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Carlin-type gold deposits are among the most important gold-bearing hydrothermal ore systems and are mainly located in Nevada, USA, and southwestern China. However, the source and evolution of the ore-forming fluids for these deposits remain controversial, especially those found within China. In this study, lithium and oxygen isotopic analyses of quartz-hosted fluid inclusions are used to elucidate the source and evolution of the giant Shuiyindong Carlin-type gold deposit. Fluid inclusions trapped in quartz of three distinct genetic stages have low salinity (0.8–6.3wt% NaCl equiv.) and moderate temperature (154–343 °C), but display variable Li and O isotope signatures. The Li and O isotopes of stage I fluids (δ7Li values from + 5.1 to + 9.1‰; δ18O values from + 6.3 to + 10.0‰) indicate predominantly a magmatic source for the initial ore-forming fluids. The large variations of Li and O isotopes of stage II fluids (δ7Li values from + 9.3 to + 16.0‰; δ18O values from + 0.1 to + 7.7‰) suggest that the fluids are controlled by mixing of magmatic fluids and meteoric water, which in turn triggered the precipitation of gold-bearing sulfides. The isotopic compositions of stage III fluids (δ7Li values from + 15.5 to + 22.8‰; δ18O values from − 5.4 to − 2.8‰) confirm that the final fluids are dominated by meteoric water. Furthermore, this work demonstrates that the combined Li–O isotopic analysis of fluid inclusions is a powerful tracer to decode the source and evolution of ore-forming fluids in hydrothermal mineralizing systems. [ABSTRACT FROM AUTHOR]

The formation of Carlin-type gold deposits is poorly constrained, mainly due to the lack of accurate ages for gold mineralization. The Youjiang basin, SW China, represents the world's second-largest Carlin-type gold province after NV, USA. In this paper, we use hydrothermal apatite U–Th–Pb dating to systemically determine the mineralization ages of five Carlin-type gold deposits, namely, Shuiyindong, Jinfeng, Zimudang, Linwang, and Jinya, in the Youjiang basin. The hydrothermal apatite is characterized by intimate intergrowth with gold-bearing sulfides, presence of primary fluid inclusions, irregular morphology and cathodoluminescence zoning, and MREE-enriched composition patterns, indicating that it is clearly associated and coeval with gold mineralization. The concentrations of lattice-bound U and Th in the apatite are highly variable, making it suitable for in situ secondary ion mass spectrometry (SIMS) U–Th–Pb dating. The dating results of hydrothermal apatite from the five deposits show that they formed at ca. 150–140 Ma, contemporary with the widespread felsic magmatism and associated W–Sn mineralization to the east of the Youjiang basin, probably in response to slab breakup of the Paleo-Pacific oceanic plate beneath the South China continental plate. Our case story suggests that hydrothermal apatite could be a robust chronometer for age dating of sedimentary rock-hosted gold mineralization worldwide. [ABSTRACT FROM AUTHOR]

Magmatic sources of porphyry deposits in postcollisional settings remain controversial. We have used new and published petrological and geochemical data for the Eocene–Oligocene porphyry Cu ± Mo ± Au deposits in the Sanjiang region, SW China, to address this outstanding issue. New data for three deposits (Machangqing, Tongchang, and Beiya) in the Ailaoshan–Red River porphyry Au-Cu-Mo belt (southern part of the Sanjiang region) suggest that ore-forming porphyries were emplaced at ~ 35 Ma, have high (87Sr/86Sr)i (0.7068–0.7071) and negative εNd(t) (− 6.9 to − 5.0), low zircon εHf(t) (− 5.3 to 4.5), and relatively high δ18O (5.9–9.0‰). Magmatic amphibole phenocryst compositions indicate that the parental magmas are all relatively oxidized (ΔFMQ = 1.7 ± 0.6), and H2O-rich (3.8 ± 0.3 wt% H2O). These results are consistent with those estimated from zircon compositions (ΔFMQ = 1.8 ± 0.8) and high whole-rock Sr/Y ratios (75 ± 31), respectively. Based on the new and published data, we suggest that the parental magmas for the Ailaoshan–Red River porphyry Au-Cu-Mo belt were derived from a preserved juvenile arc lower-crust and the underlying metasomatized subcontinental lithospheric mantle (SCLM) attributed to a Neoproterozoic subduction event, whereas the parental magmas for the Yulong porphyry Cu-Mo belt (northern part of the Sanjiang region) originated from the Permian–Triassic juvenile arc lower-crust and metasomatized SCLM. Additionally, parental magmas for these porphyry deposits are all oxidized and H2O-rich, and we attribute such characteristics to inheritance from mixed mantle-crust sources that were modified by previous oceanic slab subduction. [ABSTRACT FROM AUTHOR]

The genesis of the giant Ag-Cu-Pb-Zn polymetallic mineralization in the northern Lanping basin, Southwest China, remains controversial. To address the sources of metals, a systematic study on Hg isotope compositions was conducted for the Cu-dominated deposit at Baiyangping and the Pb-Zn-dominated deposits at Fulongchang and Liziping. The Cu deposit shows positive Δ199Hg signatures (0.14 ± 0.13‰), in contrast to the Δ199Hg of the Pb-Zn deposits (− 0.09 ± 0.06‰). As positive Δ199Hg values are commonly observed in marine sediments and the Lanping Triassic marine sedimentary rocks show exclusively positive Δ199Hg signals (0.03 ± 0.07‰), the Hg in Cu ores was mainly sourced from the Triassic strata. The negative Δ199Hg signals observed in the Pb-Zn deposits, typical of terrestrial Hg, agree roughly with those of the Jurassic to Paleocene terrestrial sedimentary rocks (− 0.05 ± 0.08 ‰), indicating that the terrestrial strata provided the Hg in Pb-Zn ores. Compared to the source rocks, the Cu deposit shows isotopically lighter Hg enrichments (δ202Hg = − 2.30 ± 0.35‰), possibly resulting from fractionations induced by Hg2+ sorption, organic complexation, and precipitation of Hg-bearing sulfides. The Pb-Zn deposits show comparable or slightly heavier δ202Hg (− 0.56 ± 0.48‰); moreover, δ202Hg values of late-stage sulfides are higher than early-stage δ202Hg values, suggesting that the δ202Hg variation was primarily caused by sulfide precipitation. Thus, Hg isotope data indicate that separate hydrothermal events resulted in Cu and Pb-Zn mineralization. More importantly, this study reveals the great potential of Hg isotopes to discriminate sedimentary sources of metals for low-temperature hydrothermal deposits. [ABSTRACT FROM AUTHOR]

The late Mesozoic antimony (Sb) mineralization belt in South China hosts a large portion of the world's Sb reserves. However, the source and mineralization processes of these Sb deposits remain controversial. Here, we measured mercury (Hg) concentrations and isotopic compositions of stibnite in the Banpo Sb-only and Woxi Sb-polymetallic ore deposits, as well as associated rocks in the Yangtze Block in order to constrain the metal sources and ore formation processes in the South China Sb mineralization belt. Stibnite samples from both deposits exhibit significant enrichment in Hg (4.23–50.6 ppm) and have higher δ202Hg values (−0.47‰ to 2.03‰) than the studied Precambrian basement rocks (−1.42‰ to 0.59‰), Paleozoic sedimentary rocks (−2.40‰ to −0.32‰), and other natural Hg reserves (e.g., marine and continental systems). This indicates that significant mass-dependent fractionation of Hg isotopes occurred during hydrothermal processes. Negative to slightly positive Δ199Hg values of −0.17‰ to 0.02‰ were obtained for stibnite from the studied deposits, similar to values for the Precambrian basement rocks, but different from those of the Paleozoic sedimentary rocks and data previously reported for mantle materials. This suggests that Precambrian basement rocks were the source of Hg and associated metals. Our data and the tectonic evolution of South China indicate that late Mesozoic asthenospheric upwelling, in response to the Paleo-Pacific oceanic slab foundering, generated heat that drove the circulation of fluids in the basement and crustal basinal rocks. These fluids leached Sb, Hg, and other metals from the Precambrian basement rocks and formed the world-class Sb mineralization belt in South China. [ABSTRACT FROM AUTHOR]

