Jiaodong Area Research Articles

Characteristics, origin and role of the carbonate minerals in gold mineralization of Dayingezhuang gold deposit, Jiaodong area

Characteristics, origin and role of the carbonate minerals in gold mineralization of Dayingezhuang gold deposit, Jiaodong area

Petrogenesis of the Weideshan Pluton in Jiaodong and Its Implications for Gold Polymetallic Mineralization: Constraints from Zircon U-Pb-Hf Isotopes, Petrogeochemistry, and Whole-Rock Sr-Nd Isotopes

The Early Cretaceous Weideshan granites are associated with large-scale Au and polymetallic Cu-Mo-Pb-Zn mineralization. To investigate the petrogenesis of the Weideshan granite and constrain its tectonic setting during the Early Cretaceous, we conducted a zircon U-Pb-Hf isotope and whole-rock geochemical and Sr-Nd isotopic study of the granite. In situ zircon U-Pb dating of three granite samples yielded Early Cretaceous ages of 112.83 ± 0.80, 112.64 ± 0.91, and 111.82 ± 0.78 Ma. The samples had high-K calc-alkaline compositions and were enriched in the light rare earth and large-ion lithophile elements (e.g., K, Rb, Ba, Th, and U) and depleted in high-field-strength elements (e.g., Nb, Ti, and P). The samples had small negative Eu anomalies and initial 87Sr/86Sr and εNd(t) values of 0.70853–0.71029 and –18 to –14, respectively. The zircon εHf(t) values varied between −16 and −12, with corresponding two-stage model ages (tDM2) of 2180–2000 Ma. These characteristics indicated that the Weideshan pluton was formed in a back-arc extensional environment caused by subduction of the Paleo-Pacific Plate toward the Asian continent during the early Cretaceous. The magma was generated by crust–mantle interaction during lithospheric thinning. The diagenetic age of the Weideshan granites was the same as the formation age of gold and polymetallic ores in the Jiaodong area. The extensive fluid circulation induced by the magma emplacement may be the main source of ore-forming materials for the gold and polymetallic Cu-Mo-Pb-Zn deposits.

Tectonic transition during the Jurassic-Cretaceous in the Jiaodong Peninsula, North China: insights from asynchronous adakitic and A-type granitic plutons

ABSTRACT Jurassic-Cretaceous magmatic rocks are widely distributed in the Jiaodong area, North China. These magmatic rocks are closely associated with gold deposits, but their petrogenesis and geodynamic background are still controversial. The Late Jurassic-Early Cretaceous granitic rocks exposed in the Guocheng area, Jiaodong Peninsula are the focus of this paper. Zircon U-Pb dating, Hf-O isotope and whole rock geochemical analysis are used to determine the petrogenesis of these rocks. Combined with previous data, the geodynamic processes of granite formation in different time intervals are investigated which provide new petrological evidence for understanding the magmatic-mineralization and tectonic background of the Jiaodong area. Samples were collected from the Queshan and Shazibu plutons. The Queshan pluton is a mylonite granite, one sample of which yields a 206U-238Pb zircon age of 156 Ma, while the Shazibu pluton is a quartz monzonite, one sample of which records a 206U-238Pb zircon age of 117 Ma. The two plutons have variable zircon Hf-O isotopic compositions: zircon εHf(t) values of the Queshan pluton are −29.2 to −22.8, and δ18O values are 7.30–7.84 ‰, while the Shazibu pluton has relatively high zircon εHf(t) values (−21.6 to −21.0) and δ18O values of 7.48–8.43 ‰. Whole-rock geochemical data shows that the Queshan pluton has high Sr/Y (60.7–169) and (La/Yb)N (34.6–65.9) values and low Y (3.11–10.3 ppm) and Yb (0.29–0.85 ppm) contents, akin to adakites, whereas granites of the Shazibu pluton are A-type with high Zr+Nb+Ce+Y contents (354–420 ppm) and zircon saturation temperatures (752–795°C). Based on the geochemical and isotopic data, the Late Jurassic Queshan pluton is the product of partial melting of thickened lower crust of the North China Block, while the Early Cretaceous Shazibu pluton formed via fractional crystallization of mafic rocks derived from partial melting of the lower crust of the North China Block. Although both plutons were derived from the lower crust of the North China Block, the nature of the lower crust was modified by involvement of more depleted mantle-derived materials during the Early Cretaceous. From the Late Jurassic to the Early Cretaceous, the rock types (from the adakite to A-type granite) and the nature of the magma source suggest a shift in geodynamic processes. Combined with previous research, the Late Jurassic Queshan pluton is proposed to have formed under low-angle subduction of the ancient Pacific Plate, while the Early Cretaceous Shazibu pluton formed subsequently during Pacific Plate rollback and extension. The Early Cretaceous transformation of tectonomagmatic environments provided favourable conditions for the formation of large-scale gold deposits in the Jiaodong region.

