NATURAL FLUID-DEPOSITED GRAPHITE - MINERALOGICAL CHARACTERISTICS AND MECHANISMS OF FORMATION

This paper focuses on the similarities and differences between metamor phic graphite (formed in situ from organic matter) and fluid-deposited graphite. We discuss the formation of fluid-deposited graphite in ter ms of the source of carbon, the characteristics of the C-bearing fluid s (the C-O-H system), the mechanisms of carbon mobilization, and the m echanisms of carbon precipitation. New and existing analytical data ar e compiled on the physical and chemical characteristics of fluid-depos ited graphite obtained by the following techniques: optical microscopy , differential thermal analysis, thermogravimetry, X-ray diffraction, Raman spectroscopy, and stable isotope mass spectrometry. Our discussi ons focus on major, that is, volumetrically significant, worldwide con centrations of graphite.