Abstract

An analysis of the Koobi Fora Plateau Gravel, N Kenya, reveals clear-cut but contradictory patterns of sedimentary sorting. Basalt particles form the major constituent and decrease in diameter downstream at a rate of 3 mm km-1, while feldspar is virtually eliminated from the sediment within 30 km. But over the same ground, agate particles increase in size more than 4-fold while the sphericity of quartzite clasts decreases. These apparently conflicting sorting patterns are used to formulate a clearer understanding of the sedimentary processes that operate in widespread gravel deposits. The nature of the basalt particle size-gradient is contrasted with those published for alluvial fans and simple undivided channels to suggest diagnostic features that distinguish braided channel deposits.

First Page Preview

First page PDF preview
You do not currently have access to this article.