Boulders created by a large dense flow of lava are at the top of a canyon slope and will eventually tumble or slide to the bottom of the canyon. Photo by Robert Dryja
By ROBERT DRYJA
Los Alamos
We previously reviewed how the composition of lava by itself contributes to the resulting rocks seen in fields. Lava that is predominately liquid to start can become dense boulders after it has cooled. Lava that is powdery or porous when created can become sandy with small stones.
A second influence is concerned with the slopes coming down from the rim of a volcanic crater. The angles of slopes are a major influence. Read More









