青海省火成岩同位素地质年代学与构造岩浆热事件对比研究

以项目组近年来在青海取得的年龄研究成果为基础,通过对搜集到的1 346个火成岩同位素年龄数据分布特征与地质演化过程对比研究,得到以下结论:①青白口纪热事件峰值特征暗示,青藏高原东北部地区在中元古代末有可能已经拉开了原特提斯洋演化的序幕。②在古特提斯演化过程中,岩浆活动相对于构造运动表现出一定的滞后性,这种滞后性在整个青藏高原东北部具有普遍性。③华力西—印支期构造演化旋回并不连续,中间可能有间断,并且间断可能发生于晚二叠世—早三叠世之间。④种种迹象表明,东昆仑地区泥盆纪处于持续强烈的伸展阶段,伴有大量具有伸展特性的基性岩以及A型花岗岩产出,该阶段从406Ma开始,结束时间不早于380Ma。

A Comparative Study on Isotopic Geochronology and Tectonic-magmatic Hydrothermal Events of Igneous Rock in Qinghai Province

Based on the age results the project team have gained in recent years,a comparative study is conducted on igneous rocks in terms of distribution and geological evolution of 1346isotopic ages collected,and conclusions are drawn as follows（1）The peak value of Qingbaikou series thermal event indicates that Proto-Tethys evolution began in the end of Mesoproterozoic Era in Northeastern Margin of the Tibetan Plateau;（2）Magmatism presents a hysteretic nature compared with tectonic movement in the evolution of Paleo-Tethys evolution,which is rather common in the whole Northeastern Margin of the Tibetan Plateau;（3）The Variscan-Indosinian tectonic evolution cycle is not continuous,specifically,interruptions may take place during the late Permian to Early Triassic;（4）All the phenomenon show that East Kunlun Devonian is in a continuous strong extension period,with a large number of elastic basic rock and A-type granite occurrence,which began from 406Ma and ended no early than 380Ma.