Of course, terrestrial life back then was more in the nature of bacterial mats than oak trees and mammals.
Modern laterites form in the tropics where large amounts of organic material rapidly decay.
Since we have now traced these laterites to 2.3 billion years ago, there must have been atmospheric oxygen and terrestrial life at that time. Ohmoto originally looked at formations in Waterval Onder, South Africa, an area near Pretoria. To get the big picture, the researchers looked at core samples drilled by miners who typically drill through these layers looking for gold and uranium ores buried much farther down. It appears that this laterite formation covers a rather large area. There are several places further west where the formation is actually exposed, but these locations had previously been dated as much younger rock.