The Washan iron deposits in Ningwu district contain different magma-related genetic natures, including magmatic, magmatic–hydrothermal and hydrothermal types, and their ore-forming processes remain a subject of debate. To elucidate the ore-forming processes of iron ores from Washan, we present textural, major element analytical, and thermal data of magnetites from various ore bodies in Washan, probing the crystallization conditions and subsequent formation sequence of magnetites. SEM analysis with back-scattered electron (BSE) imaging reveals diverse magnetite textures, including mineral inclusions, exsolution lamellae, and recrystallization features, reflecting the transitional environment from magmatic to hydrothermal. Based on Ti, V, and Cr compositions of magnetite from different ore bodies, two distinct evolution trends of genetic processes are identified, including evolution paths from porphyry-type to IOA- and IOCG-type magnetite. High-resolution WDS mapping highlights the intensifying alterations during this process. Calculated magnetite crystallization temperatures among different types of magnetite range from 597 °C to 378 °C, suggesting a cooling trend from porphyry-type magnetite (~558 °C) to IOA-type magnetite (~515–439 °C) and IOCG-type magnetite (~378 °C). These results underscore the significant role of magma-derived hydrosaline liquids and vapors in the formation of iron ores from Washan, where variations in the salinity of ore-forming fluids lead to different evolutionary paths for subsequent generations of magnetite. The metallogenic model of the Washan iron deposit suggests that highly saline, iron-rich fluids connect the varying geneses of magnetite, transitioning from deeply formed porphyry-type magnetite to IOA- or IOCG-type magnetite generated in the subaerial zone.

The Tianshui area is located at the junction of the Qinling and Qilian Orogens, the evolution of which is crucial in understanding the Early Palaeozoic tectonic evolution of the Central China Orogenic System. We present here geochronological, geochemical, and Sr-Nd isotopic data for four representative Silurian magmatic rocks, termed the Dangchuan, Huamiao, Yanjiadian, and Hongtupu, along a cross section across the main rock units of the Tianhui area. The 432 Ma Dangchuan syenogranites are peraluminous with negative epsilon(Nd)(t) values, high initial Sr-87/Sr-86 ratios, and low Rb/Sr and high CaO/Na2O ratios. We interpret the syenogranites to be generated by partial melting of metagreywackes during a Silurian orogenic event. The 436 Ma Huamiao diorites are high-Mg diorites with high MgO contents and Mg# (63-65) and enriched Sr-Nd isotopic compositions. The 445 Ma Yanjiadian diorites are high-Mg adakitic rocks with high Sr and Mg# and low Y and Yb contents. They were both generated by the interaction between sediment/slab-derived fluids/melts and mantle peridotite in the subduction-related setting. The 445 Ma Hongtupu basalts include E-MORB and IAB with depleted Sr-Nd isotopic compositions. They were derived from enriched mantle and sediment-modified mantle, respectively, and formed in a back-arc basin setting. Synthesizing our new and published data, we propose a tectonic model involving generation of Baihua-Huluhe arc-back-arc system, subduction of the Huluhe back-arc oceanic basin, and collision between the North Qinling arc terrane and North China Block, which is closely associated with the closure of the Proto-Tethys Ocean.

关于江南造山带的新元古代构造演化背景素有地幔柱—裂谷模型、岛弧模型及板块 裂谷模型之争,其争论的焦点在于扬子与华夏板块碰撞的具体时间,以及聚合后裂解的动力学环境.笔者等选取江南造山带西段湘西怀化地区～788 Ma辉绿岩中的单斜辉石和黑云母为研究对象,采用电子探针和激光剥蚀—等离子体质谱仪对其化学成分进行了精确测定,以期进一步约束该地区的成岩构造背景.怀化辉绿岩中的单斜辉石可分为普通辉石和透辉石两种,根据单斜辉石的n(Ca)/n(Al)值(3.48～7.15)和高u(Ti)/w(Eu)值(＞1500)的特征,笔者等判断江南造山带西段的新元古代地幔可能遭受了硅酸盐熔体和俯冲流体的多重交代作用.单斜辉石温压计的估算结果表明,普通辉石的结晶温度为1080～1112℃,结晶压力0.3～0.6 GPa,对应的深度为9.1～20.8 km;而透辉石的结晶温度为1237～1274℃,结晶压力1.0～1.32 GPa,对应的深度为31.8～42.6 km.综合单斜辉石和黑云母的微量元素特征(单斜辉石的Al、Ti、Ca、Na等元素和黑云母的Mg、Fe等元素)、岩浆系列和构造环境判别图解,表明该区的亚碱性拉斑玄武质岩浆来自于上地幔顶部与地壳结合的部位,是软流圈地幔部分熔融产生的板内碱性玄武质岩岩浆上升到浅部发生结晶分异作用形成的.结合区域的构造演化特征,笔者等提出一种三阶段的改进板块—裂谷模型,用以描述江南造山带西部的新元古代构造背景.

