journal is now indexed by SCI,CA and more than 20 other databases,with an impact factor varying between 1.58 and 2.15 from year to year.It is co-publishd by the Gcoloigical Society of     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and     

Message from the Editor‐in‐Chief

正Dear Authors and Readers:First of all,on behalf of the new Editorial Board,I would like to express our sincere appreciation for your continuing support of our journal.This journal,founded in 1922,is the oldest geological journal in China.As the flagship journal of the Geological Society of China,it has become more and more influential in earth sciences in China and