ARHIVELE OLTENIEI - Universitatea din Craiova

370Sandu BoengiuIt has to be underlined that these paleocoenoses were not closed; theyinterpenetrated and thus, it resulted a peat with multiple origins, fact that can bededuced from the study of the lithotypes that make up the lignite.The palynological studies made at the level of the Romanian determinedpaleophytocoenoses with Glyptostrobus, Myrica – associated with Salix, Alnus,Acer, Cyrilla, Ilex, Symplococos, Osmunda and Polypodiacee, with reeds(Phragmites, Typha, Stratiotes, Sphagnum) and with Nympheaceae, Salvinia,Botrycoccus.On the basis of the petrological analysis it is considered that the wood ofGlyptostrobus led to the appearance of xylit in proportion of 50%. Due to theresistance of Glyptostrobus wood to the transformation in humic acids ofcelluloses and lignin and to the fact that this coniferous raised in marshes withpermanent water where it could be humificated and not decomposed, it resultsthat there were gathered all the conditions of transformation into xylitic coal.The paleophytocoenosis with Phragmites led to the appearance of poorxylitic coals, while the one with Phragmites and Byttneriophyllum to detritic coal.The fruit, seeds, and especially the leaves of the trees, as well as therhizomes of different paludous and aquatic herbaceous plants, form detritic coalthrough annual accumulation and in mixture with a mineral substance.The content of macerals is well represented by textinit, followed byhuminit (testo-huminit). There also appear humodetrinit and humocolinit. Theliptinit and the inertinit are sporadic macerals. The poorly xylitic coal is made upof humeodetrinit and humeodetrinites and humeocolinites, with a low content ofliptinit and internit, while the detritic coal is made up of humodetrinit (49 –77%) and some humotelinit.The liptinit appears quite rarely and as cutinit. The chemical analysesmade upon the fusinit proved that it come from the accidental fire of the marshforests with Glyptostrobus.The modifications of the water depth induced by the tectonic andepeirogenetic movements determined the vertical alternation of thepaleophytocoenoses and the formation of the genetic series confirmed bypetrographic analyses. On the basis of the reconstitution of the genetic series,there were drawn humito-genetic maps at the level of the V coal bed, by meansof which it was established that the Glyptostrobus – Phragmites vegetal grouphad the most important (qualitative and quantitative) contribution to theformation of the lignite types from western Oltenia.As compared to the present flora, it is obvious that, during the Dacian,there predominated the east-Asian and north-American elements and not theCaucasian, Mediterranean, and central-European ones.In Romania however, it began the proliferation of the Mediterranean andcentral-European elements as compared to the Asian and Atlantic-northAmerican ones, as well as the diminution of the Dacian subtropical elements,which found a refuge west of the Motru River.