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对采自河北省迁安县水厂地区的紫苏花岗岩中的黑云母和紫苏辉石进行了~(40)Ar/~(39)Ar年龄测定,分别给出了18.7亿年和19.6亿年的~(40)Ar保存年龄。这两种矿物的年龄谱的视年龄的梯度变化表明,紫苏花岗岩形成后是缓慢冷却的。3.9亿年左右的一次热事件,造成了放射成因~(40)Ar的丢失。根据热历史和封闭温度的研究,从27亿年(侵入到该区紫花岗岩中的花岗闪长岩的锆石U-Pb年龄)到19.6亿年,紫苏花岗岩岩体的抬升速率为6.5m/Ma,但从19.6亿年到18.7亿年,其抬升速率高达111m/Ma,具有明显的构造抬升作用。
The (40) Ar / ~ (39) Ar ages of biotite and peridotite collected from the Permian granite from the Qian’an waterworks area in Hebei Province were measured, respectively 1.87 billion years and 1.96 billion years ~ (40) Ar save the age. The age-dependent changes in the age spectrum of these two minerals indicate that the perilla granulite is slowly cooled after its formation. A hot event of 390 million years led to the loss of ~ (40) Ar, a radiogenic cause. Based on the study of thermal history and closure temperature, the uplift rate of peridotite granites ranges from 2.7 billion years (zircon U-Pb age of granodiorite intrusive to purple granite in this area) to 1.96 billion years m / Ma. However, from 1.960 billion years to 1.87 billion years, its uplift rate is as high as 111m / Ma, with obvious tectonic uplift.