GM-43 — Surficial Geology of Northwest New Mexico

Compiled by Charles B. Hunt, 1978, scale 1:500,000.

The surficial geology of New Mexico is shown in detail and in color. Includes a separate explanation sheet applicable to the entire project, which entails Geologic Maps 40, 41, 42, and 43. Practically the entire area of New Mexico is mantled by unconsolidated geologic deposits. Hence, these sheets will be interesting to anyone concerned with land and land use, especially with such activities as mineral and water development, community and regional planning, farming and ranching, mining, environmental engineering, and resource planning.

Surficial geology concerns the origin, distribution, and significance of deposits and soils at or near the earth's surface. Completely bare bedrock forms probably less than 5% of New Mexico's land surface; consequently surficial materials form by far the largest and most-used part of the ground around us. Several aspects of surficial geology that contribute significantly to an understanding of our environment are water yielding properties of the ground; its susceptibility to flooding and erosion; its susceptibility to such hazards as landslides, avalanches, and earthquakes; ease of excavation; suitability for foundations and road building; agricultural potential, including suitability for irrigation or pasturage; and mineral resources potential.

Surficial materials commonly are poorly consolidated, consisting partly of bedrock weathered in situ (residuum), but mostly of sediments derived by erosion and transported by water, wind, ice, or gravity (mass wasting) to a site of temporary deposition before further eroded and transported downslope.

Four major categories of surficial materials are distinguished on the map by color: residual materials, transitional deposits, transported deposits, and miscellaneous types of ground.