Decoding authigenic and allogenic forcings on tropical fluvial landscape development during Quaternary
Late Cenozoic period of the earth’s history is marked by several episodes of crustal adjustments and climatic oscillations. The resultant fluvial landscapes represent an outcome of complex interplay of regional vis-s-vis basin scale tectonics, erosion, climate change etc. Broad correlation of climate-tectonics coupling is evidenced from much celebrated examples viz., Himalayan orogeny and Asian monsoon evolution, and also from regions like Appalachians, Alps, Andes, Pyrenees etc. It is often postulated that erosion, climate and tectonics interact with each other in a state that is usually and in most regions approximated as quasi-equilibrium and hardly leaves any one to one correlation trend. Tropical rivers, the economic engines in the tropics, are draining a variety of landforms. Tropical Rivers with high seasonal variability in discharge have a wide variety of geomorphic styles and sedimentary processes. Evolution of tropical river systems is often guided by the tectonics-climate coupling from source to sink regions. However, it is often difficult to disentangle the effects of individual factors without an in-depth understanding of spatio-temporal landscape development. Further complications arise due to synchronous and sometimes conflicting authigenic (e.g. local structure, tectonics geomorphology, geology etc.) and allogenic (e.g. sea level fluctuations, regional and global climate change, regional tectonics, and anthropogenic intervention) controls. The present session invites new findings on the evolutionary aspects of the rivers in tropical and sub-tropical settings using fluvial archives and landforms.
Rajiv Sinha and Snigdha Ghatak