Research on Parameter Optimization of the Optimal Schedule Model of Water Resources for the Jiaodong Water Transfer Project Based on the ICCP Model

Establishing an optimal operation model of water resources is a crucial mean to promote the social and economic development in the Jiaodong area, where water resources are seriously deficient. Constraints of the optimal operation model mainly include water balance constraint, discharge capacity constraint, and constraint on the full utilization of operating water. For water transfer projects that have been in operation for decades, the parameters of these constraints, such as Discharge Capacity (DC), Water Conveyance Efficiency (WCE), Evapotranspiration (E), and Water Supply Volume (WSV), have changed from their original design values, which in turn affect the results of the operation model. In order to address the uncertainties caused by corresponding parameters, according to the characteristics of each parameter, an Interval-Chance Constrained Programming (ICCP) model for the Jiaodong Water Transfer Project was proposed. Interval Programming (IP) and Chance-Constrained Programming (CCP) were used to optimize the parameters of constraints involving WCE, DC, E, and WSV. Then, the Sobol method was used to analyze the sensitivity of each parameter to the operating objective function. The results reveal that (1) total water shortage ratio decreased by [14.82%, 17.26%], [14.81%, 17.25%], and [14.82%, 17.26%], respectively, under the incoming water condition of 50%, 75%, and 95%, indicating that ICCP model can adequately consider complex uncertainties and effectively alleviate water shortage; (2) WCE and DC are important parameters for optimal operation model of water resources, and therefore, channels should be regularly maintained to ensure that WCE and DC would not reduce; (3) Decision variables in this study are in the form of intervals, which are more reasonable because they provide more decision-making options to managers.

Zircon U-Pb chronology and geochemistry of porphyritic granites: A case study of the Dalancun granites in Zhaoyuan, Shandong Province

The granite in Dalancun, Zhaoyuan, Shandong Province is mainly porphyry granite. In this paper, detailed field geology, petrology, isotopic chronology and whole-rock principal and microgeochemistry have been studied. LA-ICP-MS zircon U-Pb chronology shows that it was formed in the Early Cretaceous (129.7 ± 0.8 Ma), later than Linglong granite (160-150 Ma) and earlier than Laoshan granite (120-114 Ma). It is consistent with the main ore-forming age of Jiaodong large gold deposit and the diagenetic age of Guojialing granite (130-126 Ma). K2O+Na2O=7.41%~9.37%, K2O/Na2O=0.78~1.24; A/CNK=0.89~1.06, MgO=0.63%~1.01%, with high K, Al characteristics, belongs to the quasi-aluminum-peralumin high potassium calc-alkaline series. The strong differentiation of rare earth elements (La/Yb) N=68.24~93.96, weak positive Eu anomaly (δEu=1.26~1.769), enrichment of large ion lithophile elements Ba, Sr, high field strength elements Nb, Ta, Ti deficit, indicating the geochemical characteristics of continental lithosphere. In addition, high Sr (1817×10-6~2017×10-6), low Y (7.55×10-6~9.36×10-6), Sr/Y ratio between 199.89~262.29, Nb/Ta ratio between 14.67~16.73, consistent with continental crust ratio, It shows the characteristics of type I granite and Adakite. Combined with other geochemical indexes and regional geological studies, this paper suggests that the Dellancun porphyritic granite belongs to crust-mantle granite, which may have been formed in the arc environment of continental margin during the transition from compressive to extensional tectonic system in Jiaodong area, and is closely related to the subduction of the paleo-Pacific plate. This study not only helps to understand the Mesozoic tectonic evolution in eastern China, but also provides a basis for revealing the formation mechanism of Jiaodong gold deposit.