The Neoproterozoic evolution of the Jiangnan Orogen is important for understanding the tectonic history of South China. As a volcanic-sedimentary sequence developed in the Nanhua rift, the Banxi Group preserves the records of important magmatic and tectonic events linked to the assembly and breakup of the Rodinia supercontinent. In this study, we report the results from whole-rock major-and trace-element concentrations, with zircon LA-（MC）-ICP-MS U-Pb ages, trace elements and Lu-Hf isotopic compositions of sandstones from the Banxi Group. The rocks are characterized by high SiO 2 （65.88%–82.76%, with an average of 75.50%） contents, moderate（Fe 2 O 3 T + MgO）（1.81%–7.78%, mean: 3.79%） and TiO 2 （0.39%–0.54%, mean: 0.48%）, low K 2 O/Na 2 O（0.03–0.40, mean: 0.10） ratios and low Al 2 O 3 /SiO 2 （0.11–0.24, mean: 0.15） ratios. The sandstones have high ΣREE contents（mean: 179.1 ppm）, with chondrite-normalized REE patterns similar to the upper crust and PAAS, showing enriched LREE（（La/Yb） N mean: 14.85）, sub-horizontal HREE curves and mild Eu（Eu/Eu*: 0.75–0.89, mean: 0.81） negative anomalies. Their geochemical characteristics resemble those of passive continental margin sandstones. Most of the zircons are magmatic in origin and yield a U-Pb age distribution with three peaks: a major age peak at 805 Ma and two subordinate age peaks at 1990 Ma and 2470 Ma, implying three major magmatic sources. The Neoproterozoic zircons have ε Hf （t） values ranging from-47.4 to 12.4（mostly-20 to 0）, suggesting a mixture of some juvenile arc-derived material and middle Paleoproterozoic heterogeneous crustal sources. The Hf model ages of middle Paleoproterozoic zircons（～1990 Ma） with negative ε Hf （t） values（-12.65 to-6.21, Ave. =-9.8） concentrated around the Meso-Paleoarchean(mean T DM C = 3.3–3.1 Ga). For late Neoarchean detrital zircons（～2470 Ma）, ε Hf （t） values are divided into two groups, one with negative values（-9.16 to-0.6） with model ages of 3.5–2.9 Ga, the other featuring positive values（1.0 to 3.9） with model ages of 2.9–2.7 Ga, recording a crustal growth event at ～2.5 Ga. Neoproterozoic zircons show volcanic arc affinities with partly intraplate magmatic features. We propose that the Banxi Group formed in a rift basin within a passive continental margin setting, which derived detritus from felsic to intermediate rocks from the Yangtze Block and a small amount of arc volcanic rocks. The middle Paleoproterozoic detrital zircon data suggest Columbia-aged basement lies beneath the western Jiangnan orogen.

