Chromium and Nickel in the Fig Tree Shale from South Africa

Science  13 Oct 1967:
Vol. 158, Issue 3798, pp. 261-262
DOI: 10.1126/science.158.3798.261


Exceptionally high contents of chromium and nickel in shales from the early Precambrian Fig Tree series of South Africa (〉 3.1 x 109 years old) suggest that the ancient crustal rocks from which these sediments were derived were ultramafic in composition.