IGNEOUS AND METAMORPHIC ROCKS OF THE MINNESOTA RIVER VALLEY

Abstract

Research Article| November 01, 1956 IGNEOUS AND METAMORPHIC ROCKS OF THE MINNESOTA RIVER VALLEY ERNEST H LUND ERNEST H LUND THE FLORIDA STATE UNIVERSITY, TALLAHASSEE, FLORIDA Search for other works by this author on: GSW Google Scholar Author and Article Information ERNEST H LUND THE FLORIDA STATE UNIVERSITY, TALLAHASSEE, FLORIDA Publisher: Geological Society of America Received: 12 Nov 1954 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1956, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1956) 67 (11): 1475–1490. https://doi.org/10.1130/0016-7606(1956)67[1475:IAMROT]2.0.CO;2 Article history Received: 12 Nov 1954 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ERNEST H LUND; IGNEOUS AND METAMORPHIC ROCKS OF THE MINNESOTA RIVER VALLEY. GSA Bulletin 1956;; 67 (11): 1475–1490. doi: https://doi.org/10.1130/0016-7606(1956)67[1475:IAMROT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Precambrian igneous and metamorphic rocks exposed in the Minnesota River Valley between New Ulm and Ortonville are divided into three groups. The oldest is a basic complex of gabbro and diorite gneiss, quartz diorite gneiss, and garnetiferous quartz diorite gneiss. A few small isolated masses of serpentinized peridotite are included in the basic complex. The second group comprises varieties of granite and granite gneiss that are closely related and are assigned to the Minnesota Valley granite series. Five types are distinguished on the basis of textural and structural differences. The third and youngest group, referred to as postgranite intrusives, consists of several small and somewhat circular intrusives, a large number of basic dikes, and two small masses of late granite. Modes of the principal rock types are given.The relative ages of the three major groups were determined by intrusive relationships, but close dating of the various rocks assigned to each group is not possible. On the basis of zircon types the Minnesota Valley granite series is assigned tentatively to late pre-Huronian or Huronian, and the postgranite intrusives are assigned tentatively to Keewenawan. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.