14C Dates (yr BP) | Location, Local (L) Biozone, Depth from MSL (cm) | Biostratigraphic Zones | Environment of Deposition | Geomorphic Changes and Evolution of Bengal Delta |
5000-3000 to present | Calcutta (L) CVBZ V Depth +600 to 00 DumDum (L) D1BZIII Depth +500 to 00 Barrackpore (L) B1BZ1a Depth +600 to+65 Barrackpore (L) B1BZ1b Depth +65 to −50 | BBH. BZ. V: Heritiera-Potamogeton- Typha-Fern-Concentricystes rubinus (Type-II) Gloetrichia- Gavialis-Chitra-Bellamya- Pila Thiara-Lymnaea | Freshwater with Brackish Water Influence to Fresh Water | Delta Top to Inland |
6175 - 5000 | Calcutta (L)CVBZIV Depth 00 to −200 DumDum (L) D1BZII Depth 00 to −150 | BBH. BZ. IV: Heritiera-Bruguiera-Pandanus- Cheno-Amaranthus-Poaceae-Typha- Fern-Concentricystes rubinus (Type I) | Brackish Water Mixed Fresh Water | Delta Top |
6400 - 6175 | Calcutta (L) CV BZIII Depth −200 to −500 DumDum (L) D1BZI Depth −150 to −300 | BBH. BZ. III: Ceriops-Bruguiera-Excoecaria- Avicennia-Sonneratia Rhizophora-Heritiera-Typha- palaeocirrenalia-Callimothallus- Concentricystes rubinus (TypeI)-Bankia | Estuarine Mangrove with High Precipitation | Tidal mudflat |
6500 - 6400 | Calcutta (L) CV BZII Depth −500 to −610 Kolaghat (L)K1 BZII Depth +100 to −50 | BBH. BZ. II: Avicennia-Sonneratia-Rhizophora- Ceriops-Bruguiera-Excoecaria-Heritiera- Fern-Ammonia-Neritina-Telescopium- Geloina-Bankia-Martesia | Shallow Marine to Swampy Mangrove | Shallow marine to Delta Front |
7000 - 6500 | Calcutta (L) CV BZI Depth −610 to −625 Kolaghat (L)K1 BZI Depth −50 to −100 to −500 | BBH. BZ. I: Heritiera-Bruguiera-Acrostichum- Fern-Ammonia | Marine Inundation (Flandrian Transgression) in Freshwater Condition | Estuarine to Shallow Marine |
>7000 | Calcutta CV (L) Barren Zone Depth −625 to −700 Kolaghat K1(L) Barren Zone Depth −500 to −550 | BBH.BZ Barren zone of Kankar nodules | Arid | Dry, Upland |