There is considerable interest in the geochemistry of aluminum because of the various roles that this major earth element plays in the weathering process, in soil chemistry, and in stream chemistry. Gallium is an element with a geochemistry and solution chemistry similar to that of aluminum. Thus, gallium might serve as an analogue for aluminum. A consideration of the available knowledge about gallium suggests that the slight differences between its chemistry and that of aluminum should lead to variations in the dissolved gallium/aluminum ratio in rivers. This variation may provide useful information regarding weathering processes and aluminum geochemistry. Limited preliminary data indicate that variations in the gallium/aluminum ratio do occur. We therefore propose a more thorough preliminary study of the behavior of gallium in rivers.
