VOLUME 39 (3)/December 2010

Most of the specimens of Corynepteris collected from the Dobrudzha Coalfield sequence are small parts of pinnae. Two species – C. angustissima and C. coralloides predominate. The habitat of Corynepteris had been studied for a long time. The genus occurs in several units of clastic sediments deposited under fluviatile conditions across the prospected part of the depression, but is absent above the coal seam m₉ (middle Bolsovian). When the swamp conditions were restored briefly (coal seams n₁–n₄) or for a longer time (Gurkovo Formation) the genus did not resettle in the depression. The nearest basin with the genus Corynepteris presented at that time is in the Czech Republic, more than 800 km away, which was too far for an effective reintroduction of the genus to the Dobrudzha Coalfield. Spores of the genus range up into the Westphalian D coal seam n₃.

Part 1 of the present work elucidated some general considerations of inorganic matter in coal and determined and explained the relationships, namely statistically significant positive or negative correlations, for chemical characteristics. Complete data from chemical (proximate, ultimate and ash analyses) and mineral composition (major and minor minerals) of 37 coal samples worldwide were used for that purpose. The present Part 2 provides and explains the significant correlations for minerals of these coals. Then, some important relationships between the composition and rank and ash-fusion characteristics of the coals are described. Further, definitive mineralogical and geochemical indicators for genetic interpretations of coal formation are summarized. Finally, the potential implications of these relationships and indicators are discussed and certain new features that may be used as criteria for clarifying the coal properties and for predicting specific technological and environmental problems related to this fuel are also introduced and suggested.