Crustal thickness of the Jiaodong Peninsula in the Mesozoic: Implications for the destruction of the North China Craton

The North China Craton underwent extensive and widespread crustal reworking (or decratonization) during the Mesozoic. However, how the decratonization operated is not well understood. Zircon compositions are widely used by the scientific community to reconstruct crustal thicknesses. In this study, we sampled 13 magmatic rocks in the Jiaodong Peninsula and used zircon Eu/Eu* to constrain the crustal thickness of the Jiaodong area and reveal decratonization processes in the Mesozoic time. The reconstructed crustal thickness using zircon Eu/Eu* is approximately 70 km in the Jurassic, and this value is 89 km at around 130 Ma, after which the crustal thickness drops to 30–40 km at ca. 110 Ma. These results are generally compatible with or slightly higher than the calculation results using a whole-rock La/Yb proxy for the Jurassic and ∼130 Ma rocks. Crustal thickness estimated using a whole-rock La/Yb proxy for the ∼110 Ma rocks is thicker than 70 km, which is not consistent with the geological facts and the result given by zircon proxy. The whole-rock proxy failed in estimating crustal thickness because of amphibole fractionation for the ∼110 Ma rocks. The crustal thickening from Jurassic to ∼130 Ma was probably related to the westward subduction of the Paleo-Pacific slab. The thinning of the crust from 130 to 110 Ma is not a rapid process but occurs more slowly than expected, which might be explained by the chemical erosion process rather than a mechanical delamination model. The chemical erosion was most likely induced by a rollback of the subducting slab and an upwelling of the asthenosphere.

Petrogenesis of ore-hosting magmatic rocks from the Jiudian gold deposit in Jiaodong area, and its geological implications

胶东地区是我国最重要、规模最大的金矿集区,其中晚侏罗世玲珑花岗岩分布较为广泛,是最主要的金赋矿围岩。旧店金矿床位于胶北隆起与胶莱盆地的交界处,是招平断裂带的重要组成部分,片麻状二长花岗岩为其主要的赋矿岩体,对其岩石成因进行研究,可以为探究金成矿作用提供线索和约束。本文对旧店金矿床周围两处的片麻状二长花岗岩开展LA-ICP-MS锆石U-Pb年代学以及Lu-Hf同位素研究。分析结果显示,锆石²⁰⁶Pb/²³⁸U年龄为160.1&#177;1.1Ma、160.4&#177;0.7Ma、161&#177;0.4Ma和162.2&#177;0.9Ma,表明旧店金矿床区域内在晚侏罗世存在较强的岩浆作用。<i>ε</i>_Hf(<i>t</i>)值为-31.9~-20.8,二阶段Hf模式年龄(<i>t</i>²_DM)为2996~2516Ma,表明其岩浆来源于下地壳物质部分熔融,同时二阶段Hf模式年龄(<i>t</i>²_DM)与地幔物质加入和新生地壳产生的岩浆热事件相对应,因此旧店金矿床的围岩可能由古老镁铁质下地壳物质的部分熔融产生。研究认为二长花岗岩的形成过程可能促使了前寒武纪变质基底中成矿物质活化,同时岩体发育广泛的断裂为矿床形成提供了良好的围岩条件。

Possible source of Au in the Jiaodong area from lower crustal sulfide cumulates: Evidence from oxygen states and chalcophile elements contents of Mesozoic magmatic suites

