Abstract Detail

Paleobotanical Section

Stults, Debra [1], Axsmith, Brian [2].

Quantitative paleoclimate estimates from two Late Neogene floras of eastern North America.

Floras of two Late Neogene formations in eastern North America, the Late Miocene Brandywine Formation located within the Mid-Atlantic Coastal Plain, and the mid-Pliocene Citronelle Formation which spans the northern Gulf of Mexico Coastal Plain, have been used to generate quantitative climate information for this time period. A Co-existence Analysis of plant taxa of the Brandywine Formation has produced figures indicating that temperatures during the Late Miocene, although in the same overall climate category as today,i.e.,warm temperate, were a little warmer than currently exists in the area. Late Miocene warm month mean annual temperatures (WMMT) are estimated at 25.6C, cold month mean temperatures (CMMT) have a range of 0.1 to 7.8°C, and mean annual temperatures are within 13.3 -16.1°C. Mean annual precipitation (MAP) was 897-1206 mm and the annual pattern of precipitation apparently was similar to the current pattern. Coexistence Analysis results from the Citronelle Formation indicate the region during the mid-Pliocene had a humid/subtropical climate. The WMMT range estimate is 25.6 to 27.9C, the CMMT estimate is 4.3 to 12.6C, and the MAT estimate is 14.4 to 20.8C. This correlates closely to temperatures in the area today. Interestingly, the MAP estimate of 1122-1250 mm indicates that precipitation during the Citronelle Formation depositional period was less than current precipitation totals. It is also possible that the annual pattern of precipitation (i.e., wet months, dry months) was different than the current pattern. Future study will compare the results of this analysis to a planned, physiognomic climate analysis using these same fossils. Comparisons will also be made to results obtained from other climate proxies.

Broader Impacts:

1 - University of South Alabama, Marine Sciences, Life Sciences Building 124, Mobile, AL, 36688, United States
2 - University Of South Alabama, Department Of Biological Sciences, LSCB 124, MOBILE, AL, 36688-0002, USA

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Sections
Session: 47
Location: Forsyth Room/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 2:15 PM
Number: 47004
Abstract ID:518