On detailed field-based observations of laterite and laterization: a study in the Paschim Medinipur lateritic upland of India

摘要

The term ‘laterite’ and the process ‘laterization’—both have raised perpetual scientific debates. The present study reviews the relevant scientific pieces of literature associated with tropical red lateritic and ferralitic soils and tries to justify them with the observations in the Paschim Medinipur Lateritic Upland. This particular area is practically the natural laboratory for observing the laterization process. The area exhibits a distinctive geomorphologic, hydrological, and climatic characteristic over an evolutionary geological setting. The favorable tropical climate, intense weathering, groundwater movement with seasons, and neo-tectonic upliftment exerts complex influences on the pedo-geomorphological distinctiveness of this area. Presence of planation surfaces, typical scarp development along the surface margins and exposure of deep lateritic profiles by basal sapping, accelerated erosion of the margin, and formation of rills and gullies with waxing slope development are worthy of being synced with available scientific understandings. The study is based on extensive field observations, profile studies, and soil sample analysis from different geomorphic units. The study reveals that the role of tectono-climatic evolution has had a massive influence on characteristics and development of the present lateritic formations. Transportation and deposition of Neogene ferruginous sediments over basin shelf region as paradeltaic formation, alternating wet (June–October), and dry (November–May) monsoonal climate with adequate rainfall and iron segregation and relative accumulation along with neo-tectonic modification are the important considerations regarding ferrugination process in the area under study. The justifications of the observed attributes of this particular tropical lateritic landscape may be used as a reference work for future scientific studies and model building processes on the same in this area as well as the other parts of the world.