The reduced nature of the subducting slab has been used to explain the relatively poor endowment of economic porphyry copper deposits in Paleo-Tethyan arc systems. The presence of numerous porphyry Cu deposits in the southern Yidun terrane potentially challenges this model, because these deposits are thought to be the product of Paleo-Tethyan subduction. To investigate this, two representative deposits (i.e., Pulang and Songnuo porphyry Cu deposits) from the southern Yidun terrane have been studied. Zircon U-Pb ages of pre- and syn-mineral porphyries in Pulang are 221 ± 2 Ma (MSWD = 0.89) and 215 ± 2 Ma (MSWD = 1.50), respectively. Zircon and garnet U-Pb ages of the Songnuo syn-mineral porphyry are 217 ± 2 Ma (MSWD = 1.15) and 223 ± 5 Ma (MSWD = 0.97), respectively. The Pulang and Songnuo porphyries both have high whole-rock Sr/Y ratios with minor or no negative Eu anomalies, consistent with derivation from hydrous magmas that underwent minor early plagioclase crystallization but abundant amphibole fractionation. The two porphyry intrusions are characterized by high large-ion-lithophile elements (LILE: Th, U, Ba, Rb) abundances, and low concentrations of high-field-strength elements (HFSE: Nb, Ta, Ti, Zr, Hf). They have similar initial Sr isotope ratios from 0.7055 to 0.7073, ƐNd (t) values from − 4.3 to − 1.6 and zircon ƐHf (t) values of − 1.81 ± 1.34 (n = 47) that are distinct from published results for the Permian–Early Triassic Paleo-Tethyan arc granitoids in the Sanjiang region but similar to the Neoproterozoic arc intrusions in the nearby western Yangtze craton. The Pulang and Songnuo porphyries have relatively high zircon EuN/EuN* ratios (0.59 ± 0.04, n = 52) and calculated Δ log fO2 (FMQ) values (1.61 ± 0.23, n = 52), consistent with relatively oxidized magmas. This feature is similar to the published data for the Neoproterozoic arc intrusions (EuN/EuN* = 0.55 ± 0.08; Δ log fO2 (FMQ) = 2.14 ± 0.60), but distinct from the published data for the reduced normal Paleo-Tethyan arc magmas (EuN/EuN* = 0.29 ± 0.10; Δ log fO2 (FMQ) = − 0.68 ± 0.88). Given that the most recent tectonic reconstruction models suggest that the Paleo-Tethys Ocean closed before ~ 220 Ma, we propose that the Pulang and Songnuo porphyries Cu deposits were formed in a postsubduction setting from oxidized melts generated by reactivating the Neoproterozoic arc root, unrelated to Paleo-Tethyan subduction. [ABSTRACT FROM AUTHOR]

The Baiyangping Cu–Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, between the Jinshajiang-Ailaoshan and Lancangjiang faults, and the deposit can be divided into eastern and western ore zones. Based upon microscope observation of ore minerals and analysis of zinc, copper, and strontium isotope composition, we conclude that: (1) the zinc isotopic compositions of sphalerite from the eastern and western ore belt of the Baiyangping polymetallic ore deposits are enriched in both the heavy (− 0.09‰ to + 0.15‰) and light (− 0.19‰ to − 0.01‰) zinc isotopes. Rayleigh fractionation is likely the additional factor controlling the observed temporal and spatial variations in zinc isotopes in the two studied ore zones. The zinc isotopic composition in the Baiyangping polymetallic Pb–Zn deposits may have the same fractionation as that of magmatic-hydrothermal, VHMS, SEDEX, and MVT deposits, as demonstrated by geological and other geochemical evidence; (2) the range of δ65Cu in massive tetrahedrite is from − 0.06‰ to + 0.12 ‰ that relates to the early stages of ore-formation, which are higher than that of venial chalcopyrite (from − 0.72‰ to − 0.07‰) formed at a late ore-forming stage in the western ore belt. Different ore-forming stages and alteration or leaching processes are likely the main factors controlling the observed variations in copper isotopes in the western ore zone; (3) the 87Sr/86Sr value of hydrothermal calcite in eastern (0.7080–0.7093) and western (0.7085–0.7113) ore belt suggested that mineralization of early calcite, with 87Sr/86Sr values much higher than in ancient Late Triassic seawater, may be related to recrystallization from a radiogenic Sr-rich or silicifying fluid, either from the strata that the ore-forming fluid flows through or from other fluids. [ABSTRACT FROM AUTHOR]

It has been well established that metal and sulfur sources in mineral deposits can be very difficult to identify, especially for ore deposits hosted in sedimentary rocks. Using the world's largest Sb deposit at Xikuangshan in southern China as a case study, this study combined Hg isotopes and in situ sulfur isotope measurements to constrain the sources of Sb and sulfur. A variation of 1.1‰ in δ202Hg (0.04 to 1.15‰) was observed in stibnite ore samples, suggesting that mass-dependent fractionation of Hg isotopes occurred during the formation of the deposit. Significant mass-independent fractionation of Hg isotopes, with △199Hg ranging from − 0.03 to − 0.17‰, was also observed in the ore samples, suggesting that Hg transported by the ore fluids was inherited from Proterozoic basement metamorphic rocks as these rocks show similar △199Hg signatures (− 0.03 to 0.07‰). In situ sulfur isotope measurements yielded δ34S values that cluster in the range of + 6.8 to + 10.2‰, providing evidence that sulfur contained in ore fluids may also have been dominantly derived from underlying Proterozoic basement metamorphic rocks (δ34S = +5.6 to + 11.5‰). Using the new results from Hg and S isotopes, we proposed that deep-circulated meteoric water mobilized Sb, Hg, and S from the Proterozoic metamorphic basement, ascended along deep faults, and subsequently deposited Sb at favorable structural zones as a result of boiling of the hydrothermal fluids, generating the world-class Xikuangshan Sb deposit. This study also highlights the combined use of Hg-S isotopes as a novel method to provide new and additional insights into the source regions of ore materials for sedimentary-hosted Sb deposits. [ABSTRACT FROM AUTHOR]

The Xikuangshan Sb deposit in central Hunan, South China is the largest Sb deposit in the world, which has supplied more than 50% of the world's Sb and with total Sb metal reserves of about 2.5 Mt. However, the age of this deposit is still not well constrained due to a lack of suitable minerals for reliable radiometric dating, which hampered the generation of a generally accepted genetic model of mineralization. Since the fluid-inclusion data suggest that the temperature of ore-forming fluids in the Xikuangshan deposit is up to 360 °C, zircon (U-Th)/He thermochronometry with the closure temperature of 160–200 °C was chosen here to elucidate the age of Sb mineralization. Detrital zircons in the altered host rocks from the Xikuangshan deposit yielded two (U-Th)/He age populations of 156–117 and 97–86 Ma. The older age population (156–117 Ma), which is well in accordance with previous Sm-Nd dating on hydrothermal calcite (156–124 Ma), probably represents the timing of main-stage Sb mineralization in the Xikuangshan Sb deposit, while the younger zircon (U-Th)/He ages may result from partial loss of He in zircon caused by the distal effect of deep-seated intrusions beneath the deposit. This study demonstrates that the (U-Th)/He dating of zircon in altered host rocks can be viable for constraining the timing of low-temperature mineralization. [ABSTRACT FROM AUTHOR]

