吉林中部梨花沟石英闪长岩锆石U-Pb年龄和岩石地球化学特征

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中图分类号：P597 文献标识码：A 文章编号：2097-5465（2026）01-0012-10

Abstract：ToexplorethefinalclosuretimeoftheeastersegmentofthePaleo-AsianOcean，thisstudyfocusesonthequartzdiorite intheLiuagouareaofcentral Jilin，analyzingitsgeochemicalcharacteristicsandzircon U-Pbges.LA-ICP-MSzirconU-Pb dating results indicate that thecrystallizationageof theLihuagou quartz dioriteisLate Triasic（208 ±2 Ma）.Therock isrich in silicon，aluminum，calcium，and sodium，butpooiniron，magnesium，andpotassum.Therareearthelementsexhibita rightward sloping distribution，with weak Eu anomalies（ δEu=0.63～0.92 ）.Trace element characteristicsshow enrichment of large-ion lithophile elements （such as Rb ，Ba，Eu）and depletion of high-field strength elements（such as Ta，Nb，Ti）.The low Cr （17.7×10-6～45.2×10-6 ）， MgO （ 1.32%～2.36% ），and Mg#（42～44） values suggest that the magma source mainly originatesfrompartialmeltingofthelowercrust.TheNd/Th（1.81～4.66）andRb/Sr（O.09～0.40）ratiosindicate the involvementofmantle-derivedcomponentsduringitsformationBasedonprevioussdies，itisiferedthattheeastesgmetof thePaleo-AsianOceanclosedinteEarlytoMiddleTiassic，withpost-collsioalextensionoccurrngintheLateTriassicTe geochemicalcharacteristicsofteLiuagouquartdioitesgsttatitsfoationilatedtoextensioalctoncctivityfollowing the closure of the Paleo-Asian Ocean.

Keywords：centralJilin；quartzdiorite；LateTriasic；zirconU-Pbages；geochemical characteristics；Paleo-AsianOcea

0 引言

东北地区是中亚造山带的最东段地区，主要发育以下构造单元，自西向东分别是额尔古纳地块、兴安地块、松嫩地块以及佳木斯地块（图1a）[1]。（剩余15289字）