河南西峡晚白垩世恐龙蛋化石壳微量元素组成及其对恐龙灭绝的指示意义

恐龙蛋化石是探索恐龙生存和灭绝的重要研究材料,目前对恐龙蛋化石的研究集中在生物学和埋藏特征方面。本文利用电感耦合等离子体发射光谱法(ICP-OES)对采自河南西峡晚白垩世的12枚恐龙蛋化石壳及部分围岩进行分析测试,研究其生命微量元素组成及其与恐龙灭绝的关系。结果表明,恐龙蛋壳中缺乏碳氮磷硫等有机质元素,而主要由钙铝镁铁钾等生命必需元素和锶锰钡镧锌硼钒钴铱等微量元素组成,其中锶和铱均具有明显的超高异常,这可能与地外撞击事件引起生态环境的急剧变化有关。元素的组合规律表明西峡盆地晚白垩世应为干旱、半干旱的气候环境,来自于环境中异常含量的锶和铱共同作用使这一时期该地区大量的恐龙蛋在恐龙体内遭受污染,发育孵化机能受到影响,成为导致盆地内恐龙灭亡的主要原因之一。这一发现为探讨恐龙生活环境变化、灭绝原因以及揭示晚白垩纪古气候提供了重要依据。

Trace Element Determination of Late Cretaceous Dinosaur Eggshell Fossils from Xixia Basin, Henan Province by ICP-OES and Its Implications for Extinction of Dinosaurs

Dinosaur egg fossils are important for exploring the survival and extinction of the dinosaurs. Current researches on dinosaur egg fossils are concentrated in their biology and burial features. In this study, Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) was used to determine trace element composition of twelve dinosaur eggshell fossils in the late Cretaceous from Xixia basin and their surrounding rocks, in order to the relationship between trace elements and the extinction of dinosaurs. Results show that the dinosaur eggshell fossils are depleted in organic elements such as C, N, P and S, and mainly consist of essential elements such as Ca, Al, Mg, Fe and K and other trace elements such as Sr, Mn, Ba, La, Zn, B, V, Co and Ir. Abnormal high Ir and Sr may be related to the extraterrestrial impact event causing the dramatic changes of the ecological environment. Element assemblages indicated that the climate during the late Cretaceous in this area might have been semiarid to arid. Abnormal high Ir and Sr in the environment probably have caused structure and pathological changes of those eggs within the dinosaurs. Thereby the dinosaur eggs could not be hatched, which probably resulted in the gradual demise of dinosaurs. This study provides an important basis for investigating the living environment of dinosaurs, causes of extinction and the late Cretaceous climate.