[1] Birbal Sahni Inst Paleobot, Lucknow 226007, Uttar Pradesh, India
[2] Indian Inst Technol, Dept Geol & Geophys, Kharagpur 721302, W Bengal, India
[3] Indian Inst Sci Educ & Res, Dept Earth Sci, Kolkata 741252, Nadia, India
[4] Pondicherry Univ, Dept Earth Sci, Pondicherry 605014, India