Abstract:

Vitrinite reflectances may be described by vectors starting from the originof three-dimensional coordinate-system.The length of a reflectance vectordepends on its direction.Theoretically,any vitrinite particle has infinite reflec-tance vectors.These vectors construct a three-dimensional figure called“vitrinitereflectance solid”（VRS）.The three principal axes of VRS are maximum ref-lectance R_max intermediate reflectance R_int and minimum reflectance R_min res-pectively.The VRS may be double concave,and is not a standard ellipsoidof geometry.This paper deals with the geometrical features of VRS in detail,and provi-des a method for determining the lengths and directions of the principal axesby six readings measured on three mutually perpendicular polished-surface.This method may be used for the studies of petroleum geochemistry,coalpetrology and structural geology.