Limnology is the study of modern lakes, whereas Limnogeology is the study of lakes in the geologic record.
Lakes and their sedimentary sequences preserve high-resolution records of past environmental conditions. Recent investigations by Bohacs et al. (2000) show that the primary controls on lake sedimentation are tectonics, climate and provenance. These three factors control the three lake types, further explained on the Lake Basin Types page. Also interesting is the Lake Origins page which lists all of the different ways that a lake can form.