Lithotype chemical variation

Chemical Variation as a Function of Lithotype and Depth in Victorian Brown Coal... 

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

Coal seams display two different modes of variation rank and type. The rank of the material under consideration is anthracite. Regarding type, coal is composed of different bands of materials, distinctly contrasted in regard to physical and chemical composition. These bands are termed lithotypes in this paper, after the word coined by Seyler (2) in 1954. 

These chemical data support the concept of lithotype variation and demonstrate heterogeneity within a thick coal seam. 

---