The genesis of giant Jiaodong gold province remains perplexing although many ore-forming models have been proposed in the past decades. The key issues are what caused the burst of gold around 120 Ma and possible sources of gold. Here we report gold and platinum group elements (PGE) data and magmatic oxidation states of the pre-mineralization Mesozoic plutonic rocks and some mafic dykes to discuss their potential effects on gold mineralization. Gold concentrations of the Late Jurassic Linglong granite are 0.015–0.278 ppb. The Early Cretaceous plutonic rocks (129–127 Ma) have the same levels of Au concentrations (Au = 0.031–0.047 ppb). Both of the Jurassic and Cretaceous magmatic rocks are depleted in Au compared to normal granitic rocks worldwide (∼1 ppb). Palladium and platinum concentrations in the Linglong granite are 0.160–0.385 ppb and 0.046–0.116 ppb, respectively. Meanwhile, Pd and Pt contents of Cretaceous magmatic rocks are 0.069–0.363 ppb and 0.063–0.465 ppb, respectively.Oxygen fugacities of the Late Jurassic Linglong granite calculated by biotite oxybarometer are FMQ + 0.5 to FMQ + 1.2 (where FMQ refers to fayalite-magnetite-quartz buffer). Oxidation states of the Early Cretaceous magmatic rocks estimated via amphibole oxybarometer are from FMQ + 0.3 to FMQ + 1.1 for Guojialing granodiorite. Zircon trace element data yield overall higher fO2 values than those estimated with biotite and amphibole compositions. Oxygen fugacities are from FMQ – 0.6 to FMQ + 1.9 (sample CJ-3) and FMQ – 0.7 to FMQ + 1.1 (sample LL-1) for the two Linglong granite samples. Zircons from the Early Cretaceous Guojialing pluton yield oxidation states between FMQ – 0.8 and FMQ + 1.9 (DCW-1), which are about one log unit higher than those of the Beijie pluton (BJ-1: FMQ – 1.0 to FMQ + 0.7). However, oxidation states from nearly syn-mineralization mafic dyke reach FMQ + 2.0 to + 3.0 when estimated via zircon oxybarometer. Oxidation states given by whole rock Fe3+/Fe2+ ratios also support the results calculated by mineral compositions.There is no fractionation crystallization of redox-sensitive minerals, like magnetite or garnet, as indicated by geochemical data, which implies that the oxidation states of magmas may reflect their source regions. However, the depleted nature of Au and PGE must imply that these elements are missing. We propose that sulfide saturation at the deep crust can be invoked to explain the extremely low gold and PGE contents of these magmatic rocks. The sulfide cumulates act as sinks for sulfide-loving elements (e.g., Au), which are pre-enriched source for later large-scale gold mineralization in Jiaodong area. The underplated water-rich mafic magma from enriched mantle source ponded at the lower crust, continuously crystallized anhydrous minerals (e.g., olivine and clinopyroxene) and reached volatile saturation at the very moment. This volatile, probably carrying gold, resorbed the sulfide cumulate and escaped to shallow levels to form the giant Jiaodong gold deposits.

Analysis of cross neutralizing activity of antibodies from sera of severe fever with thrombocytopenia syndrome patients to deal with different genotype strains.

Severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) is a tick-borne virus that causes severe communicable fever with thrombocytopenia syndrome (SFTS) with an average case fatality rate of 10%. In the study, we aimed to identify the cross-neutralizing antibody (nAb) against different genotype strains from sera of SFTSV infected patients. Firstly the genotype of SFTSV was identified by constructing a phylogenetic tree based on the M segments epidemic in the Jiaodong area of Shandong province, then different sera of subjects cross reactive with recombinant Gn (rGn-Fc) or recombinant Gc (rGc-Fc) of 0921 strain were examined. The levels of polyclonal nAbs from sera of 25 convalescents were measured by a pseudovirus-based neutralizing experiment. We found local endemic strains were mainly C2 and C3 isolates of SFTSV. 14 of 15 sera from donors reacted with 0921 rGn-Fc, and 9 of 15 sera from donors reacted with 0921 rGc-Fc. Cross nAbs were produced by 10 of 25 sera from donors during the period of 2019-2021. Among these, five nAbs (A2, A4, A5, L9, and L10) neutralized the pseudoviruses of HB29, Gangwon, HN13, HN20, SPL030A, and SD4 strains. Our data suggested that epidemic strains showed relatively stable heredity. Some blood sources from patients produced cross nAbs that could neutralize all of the strains examined. These findings highlight the important role played by humoral immunity in combatting SFTSV.

Safety and Protection Measures of Underground Non-Coal Mines with Mining Depth over 800 m: A Case Study in Shandong, China

With the increase in mining depth, the risk of ground pressure disasters in yellow gold mines is becoming more and more serious. This paper carries out a borehole test for the pressure behavior in a non-coal mining area with a mining depth of more than 800 m in the Jiaodong area. The test results show that under a depth of 1050 m, the increase in the vertical principal stress is the same as the increase in the minimum horizontal principal stress, which is about 3 MPa per 100 m. When the depth increases to 1350 m, the vertical principal stress increases by about 3% per 100 m, and the self-weight stress and the maximum horizontal principal stress maintain a steady growth rate of about 3 MPa per 100 m. In addition, based on the test results, the operation of the ground pressure monitoring system in each mine is investigated. The investigation results show that in some of the roadway and stope mines with depths of more than 800 m, varying degrees of rock mass instability have occurred, and a few mines have had sporadic slight rockbursts, accounting for about 5%. There was a stress concentration area in the lower part of the goaf formed in the early stage of mining, and slight rockburst phenomena such as rock mass ejection have occurred; meanwhile, the area stability for normal production and construction was good, and there was no obvious ground pressure. This paper compares the researched mines horizontally as well as to international high-level mines and puts forward some suggestions, including: carrying out ground pressure investigations and improving the level of intelligence, which would provide countermeasures to balance the safety risks of deep mining, reducing all kinds of safety production accidents and providing a solid basis for risk prevention and supervision.

