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本文包括中国大陆科学钻(CCSD)主孔(MH)0～5000m和先导孔(PP2)0～1000m的磷灰石裂变径迹分折结果,先导孔PP2的裂变径迹表观年龄变化范围为79.5±5.1～50.4±6.2Ma,主孔的裂变径迹表观年龄变化范围为98.6±17.0～2.9±2.0Ma,主孔在4200m以下,磷灰石样品中实际上已不存在自发裂变径迹,表明裂变径迹时钟已经“置零”。实验资料表明,裂变径迹表观年龄值随样品深度的增加而逐渐减少,直到一定深度,即达到磷灰石的裂变径迹封闭温度(～120℃)以后,年龄值为零。根据主孔0～2000m和先导孔0～1000m的裂变径迹年龄剖面,作为一级近似,计算出超高压变质岩体在90～30Ma期间,平均隆升速度为～35m/Ma。对主孔测定了9个样品的约束径迹(Confined track)长度,样品约束径迹平均长度的变化范围约为13.1μ7.4μm,总的变化趋势是:约束径迹平均长度随样品深度的增加而逐渐减少。样品的约束径迹长度分布都具有双峰型特征。根据裂变径迹年龄和约束径迹长度的资料,应用计算机模拟得到了样品的时间-温度(t-T)轨迹。结果表明,岩体从早白垩世(～120Ma)快速冷却以后,在晚白垩世和始新世又经历了两次加热作用,始新世末岩体所达到的温度大约是80℃,随后岩体则一直上升和缓慢冷却到现今所处的位置。在最后～30Ma岩体的平均隆升速度为～53m/Ma。
In this paper, the results of apatite fission track analysis from 0 ~ 5000m for main hole (MH) and 0 ~ 1000m for pilot hole (PP2) of China Science Drill (CCSD) are shown. The apparent age of fission track of PP2 is 79.5 ± 5.1 ~ 50.4 ± 6.2Ma. The apparent age of fission track in the main pore ranged from 98.6 ± 17.0 to 2.9 ± 2.0Ma and the main pore was below 4200m. There was no spontaneous fission track in the apatite samples , Indicating that the fission track clock has been “zeroed ”. The experimental data show that the apparent age value of fission track gradually decreases with the increase of sample depth, and reaches a certain depth, that is, the apatite fission track closed temperature (~ 120 ℃), the age value is zero. According to the primary trace fission track ages of 0 ~ 2000m and pilot holes of 0 ~ 1000m, the first-stage approximation is that the average uplift velocity of UHP metamorphic rock mass is ~ 35m / Ma during 90 ~ 30Ma. The length of the confined track of nine samples was measured for the main hole. The average length of the constrained track of the sample was about 13.1μ7.4μm. The general trend was that the average length of the constrained track increased with the depth of the sample And gradually reduced. The constrained track length distribution of the samples has bimodal characteristics. According to fission track age and bounding track length, the time-temperature (t-T) trajectory of the sample was obtained by computer simulation. The results show that after rapid cooling from the Early Cretaceous (~ 120 Ma), the rock underwent two heating cycles in the Late Cretaceous and Eocene. The temperature reached by the Eocene rock mass was about 80 ℃, The body has been rising and cooling slowly to where it is today. In the last 30Ma, the average uplift velocity of the rock mass was ~ 53m / Ma.