The Ningzhen region of China is located in the easternmost part of the middle-lower Yangtze River Cu–Fe polymetallic metallogenic belt. From west to east, it comprises five main intermediate–acidic intrusive complex...The Ningzhen region of China is located in the easternmost part of the middle-lower Yangtze River Cu–Fe polymetallic metallogenic belt. From west to east, it comprises five main intermediate–acidic intrusive complexes: the Qilinmen, Anjishan, Xiashu–Gaozi, Shima, and Jianbi complexes. Geochemical investigations show that these five intrusive complexes exhibit high contents of SiO_2, at 64.74–73.40 wt%, Al_2O_3, at 14.15–17.37 wt%, and K_2O + Na_2O, at 6.49–8.68 wt%. The majority of the samples belong to the high-K calc-alkaline series, with a few samples plotting in the calc-alkaline and tholeiitic series. Trace element analysis shows that the samples are enriched in large ion lithophile elements(LILE) and are depleted in high field strength elements(HFSE).The chondrite-normalized rare earth element(REE) patterns are characterized by right-inclined curves, showing light rare earth element(LREE) enrichment. In addition,the(La/Yb)Nratios are high at 15.02–37.28, with an average of 29.13, and slightly negative or none Eu anomalies are present. In the(La/Yb)N–d Eu diagram, the samples plot within the crust-mantle type field. Laser ablation–inductively coupled plasma–mass spectrometry(LA–ICP–MS) zircon U–Pb dating yielded ages of122.0 ± 1.0 Ma, 106.1 ± 0.8 Ma, 108.7 ± 1.4 Ma,103.5 ± 1.9 Ma, and 96.8 ± 1.7 Ma for the Qilinmen,Anjishan, Xiashu–Gaozi, Shima, and Jianbi complexes,respectively. On the basis of this research and knowledge of several known metal deposits related to these complexes, we suggest that the Mesozoic large-scale diagenesis and metallogenesis in the Ningzhen region may have ceased at 100 Ma or about 95 Ma.展开更多
The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceou...The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions.In this study,LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks(including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry)in the Ningzhen region were systematically investigated.These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and101 Ma.We present new40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralisation in the Ningzhen region.The phlogopite in the Cishantou skarn deposits yielded a40Ar-39Ar plateau age of 104±1 Ma.This result coincides with the ages of the Anjishan and Tongshan Cu(Mo)deposits in the Ningzhen region.Our high-precision geochronological data together with recent high-precision geochronological studies(such as zircon LA-ICP-MS U-Pb,zircon SHRIMP U-Pb,molybdenite Re-Os and single-mineral40Ar-39Ar dates)reveal that there were four periods(152-135 Ma,135-127 Ma,127-121 Ma,109-101 Ma)of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt.The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt.展开更多
分析宁镇及宜溧地区中晚全新世典型剖面的地层划分与特征,采用R-Q型因子分析方法估算气候变化值,揭示5 700 a B.P.前后发生在本区的干燥降温异常气候突变事件。气候曲线与沉积相序列的对比分析表明,宝华山浅棕黄色砂土夹角砾层洪-坡积...分析宁镇及宜溧地区中晚全新世典型剖面的地层划分与特征,采用R-Q型因子分析方法估算气候变化值,揭示5 700 a B.P.前后发生在本区的干燥降温异常气候突变事件。气候曲线与沉积相序列的对比分析表明,宝华山浅棕黄色砂土夹角砾层洪-坡积相是该突变事件背景下的产物,且该突变事件还具有全球变化区域响应的征候,林峰桥同期淤泥质层中Fe3+/Fe2+比和粘土百分含量异常值进一步印证了这一论断。展开更多
基金financially supported by the Major State Basic Research Development Program of China(973 Program)(No.2014CB440906)
文摘The Ningzhen region of China is located in the easternmost part of the middle-lower Yangtze River Cu–Fe polymetallic metallogenic belt. From west to east, it comprises five main intermediate–acidic intrusive complexes: the Qilinmen, Anjishan, Xiashu–Gaozi, Shima, and Jianbi complexes. Geochemical investigations show that these five intrusive complexes exhibit high contents of SiO_2, at 64.74–73.40 wt%, Al_2O_3, at 14.15–17.37 wt%, and K_2O + Na_2O, at 6.49–8.68 wt%. The majority of the samples belong to the high-K calc-alkaline series, with a few samples plotting in the calc-alkaline and tholeiitic series. Trace element analysis shows that the samples are enriched in large ion lithophile elements(LILE) and are depleted in high field strength elements(HFSE).The chondrite-normalized rare earth element(REE) patterns are characterized by right-inclined curves, showing light rare earth element(LREE) enrichment. In addition,the(La/Yb)Nratios are high at 15.02–37.28, with an average of 29.13, and slightly negative or none Eu anomalies are present. In the(La/Yb)N–d Eu diagram, the samples plot within the crust-mantle type field. Laser ablation–inductively coupled plasma–mass spectrometry(LA–ICP–MS) zircon U–Pb dating yielded ages of122.0 ± 1.0 Ma, 106.1 ± 0.8 Ma, 108.7 ± 1.4 Ma,103.5 ± 1.9 Ma, and 96.8 ± 1.7 Ma for the Qilinmen,Anjishan, Xiashu–Gaozi, Shima, and Jianbi complexes,respectively. On the basis of this research and knowledge of several known metal deposits related to these complexes, we suggest that the Mesozoic large-scale diagenesis and metallogenesis in the Ningzhen region may have ceased at 100 Ma or about 95 Ma.
基金supported by the National Key Basic Research Program of China(2012CB416800)the Key International Science and Technology Cooperation project(2007DFA21230)
文摘The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions.In this study,LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks(including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry)in the Ningzhen region were systematically investigated.These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and101 Ma.We present new40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralisation in the Ningzhen region.The phlogopite in the Cishantou skarn deposits yielded a40Ar-39Ar plateau age of 104±1 Ma.This result coincides with the ages of the Anjishan and Tongshan Cu(Mo)deposits in the Ningzhen region.Our high-precision geochronological data together with recent high-precision geochronological studies(such as zircon LA-ICP-MS U-Pb,zircon SHRIMP U-Pb,molybdenite Re-Os and single-mineral40Ar-39Ar dates)reveal that there were four periods(152-135 Ma,135-127 Ma,127-121 Ma,109-101 Ma)of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt.The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt.
文摘分析宁镇及宜溧地区中晚全新世典型剖面的地层划分与特征,采用R-Q型因子分析方法估算气候变化值,揭示5 700 a B.P.前后发生在本区的干燥降温异常气候突变事件。气候曲线与沉积相序列的对比分析表明,宝华山浅棕黄色砂土夹角砾层洪-坡积相是该突变事件背景下的产物,且该突变事件还具有全球变化区域响应的征候,林峰桥同期淤泥质层中Fe3+/Fe2+比和粘土百分含量异常值进一步印证了这一论断。
