Multi-constraints are used in this paper to discuss the ΣCO_2 source in oreforming hydrothermal solution of granite-type uranium deposit in South China. The studies show that highly acidic and uraniferous granitic ma...Multi-constraints are used in this paper to discuss the ΣCO_2 source in oreforming hydrothermal solution of granite-type uranium deposit in South China. The studies show that highly acidic and uraniferous granitic magma cannot produce the fluid rich in ΣCO_2. Controlled by three periods of crust extension and corresponding to three major periods of U-mineralization in South China respectively, the ΣCO_2 in each ore-forming hydrothermal solutions is all mantle-derived. Our studies reasonably explain why the mineralization did not occur immediately after the end of differentiation of the granitic magma rich in uranium, and why the ore-forming time of granite-type uranium deposit focuses on the time of crust extension after the formation of the uraniferous granites.展开更多
The Jiaodong Peninsula in Shandong Province,China is the world’s third-largest gold metallogenic area,with cumulative proven gold resources exceeding 5000 t.Over the past few years,breakthroughs have been made in dee...The Jiaodong Peninsula in Shandong Province,China is the world’s third-largest gold metallogenic area,with cumulative proven gold resources exceeding 5000 t.Over the past few years,breakthroughs have been made in deep prospecting at a depth of 500‒2000 m,particularly in the Sanshandao area where a huge deep gold orebody was identified.Based on previous studies and the latest prospecting progress achieved by the project team of this study,the following results are summarized.(1)3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield,which was previously considered to consist of several independent deposits,is a supergiant deposit with gold resources of more than 1200 t(including 470 t under the sea area).The length of the major orebody is nearly 8 km,with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction.(2)Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined,forming a stepped metallogenic model from shallow to deep level.The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults,the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed.Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure,these sections along the fault plane serve as the target areas for deep prospecting.(3)Thermal uplifting-extensional structures provide thermodynamic conditions,migration pathways,and deposition spaces for gold mineralization.Meanwhile,the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks.This further led to the reactivation of ore-forming elements,which provided rich materials for gold mineralization.(4)It can be concluded from previous research results that the gold mineralization in the Ji展开更多
The Huangshan granitic intrusion in Anhui province,SE China,is tectonically located at the southeastern boundary of the Yangtze Block.Based on the contact relation and the petrography,the Huangshan granitic intrusion ...The Huangshan granitic intrusion in Anhui province,SE China,is tectonically located at the southeastern boundary of the Yangtze Block.Based on the contact relation and the petrography,the Huangshan granitic intrusion can be divided into four stages,from early to late,medium-grained monzogranite,coarse-grained porphyric granite,fine-medium grained porphyric granite,and finecoarse grained granite.All rocks from the Huangshan granitic intrusion display similar petrological and geochemical characteristics,i.e.relatively high SiO_2（〉75%） and alkali（7.85%-8.59%）,low CaO （〈1%）,high Fe-number（FeO_T/（MgO＋FeO_T） = 0.93-0.97） and A/CNK（atomic Al/（Ca＋Na＋K））=1.04- 1.19.They are also enriched in rare earth elements（REE,except for Eu,with a total REE contents ranging from 116 ppm to 421 ppm）,high strength field elements such as Zr,Hf,Nb,but depleted in Ba,Sr and Ni.The 10 000×Ga/Al ratios are higher than 2.6,which are consistent with the A-type granitoids.Based on the classification diagrams proposed by Eby,the Huangshan granite can be classified into the A2 group,which is usually believed to be formed under an extensional tectonic setting.Their Nd isotopic compositions suggest that the primary magmas of the Huangshan granite are predominantly derived from the Proterozoic andesitic rocks in the region,and this conclusion is also supported by REE modeling.The systemic investigations on the geochemistry of the Huangshan granitic intrusion can provide significant implications for the understanding of the petrogenesis and the geodynamic regime of southeastern China during the Late-Mesozoic.展开更多
Let pj ∈ N and pj ≥-1, j = 2,...,n be a fixed positive integer. In this paper a generalized Roper-Suffridge extension operator F（z） ={f（Z1）＋f＇（z1）} on Reinhardt domain is defined. Some different conditions f...Let pj ∈ N and pj ≥-1, j = 2,...,n be a fixed positive integer. In this paper a generalized Roper-Suffridge extension operator F（z） ={f（Z1）＋f＇（z1）} on Reinhardt domain is defined. Some different conditions for Pj areestablished under which the operator preserves an almost spirallike mapping of type fl and order a and spirallike mapping of type β and order α, respectively. In particular, our results reduce to many well-known results.展开更多
基金Project supported by the National Natural Science Foundation of China, and by the Fund of Laboratory of Ore Deposit Geochemistry, Academia Sinica.
