Formation and Evolution of the Late Triassic Granite Buried Hill in the Songnan Low Uplift,Qiongdongnan Basin
Yang Haizhang
Tang Huafeng
Ji Mo
Tian Zhiwen
Gao Youfeng
Abstract：To further study the evolution process of the Songnan Low Uplift granite buried hill,the basement monzogranite in well Y8-A are analysed by chronology,major and trace,Sr-Nd-Pb-Hf isotopes,apatite fission track,and zircon(U-Th)/He methods.LA-ICP-MS zircon U-Pb dating is 235.6±4.8 Ma.The mafic dikes 40Ar/39Ar flateau age is 141.57±0.63 Ma.These granites belong to high potassium calc alkaline and peraluminous S-type granite.Their(87Sr/86Sr)i,εNd(t),and εHf(t)values are 0.707 93-0.709 44,-4.45 to-6.39,and--5.6 to 1.5,respectively.The apatite fission track age is 66.3±5.6 Ma,and the single zircon(U-Th)/He particle age ranges from(82.05±1.99)to(45.93±1.14)Ma.The comprehensive study shows that the monzogranite was formed in the post-collision background after the collision between Indochina and South China.The thermal history inversion results show that the evolution of granite buried hill can be divided into five stages:emplacement,slow cooling,fast cooling,near-surface denudation and sediments burial.
Keywords：Qiongdongnan basinSongnan low upliftgranite buried hillpetrogenesistectonic evolutionpetrologygeochronology
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：20( 2124-2143 )