Typomorphic Characteristics of Gold-Bearing Pyrite and Its Genetic Implications for the Fang’an Gold Deposit, the Bengbu Uplift, Eastern China

The Fang’an quartz-vein gold deposit is located in the eastern part of the Bengbu uplift. The eastern part of the Bengbu uplift is considered to be the western extension of the Zhaoyuan gold mineralization zone in the Jiaodong area of Shandong Province and has huge mineralization potential. The Fang’an deposit was a newly discovered, small-sized gold deposit, and the research in the area is relatively weak. In this study, samples of quartz-vein type ore were collected from the ZK141, ZK1549, and ZK1665 drill holes of the Fang’an gold deposit. Based on the study of the geological characteristics, the major and trace elements of pyrite in different stages were analyzed by electron probe microanalyzer (EPMA), to explore the compositional characteristics of pyrite, the occurrence of gold, and the source of ore-forming fluid. The studies indicate that the deposit experienced four ore-forming stages: the quartz stage, the quartz-pyrite stage, the polymetallic sulfide stage, and the carbonate stage. The pyrites are grouped into three stages, corresponding to the first three ore-forming stages. The EPMA analyses showed that the major elements of pyrite were high Fe and low S, indicating that the formation was hydrothermal. The high content of Ni indicated that the metallogenic materials were derived from between the mantle and the lower crust. The general Co/Ni ratio of &gt;1, with an average of 5.34, indicated that the ore-forming fluid was derived from the magmatic–hydrothermal fluid and wall rock. The Fang’an gold deposit mainly contains nano-gold.

Petrogenesis of the Early Cretaceous Zhouguan Granodiorite in Jiaodong Peninsula: Evidence from Mineralogy, Geochemistry, Geochronology, and Sr-Nd Isotopes

The Jiaodong Peninsula is the most important gold mineralization area in China, and the formation of gold deposits is closely related to granitoids. The isotopic ages of the Early Cretaceous granodiorites in the northwestern Jiaodong Peninsula are concentrated in the range of 111~123 Ma, and are coeval with the formation of the gold deposits in the area. However, the studies on the geotectonic settings of the granodiorites, especially their petrogenesis and relationship with gold deposits in the northwestern Jiaodong Peninsula, are scarce. Based on field and petrographic observations, geochemistry, EPMA analysis, zircon U-Pb chronology, and Sr-Nd isotopes of the Early Cretaceous Zhouguan granodiorite in the Jiaodong area, the formation age of Zhouguan granodiorite is determined as 115 Ma ± 0.77 Ma; the analysis of EPMA shows that biotite is mainly composed of Fe-biotite and Mg-biotite, with its MgO content ranging from 9.797% to 11.635%. The crystallization temperature of biotite is in the range of 500 °C~625 °C and the emplacement depth of the rock mass is 3.98~8.71 km. The amphibole in the mass mainly includes magnesiohornblende, pargasite, and magnesiosadanagaite; among them, the former two are of crustal origin, while magnesiosadanagaite is of mantle origin. The crystallization pressure and depth of the former two are in the range of 0.75~3.02 kbar and 2.81~11.4 km, respectively, while the crystallization pressure and depth for the latter is 4.64 kbar and 17.53 km, respectively. The (87Sr/86Sr) values range from 0.710424 to 0.711074 and the (143Nd/144Nd) values range from 0.511530 to 0.511808. The parental magma of the Zhouguan granodiorite is highly oxidized with high-water content that is favorable for Au enrichment. Combined with the Nb-Y and Yb-Ta diagrams, a model describing the formation of Zhouguan granodiorite is proposed.

