About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 50 (1966)

Issue: 3. (March)

First Page: 643

Last Page: 644

Title: Faunal Evidence of Miocene-to-Recent Paleoclimatology in Antarctic: ABSTRACT

Author(s): Orville L. Bandy

Article Type: Meeting abstract

Abstract:

Two independent lines of faunal evidence indicate intermittent if not continuous polar ice in Antarctica from Pliocene or latest Miocene to Recent, an interval of about 11 million years. First, the area of subarctic and Antarctic planktonic Foraminifera extended far into the temperate regions during the Pleistocene; changes of almost equal magnitude are now recorded for the middle Pliocene and the latest Miocene. Second, evaluation of data from deep-sea cores in the southern Indian Ocean and the Antarctic shows dominant Antarctic cold-water radiolarians spanning the interval from latest Miocene to Recent. These data are in agreement with the isotope data by Emiliani that abyssal waters of the Pacific Ocean were reduced to about 2°C. during the Pliocene, as conditione by low surface temperatures in polar seas. Also, studies in Antarctica by Rutford, Craddock, and Bastien show possible tillites below volcanic rocks that have been dated radiometrically to be approximately latest Miocene or earliest Pliocene.

It is proposed that the upper limit of the Miocene in Antarctic deep-sea cores corresponds approximately

End_Page 643------------------------------

to the upper limit of Prunopyle titan, a cosmopolitan radiolarian that is an index to the later Miocene of California. It is further proposed that in the Antarctic the Pliocene-Pleistocene boundary is located approximately at the upper boundary of Saturnulus planetes, a level which is just below the extinction level of discoasters. Marked telescoping of faunal zones indicates significant gaps in the depositional record of some Antartic deep-sea cores, probably caused by slumping or non-deposition of sediments at different times. A transition from red clay to diatomaceous sediments occurred within the Pliocene Epoch.

End_of_Article - Last_Page 644------------

Copyright 1997 American Association of Petroleum Geologists