The Huichizi granite complex is the largest Paleozoic I-type intrusion located in the North Qinling orogenic belt (NQB). In this study, we present systematic geochemical element data, zircon U-Pb ages, Lu-Hf isotopic data, and Sr-Nd isotopic data for the Huichizi granites. In terms of mineral and chemical compositions, these granites are biotite monzonitic and alkali-feldspar granites, both of which are characterized by high TiO2 and total alkali contents and low MgO, TiO2, and TFeO contents. These granites are weakly peraluminous (A/CNK values are 1-1.06 for biotite monzonitic granites and 1.04-1.09 for alkali-feldspar granites) and possess the geochemical characteristics of adakitic rocks, e.g., high Sr contents (319 ppm-633 ppm), Sr/Y ratios (18.5-174), and (La/Yb)N ratios (17.6-57) and low MgO (0.04 wt.%-0.83 wt.%), Y (3.0 ppm-17.2 ppm), and heavy rare-earth element (HREE) contents. This indicates that these rocks were most likely derived from the partial melting of a thickened lower crust. In situ zircon U-Pb dating of these granites yields Early Caledonian ages (437 Ma for biotite monzonitic granites and 424 Ma for alkali-feldspar granites), indicating that the Huichizi granitic complex is the product of multi-periodic magmatism. The positive but varying zircon εHf(t) values (+0.6 to +8.5) suggest that this thickened lower crust was mainly juvenile, i.e., accreted from depleted mantle during the Neo-Mesoproterozoic Period, but involved the ancient recycled crust. Biotite monzonitic granites formed during crust thickening at the extrusion stage, whereas the alkali granites formed during crust thickening at the extension stage (post extrusion). The Huichizi granite complex witnessed the process of extrusion to extension because of the collision between the NCB and the Qinling microcontinent in the Caledonian. [ABSTRACT FROM AUTHOR]

The Lanuoma and Cuona sediment-hosted Pb-Zn deposits hosted by Upper Triassic limestone and sandstone, respectively, are located in the Changdu area, SW China. Mercury concentrations and Hg isotopic compositions from sulfide minerals and potential source rocks (e.g., the host sedimentary rocks and the metamorphic basement) were investigated to constrain metal sources and mineralization processes. In both deposits, sulfide minerals have higher mercury (Hg) concentrations (0.35 to 1185 ppm) than the metamorphic basement rocks (0.05 to 0.15 ppm) and sedimentary rocks (0.02 to 0.08 ppm). Large variations of mass-dependent fractionation (3.3‰ in δ202Hg) and mass-independent fractionation (0.3‰ in Δ199Hg) of Hg isotopes were observed. Sulfide minerals have Hg isotope signatures that are similar to the hydrothermal altered rocks around the deposit, and similar to the metamorphic basement, but different from barren sedimentary rocks. The variation of ∆199Hg suggests that Hg in sulfides was mainly derived from the underlying metamorphic basement. Mercury isotopes could be a geochemical tracer in understanding metal sources in hydrothermal ore deposits. [ABSTRACT FROM AUTHOR]

The contiguous region between Guangxi, Guizhou, and Yunnan, commonly referred to as the Golden Triangle region in SW China, hosts many Carlin-type gold deposits. Previously, the ages of the gold mineralization in this region have not been well constrained due to the lack of suitable minerals for radiometric dating. This paper reports the first SIMS U-Pb age of hydrothermal rutile crystals for the Zhesang Carlin-type gold deposit in the region. The hydrothermal U-bearing rutile associated with gold-bearing sulfides in the deposit yields an U-Pb age of 213.6 ± 5.4 Ma, which is within the range of the previously reported arsenopyrite Re-Os isochron ages (204 ± 19 to 235 ± 33 Ma) for three other Carlin-type gold deposits in the region. Our new and more precise rutile U-Pb age confirms that the gold mineralization was contemporaneous with the Triassic W-Sn mineralization and associated granitic magmatism in the surrounding regions. Based on the temporal correlation, we postulate that coeval granitic plutons may be present at greater depths in the Golden Triangle region and that the formation of the Carlin-type gold deposits is probably linked to the coeval granitic magmatism in the region. This study clearly demonstrates that in situ rutile U-Pb dating is a robust tool for the geochronogical study of hydrothermal deposits that contain hydrothermal rutile. [ABSTRACT FROM AUTHOR]

Mo-Cu mineralization in the Baituyingzi district of eastern Inner Mongolia occurs within a granitic complex. This paper presents and discusses zircon U-Pb ages and whole-rock geochemical and Sr-Nd-Pb isotopic data from the granitic complex as potential indicators for porphyry Mo fertility. The U-Pb ages indicate that five units of the granitic complex were emplaced between 265.2 ± 0.7 and 246.5 ± 1.0 Ma. Constrained by crosscutting dikes, Mo-Cu mineralization was probably related to the Baituyingzi monzogranite porphyry dated at 248.2 ± 0.64 Ma. The intrusions belong to high-K calc-alkaline to shoshonitic series that are characterized by highly fractionated rare earth element (REE) patterns and strong enrichments of large ion lithophile elements, relative to high-field strength elements. Apart from the ∼246-Ma dike that shows negative εNd ( t) values (−14.9 to −13.1), the intrusions have εNd( t) values ranging from −3.9 to 1.0, relatively young depleted mantle model ages (811 to 1183 Ma), Pb/Pb of 18.137-18.335, and Pb/Pb of 15.591-15.625, which are consistent with a juvenile lower crustal origin. Among the intrusions, the ∼248-Ma porphyry and the ∼246-Ma dike show adakite-like characteristics (e.g., Sr/Y = 44.9-185) and listric-shaped REE patterns that indicate amphibole fractionation and a hydrous magma source. However, the porphyry exhibits a higher differentiation index (81.4-91.5) and a steeper REE profile (e.g., La/Yb = 25.6-87.0) than those of the ∼246-Ma dike, which suggests that it is highly differentiated. We propose that the complex was generated by the partial melting of juvenile mafic lower crust (containing minor old crustal relicts) that was triggered by collision between the North China Craton and Siberian Craton. As indicated by the Th/Nb, Th/Yb, Ba/Th, and Ba/La ratios of the intrusions, the crust may have been derived from the melting of the fertile mantle wedge that was metasomatized by various amounts of slab-derived fluids or melts due to earlier subduction and was heterogeneous in terms of water, Cu, Mo, and S contents and possible oxidation state. The fertility of the porphyry was likely associated with the addition of earlier subduction-related slab melts to the magma source (leading to a hydrous and possible high oxidation state) and the long-time (∼20 Ma) collision tectonic setting in which it formed (resulting in a highly differentiated state). [ABSTRACT FROM AUTHOR]

