a suggest that, the age of Datta Formation is Hettangian-Early Bajocian
This cover tectonically undisturbed rests over an unconformity that is Bajocian
in age and forms the base of the Middle Jurassic succession (Dieni et al.
1986: The Bajocian
(Jurassic) ammonite fauna of Oaxaca, Mexico.
Based on the results of the study of the clay mineral assemblage in the Middle Jurassic sedimentary succession of the Kachchh Basin, India, the Bajocian
to Middle Bathonian time interval is interpreted to represent subtropical climatic conditions with seasonal droughts and a moderate supply of terrigenous clastics to the basin.
and belonging to the Early to Middle Bajocian
(Middle Jurassic) .
2), as it is dated in the Bifrons-Variabilis zones in this sector, while it is dated in the northernmost areas of the basin as Early Bajocian
and, in the north of the Castilian branch, it even corresponds to the Pseudoradiosa Zone (Gomez, 1979).
The lower age limit is clearly late Liassic, however, the upper limit may extend up to Bajocian
(Otsuki et al.
Recent revisions of biochronology argue that the deposition of the radiolarites occured from Bajocian
to Albian, with a depositional gap during Upper Dogger (Denyer & Baumgartner, 2006).
Overlying this hardground there are nodular and well bedded platy, bioturbated limestones of the Gorg Blau Formation with fauna of the early to middle Aalenian and the Bajocian
(Discites to Humphriesianum zones), the Concavum Zone of the late Aalenian was not found (Alvaro et al.
The Gijon and Rodiles Formations have been attributed to the upper Rhaetian-lower Bajocian
(Ramirez del Pozo, 1969; Dubar et al.
2008): Foraminifera from the Aalenian and the Bajocian
GSSP (Middle Jurassic) of Murtinheira section (Cabo Mondego, West Portugal): Biostratigraphy and paleoenvironmental implications.
1993): A comparison of the Hettangian to Bajocian
successions of Dorset and Yorkshire.