Magnetobiostratigraphic chronology of the Eocene–Oligocene transition in the CIROS-1 core, Victoria Land margin, Antarctica: Implications for Antarctic glacial history

Abstract

Research Article| January 01, 1998 Magnetobiostratigraphic chronology of the Eocene—Oligocene transition in the CIROS-1 core, Victoria Land margin, Antarctica: Implications for Antarctic glacial history Gary S. Wilson; Gary S. Wilson 1Byrd Polar Research Center, Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210 Search for other works by this author on: GSW Google Scholar Andrew P. Roberts; Andrew P. Roberts 2Department of Oceanography, University of Southampton, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom Search for other works by this author on: GSW Google Scholar Kenneth L. Verosub; Kenneth L. Verosub 3Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar Fabio Florindo; Fabio Florindo 4Istituto Nazionale di Geofisica, Via di Vigna Murata, 605, I-00143 Rome, Italy Search for other works by this author on: GSW Google Scholar Leonardo Sagnotti Leonardo Sagnotti 4Istituto Nazionale di Geofisica, Via di Vigna Murata, 605, I-00143 Rome, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information Gary S. Wilson 1Byrd Polar Research Center, Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210 Andrew P. Roberts 2Department of Oceanography, University of Southampton, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom Kenneth L. Verosub 3Department of Geology, University of California, Davis, California 95616 Fabio Florindo 4Istituto Nazionale di Geofisica, Via di Vigna Murata, 605, I-00143 Rome, Italy Leonardo Sagnotti 4Istituto Nazionale di Geofisica, Via di Vigna Murata, 605, I-00143 Rome, Italy Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1998) 110 (1): 35–47. https://doi.org/10.1130/0016-7606(1998)110<0035:MCOTEO>2.3.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 Gary S. Wilson, Andrew P. Roberts, Kenneth L. Verosub, Fabio Florindo, Leonardo Sagnotti; Magnetobiostratigraphic chronology of the Eocene—Oligocene transition in the CIROS-1 core, Victoria Land margin, Antarctica: Implications for Antarctic glacial history. GSA Bulletin 1998;; 110 (1): 35–47. doi: https://doi.org/10.1130/0016-7606(1998)110<0035:MCOTEO>2.3.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 In 1986, cores were obtained to a depth of 702 m (with 98% recovery) from the CIROS-1 drill hole beneath the Ross Sea on the Victoria Land margin. Glaciogene sediments identified near the base of the hole mark the earliest known record of Antarctic glaciation. Initial biostratigraphic analysis indicated that the lower 336 m of the core is early Oligocene in age, and that the upper 366 m is of late Oligocene–early Miocene age. Recently, the chronology of the CIROS-1 core has been questioned. We developed a magnetostratigraphy for the lower 400 m of the CIROS-1 core to clarify the chronology. Our magnetobiostratigraphic results indicate that the base of the CIROS-1 core is early-late Eocene in age (corresponding to Chron C16r; ca. 36.5 Ma). We identify the Eocene-Oligocene boundary at about 410–420 m, within a 20-m-thick, poorly stratified, bioturbated sandy mudstone. This makes the CIROS-1 core the highest latitude site (77.1°S) from which this datum event has been recognized. At 366 m, a 4 m.y. hiatus, which lies immediately beneath fluvial sediments, accounts for most of Chrons C11 and C12. We recognize three major climatic episodes in the CIROS-1 core: (1) the late Eocene (34.5–36.5 Ma, 430–702 m), when relatively warm conditions dominated and there were high sedimentation rates and some glacial activity; (2) the late Eocene-early Oligocene boundary interval (28.5–34.5 Ma, 340–430 m), which was a transition from relatively warm to cooler conditions that coincided with glacial intensification, sea-level fall, and subaerial erosion of the shelf; and; (3) the late Oligocene–early Miocene (22–28.5 Ma, 50–340 m), when large-scale glaciation dominated the region and glaciers grounded across the continental shelf. From correlation with global oxygen isotope and sea-level records, we infer that the Antarctic climate and surrounding oceans cooled after separation of Australia and Antarctica and development of deep-water circulation between them. This marked the onset of the Eocene–Oligocene transition at ca. 34.5 Ma. A major East Antarctic ice sheet did not develop until the early-late Oligocene boundary, toward the end of the Eocene-Oligocene transition (ca. 28.5 Ma). Outlet glaciers did not breach the Transantarctic Mountains and ground across the Ross Sea Shelf until 0.5 m.y. later (ca. 28 Ma). 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.