The SHRIMP U-Pb zircon dating result of the Tongshi magmatic complex in western Shandong is presented in this paper. The Tongshi magmatic complex comprises fine-grained porphyritic diorite and syenitic porphyry. Eight...The SHRIMP U-Pb zircon dating result of the Tongshi magmatic complex in western Shandong is presented in this paper. The Tongshi magmatic complex comprises fine-grained porphyritic diorite and syenitic porphyry. Eighteen analyses for fine-grained porphyritic diorite gave two concordia ages, in which ten analyses constitute the young age group, giving ^206Pb/^238U ages ranging from 167.9 Ma to 183 Ma with a weighted mean age of 175.7±3.8 Ma, and the other eight yielded ^207Pb/^206Pb ages of 2502 Ma to 2554 Ma with a weighted mean 2518±11 Ma. Two analyses for syenitic porphyry gave ages of 2485 Ma and 2512 Ma, respectively. The age of 175.7±3.8 Ma indicates that the crystallization of the Tongshi magmatic complex occurred in the Middle Jurassic, whereas that of 2518±11 Ma is interpreted as the age of inherited magmatic zircons in the Neoarchean Wutai period.展开更多
THE alkali-rich subvolcanic complex of Tongshi and the associated gold mineralization are located at thesouth boundary of Pinyi Mesozoic volcanic depression in western Shandong Province. There are morethan 30 gold dep...THE alkali-rich subvolcanic complex of Tongshi and the associated gold mineralization are located at thesouth boundary of Pinyi Mesozoic volcanic depression in western Shandong Province. There are morethan 30 gold deposits and mineralization locations around the complex, in which Guilaizhuang gold deposit and Zhuojiazhuang bonanza gold deposit with important economic value are included. This area isbecoming a perspective target of superlarge gold deposit. In the mine area, there crop out Archeangranitic gneisses, Paleozoic carbonates and Jurassic clastic rocks, which was intruded by Tongshi complexwith 30 km. The complex consists of K-high igneous rocks formed by two stages of magmatism. In thefirst stage, the monzonitic dioritic porphyrys, which belong to K-high calc-alkalic rocks, were formed andin the second stage, monzonitic-syenitic porphyrys, which belong to K-high alkalic rocks, were formed.Their Ar-Ar ages are 189 Ma and 188 Ma, respectively. At the end of the second stage, a lot of theexplosive breccias were formed. The gold mineralization in this area is closely associated in time andspace with the second stage monzonitic-syenitic porphyrys. Based on the characteristics of展开更多
Because of the complication of geological procedures,the recorded data have the feature of nonlinear.The multi-fractal singularity value decomposition (MSVD) was used to decomposed the gravity data.In this paper,the M...Because of the complication of geological procedures,the recorded data have the feature of nonlinear.The multi-fractal singularity value decomposition (MSVD) was used to decomposed the gravity data.In this paper,the MSVD was utilized to extract the gravity anomaly associated with the gold mineralization in Tongshi gold field in the southwest of Shandong province.The results showed that the Tongshi complex with negative circular gravity anomaly is an important ore-controlling factor.And the positive ring gravity anomaly distributed展开更多
基金This study was supported by the Major State Basic Rsearch Program of China(grant G1999043211)National Natural Science Foundation of China(grant 40272088).
文摘The SHRIMP U-Pb zircon dating result of the Tongshi magmatic complex in western Shandong is presented in this paper. The Tongshi magmatic complex comprises fine-grained porphyritic diorite and syenitic porphyry. Eighteen analyses for fine-grained porphyritic diorite gave two concordia ages, in which ten analyses constitute the young age group, giving ^206Pb/^238U ages ranging from 167.9 Ma to 183 Ma with a weighted mean age of 175.7±3.8 Ma, and the other eight yielded ^207Pb/^206Pb ages of 2502 Ma to 2554 Ma with a weighted mean 2518±11 Ma. Two analyses for syenitic porphyry gave ages of 2485 Ma and 2512 Ma, respectively. The age of 175.7±3.8 Ma indicates that the crystallization of the Tongshi magmatic complex occurred in the Middle Jurassic, whereas that of 2518±11 Ma is interpreted as the age of inherited magmatic zircons in the Neoarchean Wutai period.
文摘THE alkali-rich subvolcanic complex of Tongshi and the associated gold mineralization are located at thesouth boundary of Pinyi Mesozoic volcanic depression in western Shandong Province. There are morethan 30 gold deposits and mineralization locations around the complex, in which Guilaizhuang gold deposit and Zhuojiazhuang bonanza gold deposit with important economic value are included. This area isbecoming a perspective target of superlarge gold deposit. In the mine area, there crop out Archeangranitic gneisses, Paleozoic carbonates and Jurassic clastic rocks, which was intruded by Tongshi complexwith 30 km. The complex consists of K-high igneous rocks formed by two stages of magmatism. In thefirst stage, the monzonitic dioritic porphyrys, which belong to K-high calc-alkalic rocks, were formed andin the second stage, monzonitic-syenitic porphyrys, which belong to K-high alkalic rocks, were formed.Their Ar-Ar ages are 189 Ma and 188 Ma, respectively. At the end of the second stage, a lot of theexplosive breccias were formed. The gold mineralization in this area is closely associated in time andspace with the second stage monzonitic-syenitic porphyrys. Based on the characteristics of
文摘Because of the complication of geological procedures,the recorded data have the feature of nonlinear.The multi-fractal singularity value decomposition (MSVD) was used to decomposed the gravity data.In this paper,the MSVD was utilized to extract the gravity anomaly associated with the gold mineralization in Tongshi gold field in the southwest of Shandong province.The results showed that the Tongshi complex with negative circular gravity anomaly is an important ore-controlling factor.And the positive ring gravity anomaly distributed
