Paleopedological studies of late cretaceous lameta formation Jabalpur Madhya Pradesh India to reconstruct palaeoclimatic changes

Abstract

The Cretaceous sediments in Central India occur as isolated outcrops along the Narmada valley, known as the Lameta Formation. The Upper Cretaceous Lameta (~infratrappean) Formation of the Jabalpur area (Madhya Pradesh, Central India) preserves one of the most diverse Late Cretaceous reptilian assemblages (largely dominated by dinosaurs) and other significant biotic elements of the Indian subcontinent. Lithologically, the Lameta sediments comprise limestone, marl, sandstone, and paleosol as major sedimentary facies. The Lameta Formation is well studied in the context of sedimentology and paleontology, but the Lameta paleosols have undergone limited investigations. In contrast, similar Late Cretaceous sediments in other parts of the world have been extensively investigated for paleosols. The present research addresses this research gap and is based on the study of the paleosol profiles in the Late Cretaceous Mottled Nodular Bed and Lower Limestone lithounit of the Lameta Formation at Jabalpur city (Madhya Pradesh, Central India). Detailed investigations on the basis of morphological, micromorphological, and geochemical studies were undertaken for this thesis. These studies reveal the presence of various in-situ pedofeatures. For example, abundant bioturbation features, moderately developed blocky and granular microstructure, crystallitic and undifferentiated b-fabrics, Fe-Mn oxide/clay, silica to carbonate coatings, hypocoatings as well as quasicoatings, nodules/concretions, and other textural as well as depletion pedofeatures. Their degree of development and abundance suggest weakly to well-developed paleosol profiles that formed under tropical warm, humid climatic conditions, deposited in a landscape that was a mosaic of wet and dry lands. newline