Portal de Periódicos da CAPES

The spatial extension and the age of the Tomnatec formation in Audia Nappe

2001; Cluj University Press; Volume: 46; Issue: 2 Linguagem: Inglês

10.5038/1937-8602.46.2.9

1937-8602

Liviu Ionesi, Florin Florea,

Paleontology and Stratigraphy of Fossils

In the northern area of Audia Nappe, in between Sălătruc River (a right hand tributary of Moldova River) and the northern border of our country, the Tomnatec Formation crops out.It unconformably overlies the Variegated Formation (Vraconian -Maastrichtian) and is covered by Ionul Formation (Priabonian).We have to mention that the Tomnatec Formation is better developed in the eastern part of Audia Nappe whereas on the rest of it crops out only sporadically.On this basis Ionesi divided Audia Nappe (1965, p. 66-67) in two digitations: the lower one, Prisaca Digitation, in the eastern part and the upper one, Black Shales' Digitation, in the western part.The Black Shales' Digitation is overthrusting upon the Prisaca Digitation after the Feredeu Fault.The lower digitation is tectonically subsided which could explain the better preservation of it while the upper digitation is tectonically uplifted.The upper digitation position is supposed to be the explanation for the missing of Tomnatec Formation from it.The same interpretation was reconsidered and developed by Ionesi (1971, p 157-158).The two digitation defined by Ionesi (1965) are represented also on Geological Map of Romania (Câmpulung Map, 1:50 000; Săndulescu et al., 1987) edited by Geological and Geophysical Institute of Romania.Săndulescu (1984, p. 264-265), in Geotectonica României (Geotectonics of Romania) paper, names the Black Shales' Digitation as Inner Digitation.He also considers it as being an equivalent of Cernahora Unit (s.s.) is extended to south along the Audia Nappe.This means that the sandstone which cover the Variegated Formation could be equivalent to Siriu Sandstone (Senonian -Paleocene) and not to Prisaca Sandstone (= Tomnatec Sandstone) of the same digitation.This point of view is again defended by Săndulescu et al. (1990Săndulescu et al. ( , 1993)).In the latter paper the authors exclusively study the sandstone of the inner digitation, which is named Benia Digitation.This sandstone is given the same name as the digitation (Benia Sandstone).The authors think that this sandstone is Santonian -Lower Campanian (?) while the sandstone of Prisaca Digitation is considered to be Maastrichtian -Lutetian age.We consider the above introduction as being useful in the development of our paper.We propose the name Feredeu Digitation for former named Black Shales'