Comparison of the exhumed history and magnitude between Jiaojia and Linglong goldfields in the Jiaodong gold Province, North China: Constraints from zircon and apatite (U-Th)/He data

The northwestern part of the Jiaodong Peninsular is the most important gold producer in China. Recently, the discovery of gold mineralization at a depth of 3,000 m below the surface in the region has generated a great interest for profound prospecting potential among the explorers. However, the maximum exploration depth and the potential of different goldfields have yet to be clarified. This work presents two low-temperature thermochronological datasets of zircon/apatite (U-Th)/He (ZHe/AHe) data for two ∼ 2,000-m-deep vertical boreholes from the Jiaojia and Linglong goldfields in an attempt to constrain the exhumation history and provide new orientation for exploration strategies in the NW Jiaodong Peninsula. The ZHe and AHe ages are in the range of 120–60 Ma and 70–10 Ma, respectively, and suggest that the NW Jiaodong area has been under a slow exhumation process since the gold mineralization. However, ZHe and AHe ages, together with QTQt thermal modeling, revealed three relatively rapid cooling/exhumation episodes at ∼ 110 – 95 Ma, 70 – 60 Ma and 45–40 Ma or 25–20 Ma. The former two episodes are almost synchronous and can be attributed to two plate-scale collision events, whereas the last episode is asynchronous and can be attributed to local structural movements among goldfields. Our data revealed that the tectonic exhumation and cooling over the period of ∼ 110 – 95 Ma had a significant impact on the ZHe age components and its spatial distribution in the NW Jiaodong area, and the last local structural movements that occurred during the Cenozoic had an intensive impact on the AHe ages and the levels of exhumation among goldfields. Finally, this study suggests economic exploration potential at a ∼ 3.5 – 4 km depth for the Jiaojia and Sanshandao goldfields and ∼ 2.5 – 3 km for the Linglong goldfield.

The mixing of Mesozoic crust-mantle magma is the key to the source of large amounts of gold deposits in the Jiaobei uplift, China

胶东地区金矿巨量金质来源一直是学界争论的焦点，很难找到有说服力的直接证据。在没有其它更有效的直接证明巨量金质来源的情况下，本文通过胶北隆起主要地质体新鲜岩石大量微量元素地球化学数据的变化规律，间接得出中生代壳幔岩浆的混合反应是巨量金质来源的关键，即郭家岭和伟德山两期壳幔岩浆的混合反应和演化可能是巨量金质来源的主要形成机制，同时更是热量供给源，而玲珑花岗岩可能是少量金质的提供者和主要赋矿地质体。胶东地区金矿主要成矿时间（130~105Ma）与郭家岭（130~125Ma）和伟德山（126~108Ma）两期花岗岩浆演化结晶时间完全吻合，说明其关系密切，岩浆混合反应和冷凝期，岩浆热液上升运移沉淀成矿。该区中生代地质体对早前寒武纪的地球化学环境有一定的继承性，中生代地壳混合了大量地幔物质，Au丰度偏高，平均为1.31×10^-9，为地球化学高背景场。;The huge material source of gold deposits in Jiaodong area has always been the focus of academic debate, and it is difficult to find convincing evidence. In the absence of other more effective direct proof of the source of huge gold, this paper indirectly draws the conclusion that the huge gold comes from the mixing reaction of Mesozoic crust-mantle magmas based on the variation law of large amounts of trace elements geochemical data from fresh rocks of main geological bodies in Jiaobei area. The mixing reaction and evolution of the Guojialing and Weideshan crust-mantle magmatism may be the main mechanism for the formation of huge gold source, and it is also the source of heat supply. Linglong granite may be a small amount of gold supplier and the main ore-hosting geological body. The main metallogenic time of gold deposits in Jiaodong area (130~105Ma) is the same as the evolution and crystallization time of granite magma of Guojialing (130~125Ma) and Weideshan (126~108Ma) granites, which means they are closely related. During magma mixing reaction and condensation period, magmatic hydrothermal fluids ascending, migration, and precipitation mineralization. The Mesozoic geological bodies inherited geochemical environment of Early Precambrian in this area. The Mesozoic crust was mixed with a large amount of mantle materials, and the Au abundance was high, averaging 1.31×10^-9, which was a geochemical high background.

