Quaternary engineering geology

Summary The geological and geomorphological effects on the Earth’s surface during the Quaternary have been both extensive and profound. An attempt has been made to simplify and summarize these effects by considering the principal agencies at work during the Quaternary: plate tectonics, rapidly rising sea levels, rapidly falling sea levels, rapidly cooling climates and rapidly warming climates. The resulting series of major glacial and interglacial episodes have had far-reaching consequences for the engineering characteristics of the Earth’s surface. In attempting to summarize these major omissions will have been inevitable and errors will have occurred due to compression of the subject and its interpretation in a simplified manner. Table 2 summarizes the approach of the paper in itemising the principal Quaternary events, causes and effects, consequences to landscape and inferences to engineering. Each of the six events has been developed into larger tables and accompanied by some discussion and examples. The principal consequences of the events for engineering have been the production of glacial and periglacial soils,over large areas of the northern and southern hemispheres; changes in the sediment patterns on the coasts, the continental shelves and in river systems; and the development of weathering profiles of very variable type and distribution leading to development of in situ residual soils of many different engineering characteristics. The major shifts in climate associated with these events have led to migration of various surface forms which are now being exposed or covered by the present regime, leading to many active slope processes with potential instability for engineering projects and unexpected distribution of materials. The continuing events of plate tectonics which precedes the Quaternary by a long period of geological time explain the distribution of earthquake systems, growing coastlines and mountains, and the pattern of volcanic areas with their own suites of rock and soil of significance for the engineer.