现代地质2017，Vol.31Issue(6)：1187-1200,14.
吉林抚松四道砬子河岩组斜长角闪岩成因
Genesis of Amphibolite of Sidaolazihe Formation in Fusong Area, Jilin Province
摘要
Abstract
The formation age and genetic mechanism of the set of metamorphic rocks of Archean amphibolite facies,outcropped in Fusong area of Jilin Province,is a long-existed and unresolved problem.This paper selected the amphibolite from the metamorphic rocks as the studying object,and analyzed the forming process and discussed the evolution background of the contemporaneous tectonomagmatism by systematically studying petrology,mineralogy,petrogeochemistry and zircon U-Pb chronology characteristics.LA-ICP-MS U-Pb zircon dating of magmatic zircons yields the ages of (2,555 ± 13) Ma,(2,528 ± 13) Ma and (2,529 ± 9.8) Ma,which indicates that the formation age of the magma belongs to Late Neoarchean (2.55-2.50 Ga).The average contents of the major elements are similar to those of basalt;the contents of SiO2 are ranging from 46.22％ to 59.6％with the average of 51.13％;while contents of A1203 are from 11.83％ to 17.59％ with the average of 13.42％.The total REE content are ranging from 53.74 × 10-6 to 219.07 × 10-6,and the average is 108.17 × 10-6.The ratios of (La/Yb) N range from 2.07 to 8.98 with the average of 5.19,which indicates that the light rare earth elements (LREE) are relative enrichment and the light-heavy REEs are obviously fractionated.The contents of trace elements in the amphibolite are characterized by relative enrichment in large ion lithophile elements (LILE),i.e.K,Rb and Ba,and by depletion in high field-strength elements (HFSE),i.e.,Zr,Ti,Nd and Ta.The primary rock of this set of metamorphic rock association is regarded as basaltic volcanic by comprehensively studying their mineral composition and geochemical component,thus the metamorphic rocks belong to orthometamorphite.The magma,formed in the island-arc environment,is mainly derived from depleted mantle and simultaneously accompanied by the contamination and reconstruction of a small quantity of old crust.This study area was considered to be the northern extension part of Neoarchean Jilin-Liaoning-Hebei arccontinent collisional accretion-type orogenic belt of North China Craton.关键词
新太古代/斜长角闪岩/四道砬子河组/吉林Key words
Neo-Archean/amphibolite/Sidaolazihe Formation/Jilin分类
天文与地球科学引用本文复制引用
佟智强,郑常青,崔雪文,郭文科,田建东..吉林抚松四道砬子河岩组斜长角闪岩成因[J].现代地质,2017,31(6):1187-1200,14.基金项目
中国地质调查局项目“吉林抚松1∶5万开锋林场等四幅区域地质矿产调查”(12120114038401). （12120114038401）
