The city well No. 8 at Dubuque, Iowa penetrated slightly more than 15 feet of the upper part of the crystalline pre-Cambrian basement complex. This well is of particular interest because it is the southeastern-most of the 15 wells in Iowa known to reach the crystalline basement, and because samples from the well were sufficiently large to permit preparation of thin sections for petrographic examination. The well was drilled in 1946 to a depth of 1,781.7 feet by the Varner Well Company of Dubuque. Drilling was by the cable-tool method. The well is located on the floodplain of the Mississippi River at CSL SE¼ SE¼ sec. 7, T. 89 N., R. 3 E. The surface altitude is 610 feet.
Proceedings of the Iowa Academy of Science
©1950 Iowa Academy of Science, Inc.
Anderson, Keith E.
"Basement Complex Biotite Granite at Dubuque, Iowa,"
Proceedings of the Iowa Academy of Science, 57(1), 241-244.
Available at: https://scholarworks.uni.edu/pias/vol57/iss1/27