Differential post-mineralization thermal evolution of the Jiaodong and Liaodong Areas, Eastern China: An indicator of regional tectonic activity

Post-mineralization thermal evolution is an integral part of the process of formation of ore deposits. However, as two important gold mineralization regions in eastern China, the thermal histories after ore formation of the Jiaodong area is debated while that of the Liaodong area are scarce. Given that the two areas are not only in similar tectonic settings but also have gold deposits that formed in association with the thinning and destruction of the North China Craton, a comparative study can be made. Here new zircon and apatite (U–Th)/He and apatite fission track ages are presented to reconstruct the post-mineralization geological evolution. Four periods of rapid uplift and denudation happening during the 110–100 Ma, 80–70 Ma, 42–38 Ma and 35–32 Ma are defined in Liaodong, and two such periods happening during the 100–95 Ma and 80–72 Ma in Jiaodong. The small timing difference of the rapid uplift (110–100 Ma versus 100–95 Ma) can be explained by the elevation difference of the respective samples. Hence, the evolution processes between the Jiaodong and Liaodong areas are very similar during the Cretaceous, but show marked differences during the Cenozoic. After ore-formation, the erosion amount in Liaodong and Jiaodong is estimated at ∼4.8 and ∼4.7 km, respectively. Moreover, the denudation intensity in Liaodong shows an increase from southeast to northwest. The westward convergence of the Pacific Plate and associated multi-stage activity of the Tanlu and Yalujiang faults are inferred to have induced the regional-scale rapid uplift of the Jiao-Liao areas.

Analysis of the trend and spatial clustering of gastric cancer deaths in Shandong Province from 1970 to 2013

Objective: To investigate the distribution characteristics and trends of mortality and spatial aggregation of gastric cancer in Shandong Province from 1970 to 2013. Methods: The mortality data of gastric cancer from 1970 to 1974, 1990 to 1992 and 2004 to 2005 were collected from the first, second and third retrospective sampling survey of causes of death in Shandong Province, respectively. The mortality data of gastric cancer from 2011 to 2013 were collected from the all-cause surveillance data of Shandong Province. The crude mortality rate and age-standardized mortality rate were used to describe the death level of gastric cancer. The age-standardized mortality rate of Shandong Province was calculated based on Segi's world standard population, and the age-standardized mortality rate of counties (cities and districts) was calculated based on the Chinese population in 1964.The factors influencing the difference of gastric cancer mortality in different periods were decomposed by using the method of differential decomposition of mortality, and the contributions of population and non-population factors in different periods were estimated.Using ArcGIS 10.2 software, the death level of gastric cancer in different counties (cities and districts) in Shandong province from 1970 to 1974 and 2011 to 2013 were visualized. DeoDa 1.12 software was used for global and local spatial autocorrelation analysis. Results: The crude death rate and age-standardized death rate of gastric cancer in Shandong province increased firstly and then decreased during 1970-2013, and the crude death rate of gastric cancer increased from 18.33/100 000 in 1970-1974 to 28.51/100 000 in 2011-2013. Segi's age-standardized mortality rate for gastric cancer decreased from 20.94 per 100 000 in 1970-1974 to 18.17 per 100 000 in 2011-2013.From 1990 to 1992, from 2004 to 2005 and from 2011 to 2013, the contribution value of non-population factors to the increase of crude gc mortality was 95.59%, 48.45% and -20.57%, respectively, showing a continuous downward trend. The Moran's I index of crude mortality of gastric cancer in Shandong province from 1970 to 1974 and from 2011 to 2013 were 0.77 and 0.57, respectively, and the Moran's I index of age-normalized mortality was 0.75 and 0.44, respectively. Local autocorrelation analysis showed that there were 31 and 19 high aged-mortality areas of gastric cancer in 1970-1974 and 2011-2013 respectively, and 7 overlapping counties (cities and districts), 6 of which were located in Jiaodong area. Conclusion: The crude mortality and age-standardized mortality of gastric cancer in Shandong province increased first and then decreased from 1970 to 2013, and the distribution of gastric cancer mortality had obvious spatial aggregation and changed with time.

