Dever, "Hydrochemical and isotopic characterisation of the Bathonian and Bajocian
coastal aquifer of the Caen area (northern France)," Applied Geochemistry, vol.
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., 1983).
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.
The Gangni Township section yields ammonites of Sonninidae, mainly including Sonninia, Dorsetensia, Witchellia, etc., and belonging to the Early to Middle Bajocian
(Middle Jurassic) .
These tax.a suggest that, the age of Datta Formation is Hettangian-Early Bajocian
can be regarded as diachronic (Gomez, 1979), since it took place earlier in the I-LS (Bifrons-Variabilis zones) than in the remaining areas of the Iberian Range (Pseudoradiosa Zone-Lower Bajocian
), noticeably conditioning the distribution of the brachiopod successions (Garcia Joral et al., 1990).
The lower age limit is clearly late Liassic, however, the upper limit may extend up to Bajocian
(Otsuki et al., 1989).
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., 1989).