Clastic rocks associated with the Midcontinent Rift System in Iowa Anderson, Raymond R. creator author. McKay, Robert M. author. Geological Survey (U.S.) issuing body. text bibliography vau 1997 monographic eng remote 1 online resource (145 pages) : illustrations, maps. by Raymond R. Anderson and Robert M. McKay. Title from title screen (viewed Aug. 28, 2014). Includes bibliographical references (pages 138-140). n-us-ia Geology Iowa Geology, Stratigraphic Proterozoic Keweenawan Rift Geology Geology, Stratigraphic Proterozoic Geologic Period Iowa North America Keweenawan Rift From 570 million to 2 billion years ago fast I 19.3:1989-I I 19.3:1989-I Clastic rocks associated with the Midcontinent Rift System in Iowa Anderson, Raymond R. (DLC) 96050394 (OCoLC)36011670 U.S. Geological Survey bulletin ; 1989-I Strategic and critical minerals in the midcontinent region, United States ; ch. I https://purl.fdlp.gov/GPO/LPS50604 COP 140901 20211202202122.0 in00003732752 eng