Gondwana Sequence of the northern Pranhita-Godavari Valley: its stratigraphy and vertebrate faunas

Abstract

The Gondwana Sequence in the northern part of the Pranhita-Godavari Valley consists of four formations of the Lower Gondwana and seven formations of the Upper Gondwana. The gross lithological characters and mappability are considered as the major criteria for delineating the formations. The name Kamthi Formation which has been used by different authors in different senses, is here used in the sense of Sengupta (1970). The rocks between the Barakar and this Kamthi are divided into four lithozones for limitations of mappability. Although some of these lithozones have earlier been designated as formations, at present not sufficient information is available to justify this. Only two breaks, both within the Upper Gondwana, are found to be present: there is no recognisable break between the Lower and the Upper Gondwana. A summary of this succession is presented in tabular form taking into account the words of earlier authors. The alternative views that are radically different from the one presented here are also discussed briefly. The usefulness of plant megafossils and fossil vertebrates in understanding the stratigraphy is discussed briefly and their role in determining the possible geological ages of some of the formations is mentioned.
 The vertebrate fauna from a number of formations is listed. At least seven formations are fossiliferous as far as vertebrates are concerned. Of these, two belonging to the Triassic and one belonging to the Jurassic are quite well-documented. The other four are less well known, but serve as very useful time markers. All these vertebrate-bearing formations can be correlated with co-eval rocks elsewhere in the world. The difficulty of correlating continental deposits is realized and keeping this in view a tentative correlation is presented.

Reappraisal of the genus Dicroidium Gothan from the Triassic sediments of India

“…Amongst the eight species of Dicroidium known from Peninsular India, D. hughesii occurs preponderantly throughout the Parsora Formation and occasionally in the Tiki Formation. Tiki Formation has been dated as Carnian and the Parsora Formation has been dated as Norian-Rhaetian (Roy Chowdhury et al, 1975;Sastry et al, 1977;Pal, 1984aPal, , b, 1996Kutty et al, 1988;Srivastava & Jha, 1990;Pal & Ghosh, 1997;Dutta, 2002Dutta, , 2004Ghosh et al 2007;Mukherjee et al, 2012). Therefore, in India, D. hughesii is restricted to late Triassic (Carnian to Norian-Rhaetian).…”

“…Pinnule margin entire, rarely slightly wavy at places, sometimes near apex somewhat dentate; apex rounded or obtuse; acroscopic margin contracted, basiscopic margin decurrent. Veins distinct, one principal vein arise from rachis, forming a midvein, also in some cases near et al, 1975;Sastry et al, 1977;Pal, 1984aPal, , b, 1996Kutty et al, 1988;Srivastava & Jha, 1990;Pal & Ghosh, 1997;Dutta, 2002Dutta, , 2004Ghosh et al, 2007, Mukherjee et al, 2012Geological Time Scale after Gradstein et al, 2012).…”

“…Therefore, interbasinal correlation has been done on palaeontological and lithological attributes. A generalised classification of Triassic Gondwana in Peninsular India has been given in Table-2 (based on Roy Chowdhury et al 1975;Sastry et al, 1977;Pal, 1984aPal, , b, 1996Kutty et al, 1988;Srivastava & Jha, 1990;Pal & Ghosh, 1997;Dutta, 2002Dutta, , 2004Ghosh et al, 2007;Mukherjee et al, 2012).…”

Indian Gondwana palynochronology: relationships and chronocalibration

“…The Gondwana succession in Madagascar and Australia have intermittent marine control and can also provide comparative palynological data. To a large extent, the time connotations of the nonmarine fauna and flora of the peninsular India are also well established (see Borkar, 1993;Satsangi, 1987;Tiwari, 1996Tiwari, , 1999aBandopadhyay & Roy Chowdhary, 1996;Prasad & Jain, 1994;Prasad et al, 1996;Kutty et al, 1988;Prasad, 1997;Wopfner, 1999;Vijaya, 2000;Vijaya & Roy, 2000;and references therein). Event stratigraphic, radiometric and carbon-isotope studies could provide additional help in refining palynologically determined chronology.…”

Early Cretaceous flora of India- A review

“…Geology of the Gangapur Formation, along with other formations in the Pranhita-Godavari Graben, has been studied by Sen Gupta (1970Gupta ( , 2003, Rudra (1982), Bandyopadhyay and Rudra (1985), Raiverman (1986), Kutty et al(1987), Lakshminarayana and Murti (1990) Kutty et al, 1987). 1996, 2002) and Biswas (2003).…”