COAL MACERAL RATIOS AS INDICATORS OF ENVIRONMENT OF DEPOSITION - DO THEY WORK FOR OMBROGENOUS MIRES - AN EXAMPLE FROM THE MIOCENE OF NEW-ZEALAND

Maceral indices were applied to sub-bituminous coals of the Maryville Coal Measures as a means of interpreting environment of deposition. Very low amounts of inertinite and ubiquitous bituminite lead to difficulties in interpretation of the maceral ratios. Comparison with modem analogues suggests the theoretical basis for discrimination of mire type by maceral ratios is not well founded on the following grounds: absence of well structured wood tissues does not imply the absence of arborescent vegetation; inertinite formation may be unrelated to vegetation; gelification is used in a geochemical sense and does not indicate groundwater table level (as supposed for biochemical gelification); detrital macerals often result from in situ fragmentation and not transportation.