%A Dou Shiyong %T LA-ICP-MS Zircon U-Pb Dating and Geochemical Characteristics of Granitic Porphyry in Kaiyuan Area of Northern Liaoning Province %0 Journal Article %D 2020 %J Journal of Jilin University(Earth Science Edition) %R 10.13278/j.cnki.jjuese.20190198 %P 1752-1765 %V 50 %N 6 %U {http://xuebao.jlu.edu.cn/dxb/CN/abstract/article_11216.shtml} %8 2020-11-26 %X The study area is located in the eastern part of the north margin of the North China craton, which is the intersection of the North China craton and the Xingmeng orogenic belt. The author studied the detailed petrology, geochronology and geochemistry of the Fangmu granitic porphyry in Kaiyuan area of northern Liaoning Province, discussed their formation age, petrogenesis, tectonic settings, and the thinning time of North China craton. The LA-ICP-MS zircon U-Pb dating was tested for the granitic porphyry. The 206Pb/238U age is (117±1) Ma, which indicates that the granitic porphyry was formed in the Early Cretaceous. The granitic porphyry is characterized by high Si, rich in alkali,poor in Mg and Ca, rich in large ion lithophile elements (e.g. K and Rb),and high field strength elements (e.g. Th, Ta, and Nb), while deplete in Sr, Ba, P, and Ti. Besides, the REE pattern shows a typical right dipping seagull shape. There is a negative Eu anomaly, which indicates that the granitic porphyry is A-type granite (A1 subtype),and formed in the post orogenic extensional environment during paleo Pacific subduction. The magma was from the re-melting of the crustal material caused by the mantle material upwelling. In addition, the study area was a compressional orogenic environment before (156±1) Ma. Thus, we believe that the crustal thinning began in 156-117 Ma.