The Tianshui-Sunjiaxia area is located in the connection zone of West Qinling Orogen and North Qilian Orogen, which could provide great insights into the amalgamation processes between the northern and southern blocks of China. Three subduction- and rift-related rocks (gneissic granite from North Qilian arc-interarc belt (NQAI) granite and metabasalt from North Qinling back-arc basin (NQBA) are distinguished across the connection zone. The gneissic granite was generated by melts from older crustal materials of Longshan Group with the addition of a relatively juvenile basaltic source from the lower crust during the collision process. The Liwanxincun metabasalt reflects the mixing of the partial melting of the shallow asthenospheric mantle and the metasomatized mantle in a back-arc extension setting. The LA-ICP-MS zircon U-Pb dating of gneissic granite (068, 069) yields crystallization ages of 457.0 ± 1.6 Ma and 445.9 ± 2.1 Ma. The study area is divided into six tectonic units in Early Paleozoic time involving NQAI (Yanjiadian-Xinjie) continental arc, interarc rift basin (Maojiamo-Xiwali), continental arc (Chenjiahe-Wangjiacha); NQBA back-arc rift basin (Huluhe-Hongtubao), island arc and ophiolitic melange belt (North Qinling-Shangdan). A tectonic model is proposed in which the NQAI continental arc (Yanjiadian-Xinjie) might represent the early period of subduction of North Qilian Ocean (NQO) and the interarc rift is the product of the extension triggered by southward subduction of NQO. The ongoing subduction of NQO then leads to the formation of Chenjiahe-Wangjiacha continental arc, as well as the Hongtubao back-arc spreading ridge in NQBA back-arc basin (Huluhe). The tectonic evolution of the connection zone is closely associated with the closure of the North Qilian Ocean and North Qinling-Shangdan Ocean in the context of the convergence process of micro-continental blocks, including North China block, Longshan group and North Qinling Terrane.

The Bawang deposit, located in the west of Wuxu ore field, southern section of the Nandan-Hechi metallogenic belt, is a medium-sized tin–zinc polymetallic deposit. Its genesis has been a matter of debate because of lacking constraints from isotope geology. In this study, LA-MC-ICP-MS U-Pb dating of cassiterite and C-O-S-Pb isotope analyses of monominerals were used to investigate the mineralization age and source of the ore-forming minerals in the Bawang deposit. LA-ICP-MS U–Pb dating of cassiterite yielded ages of 93.1 ± 4.8 Ma and 85.3 ± 6.3 Ma, indicating that the mineralization occurred in the early Late Cretaceous. The δ13CPDB and δ18OSMOW values of calcites at the ore stage range between −0.41‰ and 0.44‰ (average = −11‰) and between 13.8‰ and 15.40‰ (average = 14.59‰), respectively. This shows that ore fluid sources were a mixture of those derived from magma and stratum. Pyrite and sphalerite have uniform δ34S values (−4.45‰~−2.20‰), indicating that sulfur is also derived from the mixing of magmatic hydrothermal and stratum fluids. The Pb isotopic composition of sulfide (206Pb/204Pb = 18.4055~18.7625, 207Pb/204Pb = 15.6745~15.7209, 208Pb/204Pb = 38.6232~39.0370) is consistent with the granite of the same age, indicating that ore-forming metals are mainly derived from magmatic hydrothermal solution. The Bawang deposit is a hydrothermal vein-type deposit in the external contact zone of Late Cretaceous granite, controlled by tectonic fractures, and formed by the interaction of magmatic hydrothermal fluid and carbonate rock. There may be large skarn-type ore bodies in the deep part. The results of this study provide insights into the research and exploration of similar deposits in Nandan-Hechi metallogenic belt and in the Youjiang Basin.

The present study aimed to investigate the effects of long non‑coding (lncRNA) dihydrofolate reductase‑like 1 (DHFRL1‑4) on cerebral ischemia/reperfusion (I/R)‑induced injury. For this purpose, mice injected with lentivirus with small interfering RNA targeting DHFRL1‑4 or negative control siRNA were used to construct models of cerebral I/R injury. Following the establishment of the model, the infarct size, neurological deficit score, apoptosis and the expression levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), Wnt family member 3a (Wnt3a), glycogen synthase kinase‑3β (GSK‑3β) and phosphorylated GSK‑3β were assessed. The expression of DHFRL1‑4 was significantly upregulated in the I/R model. In the control and sham groups, the boundaries between the cortex and gray matter were clear, and no edema or necrosis were observed. The nerve cells were arranged orderly and evenly, and the cell membranes were intact with visible nucleus and nucleolus. In the model group however, the nerve fibers were slightly necrotic and swollen, and the number of nerve cells was reduced. In the mice injected with si‑DHFRL1‑4 lentivirus, the brain tissues exhibited less liquefaction and degeneration, as well as less edema. Compared with the control and sham groups, the model group had a significantly larger infarct area, a higher apoptotic rate, higher bFGF, VEGF, Wnt3a and GSK‑3β expression levels and a greater neurological deficit score. However, the mice injected with si‑DHFRL1‑4 lentivirus exhibited a significantly reduced infarct area, a lower apoptotic rate, lower Wnt3a and GSK‑3β expression levels, a lower neurological deficit score, and significantly upregulated bFGF and VEGF levels.