Tin deposits are often closely associated with granitic intrusions. In this study, we analyzed tin partition coefficients between different fluids and melts ( $${\text{D}}_{Sn}^{aq.fl./melt}$$ ) as well as various crystals and melts $${\text{D}}_{Sn}^{aq.fl./melt}$$ ( $${\text{D}}_{Sn}^{crystal/melt}$$ ) from the Furong tin deposit associated with the Qitianling A-type granite. Our experimental results indicate that tin partition behavior is affected by the chemical compositions of fluids, melts, and minerals. Tin is prone to partitioning into the residual magma in fractional crystallization or other differential magmatic processes if the magma originated from crustal sources with high alkali content, high volatile content, and low oxygen fugacity. Highly evolved residual peralkaline granitic magma enriched in tin can lead to tin mineralization in a later stage. Furthermore, the volatiles F and Cl in the magma play important roles in tin partitioning behavior. Low F contents in the melt phase and high Cl content in the aqueous fluid phase are favorable factors for tin partitioning in the aqueous fluid phase. High Cl content in the aqueous fluid catalyzes water-rock interaction and leads to the extraction of tin from tin-bearing minerals. All these findings support a hydrothermal origin for the tin deposits. In light of the geotectonic setting, petrochemical characteristics, and mineralizing physicochemical conditions of the Furong tin deposit, it is inferred that the ore-forming fluid of the Furong tin ore deposit could have derived from the Qitianling peralkaline intrusion. [ABSTRACT FROM AUTHOR]

Miaoershan (MES) uranium ore field is one of the most important uranium sources in China, hosts the largest Chanziping carbonaceous-siliceous-pelitic rock type uranium deposit in South China together with many other granite-hosted uranium deposits. The Shazijiang (SZJ) uranium deposit is one of the representative granite-hosted uranium deposits in the MES uranium ore field, situated in the Ziyuan, Guangxi Province, South China. Uranium mineralization in the SZJ deposit mainly occurs as uraninite with quartz and calcite veins that is spatially associated with mafic dykes in the region. The hydrothermal alteration includes silicification, carbonation and hematitization. New uraninite chemical U-Pb geochronology and petrographic evidences provide the timing constraints and new insights into the formation of the SZJ uranium deposit. The results show that the first stage of uranium mineralization formed at 97.5±4.0 Ma, whereas another stage of uranium mineralization occurred at 70.2±1.6 Ma. Two stages of uranium mineralization are fairly consistent with two episodic crustal extensions that occurred at ~100 and ~70 Ma throughout South China. This study indicates that there are two uranium mineralization events in SZJ uranium ore field controlled by mafic dyke, supporting that mafic dykes play an important topochemical role in uranium concentration and/or mobilization. Therefore, geochemical U-Pb age firstly reinforces that ore-forming age of the SZJ uranium deposit mainly yields at 97.5±4.0 and 70.2±1.6 Ma. Additionally, geochemical age method is particularly useful for interest samples which record information on multi-stage uranium mineralizations in South China. [ABSTRACT FROM AUTHOR]

B Retraction Note to b : B Mineralium Deposita (2022) 57:399-415 b https://doi.org/10.1007/s00126-021-01070-3 The Editors-in-Chief have retracted this article because Table 2 contains data used in a previously published article (Liu et al. [1]). All authors agree to this retraction and to the wording of this retraction notice. [Extracted from the article]

Fe-Cu deposits in the Kangdian Fe-Cu metallogenic province, SW China, are hosted in Paleoproterozoic meta-volcanic-sedimentary sequences and are spatially associated with coeval mafic intrusions. Several well-known examples are the giant Lala, Dahongshan, and Yinachang deposits. They have a common paragenetic sequence of an early Fe-oxide stage associated with sodic alteration and a late Cu-sulfide stage associated with potassic-carbonate alteration. Magnetite dominates the Fe-oxide stage of these deposits but is also present in the Cu-sulfide stage of the Lala deposit. This study uses trace element compositions of magnetite to examine the nature and origin of the ore-forming fluids. The magnetite has variable concentrations of Ti, Al, Mg, Mn, Si, V, Cr, Ca, Co, Ni, Sc, Zn, Cu, Mo, Sn, and Ga, which are thought to have been controlled mainly by fluid compositions and/or intensive parameters (e.g., temperature and oxygen fugacity ( fO)). Fluid-rock interaction and coprecipitating mineral phases appear to be less important in controlling the magnetite compositions. Magnetite grains in the Fe-oxide stage of the Lala and Dahongshan deposits have comparable trace element compositions and were likely precipitated from chemically similar fluids. High Ni contents of magnetite in both deposits, coupled with previous isotopic data and the fact that the two deposits are spatially associated with coeval mafic intrusions, strongly suggest that the ore-forming fluids were genetically related to the mafic magmas that formed the intrusions. Magnetite grains in the Fe-oxide stage of the Yinachang deposit have much lower V and Ni but higher Sn and Mo contents than those of the Lala and Dahongshan deposits and are thus thought to have precipitated from more oxidized and Mo-Sn-rich fluids that may have evolved from relatively felsic magmas. Magnetite grains from the Cu-sulfide and Fe-oxide stages of the Lala deposit are broadly similar in composition, but those in the Cu-sulfide stage have slightly higher Cu, Zn, and Mn and are thought to have crystallized from relatively low-temperature and Cu-Zn-Mn-rich fluids evolved from the fluids of the early Fe-oxide stage. Our results show that magnetite from the Fe-Cu deposits in the Kangdian Province, banded iron formation, Fe skarn deposits, diabase-hosted hydrothermal Fe deposits, and magmatic deposits has significantly different compositions. We propose that covariations of Co-Ni, Zn-Sn, and Co/Ni-Mn can be used to effectively discriminate different deposit types. [ABSTRACT FROM AUTHOR]

The Jinshajiang-Red River alkaline igneous belt in the eastern Indian-Asian collision zone, of southwestern China, hosts abundant, economically important Cu-Mo-Au mineralization of Cenozoic age. Major- and trace-element compositions of titanites from representative Cu-mineralized intrusions determined by LA-ICP-MS show higher values for FeO/AlO, ΣREE + Y, LREE/HREE, Ce/Ce*, (Ce/Ce*)/(Eu/Eu*), U, Th, Ta, Nb and Ga, and lower values for AlO, CaO, Eu/Eu*, Zr/Hf, Nb/Ta and Sr than those for titanites from barren intrusions. Different ΣREE + Y, LREE/HREE, U, Th, Ta and Nb values of titanites between Cu-mineralized and barren intrusions were controlled mainly by the coexisting melt compositions. However, different Sr concentrations and negative Eu anomalies of titanites between Cu-mineralized and barren intrusions were most probably caused by different degrees of crystallization of feldspar from melts. In addition, different Ga concentrations and positive Ce anomalies of titanites between Cu-mineralized and barren intrusions were most likely caused by different magmatic fO conditions. Pronounced compositional differences of titanites between Cu-mineralized and barren intrusions can provide a useful tool to help discriminate between ore-bearing and barren intrusions at an early stage of exploration, and, thus, have a potential application in exploration for porphyry Cu deposits in the Jinshajiang - Red River alkaline igneous belt, and to other areas. [ABSTRACT FROM AUTHOR]

Alkaline intrusions in the eastern Shandong Province consist of quartz monzonite and granite. U-Pb zircon ages, geochemical data, and Sr-Nd-Pb isotopic data for these rocks are reported in the present paper. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb zircon analyses yielded consistent ages ranging from 114.3 ± 0.3 to 122.3 ± 0.4 Ma for six samples of the felsic rocks. The felsic rocks are characterised by a wide range of chemical compositions (SiO = 55.14-77.63 wt. %, MgO = 0.09-4.64 wt. %, FeO = 0.56-7.6 wt. %, CaO = 0.40-5.2 wt. %), light rare earth elements (LREEs) and large ion lithophile elements (LILEs) (i.e., Rb, Pb, U) enrichment, as well as significant rare earth elements (HREEs) and heavy field strength (HFSEs) (Nb, Ta, P and Ti) depletion, various and high (Sr/Sr) ranging from 0.7066 to 0.7087, low ε (t) values from −14.1 to −17.1, high neodymium model ages (T = 1.56-2.38Ga, T = 2.02-2.25Ga), Pb/Pb = 17.12-17.16, Pb/Pb = 15.44-15.51, and Pb/Pb = 37.55-37.72. The results suggested that these rocks were derived from an enriched crustal source. In addition, the alkaline rocks also evolved as the result of the fractionation of potassium feldspar, plagioclase, +/− ilmenite or rutile and apatite. However, the alkaline rocks were not affected by crustal contamination. Moreover, the generation of the alkaline rocks can be attributed to the structural collapse of the Sulu organic belt due to various processes. [ABSTRACT FROM AUTHOR]

