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碎屑矿物热年代学是了解板块碰撞、造山带抬升剥露以及盆地沉积等地质事件的重要途径之一。同一沉积区内碎屑颗粒通常是多来源的,含有不同的年龄组分,如何获得真实的年龄组分分布样式,进而准确地提取出地质年龄信息是碎屑颗粒年龄分析的关键。由于受到数学原理、组距选择和样品分析测试误差等因素的影响,常用的地质年龄频率分布图和概率密度曲线难以得到真实的年龄分布样式。本文引入一种新的同位素年龄数据统计方法——核密度估计法。该方法以同位素年龄数据为基础,根据数据密度和测试误差自适应变换带宽函数,减少了测试误差和样本数量的干扰,有效地提高了年龄分解精度。该方法尤其适用于同位素年龄样本数量少的研究新区以及测试误差大的碎屑颗粒年代学数据分析。本文应用核密度估计法,对大兴安岭地区显生宙花岗岩锆石U-Pb年龄数据库和松辽盆地碎屑磷灰石裂变径迹年龄数据进行了分析,所得到的年龄分布样式不但与区域地质背景、盆地构造-沉积记录等地质事实相吻合,还进一步准确约束了区域构造事件的年代界限。因此核密度估计法是一种能合理有效地进行地质年龄分布样式分析的先进统计方法。
Detrital mineral geothermal calculus is one of the important ways to understand the geological events such as plate collision, uplift and exhumation of the orogenic belt and basin sedimentation. In the same sedimentary area, the debris particles are usually derived from many sources and contain different age components. Therefore, how to obtain the true distribution pattern of age components and then accurately extract the geologic age information is the key to the age analysis of the debris particles. Due to the influence of mathematical principle, group distance selection and sample analysis and test error, it is difficult to get the true age distribution pattern of commonly used geo-age frequency distribution and probability density curve. This paper introduces a new statistical method of isotope age data - nuclear density estimation method. Based on the isotope age data, this method adaptively transforms the bandwidth function according to the data density and the test error to reduce the interference of the test error and the number of samples and effectively improve the age resolution accuracy. This method is especially suitable for the new study area with small number of isotope age samples and detrital chronological data analysis with large test errors. In this paper, the zircon U-Pb age database of the Phanerozoic granite in the Greater Xing’an Mountains and the fission track data of the apatite apatite fission in the Songliao Basin are analyzed using the method of nuclear density estimation. The obtained age distribution patterns are not only related to the regional geological background , Basin tectonic-sedimentary records and other geological facts are consistent, but also further accurately constrained the age of regional tectonic events. Therefore, the nuclear density estimation method is an advanced statistical method that can reasonably and effectively analyze the geological age distribution pattern.