通过对新疆温宿县巴依里煤矿中煤、主岩和围岩中微量元素的分析,探讨新疆温宿巴依里煤矿中稀土等元素的来源及其作为煤矿伴生资源的利用前景.巴依里煤矿煤中的稀土元素配分模式可分为平坦型和重稀土富集型(H型)两类.前者REY主要来源于含煤盆地基底的片麻岩;后者部分来源于热液.含煤岩系的主岩中稀土元素分布模式可分为中稀土富集型(M型)和重稀土富集型(H型)两类,分别与REY部分来源于酸性陆地水和热液有关.在煤矿REY应用前景评价判别图,即关键元素百分比(REYdef,rel)-关键元素总量与过量元素总量比(Coutl)图解中,几乎所有的样品都落在有前景成矿区域.有一半的煤样具有较高的Ga含量,接近作为煤伴生资源的边界品位.这表明,巴依里煤矿中REY和Ga作为煤矿伴生资源具有很好的利用前景.

OBJECTIVE:Histone deacetylases (HDACs) have been revealed to be involved in cerebrovascular diseases, while the role of HDAC9 in intracranial aneurysm (IA) remains seldom studied. We aim to explore the role of the HDAC9/microRNA-92a (miR-92a)/Bcl-2-like protein 11 (BCL2L11) axis in IA progression.METHODS:Expression of HDAC9, miR-92a and BCL2L11 in IA tissues was assessed. IA rat models were established by ligation of left renal artery and common carotid artery, and the rats were respectively injected with relative plasmid vectors and/or oligonucleotides. The blood pressure was measured to estimate the IA degree, and the pathological changes were observed. The expression of matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF) was detected, and the levels of inflammatory factors were evaluated. Expression of apoptosis-related proteins, HDAC9, miR-92a and BCL2L11 was assessed.RESULTS:HDAC9 and BCL2L11 were upregulated while miR-92a was downregulated in IA clinical samples and rat models. HDAC9 inhibition or miR-92a elevation improved pathological changes and repressed apoptosis and expression of MMP-2, MMP-9, VEGF and inflammatory factors in vascular tissues from IA rats. Oppositely, HDAC9 overexpression or miR-92a reduction had contrary effects. miR-92a downregulation reversed the effect of silenced HDAC9 on IA rats.CONCLUSION:HDAC9 inhibition upregulates miR-92a to repress the progression of IA via silencing BCL2L11.

大裕金矿位于广西大瑶山成矿带的古袍成矿区带,构造单元属于桂中—桂东台陷大瑶山凸起东端古袍复式向斜南翼,矿区成矿地质条件优越,但由于对成矿规律认识不足,该区找矿工作推进缓慢.选取成矿带内典型的大裕金矿为例,在总结成矿地质特征的基础上,结合钻孔资料及镜下矿石特征,分析了该区金成矿的控矿因素和成矿规律,认为该区主要控矿构造为NEE向F1和F2断裂,赋矿围岩为寒武系小内冲组和黄洞口组浅变质含炭质细碎屑岩,矿化蚀变主要为硅化—黄铁矿化和绢云母化—黄铁矿化—硅化组合蚀变.研究提出该区今后找矿应结合物化探工作,重点找矿方向有:①关注与金成矿关系密切的硅化、黄铁矿化、绢云母(水云母)化及绿泥石化等围岩蚀变线索;②建议在NE-NEE向断裂及其所挟持部位和断裂交会部位开展找矿工作.