The Xihuashan tungsten deposit, Jiangxi province, China, is a world-class vein-type ore deposit hosted in Cambrian strata and Mesozoic granitic intrusions. There are two major sets of subparallel ore-bearing quartz veins. The ore mineral assemblage includes wolframite and molybdenite, with minor amounts of arsenopyrite, chalcopyrite, and pyrite. There are only two-phase aqueous-rich inclusions in wolframite but at least three major types of inclusions in quartz: two- or three-phase CO-rich inclusions, two-phase pure CO inclusions and two-phase aqueous inclusions, indicating boiling. Fluid inclusions in wolframite have relatively higher homogenization temperatures and salinities (239-380°C, 3.8-13.7 wt.% NaCl equiv) compared with those in quartz (177-329°C, 0.9-8.1 wt.% NaCl equiv). These distinct differences suggest that those conventional microthermometric data from quartz are not adequate to explain the ore formation process. Enthalpy-salinity plot shows a linear relationship, implying mixing of different sources of fluids. Although boiling occurred during vein-type mineralization, it seems negligible for wolframite deposition. Mixing is the dominant mechanism of wolframite precipitation in Xihuashan. δS values of the sulfides range from −1.6 to +0.1‰, indicative of a magmatic source of sulfur. δO values of wolframite are relatively homogeneous, ranging from +4.8‰ to +6.3‰. Oxygen isotope modeling of boiling and mixing processes also indicates that mixing of two different fluids was an important mechanism in the precipitation of wolframite. [ABSTRACT FROM AUTHOR]

Arsenian pyrite in the Shuiyindong Carlin-type gold deposit in Guizhou, China, is the major host for gold with 300 to 4,000 ppm Au and 0.65 to 14.1 wt.% As. Electron miroprobe data show a negative correlation of As and S in arsenian pyrite, which is consistent with the substitution of As for S in the pyrite structure. The relatively homogeneous distribution of gold in arsenian pyrite and a positive correlation of As and Au, with Au/As ratios below the solubility limit of gold in arsenian pyrite, suggest that invisible gold is likely present as Au in a structurally bound Au complex in arsenian pyrite. Geochemical modeling using the laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis of fluid inclusions for the major ore forming stage shows that the dominant Au species were Au(HS) (77%) and AuHS (23%). Gold-hydroxyl and Gold-chloride complexes were negligible. The ore fluid was undersaturated with respect to native Au, with a saturation index of −3.8. The predominant As species was HAsO. Pyrite in the Shuiyindong deposit shows chemical zonation with rims richer in As and Au than cores, reflecting the chemical evolution of the ore-bearing fluids. The early ore fluids had relatively high activities of As and Au, to deposit unzoned and zoned arsenian pyrite that host most gold in the deposit. The ore fluids then became depleted in Au and As and formed As-poor pyrite overgrowth rims on gold-bearing arsenian pyrite. Arsenopyrite overgrowth aggregates on arsenian pyrite indicate a late fluid with relatively high activity of As. The lack of evidence of boiling and the low iron content of fluid inclusions in quartz, suggest that iron in arsenian pyrite was most likely derived from dissolution of ferroan minerals in the host rocks, with sulfidation of the dissolved iron by HS-rich ore fluids being the most important mechanism of gold deposition in the Shuiyindong Carlin-type deposit. [ABSTRACT FROM AUTHOR]

Over the past decade, as one of nontraditional stable isotopes, Mo isotope has developed rapidly and now become an important geochemical proxy to trace paleo-oceanic and atmospheric evolution through geological history. In this paper, Early Cambrian formations in southern China are investigated. The results indicate that δ97/95Mo values of Early Cambrian seawater may have been larger than 1.4‰, values that are close to those of the modern ocean. It was also found that the variations in Mo isotope composition in samples from two sections (Huangjiawan and Gezhongwu in Guizhou) were closely related to changes in redox conditions during sedimentary processes. Combining our results with existing data, a preliminary model for the evolution of seawater Mo isotope composition through geological history was provided. It indicated that Mo isotopic variations were generally consistent with the evolution of atmospheric oxygen. [ABSTRACT FROM AUTHOR]

The Oligocene Yao’an syenite porphyry, associated with gold mineralisation, and the Machangqing alkali granite porphyry–monzonite porphyry, associated with Cu mineralisation, belong to the Red River–Jinshajiang alkaline igneous belt that formed in a continental setting in southwestern China. A study of the mineral chemistry of major silicate minerals in these two mineralised intrusions provides insights into their overall crystallisation conditions. The temperature and pressure conditions, derived from amphibole–plagioclase and perthite–plagioclase geothermometry and Al-in-amphibole barometry, suggest that the Yao’an intrusion crystallised at around 820 ± 50°C and 0.9–1.3 kbar, whereas the Machangqing intrusion crystallised at around 730 ± 50°C and 2.2–2.8 kbar. The higher temperature and lower pressure of crystallisation for the Yao’an intrusion relative to the Machangqing intrusion indicates that it was emplaced at a shallower crustal level. Based on biotite composition, the two intrusions formed under imposed oxygen fugacities above the Ni–NiO buffer (NNO), and the Yao’an intrusion crystallised under more oxidising conditions than the Machangqing intrusion. The results show that the intrusions associated with Cu–Au mineralisation in the Red River–Jinshajiang alkaline igneous belt were emplaced at a relatively high fO2, which, together with the weakly fractionated magma, favoured Au enrichment relative to Cu in the belt. [ABSTRACT FROM AUTHOR]

In order to investigate the formation mechanism of tin ores associated with F-bearing granite, an experimental study of tin partition between F-bearing granitic melt and coexisting HCI-bearing aqueous fluid was conducted at 85°C and 100MPa with fo2 approaching NNO. Geochemical behavior of tin was traced by changes in starting solid materials with different alumina saturation index ASI, in F content and in starting fluids of various HCI concentrations. The results show that DSn increases with ASI of melt and peraluminous melt is favorable for tin partition into aqueous fluid in the F/Cl-coexisting system. Aqueous fluid of higher HCI concentrations is advantageous for enrichment of tin. Furthermore, chlorine contents in glass run products correlate positively with F and Cl contents in the magma. In the F/Cl-coexisting system, granitic melts with high F contents (> ∼1 wt%) could extract and enrich tin in the melt which can serve as a reservoir for the formation of tin ores. However, the partition coefficient of tin would increase significantly when F contents in the melt were below 1 wt%. Therefore, the decrease of F contents is favorable to the partition of tin into aqueous fluid with high HCI contents, thus promoting deposition of hydrothermal tin ores. [ABSTRACT FROM AUTHOR]

