|mhorn||Дата: Sunday, 24.01.2010, 17:33 | Сообщение # 1|
|Carevic I., Jovanovic V. (2007) Tithonian-Berriasian beds of Dedine stream near Golubac // BULLETIN OF THE SERBIAN GEOGRAPHICAL SOCIETY. Vol,.LXXXVII. no.2. P.63-66. |
In this occasion in the vicinity of Dedine stream the boundary between the Tithonian/Berriasian is placed among second and third package of beds according to the expansion of calpionellae species Calpionella alpina. The boundary between Upper Jurasic and Lower Cretaceous is not sharp and is followed by continued sedimentation, but the transition from the Tithonian to the Berriasian is gradual. The only diference is in thicker concentration of Calpionella alpina species, to whom the conditions on the very beginning of the Berriasian are extremely favorable, so there came to its “flourishing.” The first appearing of the Berriasian species Tintinnopsella carpathica is in the eleventh package of beds, while the ammonite Berriasella jacobi, also distinctive Berriasian species is determined in sixth package of beds. However, even so, the boundary Tithonian/Berriasian is placed according to the rapid expansion of Calpionella alpina species in the third package of beds, because this species represents the most important microfossile association of the Upper Jurasic/ Lower Cretaceous pelagic sediments.
Middle Jurassic - Lower Cretaceous ammonites & aptychi