MAP kinase phosphatase 1 (MKP1) has been identified as an antiapoptotic protein via sustaining mitochondrial function. However, the role of MKP1 in neuroinflammation has not been fully understood. The aim of this study is to figure out the influence of MKP1 in lipopolysaccharide (LPS)-treated microglia BV-2 cells and investigate whether MKP1 reduces BV-2 cell death via modulating endoplasmic reticulum (ER) stress and mitochondrial dysfunction. The results of this study demonstrated that MKP1 was rapidly downregulated after exposure to LPS. However, the transfection of MKP1 adenovirus could reverse cell viability and attenuate LPS-mediated BV-2 cell apoptosis. Mechanistically, MKP1 overexpression alleviated ER stress and corrected LPS-induced calcium overloading. Besides, MKP1 adenovirus transfection also reversed mitochondrial bioenergetics, maintained mitochondrial membrane potential, and blocked mitochondria-initiated apoptosis signals. Furthermore, we found that MKP1 overexpression is associated with inactivation of mitogen-activated protein kinase-c-Jun N-terminal kinase (MAPK-JNK) pathway. Interestingly, the activation of MAPK-JNK pathway could abolish the protective effects of MKP1 on BV-2 cells survival and mitochondrial function in the presence of LPS. Altogether, our results identified MKP1 as a primary defender of neuroinflammation via modulating ER stress and mitochondrial function in a manner dependent on MAPK-JNK pathway. These findings may open a new window for the treatment of neuroinflammation in the clinical setting.

文章对张家川地区的片麻状花岗闪长岩及花岗片麻岩进行了地球化学分析,研究显示,片麻状花岗闪长岩具有的较高Al2O3含量,里特曼指数σ在1.41～1.78;SiO2与P2O5为负相关关系,具有高Sr低Yb的特点,显示Ⅰ型准铝质钙碱性花岗岩的特征.经分析,样品具有岛弧花岗岩地球化学特征.结合区域构造演化,判别其是在早古生代时期商丹洋壳向华北板块俯冲时形成.花岗片麻岩样品SiO2含量主要在71.88％～73.81％,富集K、Al2O3,里特曼指数σ在0.65～2.00,亏损高场强元素而富集大离子亲石元素,P2O5与SiO2呈正相关关系,显示S型高钾钙碱性、过铝质花岗岩的特征.结合前人所做研究,判别其是在陆-陆碰撞条件下形成.

天水关子镇蛇绿岩分布于西秦岭造山带北缘,一般认为是商南—丹凤缝合带西延部分,代表了华北板块与扬子板块的结合部位.本文通过关子镇蛇绿岩中变玄武岩的主量、微量和稀土元素及Sr、Nd同位素综合分析,对关子镇蛇绿岩的源区特征及构造背景进行分析和探讨.研究表明,蛇绿岩中变玄武岩隶属于低碱、富钠低钾的拉斑玄武岩系列;稀土元素分异不明显,微量元素亏损Ba、Th、P,高场强元素无亏损现象.εNd(t)值均为正值,与MORB相近.

宁芜盆地是长江中下游成矿带的7个矿集区之一,以中生代火山岩和玢岩铁矿的广泛发育为特征.凹山铁矿床位于盆地中部,是宁芜盆地玢岩型铁矿床的重要代表之一.本文首次利用成矿元素Fe的金属矿物对宁芜盆地凹山铁矿床的黄铁矿进行了Re-Os同位素测年,获得凹山铁矿床的黄铁矿Re-Os同位素等时线年龄为127.7±2.6Ma(n=5,MSWD=0.66),直接代表凹山铁矿床的成矿年龄.187Os/188Os初始比值为1.73±0.56,γos(t)值为527.18～535.93,介于地幔与地壳之间,结合已有研究成果,认为凹山铁矿床的成矿物质主要来源于富集地幔,少量来自地壳.

