中国科学院南京地质古生物研究所机构知识库

The microfossils from Neoproterizoic Doushantuo Formation, Southeast China, include multicellular animal and algae fossils with exquisite cellular or even subcellular structure preserved, which show the beginning of biodiversity in the Precambrian ocean about 600 million years ago. The fossil cells can fluoresce when excited by laser light and have a steady fluorescence emission in the visible spectrum. The organic matter was thought as the fluorescence source. However, our observation of the microfossils from Doushantuo Formation, Weng'an reveals another fluorescence source. We found by scanning electron microscopy and transmission light microscopy that the fossil cells with fluorescence are composed of small crystals in a naturally self-assembled manner. Through energy dispersive spectroscopy we know that the crystal is mainly composed of Ca, P, O, and F elements. Furthermore, we performed powder X-ray diffraction to confirm that the crystal compound is Ca(5)(PO(4))(3)F. Therefore, we consider that crystallization of Ca(5)(PO(4))(3)F is the main reason that causes the fossil cells to illuminate.