Deciphering the Nature of 'Graphite' in Geological Samples with the Use of Laser Raman Microprobe Spectroscopy

虽然拉曼光谱在材料科学和固体物理学中一直被认为是研究含碳材料(CM)的有力工具，但它几乎没有被用于研究地质样品中的“石墨”。总体目标是评估激光拉曼显微探头(LRM)光谱在表征自然发生的CM方面的有用性。为了进行LRM分析，已经获得了几套逐步变质的CM，其中大多数已经进行了其他分析，如X射线衍射(XRD)和透射电子显微镜(TEM)。其目的是开发一种常规的LRM方法，1)相对快速地评估“石墨”的结晶度及其与纯碳的组成偏差，2)尽可能定量地表征碳的种类。这一结果将对理解含碳岩石的历史具有重要意义。

Although Raman spectroscopy long has been recognized in material science and solid state physics as a powerful tool for the study of carbonaceous materials (CM), it has barely been used to study "graphite" in samples of geological interest. The overall goal is to evaluate the usefulness of laser Raman microprobe (LRM) spectroscopy to characterize naturally occuring CM. For the purpose of LRM analysis, several suites of progressively metamorphosed CM have been obtained, most of which already have undergone other analyses, such as by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The intention is to develop a routine LRM methodogy 1) to provide relatively rapid evaluation of the degree of crystallinity of "graphite" and its compositional deviations from pure carbon and 2) to be as quantitative as possible in characterizing the kind of carbon. The results will be important in understanding the history of carbon-bearing rock.