Roraima, Tabelberg and Uatumã Formations of the Guiana Shield: a correlation

Abstract

On the western and central parts of the Guiana Shield, South America, tabular sedimentary sequences are found, consisting of sandstones, shales and conglomerates and of tuffs, tuffites and graywackes. In Venezuela, Guyana, Roraima and Surinam they have been designated the Roraima Formation; on the southern margin of the Guiana Shield in Brazil they are called the Uatumã Formation. The writer argues that they are similar in origin and probably are roughly coeval in the several parts of the Shield. Summaries and a selection of quotations are presented, in part taken from not easily available papers, and in part translated for the benefit of students who read English but not Portuguese.