The Geological Evolution of Lake Basins

Abstract

Two things are required in order for a lake to exist on the earth’s surface: a topographically closed hole in the ground and water. The subject of how topographical depressions form on the earth’s continental crust has frequently been cast as one of lake origins, emphasizing the hole’s initial formation. However, it is important to realize that the hole itself has a history, which is partly independent of the lake that fills it, and that this history interacts with that of the water body. This chapter will emphasize this dynamic interplay that occurs throughout a lake’s history between a lake and its underlying substrate. In this sense, lake basin evolution is a more useful concept than the more static one of lake origin. The basin evolution process is manifest in everything from the three-dimensional geometry of the lake deposits that underlie the lake, to the rates of sediment accumulation, and the probable history and life span of the lake. Furthermore, different types of lakes are better or worse suited to answer specific paleolimnological questions. Some evolutionary mechanisms predispose lakes to persist for millions of years. Records in these lakes are ideally suited to answer questions that require long temporal records. Other questions require high-resolution records of short duration, which may be better represented in lakes formed by different mechanisms. And still other mechanisms result in the formation of numerous lakes with similar characteristics within a region, ideally suited for comparative studies. Understanding lake basin evolution is therefore an essential element in the design of a paleolimnological study, because the quality of paleolimnological records is directly linked to the mechanisms of basin evolution. The formation of lakes has intrigued earth scientists for more than 100 years (W.M. Davis, 1882, 1887; Penck, 1882, 1894; Russell, 1895; Supan, 1896). Hutchinson (1957) elaborated on these earlier works, recognizing 11 major categories of lake origins and 76 subcategories. Numerous advances in understanding basin evolution have been made since Hutchinson’s work, especially from improved radiometric dating techniques, seismic stratigraphy, and lake drilling over the past 50 years.