The Xiadian Fault is a very important concealed active fault in the Beijing Plain. It is the seismogenic fault of the Sanhe-Pinggu MS8. 0 earthquake in 1679. The ancient earthquake sequence in the long historical peri...The Xiadian Fault is a very important concealed active fault in the Beijing Plain. It is the seismogenic fault of the Sanhe-Pinggu MS8. 0 earthquake in 1679. The ancient earthquake sequence in the long historical period is of great significance to understand accurately the activity characteristics of the fault and effectively reduce the earthquake disaster risk in Beijing. We have re-interpreted the Dahuzhuang trench,and identified three layers of buried paleosol,six collapsed wedges and one sand liquefaction event. Further,through the comparison with the landmark strata and paleo-earthquake events revealed by other trenches on the fault,an ancient earthquake sequence with a long historical period of the Xiadian Fault was established:since the 31 ka,the Xiadian Fault has 11 occurrences of earthquake events(including the 1679 earthquake),and the average recurrence interval is about 2. 8 ka. The paleo-seismic sequence also shows that there is an ancient earthquake cluster period from 25 ka to 15 ka,and there are 5 strong earthquakes in the cluster period.The average recurrence interval is about 2. 0 ka,which reflects the phase difference of the Xiadian Fault activity.展开更多
The composition of quartz inclusions and trace elements in ore indicate that gold\|bearing fluid in the Xiadian gold deposit, Shandong Province, stemmed from both mantle and magma, belonging to a composite origin. Bas...The composition of quartz inclusions and trace elements in ore indicate that gold\|bearing fluid in the Xiadian gold deposit, Shandong Province, stemmed from both mantle and magma, belonging to a composite origin. Based on theoretical analysis and high temperature and high pressure experimental studies, gold\|bearing fluid initiative localization mechanism and the forming environment of ore\|host rocks are discussed in the present paper. The composite fluid extracted gold from rocks because of its expanding and injecting forces and flew through ore\|conducive structures, leading to the breakup of rocks. The generation of ore\|host faults and the precipitation of gold\|bearing fluid occurred almost simultaneously. This study provides further information about the relationships between gold ore veins and basic\|ultrabasic vein rocks and intermediate vein rocks, the spatial distribution of gold ore veins and the rules governing the migration of ore fluids.展开更多
基金sponsored by the TeachingReform Project in Hebei Province(2017GJJG257)the National Natural Science Foundation of China(41372216)Top-quality Course Project of College of Disaster Prevention Science and Technology(JPJS2018006)
文摘The Xiadian Fault is a very important concealed active fault in the Beijing Plain. It is the seismogenic fault of the Sanhe-Pinggu MS8. 0 earthquake in 1679. The ancient earthquake sequence in the long historical period is of great significance to understand accurately the activity characteristics of the fault and effectively reduce the earthquake disaster risk in Beijing. We have re-interpreted the Dahuzhuang trench,and identified three layers of buried paleosol,six collapsed wedges and one sand liquefaction event. Further,through the comparison with the landmark strata and paleo-earthquake events revealed by other trenches on the fault,an ancient earthquake sequence with a long historical period of the Xiadian Fault was established:since the 31 ka,the Xiadian Fault has 11 occurrences of earthquake events(including the 1679 earthquake),and the average recurrence interval is about 2. 8 ka. The paleo-seismic sequence also shows that there is an ancient earthquake cluster period from 25 ka to 15 ka,and there are 5 strong earthquakes in the cluster period.The average recurrence interval is about 2. 0 ka,which reflects the phase difference of the Xiadian Fault activity.
基金TheprojectwasfinanciallysupportedjointlybytheNationalNaturalScienceFoundationofChina(No .4 0 172 0 36 )"TheKeyProgrovmofScienceandTechnologyResearch"(No .0037)sponsoredbytheMinistryofEducation theNationalClimbingPro gramofChina No .95 pre 2 5and 95 pr
文摘The composition of quartz inclusions and trace elements in ore indicate that gold\|bearing fluid in the Xiadian gold deposit, Shandong Province, stemmed from both mantle and magma, belonging to a composite origin. Based on theoretical analysis and high temperature and high pressure experimental studies, gold\|bearing fluid initiative localization mechanism and the forming environment of ore\|host rocks are discussed in the present paper. The composite fluid extracted gold from rocks because of its expanding and injecting forces and flew through ore\|conducive structures, leading to the breakup of rocks. The generation of ore\|host faults and the precipitation of gold\|bearing fluid occurred almost simultaneously. This study provides further information about the relationships between gold ore veins and basic\|ultrabasic vein rocks and intermediate vein rocks, the spatial distribution of gold ore veins and the rules governing the migration of ore fluids.
