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皖南黄山岩体一系列构造隆升事件是由古太平洋板块与欧亚板块碰撞引发驱动的.相应的低温热年代学研究能够更好地揭示隆升机制和区域构造演化.黄山岩体南部7个锆石裂变径迹(ZFT)样品的χ2检验结果显示,单颗粒年龄值分布广泛,不符合泊松单一年龄群分布特征.通过二项式峰值拟合法,4个典型ZFT样品的单颗粒年龄共区分出三个主要的年龄峰值,分别分布于113～123,72～95和49～66 Ma之间,与中国东部转入滨太平洋构造域后发生的大规模构造热事件能够很好地对应.磷灰石裂变径迹(AFT)样品的χ2检验值均大于5%,年龄分布于(15±3)～(56±6)Ma之间,明显小于母岩的形成年龄,表明曾经历后期热事件的改造.根据AFT分析结果及地形地貌特征,本文按剥蚀强度将黄山岩体划分出三个主要的剥蚀区,证实断块差异隆升对剥蚀强度影响强烈.不同断块三个样品的AFT模拟结果显示早新生代构造热事件的冷却速率分别为3.3,3.8和6.0℃Ma-1,相应的剥蚀速率为90,104和167 m Ma-1.最后一次冷却事件发生在10 Ma左右,相应的平均冷却速率约为5.6℃Ma-1,剥蚀速率约为156 m Ma-1.裂变径迹分析结果表明区域旋转挤压应力场是引发黄山岩体断块差异隆升剥蚀的主要原因.
A series of structural uplift events in the Huangshan pluton in southern Anhui were triggered by the collision between the Paleo-Pacific plate and the Eurasian plate. The corresponding low-temperature thermochronological studies can better reveal the uplift mechanism and regional tectonic evolution. The χ2 test results of zircon Zircon fission track (ZFT) samples show that the single-particle age distribution is broad and does not accord with Poisson single age distribution. By binomial peak fitting method, four typical ZFT samples with single grain age The three major age peaks were distinguished and distributed between 113 ~ 123, 72 ~ 95 and 49 ~ 66 Ma, respectively, corresponding well with the large-scale tectonic thermal events that occurred after the eastern part of China transferred to the Pacific Rim. The χ2 test values of apatite fission track (AFT) samples were more than 5%, and the age distribution was between (15 ± 3) ~ (56 ± 6) Ma, which was significantly smaller than the parent rock formation age, According to the results of AFT analysis and topographic and geomorphological features, the paper divided the Huangshan pluton into three major denudation zones according to the denudation intensity, and confirmed that the differential uplift of the fault blocks strongly affected the denudation intensity.The AFTs of three samples with different fault blocks Simulation results show premature newborn The cooling rates of the tectono-thermal event are 3.3, 3.8 and 6.0 ℃ Ma-1 respectively, and the corresponding ablation rates are 90,104 and 167 m Ma-1. The last cooling event occurred at about 10 Ma with a corresponding average cooling rate of 5.6 ℃ Ma-1, and the denudation rate is about 156 m Ma-1. The results of fission track analysis show that the regional rotational compressive stress field is the main reason for the uplift and denudation caused by the fault block fault in Huangshan.