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为了揭示下扬子南部露头区中、古生界地层的构造热演化特点及其控制环境,本文应用刻画温度与时间关系较好的锆石裂变径迹技术(ZFT),对苏皖下扬子15个中、古生界碎屑岩进行热演化分析.研究结果表明:中、古生界碎屑岩表现出214～75Ma的ZFT年龄特点,这些ZFT年龄及其颗粒年龄的变化,主要与后期差异热改造以及不同碎屑锆石的裂变径迹抵制退火的难易程度不同有关.这些碎屑岩ZFT年龄的一个显著特点是集中在157～95Ma,这一时限与下扬子乃至中国东部160～100Ma时期广泛的岩浆活动时间是一致的,可见岩浆热改造对于碎屑岩ZFT热年龄的影响是至关重要的.2个南华系碎屑岩(ZFT10和ZFT11)的ZFT测年结果(76～75Ma)与NW-SE向的区域构造带活动或者是断裂活动有关.
In order to reveal the tectonic thermal evolution characteristics and the controlled environment of Paleozoic strata in the middle and lower Paleozoic in the Lower Yangtze, this paper applied Zircon fission track technique (ZFT), which depicts the relationship between temperature and time, Mesozoic and Paleozoic clastic rocks were analyzed by means of thermal evolution.The results show that the Mesozoic and Paleozoic clastic rocks exhibit ZFT ages of 214 ~ 75Ma, and these changes of ZFT ages and their grain ages are mainly related to the late heat of differentiation Alteration and fission track of different detrital zircons are resistant to the different annealing resistance.A significant feature of ZFT ages of these clastic rocks is that they are concentrated in 157 ~ 95Ma, which is in line with the period from the Lower Yangtze to the east of China 160 ~ 100Ma Extensive magmatic activity time is consistent, showing that thermal alteration of magmatic rocks is of crucial importance for the ZFT thermal age of clastic rocks.The ZFT dating results (76-75 Ma) of the two Nanhua clastic rocks (ZFT10 and ZFT11) It is related to the regional tectonic or NW-SE tectonic activity.