Astronomical calibration age for the Oligocene-Miocene boundary

Abstract

Research Article| May 01, 2000 Astronomical calibration age for the Oligocene-Miocene boundary Nicholas J. Shackleton; Nicholas J. Shackleton 1Department of Earth Sciences, University of Cambridge, The Godwin Laboratory, Pembroke Street, Cambridge CB2 3SA, UK Search for other works by this author on: GSW Google Scholar Michael A. Hall; Michael A. Hall 1Department of Earth Sciences, University of Cambridge, The Godwin Laboratory, Pembroke Street, Cambridge CB2 3SA, UK Search for other works by this author on: GSW Google Scholar Isabella Raffi; Isabella Raffi 2Dipartimento di Scienze della Terra, Università “G. D'Annunzio,” Campus Universitario, via dei Vestini 31, 66013 Chieti Scalo, Italy Search for other works by this author on: GSW Google Scholar Lisa Tauxe; Lisa Tauxe 3Scripps Institution of Oceanography, La Jolla, California 92093-0220, USA Search for other works by this author on: GSW Google Scholar James Zachos James Zachos 4Earth Sciences Department, University of California, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (5): 447–450. https://doi.org/10.1130/0091-7613(2000)28<447:ACAFTO>2.0.CO;2 Article history received: 25 Oct 1999 rev-recd: 04 Feb 2000 accepted: 16 Feb 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Nicholas J. Shackleton, Michael A. Hall, Isabella Raffi, Lisa Tauxe, James Zachos; Astronomical calibration age for the Oligocene-Miocene boundary. Geology 2000;; 28 (5): 447–450. doi: https://doi.org/10.1130/0091-7613(2000)28<447:ACAFTO>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 SocietyGeology Search Advanced Search Abstract The stratotype section for the base of the Miocene is at a reversed (below) to normal (above) magnetic transition that is claimed to represent magnetic chron C6Cn.2n (o). Deep Sea Drilling Project (DSDP) Site 522 is the only location we are aware of that unambiguously records the three normal events of C6Cn. We have quantitatively determined the range of the short-lived nannofossil Sphenolithus delphix and the lower limit of S. disbelemnos in DSDP Holes 522 and 522A in order to calibrate their precise relationship to the magnetostratigraphy and to confirm the completeness of the record at this site. Astronomical tuning of Ocean Drilling Program (ODP) Sites 926, 928, and 929 shows that S. disbelemnos appears at 22.67 Ma and that the entire range of S. delphix is from about 22.98 Ma to 23.24 Ma. Using these ages, linear interpolation in DSDP Site 522 suggests that the age of C6Cn.2n (o) and of the Oligocene-Miocene boundary is 22.92 ± 0.04 Ma. Our value, conservatively expressed as 22.9 ± 0.1 Ma, is 0.9 m.y. younger than the currently accepted age of the Oligocene-Miocene boundary and of C6Cn.2n (o), which was assigned an age of 23.8 Ma, based on an estimate of 23.8 ± 1 Ma for the Oligocene-Miocene boundary. The bulk-sediment carbon isotope data from DSDP Site 522 is correlated to the record from benthic foraminifera at ODP Site 929 to refine the calibration of magnetic reversals from C6Cn.1n (o) to C7n.2n (o) at DSDP Site 522 on the astronomical time scale. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.