Abstract Detail

Paleobotanical Section

AXSMITH , BRIAN J [1], STULTS, DEBRA Z [2], DUNN, MICHAEL [3], HAYWICK, DOUG [4], CAREY, STEVE [5].

An early Oligocene plant fossil site in southern Alabama.

A newly discovered locality on private land in southeastern Monroe County Alabama is producing abundant fossil leaves, seeds, and fruits of Oligocene (Rupelian) age. The site exposes the upper part of the Bucatunna Formation. Plant fossils occur at several intervals, but the most productive is an approximately 5 meter thick sandy clay just under the unconformable contact with the overlying Chickasaway Formation. This contact is time correlative with the global “mid-Oligocene” unconformity and marks the top of the Vicksburg Group. The Bucatunna Formation likely represents a low-energy nearshore marine depositional environment. Leaves of at least five angiosperm morphotypes dominate the assemblage. All of these have entire margins, and several have indistinct higher order venation indicating a somewhat coriaceous texture. Considering that the Oligocene was considerably cooler than the Eocene, the complete lack of leaves with toothed margins in this assemblage is remarkable. This, along with the relatively low diversity plus evidence of deposition in a nearshore marine setting, suggest a specialized coastal plant community rather than particularly high temperatures. In addition to leaves, at least eight fruit and seed types have been recovered so far and are currently under investigation. Although many aspects of this flora are currently enigmatic with identifications hampered by a lack of coeval comparative material, continued study is warranted, as no other floras from this time are known in eastern North America.

1 - University Of South Alabama, Biology Department, 5871 USA Drive North, Room 124, MOBILE, AL, 36688-0002, USA
2 - University of South Alabama, Biology
3 - CAMERON UNIVERSITY, 2800 Gore Blvd, LAWTON, OK, 73505, USA
4 - University of South Alabama
5 - University of Mobile

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Sections
Session: 21
Location: Whitewater/Grove
Date: Tuesday, July 29th, 2014
Time: 10:15 AM
Number: 21007
Abstract ID:80
Candidate for Awards:None