Volcanic rocks preserved in the Houay kham area, Loei Fold Belt are important components of the giant Paleo-Tethyan igneous belt. These magmatic rocks, previously mapped as Triassic-Jurassic in age, are composed of dacitic tuff, brecciated rhyolite tuff and a small number of dioritic dikes. In this study, LA-ICP-MS zircon U-Pb dating results show that brecciated rhyolite tuff, dacitic tuff, and dioritic dyke samples have ages of 419.8 +/- 1.6 Ma, 449.6 +/- 2.6 Ma and 417 +/- 4.9 Ma. These are the first documented Late Ordovician to Late Silurian volcanic rocks in the Loei Volcanic Belt or in Southeast Asia. Geochemical analyses of these rocks show that all are calc-alkali to high K, formed in a subduction-related, back-arc basin and are intermediate-acid igneous rocks. Dacitic and brecciated rhyolite tuff samples originated from partial melting of mafic crust with medium to strong crustal contamination and weak to medium fractional crystallization. Dioritic dyke samples originated from simultaneous partial melting of gabbroic and metasedimentary rocks with weak to no crustal contamination or fractional crystallization. In the early Ordovician the eastern branch of the Rheic ocean opened and the Indochina terrane drifted away from NE Gondwana and subsequently an Ordovician-Silurian Palaeo-Tethyan Ocean opened. [GRAPHICS] .

伏川蛇绿岩作为华南极为重要的前寒武纪蛇绿岩之一,本文对其中的橄辉岩和辉长岩样品进行了岩石学、地球化学及同位素特征研究.研究表明,伏川蛇绿岩中橄辉岩含有极高的MgO(39.92％～44.95％)和较低的Al2O3(0.48％～4.35％)、CaO(0.11％～0.63％)和TiO2(0.01％～0.06％),稀土元素总量(7.50×10-6～10.62×10-6)低于亏损地幔,为一套高度亏损的原始地幔熔融残留物,其部分熔融程度介于22％～26％之间.具"U"型的稀土元素配分模式,ISr值显著高于地幔,富集LILE,HFSE含量变化大,既继承了亏损地幔源区的特征,又经历不同程度熔体和流体的交代作用,指示其形成于具有一定规模的弧后小洋盆背景.变辉长岩具高MgO(8.78％～13.26％)、Al2O3(17.25％～18.75％)和CaO(11.98％～15.14％),贫TiO2(0.20％～0.28％)、P2O5(0.01％～0.02％)及富钠低钾的特征,其稀土元素配分模式较为平坦,具有与亏损地幔相当的Sr、Nd同位素组成,富集LILE,亏损HFSE,显示岛弧(IAT)特点,其不活动元素比值与N-MORB相当,兼具IAT和MORB的地球化学特征,判断其形成于弧后盆地的初始扩张阶段.结合前人已有研究,认为新元古时期,皖南地区存在沟-弧-盆体系,随着华夏板块向扬子板块之下俯冲,本区弧后盆地进一步引张形成小型洋盆.

Epidermal growth factor receptor (EGFR)-Akt signaling cascade activation plays a pivotal role in gliomas malignant phenotype, especially in Classical and Mesenchymal subtype gliomas. However, the molecules and mechanisms underlying regulate and maintain the activation of EGFR-AKT signaling remains unclear. Previously reports showed that DIRAS3 inhibits cell proliferation and induces autophagy in ovarian, breast, lung and prostate cancers, which is heterozygosity loss or down-regulated in aforementioned cancers and functionally as a tumor suppressor, whereas the role of DIRAS3 in glioma is still veiled. Here, in this study, we investigated the biological function and role of DIRAS3 in gliomas, and found that DIRAS3 is up-regulated in gliomas and is positively correlated with poor prognosis of glioma patients, meanwhile, over-expressed DIRAS3 promotes glioma cells proliferation and invasion. Further mechanistic study showed that the expression level of DIRAS3 in Classical and Mesenchymal subtype GBMs is higher, and over-expression of DIRAS3 promotes EGFR-AKT signaling activation at the downstream of EGFR and increases AKT phosphorylation, meanwhile suppression of AKT by MK-2206 reverses the tumor promoting function of DIRAS3. Taken together, these findings reveal a novel oncogenic role of DIRAS3 in the development and progression of glioma, which suggest that DIRAS3 could serve as a potential diagnostic marker and a promising therapeutic target of gliomas.