文摘Multi-constraints are used in this paper to discuss the ΣCO_2 source in oreforming hydrothermal solution of granite-type uranium deposit in South China. The studies show that highly acidic and uraniferous granitic magma cannot produce the fluid rich in ΣCO_2. Controlled by three periods of crust extension and corresponding to three major periods of U-mineralization in South China respectively, the ΣCO_2 in each ore-forming hydrothermal solutions is all mantle-derived. Our studies reasonably explain why the mineralization did not occur immediately after the end of differentiation of the granitic magma rich in uranium, and why the ore-forming time of granite-type uranium deposit focuses on the time of crust extension after the formation of the uraniferous granites.
基金by the NSFC-Shandong Joint Fund Program entitled“Control Mechanisms of Faults on Deep Gold Deposits in Jiaodong Peninsula”(U2006201).
文摘The Jiaodong Peninsula in Shandong Province,China is the world’s third-largest gold metallogenic area,with cumulative proven gold resources exceeding 5000 t.Over the past few years,breakthroughs have been made in deep prospecting at a depth of 500‒2000 m,particularly in the Sanshandao area where a huge deep gold orebody was identified.Based on previous studies and the latest prospecting progress achieved by the project team of this study,the following results are summarized.(1)3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield,which was previously considered to consist of several independent deposits,is a supergiant deposit with gold resources of more than 1200 t(including 470 t under the sea area).The length of the major orebody is nearly 8 km,with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction.(2)Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined,forming a stepped metallogenic model from shallow to deep level.The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults,the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed.Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure,these sections along the fault plane serve as the target areas for deep prospecting.(3)Thermal uplifting-extensional structures provide thermodynamic conditions,migration pathways,and deposition spaces for gold mineralization.Meanwhile,the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks.This further led to the reactivation of ore-forming elements,which provided rich materials for gold mineralization.(4)It can be concluded from previous research results that the gold mineralization in the Ji
基金supported by the Application Programme for UNESCO Network of Geoparkssupported by Huangshan Management Committee,111 Project(B07011)and PCSIRT.
文摘The Huangshan granitic intrusion in Anhui province,SE China,is tectonically located at the southeastern boundary of the Yangtze Block.Based on the contact relation and the petrography,the Huangshan granitic intrusion can be divided into four stages,from early to late,medium-grained monzogranite,coarse-grained porphyric granite,fine-medium grained porphyric granite,and finecoarse grained granite.All rocks from the Huangshan granitic intrusion display similar petrological and geochemical characteristics,i.e.relatively high SiO_2（〉75%） and alkali（7.85%-8.59%）,low CaO （〈1%）,high Fe-number（FeO_T/（MgO＋FeO_T） = 0.93-0.97） and A/CNK（atomic Al/（Ca＋Na＋K））=1.04- 1.19.They are also enriched in rare earth elements（REE,except for Eu,with a total REE contents ranging from 116 ppm to 421 ppm）,high strength field elements such as Zr,Hf,Nb,but depleted in Ba,Sr and Ni.The 10 000×Ga/Al ratios are higher than 2.6,which are consistent with the A-type granitoids.Based on the classification diagrams proposed by Eby,the Huangshan granite can be classified into the A2 group,which is usually believed to be formed under an extensional tectonic setting.Their Nd isotopic compositions suggest that the primary magmas of the Huangshan granite are predominantly derived from the Proterozoic andesitic rocks in the region,and this conclusion is also supported by REE modeling.The systemic investigations on the geochemistry of the Huangshan granitic intrusion can provide significant implications for the understanding of the petrogenesis and the geodynamic regime of southeastern China during the Late-Mesozoic.
文摘Let pj ∈ N and pj ≥-1, j = 2,...,n be a fixed positive integer. In this paper a generalized Roper-Suffridge extension operator F（z） ={f（Z1）＋f＇（z1）} on Reinhardt domain is defined. Some different conditions for Pj areestablished under which the operator preserves an almost spirallike mapping of type fl and order a and spirallike mapping of type β and order α, respectively. In particular, our results reduce to many well-known results.
