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Geology topics

Charles B. Hunt

Publications and source records attributed to Charles B. Hunt.

6 recordsLinked to original sources
USGS1984

Surficial geology

Surficial materials are those at or near the Earth's surface. They constitute, by far, the largest and most used part of the ground around us. Areas not covered by surficial deposits--bare bedrock--form probably less than 5 percent of our land surface. Most surficial deposits are composed of poorly consolidated clay, silt, sand, or gravel-sized particles that are produced chiefly by erosion and are transported by and finally deposited by water, wind, or ice, but are also partly produced by the in-situ weathering of bedrock. The major genetic categories are shown on the map by various colors; the principal compositional types in each category are indicated by patterns. Colors, patterns, and letter symbols are given in the explanation which follows this summary description. Surficial deposits have characteristics important to our environment--water-bearing properties, mineral resources, and suitability as a natural foundation for buildings. They are also susceptible to flooding, erosion, ground subsidence, land slides, and earthquakes.

National Atlas of the United States of America↗
USGS1969

The Colorado River region and John Wesley Powell

A century ago John Wesley Powell-teacher, scientist, and veteran of the Civil War-set out to explore the unknown reaches of the Colorado River. He emerged from the forbidding canyons with a compelling interest in the nature of the western lands and how they could be developed for the greatest benefit to the Nation. A man gifted with imagination, yet always tempered by the scientist's appreciation for facts, Powell became one of the country's most vigorous proponents for the orderly development of the public domain and the wise use of its natural resources. Throughout his lifetime, Powell stood firm in his belief that science, as a sound basis for human progress, should serve all the people, and he played an important role in organizing and directing scientific activities of the U.S. Government. His zeal led to the establishment of the Geological Survey in the U.S. Department of the Interior and the Bureau of Ethnology in the Smithsonian Institution. On this 100th Anniversary of the Powell Colorado River Expedition, the U.S. Department of the Interior, Smithsonian Institution, and National Geographic Society (which Powell helped to found) have joined many organizations and individuals to recall the works of this man ;and to examine anew the imprints of his mind. His prescient concepts for the Nation's programs concerning people and their environment have been enhanced through a century of national development.

Colorado River↗
USGS1969

Geologic history of the Colorado River

John Wesley Powell clearly recognized that the spectacular features of the Colorado River - its many grand canyons - were dependent upon the structural history of the mountainous barriers crossed by the river. He conceived of three different historical relationships between rivers and structural features: (1) Newly uplifted land surfaces have rivers that flow down the initial slope of the uplift; these relationships he termed consequent. (2) A river may be older than an uplift that it crosses because it has been able to maintain its course by eroding downward as the uplift progresses; this relationship he named antecedent. (3) An uplifted block may have been buried by younger deposits upon which a river becomes established. The river, in cutting downward, uncovers the uplifted block and becomes incised into it; this relationship he called superimposed. The geologic history of the Colorado River involves all three relationships. In addition, although the position of the river course through a particular structural barrier may have been the result of superposition, the depth of the canyon at that point may be largely due to renewed uplift of the barrier; such deepening of the canyon, therefore, is due to antecedence. The problem of the Colorado River remains today very much as G. K. Gilbert stated it nearly 100 years ago: "How much is antecedent and how much is superimposed?" The question must be asked separately for each stretch of the river.

Colorado River↗
USGS1953

Geology and geography of the Henry Mountains region, Utah

The Henry Mountains region in southeastern Utah is one of the classic areas in geology because of the study made there by Grove Karl Gilbert in 1875 and 1876. His report on the geology of the mountains was the first to recognize that intrusive bodies may deform their host rocks and the first to show clearly the significance of the evenly eroded plains, now known as pediments, at the foot of desert mountains. The Henry Mountains with the surrounding structural basin is a rugged, dry, and sparsely settled region, a part of the Colorado Plateaus province. The natural obstacles of the region-the aridity and ruggedness-have kept it primitive. It has not been penetrated by modern methods of transportation and thus it persists as a roadless frontier. Even the Indians seem to have made little use of the region; explorers did not enter it until 1869 and settlements were not started until the eighties.

Utah↗