Natural fluid-deposited graphite: Mineralogical characteristics and mechanisms of formation

Abstract

This paper focuses on the similarities and differences between metamorphic graphite (formed in situ from organic matter) and fluid-deposited graphite. We discuss the formation of fluid-deposited graphite in terms of the source of carbon, the characteristics of the C-bearing fluids (the C-O-H system), the mechanisms of carbon mobilization, and the mechanisms of carbon precipitation. New and existing analytical data are compiled on the physical and chemical characteristics of fluid-deposited graphite obtained by the following techniques: optical microscopy, differential thermal analysis, thermogravimetry, X-ray diffraction, Raman spectroscopy, and stable isotope mass spectrometry. Our discussions focus on major, that is, volumetrically significant, worldwide concentrations of graphite.