Skip to main content
U.S. flag

An official website of the United States government

Geologic map of the Lower Valley quadrangle, Caribou County, Idaho

April 5, 2018

The Lower Valley 7.5-minute quadrangle, located in the core of the Southeast Idaho Phosphate Resource Area, includes Mississippian to Triassic marine sedimentary rocks, Pliocene to Pleistocene basalt, and Tertiary to Holocene surficial deposits. The Mississippian to Triassic marine sedimentary sequence was deposited on a shallow shelf between an emergent craton to the east and the Antler orogenic belt to the west. The Meade Peak Phosphatic Shale Member of the Permian Phosphoria Formation hosts high-grade deposits of phosphate that were the subject of geologic studies through much of the 20th century. Open-pit mining of the phosphate has been underway within and near the Lower Valley quadrangle for several decades.

Citation Information

Publication Year 2018
Title Geologic map of the Lower Valley quadrangle, Caribou County, Idaho
DOI 10.3133/sim3215
Authors H. Peter Oberlindacher, R. David Hovland, Susan T. Miller, James G. Evans, Robert J. Miller
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Scientific Investigations Map
Series Number 3215
Index ID sim3215
Record Source USGS Publications Warehouse
USGS Organization Geology, Minerals, Energy, and Geophysics Science Center