High Plains Water-Level Monitoring Study (Groundwater Resources Program)

High Plains Aquifer Water-Level Monitoring Study
Geologic units of the High Plains aquifer

Geologic units of the High Plains aquifer *
 Location where geologic unit is a substantial part of the High Plains aquifer
Geologic unit comprising the aquiferSystem (series) and High Plains aquifer comprising millions of years before presentCompositionCOKSNENMOKSDTXWY
Valley-fill and alluvial depositQuaternary (Holocene and Pleistocene), 1.8 to presentA XXX    
Dune sandQuaternary (Holocene), 0.008 to 0.0015B XX     
Ogallala FormationTertiary (Miocene), 19 to 5CX XXXXXXX
Arikaree GroupTertiary (Miocene and Oligocene), 29 to 19D  X  X X
Brule FormationTertiary (Oligocene), 31 to 29EX X    X
A = Clay, silt, sand, and gravel, unconsolidated
B = Sand, very fine to medium-grained, windblown
C = Clay, silt, sand, and gravel, generally unconsolidated; where cemented by calcium carbonate, mortar beds formed
D = Sandstone, very fine to fine-grained, with beds of volcanic ash, silty sand, and sandy clay
E = Siltstone, massive, with beds of sandstone, volcanic ash, and clay

* Table modified from Dugan and others, 1994

USGS Home Water Resources Biology Geography Geology Geospatial Program

Accessibility FOIA Privacy Policies and Notices

Take Pride in America home page. USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://ne.water.usgs.gov/ogw/hpwlms/hpgeol.html
Page Contact Information: GS-W-NE_Webmaster
Page Last Modified: Tuesday, 04-Feb-2014 12:16:49 EST