耐梅盖特组地层年代最新测定为66.7±2.5 mya（约6600万年前）

蒙古戈壁滩的涅美格特组有大量的恐龙和其他脊椎动物遗骸，由于缺乏放射性测年，其年龄尚不确定。为了更严格地限制Nemegt组的沉积年龄，我们使用激光烧蚀电感耦合等离子体质谱（LA-ICP-MS）对从Nemegt层中部采集的五颗Tarbosaurus bataar牙齿的磷灰石进行了U–Pb同位素、微量元素和Y筛选分析。因此，66.7 ± 2.5 Ma是从其中一个样本中获得的，该样本被认为受U分布二次变化的影响最小，这可以被解释为牙齿样本石化的下限。结合之前根据动物群分布提出的Nemegt组的相对年龄，我们的数据支持了马斯特里赫特阶Nemegt中上部的沉积。鉴于Nemegt组的沉积年龄尚未通过直接使用该组化石和矿物的同位素测年进行检查，本研究首次报告了戈壁中脊椎动物地层的沉积年龄可以通过磷灰石化石U–Pb测年结合Y筛选方法进行讨论。来自2023Apatite U–Pb dating of dinosaur teeth from the Upper Cretaceous Nemegt Formation in the Gobi Desert, Mongolia : Contribution to depositional age constraints

mation in the Gobi Desert, Mongolia, hosts abundant dinosaur and other vertebrate remains, the ages of which are uncertain due to a lack of radioactive dating. In order to more strictly constrain the depositional age of Nemegt Formation, we conducted U–Pb isotope, trace elements, and Y-screening analyses using laser-ablation inductively-coupled plasma-mass spectrometry (LA-ICP-MS) on apatites of five Tarbosaurus bataar teeth collected from the middle Nemegt Formation. As a result, the age of 66.7 ± 2.5 Ma was obtained from one of the samples which is suggested to be least affected by secondary alteration of the U distribution, and this can be interpreted as a lower limit for fossilization of the tooth samples. Combined with the previously suggested relative age of the Nemegt Formation based on faunal occurrences, our data supports the deposition of the middle–upper Nemegt Formation during the Maastrichtian stage. Given that the depositional age of the Nemegt Formation has not been examined by isotope dating directly using fossils and minerals from the formation, this study is the first to report that the depositional ages of the vertebrate-bearing strata in the Gobi can be discussed by fossil apatite U–Pb dating in combination with the Y-screening method.