摘要
江西庐山“星子变质核杂岩”中发育有大量中生代花岗岩 ,这些花岗岩中具有强烈的韧脆性剪切变形 ,典型的新生变质矿物为绢云母。通过对庐山海会花岗岩 (其形成年龄为 1 2 2～1 3 0 Ma)中动力变质矿物绢云母进行 4 0 Ar/ 39Ar法同位素测年 ,分别获得 1 0 4.2 2 Ma± 0 .1 8Ma和 1 0 4.95 Ma± 0 .2 2 Ma的坪年龄值 ,以及 1 0 4.7Ma± 0 .3 6Ma和 1 0 5 .0 3 Ma± 0 .8Ma的等时线年龄值 ,这表明江西庐山地区在 1 3 0～ 1 0
In order to provide radiometric constraints for the tectonic evolution of the Lushan mountain, a preliminary study of the 40 Ar/ 39 Ar dating for the newborn sericite was carried out on the two representative samples. The samples of purely sericite comes from the Haihui gneissose granite in the Lushan mountain. Theirs 40 Ar/ 39 Ar determination was carried out by Shang H.Q. in the Beijing Institute of Geology of Academia Sinica, using the RGA 10 mass spectrometer of U.K. From age spectra related to the percentage of gas released, the sericite mineral from Hu1 displays well a larger plateau age of 104.95 Ma±0.44 Ma and the 40 Ar/ 36 Ar 39 Ar/ 36 Ar isochron age of 105.03 Ma±0.80 Ma; and the sericite mineral from Hu3 displays well a larger plateau age of 104.22 Ma±0.18 Ma and the 40 Ar/ 36 Ar 39 Ar/ 36 Ar isochron age of 104.70 Ma±0.36 Ma. The age of Haihui granite is 122~130 Ma, and the age of newborn sericite mineral from Haihui granite is 104~105 Ma, so the authors think that the tectonic environment of the Lushan mountain was transformed from the extension tectonic environment to the sinistral strike slip tectonic environment in the period of 130~104 Ma.
出处
《成都理工学院学报》
CSCD
北大核心
2002年第6期646-649,共4页
Journal of Chengdu University of Technology
基金
国土资源部科技项目 (B2 -2 5 )
关键词
江西
户山
中生代
花岗岩
构造环境
氩同位素
伸展构造
Lushan mountain
Mesozoic granite
40 Ar/ 39 Ar isotopic age
the tectonic environment change
