Lower Paleozoic Rocks in Diatremes, Southern Wyoming and Northern Colorado

Abstract

Research Article| January 01, 1969 Lower Paleozoic Rocks in Diatremes, Southern Wyoming and Northern Colorado JOHN CHRONIC; JOHN CHRONIC Department of Geological Sciences, University of Colorado, Boulder, Colorado Search for other works by this author on: GSW Google Scholar MALCOLM E McCALLUM; MALCOLM E McCALLUM Department of Geology, Colorado State University, Fort Collins, Colorado Search for other works by this author on: GSW Google Scholar CLINTON S FERRIS, JR.; CLINTON S FERRIS, JR. Kerr-McGee Corporation, Arvada, Colorado Search for other works by this author on: GSW Google Scholar DAVID H EGGLER DAVID H EGGLER Department of Geochemistry and Mineralogy, Pennsylvania State University, University Park, Pennsylvania Search for other works by this author on: GSW Google Scholar Author and Article Information JOHN CHRONIC Department of Geological Sciences, University of Colorado, Boulder, Colorado MALCOLM E McCALLUM Department of Geology, Colorado State University, Fort Collins, Colorado CLINTON S FERRIS, JR. Kerr-McGee Corporation, Arvada, Colorado DAVID H EGGLER Department of Geochemistry and Mineralogy, Pennsylvania State University, University Park, Pennsylvania Publisher: Geological Society of America Received: 15 Mar 1968 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1969, 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 (1969) 80 (1): 149–156. https://doi.org/10.1130/0016-7606(1969)80[149:LPRIDS]2.0.CO;2 Article history Received: 15 Mar 1968 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 JOHN CHRONIC, MALCOLM E McCALLUM, CLINTON S FERRIS, DAVID H EGGLER; Lower Paleozoic Rocks in Diatremes, Southern Wyoming and Northern Colorado. GSA Bulletin 1969;; 80 (1): 149–156. doi: https://doi.org/10.1130/0016-7606(1969)80[149:LPRIDS]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 Twelve small serpentinite diatremes are now known near the Colorado-Wyoming border in the Precambrian core of the northern Front Range and southern Laramie Range. Five of them contain blocks of fossiliferous and nonfossiliferous sedimentary rocks of Early, Middle, and Late Ordovician and Early, Middle, and Late Silurian age. The unweathered matrix of the diatremes is serpentinite and talc, with pyrope, chrome diopside, ilmenite, and other minerals in small quantities.The diatremes occur in an area previously thought to have been above sea level during Early Paleozoic time, but the fossil-bearing xenoliths they contain show that the area was certainly covered by the sea during much of Ordovician and Silurian time. They provide the first positive identification of marine Silurian rocks within the state of Colorado.The diatremes were formed subsequent to Silurian deposition. Regional relationships indicate that they were formed before the erosional interval which removed Silurian sediments from this region prior to Devonian sedimentation. They were certainly formed before regional stripping of the pre-Pennsylvanian section that preceded deposition of Pennsylvanian red beds. 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.