DWARFING AND EXTINCTION IN EOCENE AND OLIGOCENE PLANKTONIC FORAMINIFERA

2006 Philadelphia Annual Meeting (22–25 October 2006)
Paper No. 196-8

Presentation Time: 10:15 AM-10:30 AM

DWARFING AND EXTINCTION IN EOCENE AND OLIGOCENE PLANKTONIC FORAMINIFERA
WADE, Bridget S., Institute of Marine and Coastal Science, Rutgers, The State University of New Jersey, 71 Dudley Rd, New Brunswick, NJ 08901-852, bwade@rci.rutgers.edu Dwarfing has commonly been associated with extinction events in planktonic foraminifera. Examples of dwarfing in planktonic foraminifera through the Eocene and Oligocene are species specific and do not appear to affect the entire assemblage. In many cases the smaller forms (dwarfs) survive for thousands to millions of years following the extinction of their larger counterparts. In examining the interval from the latest middle Eocene through upper Oligocene (38 – 27 Ma) a marked decrease in size is associated with the extinction of Acarinina mcgowrani, Globigerinatheka index, Subbotina linaperta, Pseudohastigerina micra, Turborotalia ampliapertura, and Paragloborotalia opima. Multispecies stable isotope analysis reveals that the extinction of Acarinina mcgowrani (38 Ma) was not associated change in sea surface temperature. Mechanisms in the extinction and dwarfing of this species may have been related to enhanced eutrophication and deterioration of algal symbiotic associations.
2006 Philadelphia Annual Meeting (22–25 October 2006) General Information for this Meeting

Session No. 196 Extinction, Dwarfing and the Lilliput Effect Pennsylvania Convention Center: 105 AB 8:00 AM-12:00 PM, Wednesday, 25 October 2006 Geological Society of America Abstracts with Programs, Vol. 38, No. 7, p. 474
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