The Petrology,Geochemistry And Petrogenesis Of Metavolcanie Rock In Shangyi Of North Hebei Province

The Shangyi meteoric volcanic rocks of north Heibei are located in north zone of Shangyi-Chongli-Akagi fault,which is generally distributed in the east-west direction.The Shangyi metamorphic volcanic rocks are widely distributed,nearly the northwest west-east east east,and reveal completely in Huangtuyao and Wushijia.The main rock type is black and cloudy long amphibolite,plagioclase amphibolite and(including feldspar)amphibolite.The main rock type is plagioclase amphibolite.Shangyi meteoric volcanic rocks can be devided into two type:(1)Basic volcanic rocks,the content of SiO2 is between the range of 46.33% ~ 50.81%,belonging to the series of volcanic basalt rock volcanic rocks.(La / Yb)CN is 0.68 ~ 1.01,which was formed in the mid-ocean ridge environment.Another kind of light rare earth is more enriched,but heavy rare earth is close to the rare earth element.In the flat type,should be the results of first type volcanic rock ‘s late transformation.(2)Neutral volcanic rocks,the content of SiO2 is between 56.33% ~ 60.66%,belonging to the calc-alkaline series volcanic rocks,with light rare earth enrichment rare earth distribution model,(La / Yb)CN is 9.73 ~ 75.07,which should be formed in the continental margin of the environment.The zircons in the metamorphic basic volcanic rock samples with a flat type rare earth partition pattern of plagioclase amphibolites were subjected to LA-ICP-MS dating to obtain a weighted average of LA-ICPMS U-Pb(206Pb / 238U)The value is 262.7 ± 2.7Ma,the Th / U value is mainly distributed between 0.044 and 0.107(0.155 respectively),which belongs to the age data of the metamorphic zircon,indicating that the time limit of the metamorphic volcanic rocks should be the Middle Perme The tectonic time should be earlier than 262.7 Ma.