The Ningwu Basin, located in the Middle-Lower Yangtze River metallogenic zone, eastern China, is characterized by the widely distributed iron oxide-apatite deposits. The Taocun magnetite deposit is one of these deposits, which is located in the middle part of the basin. On the basis of field observation, fluid inclusion and hydrogen, oxygen, and sulfur isotope analyses are carried out on purpose of delineating the origin of the ore-forming fluids, and the mineralization of the Taocun magnetite deposit. Microthermometric analyses of fluid inclusions in apatite yielded homogenization temperatures of 210 390 ? ℃ and salinities of 15% 23%NaCl? eqv. While the fluid inclusions in quartz are mainly homogenized at 330 390 ? ℃ and with salinities of 9% 13%NaCl? eqv, whereas some of the fluid inclusions in quartz show much extraordinary high salinities, indicating the heterogeneity of the ore-forming fluid. The values of δD and δ18OH2Oof the fluid inclusions and quartz vary from ?96‰ to ?54‰, and 7.7‰ to 9.8‰ (one is 14.1‰), respectively, which suggests that the original ore-forming fluid was magmatic water, and meteoric water was participated in the late stage of hydrothermal mineralization. The δ34S values of pyrite (4.8‰ to 9.3‰), which are similar to those of the ores in entire middle part of the Ningwu Basin, suggest that sulfur in ore-forming fluid has a mixed source of the magma and the Triassic evaporite strata. It is therefore inferred that Fe in the diorite-porphyry was leached by the high temperature ore-bearing magmatic fluid that assimilated mineralizers (e.g., SO42?, Cl?, Na+) from the Middle Triassic evaporate salt layers during albitization, and the ore-bearing fluids precipitated as disseminated magnetite in the upper part of diorite-porphyry, and then formed different types of magnetite veins in the margin and the top of the intrusion.

The Ningwu Volcanic Basin (NVB), located in the Lower Yangtze Metallogenic Belt, is characterized by the widespread occurrence of porphyritic iron-ore deposits. These deposits are clustered in three areas within the basin: the northern, central, and southern districts. Our study shows that the differences are existed in geochemistry of the rocks and the mineralization of the deposits among these three districts. Though results of Sr–Nd isotopes indicate that the parental magma of the sub-volcanic rocks in NVB were derived from EMI and EMII, however, the sub-volcanic rocks from the northern and southern districts have higher εNd(t) values (t = 130 Ma) and lower initial 87Sr/86Sr ratios (t = 130 Ma) than those from middle district. The rocks from northern and southern districts are similar to EMI in geochemistry; in contrast, rocks from the middle district are close to EMII. Meanwhile, the deposits from different districts show some differences in mineralization. The magnetites from the northern ore deposits are rich in Cu, Mo, Zn, and Mg and poor in Ca, Al, and Ti, which probably indicates that the magnetites from the northern ore deposits closer to hydrothermal genesis than to magmatic genesis, but the magnetites from the centre are closer to both magmatic and hydrothermal geneses. Based on the fact that a part of the sub-volcanic rocks is closer to EMI and another part to EMII in geochemistry, we suggested that the incorporation of the lower and upper crustal materials into the source regions of the sub-volcanic rocks has taken place by different manner and processes. Integrated with analysis of the tectonic evolution of NVB, we come to the conclusion that the sub-volcanic rocks have recorded the geochemical imprints of the subduction of Yangtze block towards North China block during Indosinian Period and the delamination of the lower crust of Yangtze block during Yanshanian Period.

The Ningwu basin is located in the Middle-Lower Yangtze River metallogenic zone, Eastern China. Four cycles of volcanic rocks were widely found in the basin. By the tool of geochemistry, the geochemical characteristics and magma evolution of these volcanic rocks were studied. The results show that volcanic rocks are mainly andesites, trachy-andesites and dacites. The volcanic rocks of the Longwangshan formation, which were formed earlier, are low K series while volcanic rocks of other formations vary from high K calc-alkaline to shoshonite. With the Mg indexes from 66.51 to 40.33, volcanic rocks show the similar LREE-enriched patterns and depletion in high field strength elements of Ta, Nb and Ti, suggesting that the primitive magma resulted from partial melting of enriched mantle. The decreasing Mg index and the increasing alkali also indicate that the magma experienced significant fractional crystallization after forming. Combined with regional geology and dating studies, it is thought that volcanic activities in the Ningwu basin happened at the regional lithospheric thinning, resulting from the subduction of Paleo-Pacific and post-orogen extension of Dabie Mountain. At that time, active Tanlu fault triggered partial melting of the enriched mantle beneath the Ningwu basin.