Palynological investigations of tertiary lignite and associated sediments from Cannanore, Kerala Basin, India

Abstract

The palynofloral recovered from the Tertiary lignite and associated sediments exposed along Cannanore and adjoining area of Kerala Basin consists of 50 genera and 73 species. Of these, 13 genera and 20 species are represented by pteridophytic spores and 36 genera and 52 species to angiospermous pollen. Ten species have been proposed as new. Some significant constituents of the assemblage are- Lygodiumsporites, Dictyophyllidites, Crassoretitriletes, Intrapunctisporis, Cheilanthoidspora, polypodiisporites, Retimonosulcites, Quilonipollenites, Lakiapollis, Tricolpites, Gemmatricolpites, Tricolporopollis, Dermatobrevicolporites, Margocolporites, Retitrescolpites, Meliapollis, Ctenolophonidites, Myricipites, Triporopollenites, Clavaperiporites and Malvacearumpollis. Quantative dominance of angiospermous pollen is a conspicuous feature of the assemblage. Ecological analysis of the assemblage identifies several palaeoassociations of low-land, fresh water swamp and water edge, sandy beach, montane and back mangrove vegetation. The recorded palynological assemblages indicate the prevalence of wet semi-evergreen type of vegetation with warm and humid tropical climate and plenty of rainfall during sedimentation. The brackish-water environment of deposition is indicated by back-mangrove elements (Palaeosantalaceaepites, Mavacearumpollis) and dinoflagellate cysts. On the basis of comparison of the present assemblae with the known Indian Tertiary palynoassemblages, Miocene age has been assigned.