The dataset includes abundances of major, minor and trace elements, as well as abundances and isotopic ratios of organic carbon, of rock samples from a stromatolite-bearing horizon in the Mount Ada Basalt in the Pilbara Craton in Western Australia, 3.47 Ga. The section contains the oldest known large domal stromatolites. The data indicate hydrothermal nutrient sources and limited influx of felsic detrital material.