Map of United States in the Middle Pennsylvanian Time
By Water Availability and Use Science Program
1969 (approx.)
Detailed Description
Map of United States in Middle Pennsylvanian Time (about 300 million years ago). Source: USGS Bulletin 1291.
Sources/Usage
Public Domain.
Related
National Brackish Groundwater Assessment: Sources of Dissolved Solids in Brackish Groundwater
A variety of conditions and mechanisms can cause groundwater to become brackish. An understanding of the sources of dissolved solids that contribute to the formation of brackish groundwater can help determine where brackish aquifers are likely to exist and can provide clues about other characteristics, such as the chemical composition, of brackish aquifers.
Related
National Brackish Groundwater Assessment: Sources of Dissolved Solids in Brackish Groundwater
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