Metallogenic characteristics and tectonic setting of the Jiaodong gold deposit, China

Jiaodong is the largest gold deposit concentration area in China. In recent years, great breakthroughs have been made in deep prospecting, and it has become the third largest concentration area of gold deposits in the world. A series of prospecting discoveries in the Jiaodong area provided the basic conditions for summarizing the regional metallogenic law, constructing the deposit model, carrying out research on the genesis of the deposit and innovating metallogenic theory. The Jiaodong gold deposits are mainly distributed in Northwest Jiaodong, Qi-Peng-Fu and Mu-Ru metallogenic regions, and mainly occur in Precambrian metamorphic rock series, Jurassic Linglong-type granite, Early Cretaceous Guojialing-type granite and Laiyang group. The orebodies are controlled by Sanshandao, Jiaojia, Zhaoping, Xilin-Douya, Jinniushan and other major ore-controlling fault zones. The main mineralization types include altered rock-type, quartz vein-type, stockwork type, sulfide quartz vein-type, interlayer detachment zone-type, altered conglomerate-type, basin margin fault breccia-type and pyrite carbonate vein-type and so on. The important progress of deep prospecting is summarized: two super giant deposits have been evaluated in the Sanshandao and Jiaojia areas; the amount of altered rock-type gold resources identified by deep prospecting has exceeded that of quartz vein-type gold deposits in the Linglong gold deposit field; the Hushan large scale gold deposit has been discovered in Qixia gold deposit field; and the Liaoshang large-size gold deposit is a new discovery of deep prospecting in Pengjiakuang gold deposit field. The ore-controlling faults of gold deposits have several changing steps with dip angle varying from steep to gentle along the dip angle. The gold ore bodies are mainly enriched in sections along the steep, gentle turning points and relatively gentle parts of the fault dip angle, forming a stepped distribution pattern. In the Early Cretaceous, the subduction and rollback of the Paleo-Pacific plate induced crust mantle interaction, resulting in large-scale magmatic and fluid activities. The crust tension and magma uplift form the dome extension structure of granite, which provides a channel for the migration of ore-forming fluid and also provides favorable space for the deposition of ore-forming fluid.

Micro Raman Spectral Characteristics and Implication of Pyrite in the Jiaojia Gold Deposit, Jiaodong Area, Shandong Province, China

Micro Raman Spectral Characteristics and Implication of Pyrite in the Jiaojia Gold Deposit, Jiaodong Area, Shandong Province, China

Deep Geological Characteristics and Ore Predition of Vein 175 in Linglong Gold Field in Jiaodong Area, Shandong Province

Located on the west coast of the Pacific Ocean, Jiaodong gold concentration area is one of the world's famous gold deposit areas. Its unique metallogenic environment and metallogenic background are favored by geologists of all countries, multi-level and multi-disciplinary scientific research work has been carried out in this area, and good results have been achieved. Linglong gold deposit, located 20 km northeast of Zhaoyuan, Shandong, is a quartz vein type gold deposit. Its veins are controlled by Linglong and Batouqing fault, and vein groups are developed in the area, there are 36, 48, 47, 53, 55, 108 and vein groups 175, among which vein group 175 is one of the main large vein group in Linglong Gold Mine. With the continuous exploitation and utilization of the shallow resources in Linglong Gold Mine, the amount of gold resources kept in Linglong Gold Mine has decreased sharply, and the enterprises are facing the situation of serious shortage of resources. In order to prolong the service life of mines, it is urgent to enlarge the geological reserves of gold deposits and to increase the prospecting and prospecting efforts in deep areas. In this paper are sunnarized the geological and metallogenic backgroud and geologcal characteristics of the ore vein groups 175 and ore-control factor, occurrence pattern of ore body and ore types are analyzed and metalogenic pattern described. Based on prospecting works in which ore is encountered gold ore reserve 192.44×104t (332+333) and gold metal reserve 8.5t are predicted by geologic block method bellow -800m level beteen line 11-101.

Geothermal direct contact membrane distillation system for purifying brackish water

Brackish water poses a health hazard worldwide, but especially to rural residents in China. In this study, a direct contact hollow fiber membrane distillation system was established based on a filter-pretreated hot spring resource in the Jiaodong area of China. The effects of the operating temperature, flow rate, and composition of brackish water on the properties of membrane distillation were investigated. A multistage system model was established using the Aspen plus platform and the economic cost of the system was analyzed. The results showed that the permeate flux could reach 12.599 kg/m2·h. The effect of the MgSO4 content of the brackish water on the flux decreased above 20 g/L. Electron microscopy and elemental analysis showed that carbonate crystallization occurred mainly in the scaling part. The simulation results showed that the inlet temperature of the feed side had major effects on the increase in the flux and gain output ratio. A parallel layout was more effective and the regenerator improved the gain output ratio (GOR), with a 30% maximum increase for the system. The unit water production cost decreased to $18.2/m3 as the subsystem number increased to 10. These findings may help to improve the performance and economic benefits of this special type of distillation system.