Peculiarities in the composition of the carboniferous megaflora in Svoge and Dobrudza coalfields (Bulgaria)
2011
Georgiev-Tenchov, Y., Bulgarian Academy of Sciences, Sofia (Bulgaria). Geological Institute
The Svoge Coalfield is an intramontane depression in the Variscan Range, probably 2000 metres above sea level. The Dobrudzha Coalfield is a depression in the Variscan foredeep, at least 190 metres above sea level. The composition of the Pendelian to Bolsovian megafloras of both coalfields is compared. The differences affect mainly the composition of the pteridosperms. In the Svoge Coalfield Lyginopteris, Lonchopteris, Reticulopteris and Linopteris are not present. Eusphenopteris, Alethopteris, Mariopteris, Neuropteris and Paripteris are represented by one or two species, but disappear earlier than in the Dobrudzha Coalfield. Neuralethopteris is represented by some local species and N. schlehanii also disappears earlier than in Dobrudzha. In the Dobrudzha Coalfield, genera with reticulated veins are well represented, including some neuropterids with frequently semi-reticulated veins. These differences allow for the interpretation of the effects of cooling, which are greater in the Svoge Coalfield. A sequence is established of the sensitivity of genera to cooling. Regional drought in the Dobrudzha Coalfield resulted in intensive vein reticulation in Neuropteris.
显示更多 [+] 显示较少 [-]