GMEG - Geology and Geophysics
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|Bedrock and surficial geologic mapping for land use planning:
Geologic mapping is fundamental to desert field sciences. The geologic substrate consists of soils, sediments, mineral, and bedrock geologic formation. The geologic substrate interacts with and carries water on the surface, housing water in substrate and at depth, and provide nutrients at the base of the food web. The geologic substrate materials of an area or region are important physical components that determine the susceptibilities of habitats to climate change. These materials in the surface environment are dynamic, changing with seasonal and long term climatic conditions. The stability and vulnerability of landscape substrates can define tipping points and thresholds to abrupt changes in ecosystem viability. With geographic information system (GIS), geologic maps, combined with elevation, biological, and atmospheric data, can provide insight into habitat characteristics and provide insight into phenomena related to natural hazards (floods, dust storm generation, shifting dune fields) as well as agricultural and regional development applications
Study of earth surface materials and climate/precipitation interactions is of critical importance to understanding landscape stability related to surface erosion. For land use planning, these factors are important to manage surface runoff and groundwater recharge issues, evaluate the environmental impact of landfills and septic systems, and evaluate the structural stability of housing foundations.
Geologic map showing varieties of substrate materials on the Navajo Reservation near Cameron, Arizona; tan colors are eolian and alluvial deposits of different ages; green and blue are flat-lying Mesozoic-age sedimentary formations exposed along a west-facing escarpment. Lines are linear dunes following the prevailing wind direction.
(map source: http://pubs.usgs.gov/sim/2007/2977/)