Upper Cretaceous (Maastrichtian) charophyte gyrogonites from the Lameta formation of Jabalpur, Central India: palaeobiogeographic and palaeoecological implications

作者：Khosla Ashu^*

来源：ACTA GEOLOGICA POLONICA, 2014, 64(3): 311-+.

DOI：10.2478/agp-2014-0016

• Charophyta
• Palaeobotany
• Palaeogeography
• Biogeography
• CretaceousPalaeogene boundary

A charophyte gyrogonite assemblage consisting of Plcoycham cf. sahnii, Nemegachara grambasm and Mierocham sp. is reported herein from two localities (Bara Simla Hill and Chui Hill sections) of the Lameta Formation at Jabalpur. The Lameta Formation locally underlying the Deccan traps has been shown to be pedogenically modified alluvial plain deposits containing one of the most extensive dinosaur nesting sites in the world. They are associated with dinosaur bones and freshwater ostracod assemblages that suggest a Late Cretaceous (Maastrichtian) age. This is the first detailed systematic account of charophyte gyrogonites from the Lameta Formation This charophyte assemblage is compatible with the biostratigraphic attribution provided by the ostracods. From a biogeographic viewpoint, it exhibits considerable similarity to other infiatrappean assemblages of the Nand, Dongargaon, and Dhamni-Pavna sections (Maharashtra), and some intertrappean assemblages of Kora in Gujarat, Rangapur in Andhra Pradesh and Gurmatkal in South India. Globally, the genus Micaochara is well distributed throughout Eurasia, whereas the genus Plcaychara occurs richly in the Upper Cretaceous deposits of Europe, Asia, America and Africa. However, at the specific level, Plaq'cliam cfi sahnii shows close affinities with charophytes from the Maastrichtian of Iran whilst Nemewicham grambavii shows distinct affinities with two species of Early Palaeogene deposits of China and Mongolia. The presence of charophyte gyrogonites in the Lameta sediments is attributed to local lacustrine and palustrine conditions within a flood plain envirmunent.

• 出版日期2014