 The lower Kam group consists of the Chan Formation which contains flows of pillowed basalts intruded by a series of gabbroic sills and dikes that were produced in an extensional back-arc basin setting.Sedimentary rocks exposed in the northern part of the formation are between 2.84 and 2.80 Ga.The Upper Kam Group contains three formations deposited between 2772 and 2701 Ma.