Remote sensing approaches for mapping Quaternary deposits: A synthesis

The importance of producing palaeoenvironmental, palaeoclimatic and palaeoseismological data for archaeological, environmental, climate change and active tectonic studies enhances the importance of mapping Quaternary deposits. Urbanisation mainly develops on plains that are geographically attractive and generally covered by Quaternary deposits. The basic reasons for this are related to their suitability for transportation and intersection with water resources. Beyond their characterisation as only ‘alluvium’ in almost all geological maps, detailed information about Quaternary plains is now essential for engineering purposes, particularly because of earthquakes and related liquefaction problems. In this study, remote sensing approaches for mapping Quaternary deposits are reviewed. Although the success of using airphotos, multispectral and hyperspectral (passive systems), and radar and LiDAR (active systems) images in mapping of Quaternary units is remarkable, their uses are generally individual, and thus they are far from presenting comprehensive results. We expect that the using remote sensing approach for mapping of Quaternary deposits, systematically based on mapping of lithological, geomorphological and soil characteristics together, which are mainly considered in the geological mapping of areas covered by Quaternary deposits individually, offers the most reliable approach. While the passive system sensors are particularly important for mapping lithological and soil features, the active system sensors are more convenient for geomorphological and soil mapping. Field mapping still remains essential; however, there is an increasing need for rapid mapping of Quaternary units before they are covered by anthropogenic interventions (e.g. afforestation, urbanisation, agricultural use). The combined use of different parameters outlined in this study can facilitate and accelerate more reliable mapping of Quaternary deposits according to their depositional environments.