Geologic controls of the distribution of freshwater in a regional aquifer system: Central Michigan Basin

Conference · Fri Apr 01 04:00:00 EST 1994 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6837909

Westjohn, D B ^[1]

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1. Geological Survey, Lansing, MI (United States)

The most important geologic control on the distribution of freshwater in sandstone aquifers in the central part of the Michigan Basin is direct hydraulic connection to glacial deposits of Pleistocene age. The Marshall and Parma aquifers are freshwater bearing where they subcrop beneath glacial deposits, but the width of the transition zone from freshwater to brine is as small as 10 miles down regional dip from subcrop areas. Along the limbs of low amplitude folds, where the Michigan Formation has been eroded and the Marshall aquifer directly underlies glacial deposits, the width of the transition zone is as small as four miles. An explanation for the narrow width of these transition zones is that recharge during and after Pleistocene glaciation has had limited effect on the distribution of freshwater in sandstones of the regional aquifer system. Hydraulic barriers to vertical flow also appear to effect the distribution of freshwater in the Marshall and Parma Sandstones. Vertical hydraulic conductivities are more than three orders in magnitude less than horizontal hydraulic conductivities where detrital layer-silicates are abundant, or where stratified cement occludes pore space. These vertical discontinuities could impede freshwater recharge or saline-water discharge.

• OSTI ID: 6837909
• Report Number(s): CONF-9404217--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 26:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AQUIFERS
CHEMICAL COMPOSITION
CHEMISTRY
DEVELOPED COUNTRIES
GEOCHEMISTRY
GEOLOGIC STRUCTURES
GROUND WATER
HYDRAULIC CONDUCTIVITY
HYDROGEN COMPOUNDS
MICHIGAN
NORTH AMERICA
OXYGEN COMPOUNDS
RECHARGE
ROCK-FLUID INTERACTIONS
SEDIMENTARY BASINS
USA
WATER
WATER CHEMISTRY