Development of Oxfordian (Early Upper Jurassic) in the Most Proximally Exposed Part of the Kachchh Basin at Wagad Outside the Kachchh Mainland
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The anunonoid abundant mid Middle Oxfordian Transversarium Zone succession in addition of the restricted Indo-East African mayaitins and widely distributed perisphinctins includes a few examples of the Mediterranean Gregoryceras gr. fouquei, Euaspidoceras and Taramelliceras and suggests maximum flooding and eustatic rise in the Kachchh Mesozoic in the Middle Oxfordian Schilli Subzone of the Transversarium Zone. Another significant aspect of this fauna is the marked continuous presence of the compressed platyconic densely costate lithacoceratins (Larcheria and Discosphinctes) stocks in parallel with the true perisphinctin and mayaitin lineages almost althrough the Middle Oxfordian (Krishna et al. 1994a. b, 1995, 1996a). The mayaitins are for the first time precisely ranged up to the Transversarium Zone.
The basin margin Oxfordian ammonoid succession at Wagad shows recurrence only of small portion in its basal part of the previously known Oxfordian section of the Kachchh Mainland (e.g. the common Perisphinctes-Epimayaites assemblage of bed G Lakbapur). The remainder ca 200 m thick Oxfordian at Wagad is interpreted here to correspond to the non-depositional submarine stratigraphic gap elsewhere in the relatively deeper parts of the basin from the later part of the Middle Oxfordian Plicatilis Zone to the early Early Kimmeridgian Hypselocyclum Zone.
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