ABSTRACT
Superficial deposits are mainly unconsolidated sediments that have accumulated on bedrock, weathered bedrock or earlier superficial deposits during the last tens of thousands of years and in places are still being deposited today. Climate warming since the end of the last ice age has greatly influenced the form and composition of superficial deposits because of the migration of depositional environments and the quantity of transported sediments over time. For example, the retreating glaciers in the Himalaya leave moraines in the sculptured valleys (Figure 13.1) that are then eroded, transported and deposited as alluvium in the lower reaches of the same valley that was once filled by a glacier. Sequences through many superficial deposits provide a detailed record of changing environments resulting from climate warming, tectonic uplift and/or sea level variations. Analysis of these sequences allows robust geological modelling of the ground conditions for engineering works and can establish the architecture of the deposits in relation to geotechnical parameters, hydrogeology and locations of potential risk.
