成都金沙遗址古人类与古动物牙齿的FTIR与XRD分析

利用FTIR与XRD判断成都金沙遗址古人类与古动物牙齿釉质和牙本质中羟基磷灰石受埋藏环境和成岩作用的污染程度。XRD图谱结果反映牙釉质和牙本质样品中最主要成分是羟基磷灰石，但衍射峰宽，且部分重叠，表明羟基磷灰石结晶度差。所有样品FTIR图谱中H₂O和OH-的振动带显著，PO3-₄和CO2-₃主要振动带的特征峰明显，近似现代生物羟基磷灰石。表征羟基磷灰石结晶程度的PCI指数值在2.4至4.0之间，同时利用BPI指数估算的羟基磷灰石中CO2-₃含量较高, 说明样品结晶程度不高。上述结果表明，所取的金沙遗址古人类与古动物牙釉质和牙本质中羟基磷灰石受埋藏和成岩作用的污染小。

FTIR and XRD Analysis of Hydroxyapatite from Fossil Human and Animal Teeth in Jinsha Relict, Chengdu

Diagenetic effect during burial on the hydroxyapatite in enamel and dentin from fossil human and animal teeth was examined,using X-ray diffraction(XRD) and Fourier transform infrared spectroscopy(FTIR).For the enamel and dentin of all fossil teeth,XRD patterns exhibit bulge line and overlap between major reflections of hydroxyapatite,and the crystallinity of hydroxyapatite is low.For each infrared spectrum,H2O and OH-have distinct peaks of absorbance,and PO3-4and CO2-3 ions have intensive infrared vibration modes at the fundamental wave numbers.The component of hydroxyapatite of all fossil teeth is similar to the modern biological hydroxyapatite.Furthermore,the index(PCI) which reflects the hydroxyapatite crystallinity of each sample ranges from 2.4 to 4.0 while the index(BPI) reflecting the amount of type B carbonate to phosphate indicates that the values of CO2-3 content in hydroxyapatite are rather high,accordingly the crystallinity of all fossil hydroxyapatites are poor.It could be concluded that little alteration of hydroxyapatites from fossil human and animal teeth occurred in the process of diagenesis in Jinsha Relict,Chengdu,China.