摘要
对江西金滩和湖南白马山印支期花岗岩体高精度的LA-ICPMS锆石U-Pb年代学研究表明:金滩黑云母二长花岗岩体给出了(222.1±1.6)Ma的谐和年龄,属印支中晚期,而不是以往所认为的形成于海西期;白马山印支期的黑云母二长花岗岩和黑云母花岗闪长岩分别给出了(223.3±1.4)Ma、(204.5±2.2)Ma的谐和年龄。融合其他年代学数据,湖南白马山印支期花岗质岩浆可能经历了三期侵入活动:其中第一次侵入在印支早期(240Ma左右),其后又经历了220Ma左右和204Ma的另外两幕侵入活动。结合其他相关研究资料进一步表明220Ma左右华南内陆地区可能存在一次广泛的构造-岩浆活动。
The Indosinian tectonic setting of the South China Block is long-debated due to poor understanding of precise geochronology of the associated magmatism. Our studies of highly precise LA-ICPMS zircon U-Pb geochronology on Indosinian granitic plutons in the Baimashan （Hunan） and Jintan areas（Jiangxi） show that the biotite monzonitic granite from the Jintan area yielded a weighted mean ^206Pb/^238U age of （222.1±1.6）Ma,and biotite monzonitic granite and biotite granodiorite from the Baimashan area yielded the concordant ages of （223.3±1.4）Ma and （204.5±2.2）Ma,respectively. These ages represent the formation age of the granitic plutons. In conjunction with other geochronological data,it is inferred that there may be three-episode magma activities for Hunan Baimashan intrusion during the Indosinian involving the first intrusion at about 240Ma,and subsequent intrusion activities of 220Ma and 204Ma,respectively. It is additionally showed an extensive tectono-magmatic activity at about 220Ma for the hinterland of the South China Block.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2010年第2期282-290,共9页
Geotectonica et Metallogenia
基金
中国科学院创新项目(KZCZ2-YW-128
40830319
KZCX1-YW-15-1)
国家自然科学基金(40825009
40772129)资助