In this paper the authors present the REE concentrations and Sr and Nd isotopic compositions of fluorites from the Bailashui tin deposit of the Furong ore field, southern Hunan Province. The results showed that the total amount of REE in fluorites is usually low, ranging from 0.705 to 8.785 μg/g with the chondrite-normalized REE distribution patterns similar to those of the Qitianling granites in the study area, characterized by LREE-enrichment patterns with pronounced negative Eu anomalies. The fluorites vary in Sr isotopic composition within the range of 0.7083–0.7091, the values are lower than those of the granites and higher than those of the host carbonate rocks in this area. The ɛNd( t) values of fluorites vary between −9.4 and +10.3, revealing that both the crust-and mantle-source materials were involved in the ore-forming hydrothermal fluids. Combined with previous studies on this ore deposit, the Bailashui tin deposit is temporally and spatially closely related with granitic magmatism in this area. The hydrothermal fluorites are the product of fluid/rock interactions between granitic magmatic hydrothermal fluid and marine carbonate rocks. The REE and F in the ore-forming fluid were derived from the granites, whereas Sr in the ore-forming fluid came mainly from the granitic magmatic hydrothermal fluid and marine carbonate rocks, although variations in Sr isotopic composition cannot be explained by a simple mixture of these two end-members. Evidence demonstrated that the ore-forming fluids are of crustal-mantle mixing origin, but that the fluids were probably incompletely homogenized and this may be caused by inhomogeneous mixing of the fluids of different sources. [ABSTRACT FROM AUTHOR]

Standard reference material and different geological samples were dissolved by system A (the mixture of nitric and perchloric acids) and system B (mixture of nitric, perchloric and hydrofluoric acids), and total Se in all samples was measured by hydride-generation atomic fluorescence spectrometry (HG-AFS) after concentration with thiol cotton fiber (TCF). The analytical results obtained by the two digestion method are in good agreement (within the limit of errors) for most of the samples, particularly for those having recommended values. The Se concentrations determined by the two methods are of no difference, and the correlation coefficient is 0.9986; the relative standard deviation (RSD) for the determination of 0.04 μg/g Se is 10.2%. The recovery rates of systems A and B by the standard-addition method were 96%–106% and 99%–104%, respectively. [ABSTRACT FROM AUTHOR]

The No. 302 uranium deposit, located in Guangdong Province, is a typical granite-type uranium ore deposit. REE geochemical characteristics of the wall rocks, pitchblende, altered rocks, calcite and fluorite from this deposit have been systematically studied in this paper. The result showed that the alkali-metasomatic granites and other altered rocks have the same REE distribution patterns as Indosinian granites. It is indicated that the hydrothermal ore-forming solution had altered the Indosinian granites, and ore-forming materials may directly originate from the Indosinian granites. Calcite and fluorite of different stages are the products derived from the same source but different stages. The evolution and degassing of the mineralizing solution might induce LREE enrichment to varying degree. Mantle fluid and a large volume of mineralizer may be the crucial factors controlling uranium mineralization, and the hydrothermal solution with mineralizer played an important role in U transport and concentration. Meanwhile, the degassing of CO2 might promote U and REE precipitation. [ABSTRACT FROM AUTHOR]

The selenium isotopic ratios have been measured in the Yutangba Se deposit, Hubei Province, China. The results show that the δ82/76SeNIST values vary from -12.77‰ to 4.93‰, which is the largest Se isotopic variation found so far in natural terrestrial samples. The sample Ytb-5 of high-selenium carbonaceous shale has the lightest Se isotopic composition with a δ82/76SeNIST value of -12.77‰. On the basis of variations of Se isotope in the deposit along with other geological and geochemical evidence, the ‘redox model’ is suggested to favor the explanation of the occurrence of native Se in the deposit. The application to the Yutangba Se deposit with the discovery of large Se isotopic fractionation for natural samples indicates the potential of Se isotope as a new geochemical tracer. [ABSTRACT FROM AUTHOR]

The Bancun diabase dyke and the Bali hornblende gabbro dyke in western Fujian Province were emplaced in the Early and Late Cretaceous periods, respectively; the former is designated to calc-alkaline series and the latter to K-high-calc-alkaline rock series. Both the dykes are characterized by such geochemical characteristics as high Al and Na2O>K2O. As for the Bancun dyke, Al2O3=16.32%−17.54% and K2O/Na2O=0.65−0.77; as for the Bali dyke, Al2O3=16.89%−17.81% and K2O/Na2O=0.93−0.99. Both the Bancun and Bali mafic dykes are relatively enriched in LILE and LREE, but depleted in HSFE, displaying the geochemical characteristics of continental marginal arc, with high initial Sr isotopic ratios and low ɛNd( t) values. The (87Sr/86Sr)i ratios of the Bancun diabase dyke are within the range of 0.708556–0.70903 and their ɛNd( t) values vary between −6.8 and −6.3; those of the Bali hornblende dyke are within the range of 0.710726–0.710746 and their ɛNd( t) values are −4.7–−4.9, showing the characteristics of enriched mantle EM II. The isotope and trace element data showed that the mafic dykes have not experienced obvious crustal contamination, and metasomatism caused by subduction fluids is the main factor leading to LILE and LREE enrichments. The enriched mantle is the source region for the mafic dykes, and mixing of subduction fluid metasomatized enriched mantle and EM II-type mantle constituted the mantle source region of both the Bancun and Bali mafic dykes. Upwelling of the asthenosphere mantle provided sufficient heat energy for the generation of magmas. In accordance with the discrimination diagram of their tectonic settings as well as their trace element geochemical characteristics, it is considered that the dykes both at Bancun and Bali possess the characteristics of continental marginal arc, revealing the tectonic environment of formation of the mafic dykes, the continental dynamic background as an intraplate tensional belt in which the mafic dykes were emplaced. Meanwhile, it is also indicated that the tensional tectonic stress mechanism is responsible for the formation of the mafic dykes in western Fujian Province. [ABSTRACT FROM AUTHOR]

Using the solubility method, the solubility of CuCl2 in liquid-undersaturated HCl-bearinq water vapor was investigated experimentally at temperatures of 330–370°C and pressures of 4.2–10 MPa. The results have shown that hydration could significantly enhance copper solubility and the concentrations of copper were positively correlated with PH2O. The solubility of copper in vapor phase increased with increasing PH2O at the constant temperature. CuCl2 was transported as hydrated species CuCl2(H2O)ngas in water vapor. The formation of complexes is proposed to be the result of the following reaction: CuCl2solid + nH2Ogas = CuCl2 (H2O)ngas The hydration number n decreased slightly with increasing temperature. Statistical hydration numbers are 4.0, 3.6 and 3.3 at 330, 350 and 370°C, respectively. [ABSTRACT FROM AUTHOR]

Alkali-rich intrusive rocks in western Yunnan were derived from an enriched lithospheric mantle (EM II) source. The data available indicated they are alkali-rich (K2O + Na2O > 8wt%) and shoshonitic. Although formed in a within-plate environment they exhibit signatures of arc magmatic rocks, such as high amounts of LILE and LREE relative to the HFSE and HREE, and thus high Ba/Nb, Ba/Zr, Sr/Y, La/Yb ratios as well as mimic chondrite-normalized REE and primitive mantle-normalized trace element patterns of subducted sediments, and they fall in the collision- or arc-related tectonic setting field on all discrimination diagrams. This might suggest the enrichment be related to the substantial extent of sediment contamination by the Mesozoic Tethyan subduction processes. [ABSTRACT FROM AUTHOR]

The sedimentary-volcanic tuff (locally called "green-bean rock") formed during the early Middle Triassic volcanic event in Guizhou Province is characterized as being thin, stable, widespread, short in forming time and predominantly green in color. The green-bean rock is a perfect indicator for stratigraphic division. Its petrographic and geochemical features are unique, and it is composed mainly of glassy fragments and subordinately of crystal fragments and volcanic ash balls. Analysis of the major and trace elements and rare-earth elements (REE) , as well as the related diagrams, permits us to believe that the green-bean rock is acidic volcanic material of the calc-alkaline series formed in the Indosinian orogenic belt on the Sino-Vietnam border, which was atmospherically transported to the tectonically stable areas and then deposited as sedimentary-volcanic rocks there. According to the age of green-bean rock, it is deduced that the boundary age of the Middle-Lower Triassic overlain by the sedimentary-volcanic tuff is about 247 Ma. [ABSTRACT FROM AUTHOR]

