|mhorn||Дата: Saturday, 02.03.2013, 10:55 | Сообщение # 1|
|Patel S.J., Joshi P.N., Joseph J.K. (2012) Ammonite zonation of the Jurassic rocks of the Gangta Bet area, Wagad region, eastern Kachchh, India // Journal of the Palaeontological Society of India. Vol.57. no.2. P.35-39. |
Gangta Bet, a structurally controlled elliptical dome, occurs as small detached landmass situated onthe western fringe of Wagad highland and comprises thick marine clastic and non-clastic sequence of the Upper-Middle Jurassic. It comprises 103 meter thick exposed sequence, which consists of various types of sandstones, shale, c onglome rate, and limestone. Top part of the sequence is composed of abundant ammonitic fauna; the intercalated calcareous sandstone-shale consists of Peltoceras athleta, Peltoceratoides semirugosum; the Gangta ammonite band, a limestone unit, occurs near the top of the sequence as an important marker horizon and consists of Mayaites (Mayaites) maya, Mayaites sp. Perisphinctes (Arisphinctes) helenae, Perisphinctes (Kranosphinctes) kranaus, Perisphinctes (Dichotomosphinctes) and Perisphinctes sp. The ammonite species of Gangta Bet display three Biozones and five subzones which indicate that the age of the Gangta Bet rocks ranges from Late Callovian to Early Middle Oxfordian.
Middle Jurassic - Lower Cretaceous ammonites & aptychi