Paleogene magnetic stratigraphy in Umbrian pelagic carbonate rocks: The Contessa sections, Gubbio

Research Article| May 01, 1982 Paleogene magnetic stratigraphy in Umbrian pelagic carbonate rocks: The Contessa sections, Gubbio WILLIAM LOWRIE; WILLIAM LOWRIE 1Institut für Geophysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar WALTER ALVAREZ; WALTER ALVAREZ 2Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar GIOVANNI NAPOLEONE; GIOVANNI NAPOLEONE 3Istituto di Geologia e Paleontologia, University of Florence, Florence, Italy Search for other works by this author on: GSW Google Scholar KATHARINA PERCH-NIELSEN; KATHARINA PERCH-NIELSEN 4Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar ISABELLA PREMOLI SILVA; ISABELLA PREMOLI SILVA 5Istituto di Paleontologia, University of Milan, Milan, Italy Search for other works by this author on: GSW Google Scholar MONIQUE TOUMARKINE MONIQUE TOUMARKINE 6Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information WILLIAM LOWRIE 1Institut für Geophysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland WALTER ALVAREZ 2Department of Geology and Geophysics, University of California, Berkeley, California 94720 GIOVANNI NAPOLEONE 3Istituto di Geologia e Paleontologia, University of Florence, Florence, Italy KATHARINA PERCH-NIELSEN 4Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland ISABELLA PREMOLI SILVA 5Istituto di Paleontologia, University of Milan, Milan, Italy MONIQUE TOUMARKINE 6Geologisches Institut, ETH-Zentrum, CH-8092 Zürich, Switzerland Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1982) 93 (5): 414–432. https://doi.org/10.1130/0016-7606(1982)93<414:PMSIUP>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation WILLIAM LOWRIE, WALTER ALVAREZ, GIOVANNI NAPOLEONE, KATHARINA PERCH-NIELSEN, ISABELLA PREMOLI SILVA, MONIQUE TOUMARKINE; Paleogene magnetic stratigraphy in Umbrian pelagic carbonate rocks: The Contessa sections, Gubbio. GSA Bulletin 1982;; 93 (5): 414–432. doi: https://doi.org/10.1130/0016-7606(1982)93<414:PMSIUP>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 Umbrian sequence of pelagic carbonate rocks provides an opportunity for precise correlation between Paleogene biostratigraphy and geomagnetic polarity history. The red-to-pink, Paleocene to middle Eocene Scaglia Rossa limestone, the varicolored upper Eocene Scaglia Variegata limestone, and the gray-green Oligocene Scaglia Cinerea marlstone form a 250-m-thick, continuous exposure in the Contessa Valley near Gubbio, Italy. Magnetostratigraphic, lithostratigraphic, and biostratigraphic investigations in three sections covering the entire Paleogene have confirmed and dated the geomagnetic reversal sequence for most of this period. The ferromagnetic mineral in the Scaglia Cinerea is magnetite and AF demagnetization to peak fields of 20 mT is sufficient to define the characteristic remanent magnetization. The Scaglia Variegata and pink Scaglia Rossa samples contain an additional hematite component which is very pronounced in dark red Paleocene Scaglia Rossa samples. Changes of magnetic mineralogy take place in these limestones during heating, especially above 500 °C. However, thermal demagnetization is effective in isolating the characteristic remanence vectors, which form almost antipodal clusters of directions representing normal and reversed polarities. The directions are rotated counterclockwise, partly due to post-Oligocene tectonism. Paleontological zonations of planktic foraminifera and calcareous nannofossils were hampered by poor preservation, but the major epoch and stage 29, as in the Gubbio Bottaccione section; Paleocene-Eocene, just above anomaly 25; Eocene-Oligocene, between anomalies 13 and 15; Oligocene-Miocene, just below anomaly 6C. These correlations require slight modifications to previous conclusions on Paleogene sea-floor spreading rates. 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.