187Os/188Os ratios in all sub-layers of the Co-rich ferromanganese crust MP5D17 from Line Seamount in Central Pacific have been systematically determined. The 187Os/188Os values in this crust are highly variable, ranging from 0.4262 to 1.0155. From the bottom to the top, the osmium isotopic ratios of the crust display a regular variation trend, which correlates well with its changes in structure and texture in the vertical profile. In comparison with the evolution curve of Os isotopic composition in seawater over the past 80 Ma, a similar evolution tendency can be found with respect to the Os isotopic composition of the crust in this study, it is preliminarily concluded that the crust MP5D17 began to grow at about 72 Ma, and underwent three growth hiatuses, corresponding to the geological ages of 64, 53 and 37 Ma, respectively. [ABSTRACT FROM AUTHOR]

Sm-Nd isotope systematics of ores and fluorites places precise time constraints on REE mineralization of the Yinachang Fe-Cu-REE deposit in Yunnan Province which occur in the Proterozoic Kunyan group. The ore-related fluorites contain high abundant REE, and show a strong enrichment of LREE and a positive Eu anomaly, which is in marked contrast to post-ore fluorites that are HREE enriched. The Sm-Nd isochron ages of the ores and fluorites are 1539±40 Ma and 1617±100 Ma, respectively, and calculated ϵNd(t) are -4.6 and -3.2. Accurate age determinations of the mineralization demonstrate that the REE mineralization took place during early Mesoproterozoic. Together with other geological evidence from the ore deposit, the primary REE-bearing ore-forming fluids are suggested to have been derived from the Enriched Mantle, and the Yinachang Fe-Cu-REE ore deposit is of volcanic exhalation-hydrothermal sedimentary origin. This study also imply that the sudden large-scale REE mineralization in the Mesoproterozoic epoch may have been induced by alkaline-rich anorogenic magmatism which occurred at marginal rifts of the continent in the Mesoproterozoic. [ABSTRACT FROM AUTHOR]

The interaction between peat, lignite and germanium(Ge)-bearing solution with an initial Ge concentration of 5 mg/L was studied at 25.100. and at pH 2.96.12.08. The results show that the apparent transfer ratios of peat and lignite for Ge in the solution were positively correlated with temperature in acid environment (initial pH=2.96), and the ratios (up to 86.5%) of lignite were obviously higher than those (up to 58.5%) of peat, but the organic transfer ratios of lignite were lower than those of peat. The activation energy values for interaction between peat, lignite and Ge-bearing solution are 30.96 and 15.67 kJmol.1, respectively. The strong acid (initial pH=2.96) and the strong alkaline (initial pH=12.08) environment contribute to the transfer of Ge in the solution. At 4

The Cambrian Gezhongwu Formation in Southwest China is the lowest Cambrian phosphorite unit. The Formation belongs to the Meishucun stage with small shelly fossils. Rare-earth element (REE) data from the Gezhongwu phosphorites of Zhijin documented the depositional conditions. The total REE concentrations are high in the Gezhongwu phosphorites, which are especially rich in yttrium. The PAAS-normalized REE patterns of the Gezhongwu phosphorites are characterized by negative Ce anomalies and slight enrichment of MREE, as being ha!-shaped. The hat-shaped patterns suggest that the REE originated from depositional environments rather than from subsequent diagenesis. The negative Ce anomalies indicate that the depositional environments are oxic. The positive Eu anomaly, the high total REE and the hat-shaped REE pattern revealed contributions from the normal marine environment mixed with hydrothermal water to the REE budget of the Gezhongwu phosphorites. [ABSTRACT FROM AUTHOR]

On the basis of an experimental study and thermodynamic calculation, the mechanisms of paragenesis and separation of silver, lead and zinc in the hydrothermal system have been studied. At acidic to nearly neutral pH, their chloride complexes are stable, and among them the chloride complexes of zinc are most stable. And the sulfide complexes are the dominant species at nearly neutral to alkaline pH, while the sulfide complexes of silver are most stable. With decreasing temperature, [Cl-], fO2 and increasing pH, the solubilities of silver, lead and zinc will decrease, leading to their deposition and separation. For sulfide complexes, the concentrations of reduced sulfur and pH are two important factors affecting their stabilities. Complexes of different forms and stabilities respond to the variation of conditions to different extents, which gave rise to the paragenesis and separation of silver, lead and zinc in the whole ore-forming process of dissolution, transport and deposition. [ABSTRACT FROM AUTHOR]

There are abundant hydrothermal sedimentary structures and plant fragment fossils in the siliceous rocks from the Lincang Ge deposit. The major element compositions of these siliceous rocks are characterized by high content SiO2, low TiO2 and Al2O3 concentrations, and low Al/(Al+Fe+Mn) ratios (0.010 on average). The siliceous rocks are distinctly enriched in Ge, Sb, As, W, and secondly enriched in Cs, U, Mo and Tl. Their total REE content are generally less than 1μg/g, LREE relatively concentrated, and the values of Eu anomaly and Ce anomaly vary from 0.452 to 5.141 and 0.997 to 1.174, respectively. Their NAS-normalized REE patterns are plain or left-inclined. The Oxygen isotope compositions of these siliceous rocks are similar to those of the hydrothermal siliceous sinter. The above characteristics, as well as the geological setting of the deposit, indicate these siliceous rocks formed in continental hydrothermal environment. As the interlayer or cliff of the Ge-rich coal seams, siliceous rocks tightly contacted with ore-body, and the contents of Ge in siliceous rocks vary from 5.6 to 360 μg/g (78 μg/g on average). The Ge content increased in coal which close to the siliceous rocks. With the increase of Ge content, the typical trace element ratios (i.e., Ge/Ga, Nb/Ta and U/Th) and REE patterns of Ge-rich coal are more close to those of the siliceous rocks. The Ge concentrated in coal seams of the Lincang Ge deposit might be transported by the hydrothermal water, which demonstrated by the siliceous rocks, during the coal-forming processes. [ABSTRACT FROM AUTHOR]

REE and other trace elements in ores, wall rocks, alkaline volcanic rocks and diabase dikes have been determined in the Yinachang Fe-Cu-REE deposit. Comparative studies of REE and trace element geochemical characteristics of these geological bodies indicate that the ores and alkaline volcanic rocks contain abundant REE and Y (65.9 - 4633) x 10-6, with higher abundances of As, Mo, Nb, Co and U than those of the crust. Their chondrite-normalized patterns show a strong enrichment of LREE and a positive Eu anomaly, in contrast to those of the dolomites which are characterized by slight LREE enrichment and moderate negative Eu anomaly. The REE patterns of ores are similar to those of hydrothermal sediment cores in the East Pacific Rise, whereas the REE patterns of dolomites are similar to those of PAAS (Post-Archean Average Shale). In combination with the geological setting of the deposit, the primary ore-forming fluids might have higher REE and volatile elements, and might have been derived from mantle degassing, or the alkaline volcanic magmas. The Yinachang Fe-Cu-REE ore deposit is considered to be of volcanic exhalation-hydrothermal sedimentary origin. [ABSTRACT FROM AUTHOR]

