Abstract: Fission track analyses were performed for 4 apatites. They were collected from gneiss and mylonite of Red River fault between the Yuan Yang and Gasa. The FT ages at this area were 5.61～10.64Ma. We had found that the age of FT also had a tending becoming younger from SE to NW. Using FT age combined with results of multiple diffusion domain (MDD) model of K feldspars a slow cooling process among 150～110℃ and cooling velocity of 3.4～9.5℃/Ma are obtained. The characteristic shown by results of FT is consistent with the conclusion that the faults were transtensional prior to 15.5Ma and became transpressional later.

Key words: Fission track, Honghe fault zone, Left-lateral slip

摘要： 对采自红河断裂带元阳—嘎洒段的4个片麻岩和糜棱岩样品中的磷灰石进行裂变径迹(FT)测年,得到5.61～10.64Ma的年龄范围。结果表明,RRFZ段磷灰石FT年龄有从东南向西北变新的趋势。结合已有的钾长石多重扩散域(MDD)模式结果,得到该段150℃至110℃温度范围的冷却过程(冷却速度为3.4～9.45℃/Ma)。FT结果反映的特征与南海盆地得到的15Ma时断裂带所受力的转换的结果是一致的。

关键词: 裂变径迹, 红河断裂带, 左旋断层