The Oligocene-Miocene boundary in the South Pacific

Abstract

Research Article| June 01, 1983 The Oligocene-Miocene boundary in the South Pacific M. S. SRINIVASAN; M. S. SRINIVASAN 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 028812Present address: Geology Department, Banaras Hindu University, Varanasi. India. Search for other works by this author on: GSW Google Scholar J. P. KENNETT J. P. KENNETT 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Search for other works by this author on: GSW Google Scholar Author and Article Information M. S. SRINIVASAN 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 028812Present address: Geology Department, Banaras Hindu University, Varanasi. India. J. P. KENNETT 1Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02881 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1983) 94 (6): 798–812. https://doi.org/10.1130/0016-7606(1983)94<798:TOBITS>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 MailTo Tools Icon Tools Get Permissions Search Site Citation M. S. SRINIVASAN, J. P. KENNETT; The Oligocene-Miocene boundary in the South Pacific. GSA Bulletin 1983;; 94 (6): 798–812. doi: https://doi.org/10.1130/0016-7606(1983)94<798:TOBITS>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 Qualitative and quantitative planktonic foraminiferal trends have been examined across the Oligocene-Miocene transition in three Deep Sea Drilling Project sites (DSDP 289, 208, 206) in the South Pacific ranging from the equator to temperate regions. Primary objectives were to determine main changes in planktonic foraminiferal assemblages over the Oligocene-Miocene transition.Of available planktonic foraminiferal datums in the South Pacific sequences, Globoquadrina dehiscens is the most useful for designation and correlation of the Oligocene-Miocene boundary. The stratotype Aquitanian stage (earliest Miocene) in France contains Gq. dehiscens. Although the base of the Aquitanian stratotype is marked by an unconformity, biostratigraphic data elsewhere within the basin suggest that the evolutionary appearance of Gq. dehiscens occurred close to the time of the oldest stratotypic sediments. Therefore, the evolutionary appearance of Gq. dehiscens seems to represent one of the most reliable datums for interregional correlation of the Oligocene-Miocene boundary, one that occurs within the biostratigraphic range of Globorotalia (Fohsella) kugleri and marks the boundary between zones N4A and N4B. Globigerinoides first evolved during the late Oligocene and is not coincident with the Oligocene-Miocene boundary.Unlike the Eocene-Oligocene boundary, the Oligocene-Miocene boundary is not marked by a crisis in the Oligocene planktonic foraminiferal assemblages. Most Oligocene forms continue their range upward into the early Miocene, where most are replaced by typical Neogene forms. The only important Oligocene phylogenetic lineage to be essentially eliminated during the Oligocene-Miocene transition is Catapsydrax, the last important forms of which disappeared during earliest Miocene.Evolution of Gq. dehiscens effectively heralds the beginning of major evolutionary radiations in planktonic foraminifera that led to the distinctive Neogene phylogenies. Appearance of this form was followed by evolutionary radiation of Globigerinoides into a number of species; initial evolution of Globorotalia (Globoconella) incognita, which forms the earliest ancestral form of Globoconella; evolution of the Globigerina woodi group; Sphaeroidinellopsis disjuncta (the ancestral stock of the Sphaeroidinellopsis-Sphaeroidinella lineage); Globorotalia (Fohsella) peripheroronda from Gr. (F.) kugleri (representing the continued development toward the classic Fohsella forms); and typical forms of the Dentoglobigerina stock represented by Dentoglobigerina altispira. These evolutionary radiations are reflected by a general increase in simple species diversity through early Miocene. At all three sites, species diversity is lowest in the interval near the Oligocene-Miocene boundary. Among the three sites examined, diversity is highest in warm-subtropical Site 208, because at this latitude faunas include both tropical and temperate forms.The earliest Miocene is marked by high frequencies of Gr. (F) kugleri in tropical areas and Gq. dehiscens in warm-subtropical to temperate areas. 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.