The Yutangba Se deposit is a rare high-Se deposit in the world and it is well known for its high contents of Se, which reach 8590 x 10-6. The ore-hosted rocks are dominated by cherts that have been well developed. Enrichment of selenium in Se-rich ores is obviously controlled by stratigraphic position and lithological character. The closer the rocks are to the Maok-ou Formation cherts, the more they contain selenium, but in case the stratigraphic horizons are close to one another, the enrichment of selenium would be controlled by lithological character. In the Se ores and abandoned stone coal pile at the Yutangha Se deposit there have been found large amounts of independent Se minerals, for instance, achavalite and a variety of forms of native selenium. Native selenium minerals present in the abandoned slone coal pile are the outcome of a combination of natural factors and anthropologic activities. For example, lime making will create a dosed environment favoring the growth of native selenium, and the reduction of selenium will lead to its secondary enrichment. Starting with the study of ore-forming fluids. Systematic studies have been conducted on fluid inclusions separated from the main ore veins in the mining district for their homogenization temperatures, salinities and density, and the results show that fluid inclusions contained in ores from the Yutangba Se deposit are large in number and diverse in form, dominated by primary ones. The homogenization temperatures of two types of fluid inclusions are within the range of 173.2 - 247.5°C, individually up to 300°C or even higher; the salinities of fluids in fluid inclusions in quartz and calcite are 5.9% - 10.1% and 3.9% - 4.5 %, respectively; their densities vary from 0.79 - 0.93 g/cm. Extensive discovery of Se minerals due to secondary enrichment of selenium in the slone coal provides important clues to the improvements on the metallurgical and recovery technologies for selenium in the... [ABSTRACT FROM AUTHOR]

A set of unique sodium lamprophyres is developed in the Cenozoic intraconti-nental extensional zone of northeastern Hunan. These lamprophyres are significantly different in major and trace elements and Sr, Nd isotopes from ordinary potassic lamprophyres. The rocks are characterized as being enriched in Na2O and high in TiO2 and weakly enriched in Nb, Ta, Nd and LREE with no negative Eu anomaly. The trace elements and Sr, Nd isotopic compositions are typical of the mantle source region of oceanic island basalts (OIB). The average initial 87Sr/86Sr ratio is 0.705332, and the average initial 143Nd/144Nd ratio is 0.512650, with ɛNd(t) being +3.5–+3.9, marking a mantle source region of unique sodium lamprophyres. The lamprophyres were formed by metasomatism of the primitive mantle at the bottom of lithosphere by vola-tile-containing fluids/melts from the asthenosphere. The measured Rb-Sr isochron age of sodium lamprophyre is 136.61 Ma, representing a period in which the tectonic setting changed from compressive to extensional. Sodium lamprophyres were formed in a mantle plume tectonic set-ting characterized by mantle upwelling from the asthenosphere within the continent. As-theno-spheric mantle upwelling is the principal geodynamic factor leading to the formation of sodium lamprophyres and constraining the Yanshanian intracontinental extensional activity in northeast-ern Hunan, China. [ABSTRACT FROM AUTHOR]

Reports on scheelite Sm-Nd and quartz Ar-Ar dating for the Woxi Au-Sb-W deposit in western Hunan. High level of Sm and Nd concentrations of scheelite; Finding that the disseminated scheelites demonstrate a good linear array, which corresponds to an isochron age of 402 ± 6 Ma; Indication that the Ar-Ar age spectra for 2 quartz samples show the saddle shape; Overlap in the minimum apparent age, plateau age and isochron age of each quartz sample; Suggestion that the minimum apparent ages of 420 ± 20 and 414 ± 19 Ma coincide with the scheelite Sm-Nd age; Assertion that the Au-Sb-W mineralization at Woxi district took place in the Late Caledonian period, which agrees with the tectonic evolution of the Xuefengshan district and with geochronological data available for Au, Sb and W deposits in this area; Inference from the low initial Nd isotope ratio of scheelites that the fluid responsible for Au-Sb-W mineralization is of deep crustal origin; Suggestion that it originated from the Archacan continental basement rather than the Proterozoic strata.

The geochemical composition of sandstones in the sedimentary basin is controlled mainly by the tectonic setting of the provenance, and it is therefore possible to reveal the tectonic setting of the provenance and the nature of source rocks in terms of the geochemical composition of sandstones. The major elements, rare-earth elements and trace elements of the Mesozioc-Cenozoic sandstones in the Lanping Basin are studied in this paper, revealing that the tectonic settings of the provenance for Mesozoic-Cenozoic sedimentary rocks in the Lanping Basin belong to a passive continental margin and a continental, island are. Combined with the data on sedimentary facies and palaeogeography, it is referred that the eastern part of the basin is located mainly at the tectonic setting of the passive continental margin before Mesozoic, whereas the western part may be represented by a continental island arc. This is compatible with the regional geology data. The protoliths of sedimentary rocks should be derived from the upper continental crust, and are composed mainly of felsic rocks, mixed with some andesitic rocks and old sediment components. Therefore, the Lanping Mesozoio-Cenozaic Basin is a typical continental-type basin. This provides strong geochemical evidence for the evolution of the paleo-Tethys and the basin-range transition. [ABSTRACT FROM AUTHOR]

Causes of Keshan–Beck disease (KBD) are still being probed and monitored in China. Relationships between trace elements from eco-environmental systems and KBD are poorly understood although relationships between environmental Se and human health have received extensive attention. In order to investigate relationships between eco-environmental geochemistry and KBD, we selected the Chousang KBD area in Yao County, Shaanxi Province, China, as an example of a prevailing KBD area applying I–Se-rich salts instead of utilizing Se-rich fertilisers on food crops to prevent local residents from developing KBD before 1995. Environmentally geochemical samples (rocks, soils, plants and children’s hair) were collected from the Chousang KBD area. Soils in the study area contain 0.11±0.02 µg Se g-1, 0.75±0.11 µg Mo g-1, and 34.5±1.5 µg B g-1 on average, indicating that the study area is a deficient-Se–Mo–B area. Se (0.07±0.007 µg g-1), Mo (0.35±0.09 µg g-1) and B (3±0 µg g-1) contents are low in wheat and corn used as a daily main food staple of local inhabitants. It is indicated that the study area is deficient in environmental Se–Mo–B for the local residents. Se contents of children’s hair from the Yangyuan Elementary School in the study area range from 0.09 to 0.26 µg Se g-1 with an average of 0.165±0.05 µg Se g-1 (n=10) in this KBD endemic area. Due to the low levels of Se, Mo and B available in soils and rocks, crops including wheat and corn are deficient in these elements, accordingly, the deficiency of Se, Mo and B in this area may be linked to the daily consumption of wheat and corn deficient in Se, Mo and B. Therefore, local inhabitants should be encouraged to fertilise mixtures of Se, Mo and B on crop plants in order to avoid development of KBD and guarantee a good harvest of crops. [ABSTRACT FROM AUTHOR]

Comprehensive studies, based on isotope geochemistry of C, H, O, S and Sr, chronology, common element and trace element geochemistry of fluid inclusions for the epithermal Au, As, Sb and Hg deposits in the Youjiang Basin and its peripheral areas, suggested that the ore fluid was the basin fluid with abundant metallic elements and the large-scale fluid flow of the same source in the late Yenshan stage was responsible for huge epithermal mineralization and silicification. The ore fluid flowed from the basin to the platform between the basin and the platform and migrated from the inter-platform basin to the isolated platform in the Youjiang Basin. The synsedimentary faults and paleokast surface acted respectively as main conduits for vertical and lateral fluid flow. [ABSTRACT FROM AUTHOR]

Focuses on the emplacement ages of lamproites in the Guinzhou Province in China. Influence of the whole-rock Sm-Nd and Rb-Sr isochron methods in constraining the lamproites; Occurrence of intrusive activities of lamproites in the region; Emplacement of the upwelling of hot materials derived from the deep mantle from the Late Cambrian to the Early Ordovician.