Map 5.1, located on the next page, is a portion of a topographic map from Royal Gorge, Colorado, courtesy of the USGS. Study the
map and answer the questions below. What type of stream drainage pattern is present on this map? This may be easier to determine by examining the tributaries to the main stream.
A dendritic drainage pattern is the most common form and looks like the roots of trees branching pattern. It is a drainage pattern in which streams branch in many directions randomly at different angles as well. It develops in regions that have underlying homogeneous material. This means the subsurface geology has a similar resistance to weathering resulting in no seeming control over the direction the tributaries take. It is produce in streams that receive several tributaries that are fed by smaller ones. Tributaries link up a larger stream at acute angle ( angle less than 90 degrees). It can be indicated when streams flow across horizontally and complex crystalline rock/homogeneous strata help in resisting erosion uniformly.
<span>Andesite: </span><span>a dark, fine-grained, brown or grayish volcanic rock that is intermediate in composition between rhyolite and basalt.</span>
