Micro X-Ray Fluorescence Technology Reveals Macrofossil Bones and Surrounding Matrix Element Characteristics——A Case Study of the Middle Triassic Mixosaurus panxianensis
WANG Yi-nuo1, FU Wan-lu1, 2, ZHOU Min1*, LU Hao3, SUN Zuo-yu1, YAO Ming-tao1, JIANG Da-yong1*
1. Department of Geology and Geological Museum, Peking University, Beijing 100871, China
2. State Key Laboratory of Palaeobiology and Stratigraphy (Nangjing Institute of Geology and Palaeontology, Chinese Academy of Sciences), Nangjing 210008, China
3. School of History, Beijing Normal University, Beijing 100875, China
Abstract：We apply the Micro-XRF, which can be used to in situ non-destructively study the element distribution of the skeleton and surrounding matrix in vertebrate fossils to scan the holotype and paratype of the Middle Triassicmarine reptile Mixosauruspanxianensis (~244 Ma), visualizing the overall element distribution of the specimens. Additionally, the paratype's regions of interest are tested using a handheld X-ray fluorescence spectrometer as an adjunct. The research results show that the bone and matrix elements present a different distribution pattern. The skeleton clearly controls Ca, P, Sr and Y. The matrix where the fossil is preserved is rich in Ca, K, Fe, and Mn. In addition, Zn is variouslydistributed in different fossil bone parts of the paratype specimen, where the Zn content is higher in the trunk region than in the skull. In terms of fossil morphology, the maps clearly resolve the fossil morphology. The right forelimb and gastralium of the paratype specimen, which are invisible in regular light, are particularly well-resolved by the elemental maps. At the same time, the calcareous matrix and bone can be distinguished better. In taphonomy, comparing the elemental features of fossilized marine and terrestrial fossils demonstrates how the burial environment affects the distribution characteristics of certain elements. Th, Ce, Cu and Sr responded to the burial environment, while some elements related to bone, such as Ca, P, and Y, were less affected by the burial environment. The distribution of Zn in different bone regions was altered by bone development, and the paratype specimen's centrums and ribs, where Zn is elevated, are likely to be in the stage of rapid ossification, indicating that the paratype specimen was subadult.
Key words：Micro X-ray fluorescence; Mixosaurus panxianensis; Fossil; Surrounding rock; Element distribution
王一诺，付宛璐，周 敏，鲁 昊，孙作玉，姚明涛，江大勇. 微区X射线荧光技术揭示宏体化石骨骼以及埋藏环境元素特征——以中三叠世盘县混鱼龙为例[J]. 光谱学与光谱分析, 2024, 44(07): 1974-1981.
WANG Yi-nuo, FU Wan-lu, ZHOU Min, LU Hao, SUN Zuo-yu, YAO Ming-tao, JIANG Da-yong. Micro X-Ray Fluorescence Technology Reveals Macrofossil Bones and Surrounding Matrix Element Characteristics——A Case Study of the Middle Triassic Mixosaurus panxianensis. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2024, 44(07): 1974-1981.
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