蒙古戈壁灘的涅美格特組有大量的恐龍和其他脊椎動物遺骸，由于缺乏放射性測年，其年齡尚不確定。為了更嚴格地限制Nemegt組的沉積年齡，我們使用激光燒蝕電感耦合等離子體質(zhì)譜（LA-ICP-MS）對從Nemegt層中部采集的五顆Tarbosaurus bataar牙齒的磷灰石進行了U–Pb同位素、微量元素和Y篩選分析。因此，66.7?±?2.5?Ma是從其中一個樣本中獲得的，該樣本被認為受U分布二次變化的影響最小，這可以被解釋為牙齒樣本石化的下限。結(jié)合之前根據(jù)動物群分布提出的Nemegt組的相對年齡，我們的數(shù)據(jù)支持了馬斯特里赫特階Nemegt中上部的沉積。鑒于Nemegt組的沉積年齡尚未通過直接使用該組化石和礦物的同位素測年進行檢查，本研究首次報告了戈壁中脊椎動物地層的沉積年齡可以通過磷灰石化石U–Pb測年結(jié)合Y篩選方法進行討論。來自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.